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Sample records for cementless forged titanium

  1. Phased Array Ultrasonic Inspection of Titanium Forgings

    SciTech Connect

    Howard, P.; Klaassen, R.; Kurkcu, N.; Barshinger, J.; Chalek, C.; Nieters, E.; Sun, Zongqi; Fromont, F. de

    2007-03-21

    Aerospace forging inspections typically use multiple, subsurface-focused sound beams in combination with digital C-scan image acquisition and display. Traditionally, forging inspections have been implemented using multiple single element, fixed focused transducers. Recent advances in phased array technology have made it possible to perform an equivalent inspection using a single phased array transducer. General Electric has developed a system to perform titanium forging inspection based on medical phased array technology and advanced image processing techniques. The components of that system and system performance for titanium inspection will be discussed.

  2. Initial mechanical stability of cementless highly-porous titanium tibial components

    SciTech Connect

    Stone, Timothy Brandon; Amer, Luke D; Warren, Christopher P; Cornwell, Phillip; Meneghini, R Michael

    2008-01-01

    Cementless fixation in total knee replacement has seen limited use since reports of early failure surfaced in the late 80s and early 90s. However the emergence of improved biomaterials, particularly porous titanium and tantalum, has led to a renewed interest in developing a cementless tibial component to enhance long-term survivorship of the implants. Cement is commonly employed to minimize micromotion in new implants but represents a weak interface between the implant and bone. The elimination of cement and application of these new biomaterials, which theoretically provide improved stability and ultimate osseointegration, would likely result in greater knee replacement success. Additionally, the removal of cement from the procedure would help minimize surgical durations and get rid of the time needed for curing, thereby the chance of infection. The purpose of this biomechanical study was twofold. The first goal was to assess whether vibration analysis techniques can be used to evaluate and characterize initial mechanical stability of cementless implants more accurately than the traditional method of micromotion determination, which employs linear variable differential transducers (LVDTs). Second, an evaluative study was performed to determine the comparative mechanical stability of five designs of cementless tibial components under mechanical loading designed to simulate in vivo forces. The test groups will include a cemented Triathlon Keeled baseplate control group, three different 2-peg cementless baseplates with smooth, mid, and high roughnesses and a 4-peg cement/ess baseplate with mid-roughness.

  3. Microstructure development during conventional and isothermal hot forging of a near-gamma titanium aluminide

    SciTech Connect

    Semiatin, S.L. ); Seetharaman, V. ); Jain, V.K. . Mechanical and Aerospace Engineering Dept.)

    1994-12-01

    The breakdown of the lamellar preform microstructure in the ingot metallurgy near-gamma titanium aluminide, Ti-45.5Al-2Cr-2Nb (atomic percent), was investigated. Microstructures developed during canned, conventional hot forging were compared to those from isothermal hot forging. The higher rate of deformation in conventional forging led to considerably finer and almost completely broken-down structures in the as-forged condition. Several nontraditional approaches, including the isothermal forming of a metastable microstructure (so-called alpha forging'') and the inclusion of a short static recrystallization anneal during forging, were found to produce a more fully broken-down structure in as-isothermally forged conditions. Despite the noticeable microstructure differences after forging, a conventionally and isothermally forged material responded similarly during heat treatment. In both cases, almost totally recrystallized structures of either equiaxed gamma or transformed alpha grains surrounded by fine gamma grains were produced depending on the heat-treatment temperature. Metallography on forged and heat-treated pancake macroslices was useful in delineating small differences in composition not easily detected by analytical methods.

  4. Use of an Electron Beam Melting Manufactured Titanium Collared Cementless Femoral Stem to Resist Subsidence After Canine Total Hip Replacement.

    PubMed

    Liska, William D; Doyle, Nancy D

    2015-10-01

    To evaluate the effect of a collared electron beam melting (EBM)-manufactured titanium cementless femoral stem on implant subsidence after total hip replacement (THR). Prospective study Dogs (n = 26); 33 THR. Records were maintained on the first 110 consecutive THR using an EBM collared femoral stem. Radiographs on the first 33 THR that had 6-months follow-up were evaluated for implant subsidence. These results were compared to 27 dogs with subsidence after THR with a Co Cr collarless stem. Dogs that had EBM collared stem THR had a mean body weight of 35.4 kg, body condition score (BCS) of 6.21, and mean canal flare index (CFI) of 1.56. EBM stem sizes used (number implanted) were #7 (13), #8 (10), #9 (8), and #10 (2). Subsidence of collared stems did not occur if the collar was in contact with cortical bone during surgery. Subsidence of 1-3 mm occurred closing a gap between the collar and bone if contact was not made during surgery, but subsidence stopped once contact was made. No major complications directly related to the EBM collared stem were encountered. A collar on a cementless femoral stem in contact with cortical bone resists subsidence. © Copyright 2015 by The American College of Veterinary Surgeons.

  5. Delivery of antibiotics from cementless titanium-alloy cubes may be a novel way to control postoperative infections.

    PubMed

    Bezuidenhout, Martin B; van Staden, Anton D; Oosthuizen, Gert A; Dimitrov, Dimitar M; Dicks, Leon M T

    2015-01-01

    Bacterial colonisation and biofilm formation onto orthopaedic devices are difficult to eradicate. In most cases infection is treated by surgical removal of the implant and cleaning of the infected area, followed by extensive treatment with broad-spectrum antibiotics. Such treatment causes great discomfort, is expensive, and is not always successful. In this study we report on the release of vancomycin through polyethersulfone membranes from channels in cementless titanium-alloy cubes. The cubes were constructed with LaserCUSING from Ti6Al4V ELI powder. Vancomycin was released by non-Fickian anomalous (constraint) diffusion. Approximately 50% of the vancomycin was released within the first 17 h. However, sustained delivery of vancomycin for 100 h was possible by reinjecting the channels. Refillable implants may be a novel way to control postoperative infections.

  6. Delivery of Antibiotics from Cementless Titanium-Alloy Cubes May Be a Novel Way to Control Postoperative Infections

    PubMed Central

    Bezuidenhout, Martin B.; van Staden, Anton D.; Oosthuizen, Gert A.; Dimitrov, Dimitar M.; Dicks, Leon M. T.

    2015-01-01

    Bacterial colonisation and biofilm formation onto orthopaedic devices are difficult to eradicate. In most cases infection is treated by surgical removal of the implant and cleaning of the infected area, followed by extensive treatment with broad-spectrum antibiotics. Such treatment causes great discomfort, is expensive, and is not always successful. In this study we report on the release of vancomycin through polyethersulfone membranes from channels in cementless titanium-alloy cubes. The cubes were constructed with LaserCUSING from Ti6Al4V ELI powder. Vancomycin was released by non-Fickian anomalous (constraint) diffusion. Approximately 50% of the vancomycin was released within the first 17 h. However, sustained delivery of vancomycin for 100 h was possible by reinjecting the channels. Refillable implants may be a novel way to control postoperative infections. PMID:25861649

  7. Research on the Influence of Technological Forging Parameters on the Quality of Biphasic Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Mashekov, S. A.; Smaylova, N. T.; Alshynova, A. M.; Mashekova, A. S.

    2015-12-01

    The deflected mode (DM) during the preparation of the broach in the flat and combined baizes and also on radial forging machine (RFM) was investigated for creating the rational technology of a broach and determining the optimum size of the angles of rotation and single squeeze reduction. The quantitative data was obtained by the method of final elements and the MSC.Super Forge program; the main consistent patterns of stress-strain state (SSS) distribution and temperature while modeling forging in flat and combined baizes, also on RFM with various angles of rotation and sizes of squeeze reduction were determined. The rational trial technology of forging of biphasic titanium alloys was developed and tested.

  8. Forge-Diffusion Bond Titanium Rotor Hub Evaluation.

    DTIC Science & Technology

    1975-07-01

    beta temperature • of 1750°F, diffusion treated at 1900°F, water —quenched, and then overaged at 1300°F for two hours. Separately forged upper and... FRACTU RE SURFACE , TRIAL PANCAKE ASSEMBLIES. . . . . . . . . . . . . . . . . . . 37 x - .— ~~- - -• FIGU RE PAGE 33. MEAN S/N CURVE FOR VARIOUS...optimum process to be an alpha—beta forging, forge—diffusion bonded at 1750°F , diffusion treated at 1900°F, water -quenched, and then overaged at

  9. Effect of Variants of Thermomechanical Working and Annealing Treatment on Titanium Alloy Ti6Al4V Closed Die Forgings

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Kumar, V. Anil; Kumar, P. Ram

    2016-06-01

    Performance of titanium alloy Ti6Al4V pressure vessels made of closed die forged domes of route `B' (multiple step forged and mill annealed) is reported to be better than route `A' (single/two step forged and mill annealed). Analysis revealed that forgings processed through route `B' have uniformity in microstructure and yield strength at various locations within the forging, as compared to that of route `A.' It is attributed to in-process recrystallization (dynamic as well as static) of route `B' forgings as compared to limited recrystallization of route `A' forgings. Further, post-forging recrystallization annealing (RA) effect is found to be more significant for route `A' forgings in achieving uniform microstructure and mechanical properties, since route `B' forgings have already undergone similar phenomenon during the thermomechanical working process itself. Considering prime importance of yield strength, statistical scatter in yield strength values within the forgings have been evaluated for forgings of both the routes. Standard deviation in the yield strength of route `B' forgings was lower (<10 MPa) as compared to route `A' (>15 MPa), which later became lower (~10 MPa) after RA with a minor decrease in yield strength. The present work discusses these variants of thermomechanical processing along with annealing to achieve better uniformity in properties and microstructure.

  10. Phased Array Inspection of Titanium Disk Forgings Targeting no. 1/2 FBH Sensitivity

    SciTech Connect

    Roberts, R.A.; Friedl, J.

    2005-04-09

    The phased array implementation of a focused zoned ultrasonic inspection to achieve a >3dB signal-to-noise for no. 1/2 flat bottom holes (FBH) in titanium is reported. Previous work established the ultrasound focusing required to achieve the targeted sensitivity. This work reports on the design of a phased array transducer capable of maintaining the needed focus to the depths required in the forging inspection. The performance of the phased array inspection is verified by examining signal-to-noise of no. 1/2 FBHs contained in coupons cut from actual forgings.

  11. A new cementless total hip arthroplasty with bioactive titanium porous-coating by alkaline and heat treatment: average 4.8-year results.

    PubMed

    Kawanabe, Keiichi; Ise, Kentaro; Goto, Koji; Akiyama, Haruhiko; Nakamura, Takashi; Kaneuji, Ayumi; Sugimori, Tanzo; Matsumoto, Tadami

    2009-07-01

    A method has been developed for creating a bioactive coating on titanium by alkaline and heat treatment, and shown that it forms a thin layer of hydroxyapatite (HA) on the surface of implants when soaked in simulated body fluid. A series of 70 cementless primary total hip arthroplasties using this coating technique on a porous titanium surface was performed, and followed up the patients for a mean period of 4.8 years. There were no instances of loosening or revision, or formation of a reactive line on the porous coating. Although radiography just after operation showed a gap between the host bone and the socket in over 70% of cases, all the gaps disappeared within a year, indicating the good osteoconduction provided by the coating. Alkaline-heat treatment of titanium to provide a thin HA coating has several advantages over plasma-spraying, including no degeneration or absorption of the HA coating, simplicity of the manufacturing process, and cost effectiveness. In addition, this method allows homogeneous deposition of bone-like apatite within a porous implant. Although this was a relatively short-term study, treatment that creates a bioactive surface on titanium and titanium alloy implants has considerable promise for clinical application.

  12. Forging And Milling Contribution On Residual Stresses For A Textured Biphasic Titanium Alloy

    SciTech Connect

    Deleuze, C.; Fabre, A.; Barrallier, L.; Molinas, O.

    2011-01-17

    Ti-10V-2Fe-3Al is a biphasic titanium alloy ({alpha}+{beta}) used in aeronautical applications for its mechanical properties, such as its yield strength of 1200 MPa and it weighs 40% less than steel. This alloy is particularly useful for vital parts with complex geometry, because of its high forging capability. In order to predict the capability for fatigue lifetime, the designers need to know the residual stresses. X-Ray diffraction is the main experimental technique used to determine residual stresses on the surface. In this case, stress levels are primarily influenced by the complex forging and milling process. On this alloy in particular, it may be difficult to characterize stress due to modification of the microstructure close to the surface. Results obtained by x-ray analysis depend on the correct definition of the shape of the diffraction peaks. The more precisely defined the position of the peak, the more accurately the stresses are evaluated. This paper presents a method to detect if residual stresses can be characterized by x-ray diffraction. The characterization of hardness seems to be a relevant technique to quickly analyze the capability of x-ray diffraction to determine residual stresses.

  13. Pod of Ultrasonic Detection of Synthetic Hard Alpha Inclusions in Titanium Aircraft Engine Forgings

    NASA Astrophysics Data System (ADS)

    Thompson, R. B.; Meeker, W. Q.; Brasche, L. J. H.

    2011-06-01

    The probability of detection (POD) of inspection techniques is a key input to estimating the lives of structural components such as aircraft engines. This paper describes work conducted as a part of the development of POD curves for the ultrasonic detection of synthetic hard alpha (SHA) inclusions in titanium aircraft engine forgings. The sample upon which the POD curves are to be based contains four types of right circular SHAs that have been embedded in a representative titanium forging, as well as a number of flat bottomed holes (FBHs). The SHAs were of two sizes, ♯3 and ♯5, with each size including seeds with nominal nitrogen concentrations of both 3 and 17 wt. %. The FBHs included sizes of ♯1, ♯3, and ♯5. This discreteness of the data poses a number of challenges to standard processes for determining POD. For example, at each concentration of nitrogen, there are only two sizes, with 10 inspection opportunities each. Fully empirical, standard methodologies such as â versus a provide less than an ideal framework for such an analysis. For example, there is no way to describe the beam limiting effect whereby the signal no longer increases the flaw grows larger than the beam, one can only determine POD at the two concentration levels present in the block, and confidence bounds tend to be broad because of the limited data available for each case. In this paper, we will describe strategies involving the use of physics-based models to overcome these difficulties by allowing the data from all reflectors to be analyzed by a single statistical model. Included will be a discussion of the development of the physics-based model, its comparison to the experimental data (obtained at multiple sites with multiple operators) and its implications regarding the statistical analysis, whose details will be given in a separate article by Li et al. in this volume.

  14. Determination of interfacial heat transfer coefficient for TC11 titanium alloy hot forging

    NASA Astrophysics Data System (ADS)

    Lu, Baoshan; Wang, Leigang; Geng, Zhe; Huang, Yao

    2017-10-01

    In this paper, based on self-developed experimental apparatus, the upsetting test of TC11 titanium alloy on the hot flat die was conducted and Beck's nonlinear inverse estimation method was adopted to calculate the interfacial heat transfer coefficient (IHTC) and the change rules of IHTC following billet deformation rate, average interfacial temperature and holding time were investigated respectively. Experimental results indicate that IHTC increases with the increase of deformation rate as a whole, and the billet deformation heat and interfacial friction heat during forming that remarkably contribute to IHTC and the contributions by heat conduction to IHTC is differ from that by friction; the glass lubricant coated on the billet surface that weakens the heat transfer situation in the early stage of forging, however, this blocking effect of lubricant on IHTC soon vanishes with increasing deformation rate and it enhances the interface heat transfer later; the average interfacial temperature impacts on IHTC in many aspects and a high average interfacial temperature IHTC corresponds to a high IHTC when the deformation rate is certain, but this changing trend is not monotonous; the IHTC decreases with the increase of holding time due to oxidation. After certain holding time, the IHTC is only related to temperature and pressure in the absence of deformation rate, and the influence of pressure on IHTC is larger than that of temperature on it.

  15. Microstructure prediction of two-phase titanium alloy during hot forging using artificial neural networks and FE simulation

    NASA Astrophysics Data System (ADS)

    Kim, Jeoung Han; Reddy, N. S.; Yeom, Jong Taek; Hong, Jae Keun; Lee, Chong Soo; Park, Nho-Kwang

    2009-06-01

    The microstructural evolution of titanium alloy under isothermal and non-isothermal hot forging conditions was predicted using artificial neural networks (ANN) and finite element (FE) simulation. In the present work, the change in phase volume fraction, grain size, and the volume fraction of dynamic globularization were modelled considering hot working conditions. Initially, an ANN model was developed for steady-state phase volume fraction. The input parameters were the alloy chemical composition (Al, V, Fe, O, and N) and the holding temperature, and the output parameter was the alpha/beta phase volume fraction at steady state. The non-steady state phase volume fraction under non-isothermal conditions was subsequently modelled on the basis of 4 input parameters such as initial specimen temperature, die (or environment) temperature, steady-state phase volume fraction at die (or environment) temperature, and elapsed time during forging. Resulting ANN models were coupled with the FE simulation (DEFORM-3D) in order to predict the variation of phase volume fraction during isothermal and non-isothermal forging. In addition, a grain size variation and a globularization model were developed for hot forging. To validate the predicted results from the models, Ti-6Al-4V alloy was hot-worked at various conditions and then the resulting microstructures were compared with simulated data. Comparisons between model predictions and experimental data indicated that the ANN model holds promise for microstructure evolution in two phase Ti-6Al-4V alloy.

  16. Hydroxyapatite in total hip arthroplasty. Our experience with a plasma spray porous titanium alloy/hydroxyapatite double-coated cementless stem

    PubMed Central

    Castellini, Iacopo; Andreani, Lorenzo; Parchi, Paolo Domenico; Bonicoli, Enrico; Piolanti, Nicola; Risoli, Francesca; Lisanti, Michele

    2016-01-01

    Summary Purpose Total hip arthroplasty could fail due to many factors and one of the most common is the aseptic loosening. In order to achieve an effective osseointegration and reduce risk of lossening, the use of cemented implant, contact porous bearing surface and organic coating were developed. Aim of this study was to evaluate clinical and radiological mid-term outcomes of a porous titanium alloy/hydroxyapatite double coating manufactured cementless femoral stem applied with “plasma spray” technique and to demonstrate the possibility to use this stem in different types of femoral canals. Methods Between January 2008 and December 2012, 240 consecutive primary total hip arthroplasties (THAs) were performed using a porous titanium alloy/hydroxyapatite double coating manufactured cementless femoral stem. 182 patients were examined: 136 were females (74.7%) and 46 males (25.2%); average age was 72 years old (ranging from 26 to 92 years old). For each patient, Harris Hip Scores (HHS) and Womac Scores were collected. All X-ray images were analyzed in order to demonstrate stem survival rate and subsidence. Results Harris Hip Score was good or excellent in 85% of the cases (average 90%) and mean WOMAC score was 97.5 (ranging from 73.4 to 100). No cases of early/late infection or periprosthetic fracture were noticed, with an excellent implant survival rate (100%) in a mean period of 40 months (ranging from 24 and 84 months). 5 cases presented acute implant dislocation, 2 due to wrong cup positioning in a dysplastic acetabulum and 3 after ground level fall. Dorr classification of femoral geometry was uses and the results were: 51 type A bone, 53 type B bone and 78 type C bone. Stem subsidence over 2 mm was considered as a risk factor of future implant loosening and was evidenced in 3 female patients with type C of Dorr classification. No radiolucencies signs around the proximally coated portion of stem or proximal reabsorption were visible during the radiographic

  17. Comparison of cementless and hybrid cemented total knee arthroplasty.

    PubMed

    Lass, Richard; Kubista, Bernd; Holinka, Johannes; Pfeiffer, Martin; Schuller, Spiro; Stenicka, Sandra; Windhager, Reinhard; Giurea, Alexander

    2013-04-01

    Cementless total knee arthroplasty (TKA) implants were designed to provide long-term fixation without the risk of cement-associated complications. The purpose of this study was to evaluate the outcome of titanium-coated cementless implants compared with hybrid TKA implants with a cemented tibial and a cementless femoral component. The authors performed a case-control, single-center study of 120 TKAs performed between 2003 and 2007, including 60 cementless and 60 hybrid cemented TKAs. The authors prospectively analyzed the radiographic and clinical data and the survivorship of the implants at a minimum follow-up of 5 years. Ninety patients who underwent TKA completed the 5-year assessment. Knee Society Scores increased significantly in both groups (P<.001). In both groups, 2 patients underwent revision due to aseptic tibial component loosening, resulting in a 96% implant survival rate. Radiographs showed significantly less radiolucent lines around the tibial baseplate in the cementless group (n=12) than in the hybrid cemented group (n=26) (P=.009).At 6-year mean follow-up, no significant difference existed between the cementless and hybrid cemented tibial components in TKA in terms of clinical and functional results and postoperative complications. The significantly smaller number of radiolucent lines in the cementless group is an indicator of primary stability with the benefit of long-term fixation durability of TKA.

  18. Development of {gamma}+{alpha}{sub 2}+B2 type titanium aluminide for forged turbine rotors

    SciTech Connect

    Tetsui, Toshimitsu

    1995-12-31

    In order to apply TiAl for forged turbine rotors, hot deformability at manufacturing process and high temperature strength at application are both required. For these requirements a new {gamma}+{alpha}{sub 2}+B2 type TiAl (named KAT-3) has been developed. The alloy composition is Ti-45Al-8Nb-2Cr (at%) and this alloy consists of three phases: {gamma}, {alpha}{sub 2} and B2. Because B2 phase has excellent hot deformability and {gamma}/{alpha}{sub 2} lamellar structure has excellent high temperature strength, the above contradictory requirements for TiAl can both be achieved by optimizing the manufacturing process. In this paper various properties required for turbine rotor materials of this alloy were investigated, especially in comparison with Inconel 713C.

  19. Manufacturing of Precision Forgings by Radial Forging

    NASA Astrophysics Data System (ADS)

    Wallner, S.; Harrer, O.; Buchmayr, B.; Hofer, F.

    2011-01-01

    Radial forging is a multi purpose incremental forging process using four tools on the same plane. It is widely used for the forming of tool steels, super alloys as well as titanium- and refractory metals. The range of application goes from reducing the diameters of shafts, tubes, stepped shafts and axels, as well as for creating internal profiles for tubes in Near-Net-Shape and Net-Shape quality. Based on actual development of a weight optimized transmission input shaft, the specific features of radial forging technology is demonstrated. Also a Finite Element Model for the simulation of the process is shown which leads to reduced pre-processing effort and reduced computing time compared to other published simulation methods for radial forging. The finite element model can be applied to quantify the effects of different forging strategies.

  20. Improvement of fracture toughness of forging steels microalloyed with titanium by accelerated cooling after hot working

    SciTech Connect

    Linaza, M.A.; Romero, J.L.; Rodriguez-Ibabe, J.M.; Urcola, J.J. )

    1993-11-01

    Ti addition is becoming common practice in the fabrication of many grades of engineering steels. In general it is used with the aim of refining the microstructure through the inhibiting effect to grain coarsening exerted by small TiN precipitates. Although a number of recommendations are made for obtaining the maximum yield of fine TiN precipitates, nonetheless a certain proportion of the precipitate volume fraction is usually in the form of coarse TiN precipitates. Several authors suggest that such coarse TiN particles are simply ineffective in pinning the grain boundaries without impairing other properties. In a recent paper it was shown that these coarse TiN particles act as cleavage nucleation sites, impairing the fracture toughness of steel with coarse ferrite-pearlite microstructures. The present work reports further fracture toughness results and fracture mechanisms for Ti treated microalloyed forging steels. They show that after hot working and accelerated cooling transforming the austenite mainly in an acicular microstructure, ductile rupture results without any cleavage nucleated in the coarse TiN particles, as occurred when the same material had a coarse ferrite-pearlite microstructure.

  1. Achieving Fine Beta Grain Structure in a Metastable Beta Titanium Alloy Through Multiple Forging-Annealing Cycles

    NASA Astrophysics Data System (ADS)

    Zafari, Ahmad; Ding, Yunpeng; Cui, Jianzhong; Xia, Kenong

    2016-07-01

    A coarse-grained (order of 1 mm) Ti-5553 metastable beta alloy was subjected to multiple passes of low-temperature forging and multiple forging plus annealing cycles, respectively. In the forging only processing, strain was concentrated in the shear bands formed and accumulated with each forging pass, resulting in a heterogeneous microstructure and eventual cracking along the shear bands. In contrast, the introduction of a short beta annealing after each forging step led to fine recrystallized grains (50 to 100 µm) formed in the shear bands, and a uniformly refined beta grain structure after four cycles. This is attributed to the strengthening effect of the fine grains, causing redistribution of most severe strains to the coarse grain region in the subsequent forging, consistent with the simulated results by finite element analysis. The analyses of the microstructures and simulated strain distributions revealed that the critical strain for recrystallization is between 0.2 and 0.5 and the strain to fracture to be ~0.8 to 0.9. The fine-grained (50 to 100 µm) beta alloy, however, fractured at a much smaller strain of <0.4 during the next forging step, owing to the formation of stress-induced martensitic α″ which is more prevalent in fine grains than in coarse ones.

  2. Cementless acetabular revision arthroplasty

    PubMed Central

    Jain, Rina; Schemitsch, Emil H.; Waddell, James P.

    2000-01-01

    Objective To evaluate the effects of clinical factors on outcome after acetabular revision with a cementless beaded cup. Design Retrospective case series. Setting Tertiary care referral centre. Patients Forty-one patients who underwent acetabular revision with a cementless cup were followed up for a mean of 3.4 years. Interventions Acetabular revision with a beaded cementless cup in all patients. A morcellized allograft was used in 10 patients. Outcome measures A modified Harris hip score (range of motion measurement omitted), the SF-36 health survey, and the Western Ontario McMaster (WOMAC) osteoarthritis index. Multivariate analysis was used to evaluate the effects of age, gender, morcellized allografting, time to revision from the previous operation, acetabular screw fixation and concurrent femoral revision on outcome. Results Gender accounted for a significant portion of the variation seen in the SF-36 physical component scores (r = 0.36, p = 0.02), with women tending to have worse results. Increasing age was associated with lower WOMAC index function scores (r = 0.36, p = 0.03), whereas concurrent femoral revision tended to have a positive effect on WOMAC index function (r = 0.39, p = 0.01). None of the potential clinical predictors had any significant effect on the SF-36 mental component scores, or WOMAC index pain and stiffness scores. Conclusions In cementless acetabular revision arthroplasty, physical function, as measured by generic and limb-specific scales, may be affected by gender, age and the presence of a concurrent femoral revision. Time to revision from the previous operation, morcellized allografting and screw fixation of the acetabulum did not affect outcomes. This information may provide some prognostic value for patients’ expectations. PMID:10948687

  3. Effect of hot-forging on beta phase transformation of a high niobium containing titanium aluminide alloy

    NASA Astrophysics Data System (ADS)

    Cheng, Liang; Xue, Xiangyi; Tang, Bin; Kou, Hongchao; Li, Jinshan

    2015-03-01

    In this paper, ingot breakdown process of a high Nb containing TiAl alloy with a chemical composition of Ti-42.63Al-8.11Nb-0.21W-0.09Y (at.%) has been investigated under conventional forging conditions. It was found that the present alloy possesses superior hot-workability that can be successfully forged by conventional upsetting route due to the appearance of large amount of β/B2 phase, though shear band was observed in the forged-pancake. Further studies revealed that hot-working performed in (α + β) phase region which can effectively impede the β → α transformation and thus significantly increase the volume fraction of β/B2 phase. In contrast, the amount of β/B2 phase was notably reduced by heat treatment at the same conditions. This stress-induced effect is considered to be responsible to the superior hot-workability of the present alloy and the mechanism has been discussed and reasonably clarified. It was also suggested that the stress-induced effect has practical significance that it allows the implementation of conventional multi-step forging process which can develop fine and uniform microstructures suitable for secondary processing.

  4. Texture heterogeneities in alpha/alpha titanium forging analysed by EBSD-relation to fatigue crack propagation.

    PubMed

    Uta, E; Gey, N; Bocher, P; Humbert, M; Gilgert, J

    2009-03-01

    The microstructure and the local texture of a large IMI 834 forging were characterized using the Electron Back Scattered Diffraction (EBSD) technique. Crystallographic domains called macrozones and formed by a majority of primary alpha(p) grains with their axes in nearly the same direction were found. They had a band-like structure, parallel to the axial direction of the forging. The influence of these macrozones on the cold dwell-fatigue properties was studied. Several samples were tested under cold dwell-fatigue conditions. The crack initiation and the short-distance propagation region optically matched a bright region that contained numerous quasi-cleavage facets. The analysis of the EBSD measurements showed that this bright region was enclosed within a sharp textured region with axes at less than 30 degrees from the loading axis. The crystallographic features of the crack nucleation site and the crack propagation path were also analysed.

  5. Cementless revisions of failed aseptic cemented and cementless total hip arthroplasties. 284 cases.

    PubMed

    Lord, G; Marotte, J H; Guillamon, J L; Blanchard, J P

    1988-10-01

    Over the past 13 years, 284 revisions of aseptic total hip arthroplasty failures have been performed with cementless implants. There were 213 cases involving cemented implant failures and 71 involving cementless ones. Considered as salvage procedures, these revisions provided a satisfactory result in about 70% of the reviewed patients after five years. A biologic fixation by bony ingrowth can be expected under certain conditions from decorticated living bone, a tight mechanical fitting, and a retentive corrugated surface of the implant. A prosthetic reimplantation, safely done without cement, appears more economical for the bone stock and prevents the long-term complications related with cement. Bone grafts are often required but cannot ensure the incoming osteogenic fixation of the implant. Long-term results and complications mandate harmless extractability of the revisional implant, a forged stem, an easy exchange of the plastic liner (in a two-part acetabular component), and an updated low-friction system (high-density polyethylene wear being a potential long-term problem).

  6. Forging Advisor

    SciTech Connect

    Kerry Barnett

    2003-03-01

    Many mechanical designs demand components produced to a near net shape condition to minimize subsequent process steps. Rough machining from slab or bar stock can quickly and economically produce simple prismatic or cylindrical shapes. More complex shapes can be produced by laser engineered net shaping (LENS), casting , or forging. But for components that require great strength in mission critical applications, forging may be the best or even the only option. However, designers of these parts may and often do lack the detailed forging process knowledge necessary to understand the impact of process details such as grain flow or parting line placement on both the forging process and the characteristics of the forged part. Economics and scheduling requirements must also be considered. Sometimes the only viable answer to a difficult problem is to re-design the assembly to reduce loading and enable use of other alternatives.

  7. New Trends in Forging Technologies

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Hagen, T.; Knigge, J.; Elgaly, I.; Hadifi, T.; Bouguecha, A.

    2011-05-01

    Limited natural resources increase the demand on highly efficient machinery and transportation means. New energy-saving mobility concepts call for design optimisation through downsizing of components and choice of corrosion resistant materials possessing high strength to density ratios. Component downsizing can be performed either by constructive structural optimisation or by substituting heavy materials with lighter high-strength ones. In this context, forging plays an important role in manufacturing load-optimised structural components. At the Institute of Metal Forming and Metal-Forming Machines (IFUM) various innovative forging technologies have been developed. With regard to structural optimisation, different strategies for localised reinforcement of components were investigated. Locally induced strain hardening by means of cold forging under a superimposed hydrostatic pressure could be realised. In addition, controlled martensitic zones could be created through forming induced phase conversion in metastable austenitic steels. Other research focused on the replacement of heavy steel parts with high-strength nonferrous alloys or hybrid material compounds. Several forging processes of magnesium, aluminium and titanium alloys for different aeronautical and automotive applications were developed. The whole process chain from material characterisation via simulation-based process design to the production of the parts has been considered. The feasibility of forging complex shaped geometries using these alloys was confirmed. In spite of the difficulties encountered due to machine noise and high temperature, acoustic emission (AE) technique has been successfully applied for online monitoring of forging defects. New AE analysis algorithm has been developed, so that different signal patterns due to various events such as product/die cracking or die wear could be detected and classified. Further, the feasibility of the mentioned forging technologies was proven by means

  8. Cementless hydroxyapatite coated hip prostheses.

    PubMed

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda; Gracia, Luis

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality.

  9. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  10. Titanium

    SciTech Connect

    Fox, G.J.

    1997-01-01

    The article contains a summary of factors pertinent to titanium use. Geology and exploitation, production processes, global production, titanium dioxide and alloy applications, and the titanium market are reviewed. Potential applications outlined are for oil and gas equipment and for the automotive industry. Titanium alloys were selected for drilling risers for North Sea oil and gas drilling platforms due to a high strength-to-weight ratio and corrosion resistance. These properties also make titanium alloys attractive for auto parts, although the cost is currently prohibitive.

  11. Implant Design in Cementless Hip Arthroplasty

    PubMed Central

    Kim, Jung Taek

    2016-01-01

    When performing cementless hip arthroplasty, it is critical to achieve firm primary mechanical stability followed by biological fixation. In order to achieve this, it is essential to fully understand characteristics of implant design. In this review, the authors review fixation principles for a variety of implants used for cementless hip replacement and considerations for making an optimal selection. PMID:27536647

  12. Forging process design for risk reduction

    NASA Astrophysics Data System (ADS)

    Mao, Yongning

    In this dissertation, forging process design has been investigated with the primary concern on risk reduction. Different forged components have been studied, especially those ones that could cause catastrophic loss if failure occurs. As an effective modeling methodology, finite element analysis is applied extensively in this work. Three examples, titanium compressor disk, superalloy turbine disk, and titanium hip prosthesis, have been discussed to demonstrate this approach. Discrete defects such as hard alpha anomalies are known to cause disastrous failure if they are present in those stress critical components. In this research, hard-alpha inclusion movement during forging of titanium compressor disk is studied by finite element analysis. By combining the results from Finite Element Method (FEM), regression modeling and Monte Carlo simulation, it is shown that changing the forging path is able to mitigate the failure risk of the components during the service. The second example goes with a turbine disk made of superalloy IN 718. The effect of forging on microstructure is the main consideration in this study. Microstructure defines the as-forged disk properties. Considering specific forging conditions, preform has its own effect on the microstructure. Through a sensitivity study it is found that forging temperature and speed have significant influence on the microstructure. In order to choose the processing parameters to optimize the microstructure, the dependence of microstructure on die speed and temperature is thoroughly studied using design of numerical experiments. For various desired goals, optimal solutions are determined. The narrow processing window of titanium alloy makes the isothermal forging a preferred way to produce forged parts without forging defects. However, the cost of isothermal forging (dies at the same temperature as the workpiece) limits its wide application. In this research, it has been demonstrated that with proper process design, the die

  13. Titanium

    USGS Publications Warehouse

    Bedinger, G.M.

    2013-01-01

    Titanium is the ninth most abundant element in the earth’s crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  14. Unicondylar knee arthroplasty: a cementless perspective

    PubMed Central

    Forsythe, Michael E.; Englund, Roy E.; Leighton, Ross K.

    2000-01-01

    Objective To compare the results of cementless unicondylar knee arthroplasty (UKA) with those already reported in a similar study on cemented UKA. Design A case-series cross-sectional study. Setting The Queen Elizabeth II Health Sciences Centre, Dalhousie University, Halifax. Patients Fifty-one patients who underwent a total of 57 UKAs between May 1989 and May 1997. Inclusion criteria were osteoarthritis involving the predominantly the medial compartment of the knee, relative sparing of the other compartments, less than 15° of varus, minimal knee instability, and attendance at the postoperative clinical visit. Intervention Cementless UKA. Main outcome measures Clinical parameters that included pain, range of motion and the Knee Society Clinical Knee Score. Roentgenographic parameters that included α, β, γ and σ angles and the presence of periprosthetic radiolucency or loose beads. Results Age, weight, gender and follow-up interval did not significantly affect the clinical results in terms of pain, range of motion or knee score. Knees with more than 1 mm of radiolucency had significantly lower knee scores than those with no radiolucency. Knees that radiologically had loose beads also had significantly lower knee scores. The clinical outcomes of cementless UKA were comparable to those already reported on cemented UKA. Cementless femurs had less radiolucency than the cemented femurs, whereas cementless tibias had more radiolucency than their cemented counterparts. Conclusions Cementless UKA seems to be as efficacious as cemented UKA. However, there is some concern about the amount of radiolucency in the cementless tibial components. A randomized clinical trial comparing both cementless and cemented tibial components with a cementless femur (hybrid knee) is needed to further assess this controversial issue in UKA. PMID:11129829

  15. Cemented and cementless fixation: results and techniques.

    PubMed

    Silverton, Craig D

    2006-01-01

    There are multiple reports of successful cemented and cementless total knee arthroplasty in the current literature. Although technically more demanding to implant, selected cementless designs, with nearly 20 years of follow-up, demonstrate near-equal success compared with cemented implants, the gold standard. Far more important than the decision to use a cemented or cementless implant is the use of precise technique, adequate balancing of the soft tissues, and proper overall alignment. Failure to achieve these basic principles can lead to early failure in any total knee replacement system.

  16. [Cementless total hip arthroplasty: a review].

    PubMed

    Diehl, Peter; Haenle, Maximilian; Bergschmidt, Philipp; Gollwitzer, Hans; Schauwecker, Johannes; Bader, Rainer; Mittelmeier, Wolfram

    2010-10-01

    The purpose of total hip replacement (THR) is the restoration of a painless functioning hip joint with the main focus on the biomechanical properties. Advances in surgical techniques and biomaterial properties currently allow predictable surgical results in most patients. Despite the overwhelming success of this surgical procedure, the debate continues surrounding the optimal choice of implants and fixation. Femoral and acetabular implants with varying geometries and fixation methods are currently available. Problems inherent with acrylic bone cement, however, have encouraged surgeons to use alternative surfaces to allow biologic fixation. Optimal primary and secondary fixation of cementless hip stems is a precondition for long-term stability. Important criteria to achieve primary stability are good rotational and axial stability by press-fit fixation. The objective of the cementless secondary fixation is the biological integration of the implant by bony ingrowth. Nevertheless, current investigations show excellent results of cementless fixation even in older patients with reduced osseous quality. The main advantages of cementless fixation include biological integration, reduced duration of surgery, no tissue damage by cement polymerization and reduction of intraoperative embolisms. In comparison to cemented THR both, cementless sockets and stems provide good long-term results.

  17. Steel forgings: Second volume

    SciTech Connect

    Nisbett, E.G.; Melilli, A.S.

    1997-12-31

    Steel is supplied in many product forms, most of which are produced in terms of basic dimensions such as width and thickness, or diameter and with length describing quantity. Forgings and castings by contrast are diverse in shape and form and are individually made for a specific purpose, either as self contained units such as crankshafts, valve bodies or turbine rotors, or as discrete components to be fabricated into a larger assembly, as for example a nozzle for a pressure vessel. The specification and testing of forgings is therefore more varied, complex, and demanding than is the case for other product forms. This is augmented by the fact that forgings are often expected to give better reliability and service performance than can be expected when the same part is fabricated from sections of other steel product forms, if this were in fact practical. Given these unique circumstances the exchange of ideas on forging manufacturing techniques and experience, materials data and service experience has been an essential driving force in developing forging techniques and applications in every industrial field. The format of the symposium was similar to that of Williamsburg, focusing on the scope of the subcommittee in the areas of pressure vessel and nuclear forgings, turbine and generator forgings, general industrial forgings, and test methods for forgings. Separate abstracts were prepared for 17 papers.

  18. HYDRODYNAMIC COMPRESSIVE FORGING.

    DTIC Science & Technology

    HYDRODYNAMICS), (*FORGING, COMPRESSIVE PROPERTIES, LUBRICANTS, PERFORMANCE(ENGINEERING), DIES, TENSILE PROPERTIES, MOLYBDENUM ALLOYS , STRAIN...MECHANICS), BERYLLIUM ALLOYS , NICKEL ALLOYS , CASTING ALLOYS , PRESSURE, FAILURE(MECHANICS).

  19. Cementless acetabular revision: past, present, and future

    PubMed Central

    Pulido, Luis; Rachala, Sridhar R.

    2011-01-01

    Background Acetabular revision is probably the most difficult aspect of hip reconstructive surgery. Although the majority of acetabular revisions can be performed using an uncemented hemispherical acetabular device with ancillary fixation, patients with severe acetabular deficiencies and poor bone quality require more complex alternatives for revision. The limitations of traditional cementless acetabular implants has promoted the development of improved methods of fixation and revision techniques. Highly porous metals have been introduced for clinical use in arthroplasty surgery over the last decade. Their higher porosity and surface friction are ideal for acetabular revision, optimising biological fixation. The use of trabecular metal cups in acetabular revision has yielded excellent clinical results. Purpose This review focuses on the use of cementless implants for acetabular revision. The use of trabecular metal cups, augments, jumbo cups, oblong cups, cages, and structural grafting are also discussed. PMID:21234562

  20. Navigated Cementless Total Knee Arthroplasty - Medium-Term Clinical and Radiological Results§

    PubMed Central

    Schüttrumpf, Jan P; Balcarek, Peter; Sehmisch, Stephan; Frosch, Stephan; Wachowski, Martin M; Stürmer, Klaus M; Walde, Hans-Joachim; Walde, Tim A

    2012-01-01

    Purpose: The objective of this prospective study was to evaluate the medium-term clinical and radiological results after navigated cementless implantation, without patella resurfacing, of a total knee endoprosthesis with tibial and femoral press-fit components, with a focus on survival rate and clinical outcome. The innovation is the non-cemented fixation together with the use of a navigation system. Scope and Methods: Sixty patients with gonarthrosis were included consecutively in this study. In all cases, the cementless Columbus total knee endoprosthesis with a coating out of pure titanium was implanted, using a navigation system. The Knee Society Score showed a statistically significant increase from 75 (± 21.26) before surgery to 180 (± 16.15) after a mean follow-up of 5.6 (± 0.25) years. The last radiological examination revealed no osteolysis. No radiolucent lines were seen at any time in the area of the femoral prosthetic components. In the tibial area, radiolucent lines were seen in 24.4 % of the cases, mostly in the distal uncoated part of the stem. During follow-up, no prosthesis had to be replaced because of aseptic loosening while in 2 cases revision surgery was necessary due to septic loosening and in 1 case due to unexplainable pain. Results and Conclusions: Navigated cementless implantation of the Columbus total knee endoprosthesis yielded good clinical and radiological results in the medium term. The excellent radiological osteointegration of the prosthetic components, coated with a microporous pure titanium layer and implanted with a press-fit technique, should be emphasized. PMID:22550552

  1. Influence of cementless cup surface on stability and bone fixation 2 years after total hip arthroplasty.

    PubMed

    Urbański, Wiktor; Krawczyk, Artur; Dragan, Szymon Ł; Kulej, Mirosław; Dragan, Szymon F

    2012-01-01

    Loss of fixation between bone and implant surface is one of the main treatment problems in total hip arthroplasty. It might lead to implant instability, bone loss and treatment failure resulting in revision surgery. Surface modification is a method for improving bone response to implant and increasing implant osseointegration. However, the currently applied modifications such as hydroxyapatite coatings do not meet expectation and do not provide good clinical result. The object of the study was to evaluate the influence of acetabular cup surface modification on fixation and bone remodelling in total hip arthroplasty. Clinical and radiological outcomes were evaluated in patients two years after cementless total hip replacement. Two groups were compared: patients with acetabular component with uncoated titanium surface and patients with hydroxyapatite-coated acetabular surface. Hips X-rays were analysed for early signs of losing stability of acetabular cups. Two years after surgery the analysis of X-rays did not reveal any statistical differences in stability, migration of acetabular components of endoprosthesis between both groups. No differences were also observed in bone remodelling around implants. Particularly high percentage of cups, i.e. 17.64%, were classified into the group with high risk of early implant loosening, i.e., the group with HA coatings. Hydroxyapatite coatings on titanium cementless acetabular cups implanted by press-fit technique have no influence on their stability, bone-implant fixation and the remodelling of bone surrounding an implant two years after surgery.

  2. Cementless total hip replacement: past, present, and future.

    PubMed

    Yamada, Harumoto; Yoshihara, Yasuo; Henmi, Osamu; Morita, Mitsuhiro; Shiromoto, Yuichiro; Kawano, Tomoki; Kanaji, Arihiko; Ando, Kennichi; Nakagawa, Masato; Kosaki, Naoto; Fukaya, Eiichi

    2009-03-01

    Cementless total hip replacement (THR) is rapidly being accepted as the surgery for arthritic diseases of the hip joint. The bone-ingrowth rate in porous-type cementless implants was about 90% over 10 years after surgery, showing that biological fixation of cementless THR was well maintained on both the stem and cup sides. As for the stress shielding of the femur operated using a distal fixation-type stem, severe bone resorption was observed. The severe bone resorption group showed continuous progression for more than 10 years after surgery. Stem loosening directly caused by stress shielding has been considered less likely; however, close attention should be paid to bone resorption-associated disorders including femoral fracture. Cementless cups have several specific problems. It is difficult to decide whether a cup should be placed in the physiological position for the case of acetabular dysplasia by bone grafting or at a relatively higher position without bone grafting. The bone-ingrowth rate was lower in the group with en bloc bone grafting, and the reactive line was frequently noted in the bone-grafted region. Although no data indicated that en bloc bone grafting directly led to poor outcomes, such as loosening, cup placement at a higher site without bone grafting is now selected by most operators. The polyethylene liner in a cementless cup is thinned due to the metal cup thickness; however, it has been suggested that the apparent relation between the cup size and the wear rate was absent as long as a cementless cup is used. Comparative study indicated cementless THR was inferior with regard to the yearly polyethylene wear rate and incidence of osteolysis on both the stem and cup sides. Meta-analysis study on the survival rate between cement and cementless THR reported that cemented THR was slightly superior. It should be considered that specific problems for cementless THR, especially with regard to polyethylene wear, do occur.

  3. Cold Rotary Forging

    DTIC Science & Technology

    1975-09-01

    highly non-uniform in the as- forged and thermal treated conditions. Because of the magnitude of the stresses, no determination can be made as to their effects on tube fatigue life. 39 ...strength after forging. This behavior was attributed to the bauschinger effect. It was possible to recover the strength by,a thermal treatment at 800oF...that both compressive and tensile residual stresses were observed. However, in general, the stresses were low. The thermal treatments which

  4. Forging Long Shafts On Disks

    NASA Technical Reports Server (NTRS)

    Tilghman, Chris; Askey, William; Hopkins, Steven

    1989-01-01

    Isothermal-forging apparatus produces long shafts integral with disks. Equipment based on modification of conventional isothermal-forging equipment, required stroke cut by more than half. Enables forging of shafts as long as 48 in. (122 cm) on typical modified conventional forging press, otherwise limited to making shafts no longer than 18 in. (46cm). Removable punch, in which forged material cools after plastic deformation, essential novel feature of forging apparatus. Technology used to improve such products as components of gas turbines and turbopumps and of other shaft/disk parts for powerplants, drive trains, or static structures.

  5. Preclinical trial of a novel surface architecture for improved primary fixation of cementless orthopaedic implants.

    PubMed

    Harrison, Noel; Field, John R; Quondamatteo, Fabio; Curtin, William; McHugh, Peter E; Mc Donnell, Pat

    2014-09-01

    A new surface architecture for cementless orthopaedic implants (OsteoAnchor), which incorporates a multitude of tiny anchor features for enhancing primary fixation, was tested in an ovine hemi-arthroplasty pilot study. Test animals were implanted with a hip stem component incorporating the OsteoAnchor surface architecture produced using additive layer manufacturing and control animals were implanted with stems containing a standard plasma sprayed titanium coating. Intra-operative surgeon feedback indicated that superior primary fixation was achieved for the OsteoAnchor stems and rapid return to normal gait and load bearing was observed post-operation. Following a 16-week recovery time, histological evaluation of the excised femurs revealed in-growth of healthy bone into the porous structure of the OsteoAnchor stems. Bone in-growth was not achieved for the plasma sprayed stems. These results indicate the potential for the OsteoAnchor surface architecture to enhance both the initial stability and long term lifetime of cementless orthopaedic implants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Deformation processes in forging ceramics

    NASA Technical Reports Server (NTRS)

    Cannon, R. M.; Rhodes, W. H.

    1972-01-01

    The deformation processes involved in the forging of refractory ceramic oxides were investigated. A combination of mechanical testing and forging are utilized to investigate both the flow and fracture processes involved. An additional hemisphere forging was done which failed prematurely. Analysis and comparison with available fracture data for AL2O3 indicated possible causes of the failure. Examination of previous forgings indicated an increase in grain boundary cavitation with increasing strain.

  7. Modeling of Closed-Die Forging for Estimating Forging Load

    NASA Astrophysics Data System (ADS)

    Sheth, Debashish; Das, Santanu; Chatterjee, Avik; Bhattacharya, Anirban

    2017-02-01

    Closed die forging is one common metal forming process used for making a range of products. Enough load is to exert on the billet for deforming the material. This forging load is dependent on work material property and frictional characteristics of the work material with the punch and die. Several researchers worked on estimation of forging load for specific products under different process variables. Experimental data on deformation resistance and friction were used to calculate the load. In this work, theoretical estimation of forging load is made to compare this value with that obtained through LS-DYNA model facilitating the finite element analysis. Theoretical work uses slab method to assess forging load for an axi-symmetric upsetting job made of lead. Theoretical forging load estimate shows slightly higher value than the experimental one; however, simulation shows quite close matching with experimental forging load, indicating possibility of wide use of this simulation software.

  8. Improved design of cementless hip stems using two-dimensional functionally graded materials.

    PubMed

    Hedia, H S; Shabara, M A N; El-Midany, T T; Fouda, N

    2006-10-01

    Increasingly, it is acknowledged that bone resorption around cementless hip implants may cause future problems. The solution is frequently sought in reducing implant stiffness. However, this confronts the designer with a true design conflict: how to reduce the stiffness without excessively loading the proximal bone/prosthesis interface? The aim of this work is to improve the design of cementless hip stem material, using two-dimensional (2D) functionally graded material (FGM) concept in order to solve the above problems. Two models were used in this analysis, using three materials with different elastic moduli, E(1), E(2), and E(3). In model I, the elastic moduli E(1) and E(2) gradually change along the upper stem surface, while E(3) is maintained constant along all the lower surface of the stem. However, in model II, the elastic moduli E(1) and E(2) gradually change along the lower stem surface, while E(3) is maintained constant all along the upper stem surface. It is found that the recommended model is model I, which has three distinct materials of hydroxyapatite, Bioglass, and collagen. The recommended design of 2D FGM is expected to reduce the stress shielding by 91% and 12%, respectively, compared with titanium stem and model II of FGM. It is found that this new design reduces the maximum interface shear stress at the lateral and medial sides of the femur by about 50%, compared with titanium stem. Furthermore, the maximum interface shear stress is reduced by about 17% and 11% at the lateral and medial sides of the femur, respectively, compared with that of model II of FGM.

  9. Fallon FORGE Well Lithologies

    SciTech Connect

    Doug Blankenship

    2016-03-01

    x,y,z text file of the downhole lithologic interpretations in the wells in and around the Fallon FORGE site. All the relevant information is in the file header (the spatial reference, the projection etc.) In addition all the fields in the data file are identified in the header.

  10. Partners: Forging Strong Relationships.

    ERIC Educational Resources Information Center

    Spears, Ellen, Ed.

    1999-01-01

    This newsletter issue asserts that sound, effective relationships in which diverse groups of people and organizations work together toward a common goal are the basis of the collaborative efforts in education that can accomplish change. The first article, "Partners: Forging Strong Relationships" (Sarah E. Torian), briefly describes the…

  11. Productivity and the forging industry

    NASA Astrophysics Data System (ADS)

    Stocking, A.

    The ways in which the machinery, manpower, material, and money may be applied in more productive and profitable ways within the forging industry of South Africa are discussed from a practical viewpoint. The basic aspects of forging plant selection are discussed in an attempt to help management within the industry make the best choice of forging machine and correctly choose its capacity for the market sector for which it is aimed. Some information is given on furnaces and ancillary forging equipment as well as on estimates of the cost of heating in the forge.

  12. Antibacterial efficacy of a new gentamicin-coating for cementless prostheses compared to gentamicin-loaded bone cement.

    PubMed

    Neut, Daniëlle; Dijkstra, René J B; Thompson, Jonathan I; van der Mei, Henny C; Busscher, Henk J

    2011-11-01

    Cementless prostheses are increasingly popular but require alternative prophylactic measures than the use of antibiotic-loaded bone cements. Here, we determine the 24-h growth inhibition of gentamicin-releasing coatings from grit-blasted and porous-coated titanium alloys, and compare their antibacterial efficacies and gentamicin release-profiles to those of a commercially available gentamicin-loaded bone cement. Antibacterial efficacy increased with increasing doses of gentamicin in the coating and loading with 1.0 and 0.1 mg gentamicin/cm(2) on both grit-blasted and porous-coated samples yielded comparable efficacy to gentamicin-loaded bone cement. The coating had a higher burst release than bone cement, and also inhibited growth of gentamicin-resistant strains. Antibacterial efficacy of the gentamicin coatings disappeared after 4 days, while gentamicin-loaded bone cement exhibited efficacy over at least 7 days. Shut-down after 4 days of gentamicin-release from coatings is advantageous over the low-dosage tail-release from bone cements, as it minimizing risk of inducing antibiotic-resistant strains. Both gentamicin-loaded cement discs and gentamicin-coated titanium coupons were able to kill gentamicin-sensitive and -resistant bacteria in a simulated prothesis-related interfacial gap. In conclusion, the gentamicin coating provided similar antibacterial properties to those seen by gentamicin-loaded bone cement, implying protection of a prosthesis from being colonized by peri-operatively introduced bacteria in cementless total joint arthroplasty.

  13. A gentamicin-releasing coating for cementless hip prostheses-Longitudinal evaluation of efficacy using in vitro bio-optical imaging and its wide-spectrum antibacterial efficacy.

    PubMed

    Neut, Daniëlle; Dijkstra, René J B; Thompson, Jonathan I; van der Mei, Henny C; Busscher, Henk J

    2012-12-01

    Cementless prostheses are increasingly popular in total hip arthroplasties. Therewith, common prophylactic measures to reduce the risk of postoperative infection like the use of antibiotic-loaded bone cements, will no longer be available. Alternative prophylactic measures may include the use of antibiotic-releasing coatings. Previously, we developed a gentamicin-releasing coating for cementless titanium hip prostheses and derived an appropriate dosing of this coating by adjusting the amount of gentamicin in the coating to match the antibacterial efficacy of clinically employed gentamicin-loaded bone cement. In this manuscript, we investigated two important issues regarding the prophylactic use of this 1 mg cm(-2) bioactive gentamicin-releasing coating in cementless total hip arthroplasty: (1) its ability to prevent bacterial growth in a geometrically relevant set-up and (2) its antibacterial spectrum. A geometrically relevant set-up was developed in which miniature titanium stems were surrounded by agar, contaminated with bioluminescent Staphylococcus aureus. Novel, bio-optical imaging was performed allowing noninvasive, longitudinal monitoring of staphylococcal growth around miniature stems with and without the gentamicin-releasing coating. Furthermore, the antibacterial efficacy of the gentamicin-releasing coating was determined against a wide variety of clinical isolates, including bioluminescent Staphylococcus aureus strains, using traditional zone of inhibition measurements. The gentamicin-releasing coating demonstrated a wide-spectrum of antibacterial efficacy and successfully prevented growth of bioluminescent staphylococci around a miniature stem mounted in bacterially contaminated agar for at least 60 h. This implies that the gentamicin-releasing coating has potential to contribute to the improvement of infection prophylaxis in cementless total hip arthroplasty.

  14. A novel process for breakdown forging of coarse-grain intermetallic alloys

    SciTech Connect

    Semiatin, S.L. . Materials Directorate); McQuay, P.A. . Asian Office of Aerospace R and D); Seetharaman, V. )

    1993-11-01

    The objective of the present work was to develop a novel hot forging process for breakdown of high-temperature intermetallic alloys which exhibit dynamic recrystallization during hot working. During typical forging processes in hydraulic processes, be they based on isothermal or conventional approaches, the ram speed (or sometimes the effective strain rate) is held constant during the forging stroke. In the method introduced here, the ram speed is increased substantially during the forging stroke as the material recrystallizes to a finer-grained structure and its hot workability increases. By this means, fracture is avoided, grain size is reduced, and processing time is decreased, thus improving material quality and reducing cost. The material used to develop and demonstrate the novel forging process was the single phase gamma titanium aluminide, Ti-51Al-2Mn.

  15. Superplastic forging nitride ceramics

    DOEpatents

    Panda, Prakash C.; Seydel, Edgar R.; Raj, Rishi

    1988-03-22

    The invention relates to producing relatively flaw free silicon nitride ceramic shapes requiring little or no machining by superplastic forging This invention herein was made in part under Department of Energy Grant DE-AC01-84ER80167, creating certain rights in the United States Government. The invention was also made in part under New York State Science and Technology Grant SB1R 1985-10.

  16. FEM simulation of hot forging process to predict microstructure evolution

    NASA Astrophysics Data System (ADS)

    Zhang, Shi-Hong; Zhang, Hai-Yan; Song, Hong-Wu; Cheng, Ming

    2013-05-01

    Two phase titanium alloy-TC11 alloy and Superalloy-IN718 alloy are being considered for high-temperature structural applications in aero-engine because of their excellent mechanical properties at elevated temperatures. The mechanical properties of their forgings are sensitive to the microstructure. Therefore, it is crucial to obtain a corresponding microstructure by controlling the hot working process. For the forging of TC11 alloy, the ingot break down in the subtransus region is an important process which acted as the primary role in the transformation of lamellar structure to equiaxed one as well as its poor formability because of lower deformation temperature. In this paper, the lamellar globularization kinetics and fracture behavior during forging are studied and modeled. For the hot forging of IN718 alloy. the grain size evolution is an important process. As the δ phase in the alloy can control grain growth through the strong pinning effect, the effect of δ phase on the microstructure evolution during hot working has been considered in this paper, and the microstructure evolution model has been established. As a applications, The lamellar globularization and fracture during the subtransus cogging process of large size TC11 alloy billet, and the microstructure development during the hot forging process of IN718 alloy turbine disk have been investigated commercial FE Software with user subroutines. The prediction results showed good agreement with the actual ones.

  17. Ten-year results after cementless THA with a sandwich-type alumina ceramic bearing.

    PubMed

    Park, Youn-Soo; Park, Se-Jun; Lim, Seung-Jae

    2010-11-02

    We analyzed the long-term results of a single-surgeon series of 102 cementless total hip arthroplasties (THAs) performed using a sandwich-type alumina ceramic bearing. The prostheses involved a porous-coated acetabular socket, a polyethylene-alumina composite liner, a 28-mm alumina head, and a grit-blasted titanium-alloy stem. Mean patient age at the time of THA was 39 years (range, 18-66 years), and 76% of the patients were younger than 50 years. All procedures were performed with use of the same surgical technique and the same implant at a single center. Mean follow-up was 115 months (range, 84-133 months). When failure was defined as revision of either the acetabular or the femoral component for any reason, Kaplan-Meier survival probability at 10 years was 95.3% (95% confidence interval, 89.5%-100%). Mean Harris Hip Score improved from 47 points (range, 16-70 points) preoperatively to 95 points (range, 85-100 points) at final follow-up. No radiographically detectable osteolysis around the acetabular or femoral component was observed in any hip. No patient reported squeaking in the operated hip. During the follow-up period, 3 hips (3%) required revision surgery; 2 underwent acetabular revision because of a ceramic liner fracture and 1 underwent revision for early loosening of the acetabular cup. Ten-year results of cementless THA with a sandwich-type alumina ceramic bearing were encouraging, and no great increase in ceramic failure rate was observed, which contrasts with the findings of previously reported short-term follow-up studies. Copyright 2010, SLACK Incorporated.

  18. Method of making multilayered titanium ceramic composites

    SciTech Connect

    Fisher, George T., II; Hansen; Jeffrey S.; Oden; Laurance L.; Turner; Paul C.; Ochs; Thomas L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  19. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, G.T. II; Hansen, J.S.; Oden, L.L.; Turner, P.C.; Ochs, T.L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body followed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet. 3 figs.

  20. Method of making multilayered titanium ceramic composites

    SciTech Connect

    Fisher, II, George T.; Hansen, Jeffrey S.; Oden, Laurance L.; Turner, Paul C.; Ochs, Thomas L.

    1998-01-01

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  1. Method of making multilayered titanium ceramic composites

    SciTech Connect

    Fisher, G.T. II; Hansen, J.S.; Oden, L.L.; Turner, P.C.; Ochs, T.L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body followed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet. 3 figs.

  2. Tailorable Burning Behavior of Ti14 Alloy by Controlling Semi-Solid Forging Temperature

    PubMed Central

    Chen, Yongnan; Yang, Wenqing; Zhan, Haifei; Zhang, Fengying; Huo, Yazhou; Zhao, Yongqing; Song, Xuding; Gu, Yuantong

    2016-01-01

    Semi-solid processing (SSP) is a popular near-net-shape forming technology for metals, while its application is still limited in titanium alloy mainly due to its low formability. Recent works showed that SSP could effectively enhance the formability and mechanical properties of titanium alloys. The processing parameters such as temperature and forging rate/ratio, are directly correlated with the microstructure, which endow the alloy with different chemical and physical properties. Specifically, as a key structural material for the advanced aero-engine, the burn resistant performance is a crucial requirement for the burn resistant titanium alloy. Thus, this work aims to assess the burning behavior of Ti14, a kind of burn resistant alloy, as forged at different semi-solid forging temperatures. The burning characteristics of the alloy are analyzed by a series of burning tests with different burning durations, velocities, and microstructures of burned sample. The results showed that the burning process is highly dependent on the forging temperature, due to the fact that higher temperatures would result in more Ti2Cu precipitate within grain and along grain boundaries. Such a microstructure hinders the transport of oxygen in the stable burning stage through the formation of a kind of oxygen isolation Cu-enriched layer under the burn product zone. This work suggests that the burning resistance of the alloy can be effectively tuned by controlling the temperature during the semi-solid forging process. PMID:28773820

  3. Superplastic forging nitride ceramics

    DOEpatents

    Panda, P.C.; Seydel, E.R.; Raj, R.

    1988-03-22

    A process is disclosed for preparing silicon nitride ceramic parts which are relatively flaw free and which need little or no machining, said process comprising the steps of: (a) preparing a starting powder by wet or dry mixing ingredients comprising by weight from about 70% to about 99% silicon nitride, from about 1% to about 30% of liquid phase forming additive and from 1% to about 7% free silicon; (b) cold pressing to obtain a preform of green density ranging from about 30% to about 75% of theoretical density; (c) sintering at atmospheric pressure in a nitrogen atmosphere at a temperature ranging from about 1,400 C to about 2,200 C to obtain a density which ranges from about 50% to about 100% of theoretical density and which is higher than said preform green density, and (d) press forging workpiece resulting from step (c) by isothermally uniaxially pressing said workpiece in an open die without initial contact between said workpiece and die wall perpendicular to the direction of pressing and so that pressed workpiece does not contact die wall perpendicular to the direction of pressing, to substantially final shape in a nitrogen atmosphere utilizing a temperature within the range of from about 1,400 C to essentially 1,750 C and strain rate within the range of about 10[sup [minus]7] to about 10[sup [minus]1] seconds[sup [minus]1], the temperature and strain rate being such that surface cracks do not occur, said pressing being carried out to obtain a shear deformation greater than 30% whereby superplastic forging is effected.

  4. Developments in forging ingot production at BethForge Inc.

    SciTech Connect

    Fielding, J.E.; Focht, R.B.; Reppert, K.F.; Tihansky, E.L.

    1997-12-31

    BethForge manufactures precision custom forgings for diverse applications including turbine and generator rotors, components for nuclear reactors and other pressure vessels, and rolls for steel and aluminum rolling mills. This paper will discuss the production of forging ingots for BethForge at the modernized steel making facility in Steelton, PA. The facility is operated as part of a joint effort with Pennsylvania Steel Technologies, Inc. (also a wholly owned subsidiary of Bethlehem Steel) and consists of a 150 ton (136 metric ton) DC electric arc furnace, a ladle refining station including a ladle furnace and ladle degasser, and teeming facilities which include bottom pouring and vacuum stream degassing. Steel is produced for BethForge ingots as well as continuously cast for the Pennsylvania Steel Technologies product lines. Forging, heat treating and machining operations remain at Bethlehem, PA and ingots as large as 130 inches diameter (3,300 mm) and 290 tons (263 metric tons) are hot transported the 90 mile (145 km) distance from Steelton to Bethlehem in specially constructed insulated railcars. In addition to describing the facilities and operations, the presentation will focus on solutions to several of the unique engineering and technical challenges realized in successfully bringing this operation on line.

  5. Nonconforming Titanium Task Force Actions to Resolve Aircraft Safety Issues due to Improperly Substituted Material

    DTIC Science & Technology

    2012-06-21

    plate • AMS-T-9047 Bar • Extrusions • Die Forgings • Rod • Wire Hot Rolling • AMS-T-9046 sheet and strip • Heating • Forging • Cooling Ingots...plate • AMS-T-9047 Bar • Extrusions • Die Forgings • Rod • Wire Hot Rolling • AMS-T-9046 sheet and strip 29 Titanium plate and sheet is...Reforging Stock Hot Rolling Hot Forging/ Rolling High Deformation Processes • AMS-T-9046 plate • AMS-T-9047 Bar • Extrusions • Die Forgings • Rod

  6. Intraoperative Proximal Femoral Fracture in Primary Cementless Total Hip Arthroplasty.

    PubMed

    Ponzio, Danielle Y; Shahi, Alisina; Park, Andrew G; Purtill, James J

    2015-08-01

    Intraoperative proximal femoral fracture is a complication of primary cementless total hip arthroplasty (THA) at rates of 2.95-27.8%. A retrospective review of 2423 consecutive primary cementless THA cases identified 102 hips (96 patients) with fracture. Multivariate analysis compared fracture incidences between implants, Accolade (Stryker Orthopaedics) and Tri-Lock (DePuy Orthopaedics, Inc.), and evaluated potential risk factors using a randomized control group of 1150 cases without fracture. The fracture incidence was 4.4% (102/2423), 3.7% (36/1019) using Accolade and 4.9% using Tri-Lock (66/1404) (P=0.18). Female gender (OR=1.96; 95% CI 1.19-3.23; P=0.008) and smaller stem size (OR=1.64; 95% CI 1.04-2.63; P=0.03) predicted increased odds of fracture. No revisions of the femoral component were required in the fracture cohort.

  7. Large forging manufacturing process

    DOEpatents

    Thamboo, Samuel V.; Yang, Ling

    2002-01-01

    A process for forging large components of Alloy 718 material so that the components do not exhibit abnormal grain growth includes the steps of: a) providing a billet with an average grain size between ASTM 0 and ASTM 3; b) heating the billet to a temperature of between 1750.degree. F. and 1800.degree. F.; c) upsetting the billet to obtain a component part with a minimum strain of 0.125 in at least selected areas of the part; d) reheating the component part to a temperature between 1750.degree. F. and 1800.degree. F.; e) upsetting the component part to a final configuration such that said selected areas receive no strains between 0.01 and 0.125; f) solution treating the component part at a temperature of between 1725.degree. F. and 1750.degree. F.; and g) aging the component part over predetermined times at different temperatures. A modified process achieves abnormal grain growth in selected areas of a component where desirable.

  8. Pilot Plant Forging of Hydrogenated Ti-6Al-4V.

    DTIC Science & Technology

    1980-06-01

    inserted into an M-246 nickel base superalloy die block with 713C alloy flat dies positioned on the heated die block. The entire die system was enclosed...side if neceaary and identify by block number) Hydrogenation Isothermal Forging Ring Test Titanium Alloy Ti-6A1-4V Flow Stress 20. k9Sr9Xd1’ (Continue on...5 Rack used to hold Specimens during Hydrogenation 29 6 Flow Stress-Plastic Strain Relation for Ti-6AI-4V Alloy (Heat A) with Various Hydrogen

  9. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Forging machines. 1910.218 Section 1910.218 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a... other identifier, for the forging machine which was inspected. (ii) Scheduling and recording the...

  10. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Forging machines. 1910.218 Section 1910.218 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a... other identifier, for the forging machine which was inspected. (ii) Scheduling and recording...

  11. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Forging machines. 1910.218 Section 1910.218 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a... other identifier, for the forging machine which was inspected. (ii) Scheduling and recording...

  12. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Forging machines. 1910.218 Section 1910.218 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a... other identifier, for the forging machine which was inspected. (ii) Scheduling and recording...

  13. 29 CFR 1910.218 - Forging machines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Forging machines. 1910.218 Section 1910.218 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a... other identifier, for the forging machine which was inspected. (ii) Scheduling and recording...

  14. Five-year experience of cementless Oxford unicompartmental knee replacement.

    PubMed

    Pandit, H G; Campi, S; Hamilton, T W; Dada, O D; Pollalis, S; Jenkins, C; Dodd, C A F; Murray, D W

    2017-03-01

    Cementless unicompartmental knee replacement (UKR) was introduced to address some of the problems that can occur following cemented UKR. The aim of this study was to report the 5-year experience of the first 512 medial cementless Oxford UKR implanted by two surgeons for the recommended indications. The first consecutive 512 cementless Phase 3 Oxford UKRs implanted by two surgeons for the recommended indications between June 2004 and October 2013 were prospectively identified and followed up independently. All the procedures were carried out through a minimally invasive approach without eversion or dislocation of the patella. Patients were assessed clinically pre-operatively and at 1, 2, 5, 7 and 10 years after surgery with functional outcome scores and radiographs. There were eight reoperations of which six were revisions giving a 5-year survival of 98 % (95 % CI 94-100 %). At a mean follow-up of 3.4 years (1.0-10.2), the mean OKS was 43 (SD 7), AKSS (objective) was 81 (SD 13), and AKSS (functional) was 86 (SD 17). The first 120 cases had a minimum follow-up of 5 years (mean 5.9; range 5-10.2). In these patients, the mean OKS was 41 (SD 8), AKSS (objective) was 81 (SD 14), and AKSS (functional) was 82 (SD 18). There were no femoral radiolucencies and no complete tibial radiolucencies. 11 % of tibial components had partial radiolucent lines; the remaining 89 % had no radiolucencies. The clinical results are as good as or better than those previously reported for cemented fixation. The radiographic results are better with secure bony attachment to the implants in every case. IV.

  15. [Revision total hip arthroplasty using a cementless prosthesis].

    PubMed

    Jiang, Qing; Xu, Zhi-hong; Chen, Dong-yang; Shi, Dong-quan; Qin, Jiang-hui; Dai, Jin; Weng, Wen-jie; Yuan, Tao

    2012-05-01

    To assess the operative technique and results with the usage of cementless prosthesis in hip revision. Retrospective study was done on revision of total hip arthroplasty with cementless prosthesis in 72 patients (41 males and 31 females) with an average age of 65.7 years (28-82 years) from January 2004 to December 2009. The reason for revision was 2 infection, 54 aseptic loosening, 4 periprosthetic fractures, 5 fracture of femoral stems and 7 cases of acetabular abrasion after hemi-arthroplasty. The operation time, bleeding loss, complications of infection, dislocation, periprosthetic fractures and loosening were evaluated. The Harris score were used for hip function evaluation. The average operation time was (146±47) minutes (70-280 minutes) and bleeding loss during the operation was (970±540) ml (200-2500 ml). Bacterium cultivation during operation demonstrated infection in 2 patients. Bone windows at the lateral femoral were opened in 4 patients and extend trochanteric osteotomy was done in 7 patients. Fracture of the proximal femur occurred in 8 cases. Twenty-nine patients were treated with bone graft including 18 autografts and 11 allografts. Sixty-seven patients were followed up for an average time of 66 months (20-92 months). Additional revisions were performed in 3 cases including 2 dislocations and 1 infection. There were no death, no damage of major blood vessels and nerves. The bone graft healed during 3-5 months. The survival rates of the femoral prosthesis and the acetabulum prostheses were 95.5% and 98.4%. The mean Harris score was 86±8 (55-95 points). Osteolysis were seen in 13 hips but migration was seen in only 1 patient. The cementless prosthesis is useful in revision total hip arthroplasty and the perfect clinical results are related to the reliable primary fixation.

  16. Thermal-mechanical processing of a 48-2-2 {gamma}-titanium aluminide

    SciTech Connect

    Davey, S.; Loretto, M.H.; Dean, T.A.; Huang, Z.W.; Blenkinsop, P.; Evans, R.W.; Jones, A.

    1995-12-31

    The paper describes the hot working behavior of a cast 48-2-2 titanium aluminide. Constant strain rate isothermal forging tests have been conducted over the temperature range 900 C to 1,220 C and at strain rates between 0.0001s{sup {minus}1} and 50s{sup {minus}1}. A forging regime, in terms of temperature and strain rate, exists which allows large strain hot forging to be carried out with the production of sound forgings. In addition considerable microstructure refinement is achieved through dynamic recrystallization. Constitutive relationships for deformation and for microstructural evolution have been derived. Larger scale forgings have been carried out isothermally and have been used to establish that the relationships are applicable to the hot forging of TiAl under conditions likely to be met in industrial forging operations.

  17. [Second-generation metal bearings in cementless primary total hip arthroplasty: rationale, French homologation and preliminary results].

    PubMed

    Delaunay, C

    2000-12-01

    Long-term outcome of Charnley low-friction arthroplasty in young active patients is impaired worldwide due to wear of the polyethylene (PE) component and osteolysis. In the late eighties, reports of possible low wear with some former metal on metal total hip arthroplasties led to the reintroduction of metallic bearings. The aims of this work were to examine the rationale for using metal on metal bearings in primary total hip arthroplasty (THA) and report preliminary results obtained with cementless Metasul -Alloclassic hips. From January 1994 to March 1997, 64 cementless primary Alloclassic-THA (grit-blasted titanium SL stems and CSF treaded cups) with 28 mm Metasul bearings were performed. Mean age at surgery was 60 years (range, 36-73). Diagnoses were usual, mainly primary osteoarthrosis in 70 p. 100 of the hips. Two bearing surfaces were exchanged for late dislocation at 2.6 and 2.9 years. Thus, 62 hips in 58 active patients (4 bilateral) were reviewed after a minimum 2-year follow-up (mean 3.2 years, range 24-66 months). Clinical results according to the Merle d'Aubigne and Charnley rating system were graded excellent or good in all 62 hips. Radiologically, calcar, atrophy and spot welds were noted in 93 p. 100 and 82 p. 100 of hips respectively. Proximal reactive and lucent lines and mild proximal stress shielding were observed in 8 p. 100 and 4.8 p. 100 of hips respectively. No osteolysis granuloma has thus far been observed in the vicinity of any component. Cobalt blood level remained normal, except in 6 cases due to occupational exposure (n=1), possible impingement (n=1) or an unknown cause (n=4). All elevated cobalt levels (range 7 to 25 microg/l) were nevertheless far below the toxic limit. Dislocation may be due either to the posterolateral surgical approach and/or early impingement with the first Metasul bearing design (head sleeve). Metasul acetabular component fixation is not restricted to only cementless metal-backing, unlike alumina-ceramic cups

  18. Effects of an AST program on US titanium story

    NASA Technical Reports Server (NTRS)

    Fitzsimmons, R. D.

    1980-01-01

    The singular importance of titanium as the primary structural material for an efficient advanced supersonic transport (AST) is outlined. The advantages of titanium over other metals are shown to apply to future subsonic aircraft as well as for supersonic designs. The cost problem of titanium is addressed and shown to be markedly reduced by the emerging technologies of superplastic forming/diffusion bonding sandwich, hot isostatic pressing of titanium powders, and isothermal forgings if demonstration programs should validate preliminary findings. The impact of a U.S. AST program on the United States titanium supply and demand picture is postulated.

  19. Powder Metallurgy Forged Gear Development

    DTIC Science & Technology

    1985-03-01

    Unclassified) 12. PERSONAL AUTHOR(S) D. H. Ro, B. L. Ferguson, S. Pillay, D. T. Ostberg 13a. TYPE OF REPORT 13b. TIME COVERED 14. DATE OF REPORT (Year, Month...Method Water Atomized SelecCion -Initial Alloy Distribution Prealloyed -Particle Size Distribution -100 Mesh kForging Quality) Uxmtpaction -Lubricant Zinc

  20. Heat treatment of forging dies

    NASA Astrophysics Data System (ADS)

    Dovnar, S. A.; Kadnikov, S. A.

    1987-08-01

    In forging-die production there is a considerable range of forging dies which are promising for a changeover into advanced heat treatment involving bulk temper hardening and surface hardening using induction heating. The heat treatment suggested provides a saving of material resources as a result of improving the life of forging dies by a factor of 1.5-3 depending on the grade of die steel. As a result of induction hardening of forging dies, after temper hardening close to the boundary of the hardened layer a zone of reduced hardness forms whose unfavorable effect may be reduced by using before induction surface hardening bulk warming in a furnace or deep induction heating with a reduced energy concentration in the heating zone to the tempering temperature in the temper hardening cycle. In order to improve the uniformity of induction surface hardening for dies with a complex working shape it is desirable to use heating at reduced power with an increase in heating time.

  1. Cementless RM Pressfit Cup: a clinical and radiological study of 91 cases with at least four years follow-up.

    PubMed

    Lafon, L; Moubarak, H; Druon, J; Rosset, P

    2014-06-01

    Cementless metal-back acetabular cups have good long-term results, but some problems have appeared due to the shell's stiffness, modularity and required bearing surfaces. The RM Pressfit Cup is a single-piece polyethylene cementless acetabular cup that is covered by a thin layer of titanium. This allows for bone integration without limitations related to the stiffness of a metal-back shell. There is very little published information about this new, innovative implant design. The purpose of this study was to evaluate the clinical and radiological results from a continuous series of 91 cups (85 patients) with a follow-up of at least 4 years. No patients were lost to follow-up. The Harris Hip Score (HHS) was used to assess the clinical outcome. To assess the radiological outcomes, digital X-rays were used to evaluate the cup position and integration; wear was measured using Livermore's technique. The clinical results were excellent: the mean HHS was 94 and 82% of cases had good or excellent scores. Three of the cups had to be revised because of dislocation brought on by incorrect positioning. X-rays revealed that three implants had shifted during the first 6 weeks, but had stabilized afterwards. Bone integration on X-rays was satisfactory in all cases with no signs of osteolysis. The configuration of the bone trabeculae showed that loads between the implant and peri-acetabular cancellous bone were evenly distributed. The wear of the polyethylene cup-ceramic head bearing was 0.07 mm/year. The results of this series are consistent with recent published studies with the RM Pressfit Cup. IV. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  2. Hot forging of graphite-carbide composites. Final report

    SciTech Connect

    Jenkins, G.M.; Holland, L.R.

    1998-07-15

    This project was aimed at hot shaping of titanium carbide/graphite and vanadium carbide/graphite composite materials by heating them to above 2000 degrees celsius and pressing into an electrographite die. The sample was to be a preformed cylinder of powdered graphite mixed with powdered titanium or vanadium, lightly sintered. The preform would be heated in a hot press and the titanium or vanadium would react with some of the graphite to form titanium or vanadium carbide. The remaining (excess) graphite would form a composite with the carbide, and this could then be deformed plastically at temperatures well below the onset of plasticity in pure graphite. There were to be two major thrusts in the research: In the first, an electron beam furnace at Sandia Laboratory was to be used for rapid heating of the sample, which would then be transferred into the press. The second thrust was to be entirely at Alabama A and M University, and here they intended to use a heated, controlled atmosphere press to forge the graphite/carbide preforms at a steady temperature and measure their viscosity as a function of temperature. This report discusses the progress made on this project.

  3. Successful cementless cup reimplantation using cortical bone graft augmentation after an acetabular fracture and cup displacement.

    PubMed

    Torres, Bryan T; Chambers, Jonathan N; Budsberg, Steven C

    2009-01-01

    To report repair of a periprosthetic acetabular fracture with concurrent component displacement after cementless total hip arthroplasty (THA). Clinical case report. Dog (n=1) with an acetabular fracture after THA. Acetabular repair was performed on a highly comminuted periprosthetic acetabular fracture after cementless THA. A bulk, structural corticocancellous autograft from the ipsilateral ilial wing was used for repair and reconstruction of the dorsal acetabular wall before reimplantation of a cementless acetabular component. Repair of a periprosthetic acetabular fracture with a bulk structural autograft was successful in reconstruction of the dorsal acetabular wall and in reestablishing a stable, functional cementless THA acetabular prosthesis. Structural corticocancellous autografts from the ilium can be successfully used in repair of periprosthetic acetabular fractures after THA. Structural corticocancellous grafting from the ilium can be considered as a treatment option for repair of periprosthetic acetabular fractures after THA.

  4. Deformation processes in forging ceramics

    NASA Technical Reports Server (NTRS)

    Cannon, R. M.; Rhodes, W. H.

    1973-01-01

    The deformation processes involved in the forging of refractory ceramic oxides were investigated. A combination of mechanical testing and forging was utilized to investigate both the flow and fracture processes involved. Deformation studies of very fine grain Al203 revealed an apparent transition in behavior, characterized by a shift in the strain rate sensitivity from 0.5 at low stresses to near unity at higher stresses. The behavior is indicative of a shift in control between two dependent mechanisms, one of which is indicated to be cation limited diffusional creep with significant boundary enhancement. The possible contributions of slip, indicated by crystallographic texture, interface control of the diffusional creep and inhomogeneous boundary sliding are also discussed. Additional experiments indicated an independence of deformation behavior on MgO doping and retained hot pressing impurities, at least for ultrafine grained material, and also an independence of test atmosphere.

  5. Removal of well-fixed, cementless, acetabular components in revision hip arthroplasty.

    PubMed

    Mitchell, P A; Masri, B A; Garbuz, D S; Greidanus, N V; Wilson, D; Duncan, C P

    2003-09-01

    Removal of well-fixed, cementless, acetabular components during revision arthroplasty remains a challenging problem. Further damage to host bone may limit options for reconstruction and compromise the long-term result of the revision operation. We report the results of 31 hips with well-fixed, cementless sockets which were removed using a new cup extraction system. In all hips the socket was removed without difficulty and with minimal further bone loss.

  6. Sintering titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-09-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  7. Fallon FORGE Well Temp data

    SciTech Connect

    Doug Blankenship

    2016-03-01

    x,y,z downhole temperature data for wells in and around the Fallon FORGE site. Data for the following wells are included: 82-36, 82-19, 84.31, 61-36, 88-24, FOH-3D, FDU-1, and FDU-2. Data are formatted in txt format and in columns for importing into Earthvision Software. Column headers and coordinate system information is stored in the file header.

  8. Forgings meet the challenges of the future

    SciTech Connect

    Mochnal, G.

    1996-04-01

    To meet and exceed the requirements of the customer of the future, the forging industry is entering a new era of increased productivity and technical advancements. The tools for this task have been developed as a result of a partnership among industry, government, and academia. As another consequence of this partnership, the Forging Industry Association and the Forging Industry Educational and Research Foundation are in the process of creating a Vision of the Future. This article will discuss advances in metal-forming simulation, billet heating systems, advanced die materials, and advanced forging presses.

  9. Cementless revision for infection following total hip arthroplasty.

    PubMed

    Mitchell, Philip A; Masri, Bassam A; Garbuz, Donald S; Greidanus, Nelson V; Duncan, Clive P

    2003-01-01

    Eradication of chronic infection complicating total hip arthroplasty requires removal of all infected, devitalized and foreign tissue, including the arthroplasty components. Reimplantation into a sterile bed is the goal of treatment in most patients and successful reimplantation yields better functional results than excision arthroplasty. Reimplantation may be performed at the same stage as débridement as part of a single-stage procedure, using cemented components with antibiotic-loaded cement. Alternatively, a two-stage procedure may be performed so that the débridement and reimplantation are separated by a period of antibiotic delivery, both locally and systemically. The results of these treatment regimens and the rationale for cementless reconstruction at the second stage of a two-stage treatment protocol are important considerations in the treatment of periprosthetic infection.

  10. Immediate Cementless Hemiarthroplasty for Severe Destructive Glenohumeral Tuberculous Arthritis

    PubMed Central

    Kosiyatrakul, Arkaphat

    2013-01-01

    The glenohumeral joint tuberculosis (TB) is rare as compared with other joints. Plaster immobilization, arthrodesis, and resection arthroplasty have been proposed as the additional treatments with anti-TB medications in severe destructive arthritis. To our knowledge, however, the surgical treatment with shoulder arthroplasty has never been reported. We present two cases of active TB with unsalvageable glenohumeral joint. The cementless hemishoulder arthroplasties were performed immediately following the radical debridement. Anti-TB medications were given for 12 months after the surgery. Postoperatively, the patients were satisfied with the rapid symptomatic relief and significant functional recovery. With the follow-up period of 5 years, the operative results were still satisfactory and the reactivation of the infection was not detected. PMID:24167752

  11. Titanium Aluminide Casting Technology Development

    NASA Astrophysics Data System (ADS)

    Bünck, Matthias; Stoyanov, Todor; Schievenbusch, Jan; Michels, Heiner; Gußfeld, Alexander

    2017-08-01

    Titanium aluminide alloys have been successfully introduced into civil aircraft engine technology in recent years, and a significant order volume increase is expected in the near future. Due to its beneficial buy-to-fly ratio, investment casting bears the highest potential for cost reduction of all competing production technologies for TiAl-LPTB. However, highest mechanical properties can be achieved by TiAl forging. In view of this, Access e.V. has developed technologies for the production of TiAl investment cast parts and TiAl die cast billets for forging purposes. While these parts meet the highest requirements, establishing series production and further optimizing resource and economic efficiency are present challenges. In order to meet these goals, Access has recently been certified according to aircraft standards, aiming at qualifying parts for production on technology readiness level 6. The present work gives an overview of the phases of development and certification.

  12. Automated Welding of Rotary Forge Hammers

    DTIC Science & Technology

    1994-05-01

    NUMBER OF PAGES Plasma Transferred Arc (PTA) Welding. Metal Inert Gas (MIG) Welding, 34 Metal Powder, Rotary Forge Hammers. Hardfacing 16. PRICE CODE 17...filled with required hardfacing materials ............................................... 26 8. Top and side schematic views, respectively, of forging...superalloy hardfacing deposit. In addition to the hardfacing layer, an underlying layer of buffer material must first be deposited to minimize cracking

  13. Reactor pressure vessel with forged nozzles

    DOEpatents

    Desai, Dilip R.

    1993-01-01

    Inlet nozzles for a gravity-driven cooling system (GDCS) are forged with a cylindrical reactor pressure vessel (RPV) section to which a support skirt for the RPV is attached. The forging provides enhanced RPV integrity around the nozzle and substantial reduction of in-service inspection costs by eliminating GDCS nozzle-to-RPV welds.

  14. Effects of Process Parameters on Deformation and Temperature Uniformity of Forged Ti-6Al-4V Turbine Blade

    NASA Astrophysics Data System (ADS)

    Luo, Shiyuan; Zhu, Dahu; Hua, Lin; Qian, Dongsheng; Yan, Sijie; Yu, Fengping

    2016-11-01

    This work is motivated by the frequent occurrence of macro- and microdefects within forged Ti-6Al-4V turbine blades due to the severely nonuniform strain and temperature distributions. To overcome the problem of nonuniformity during the blade forging operation, firstly, a 2D coupled thermo-mechanical finite element approach using the strain-compensated Arrhenius-type constitutive model is employed to simulate the real movements and processing conditions, and its reliability is verified experimentally. Secondly, two evaluation indexes, standard deviation of equivalent plastic strain and standard deviation of temperature, are proposed to evaluate the uniformity characteristics within the forged blade, and the effects of four process parameters including the forging velocity, friction factor, initial workpiece temperature and dwell time on the uniformity of strain and temperature distributions are carefully studied. Finally, the numerically optimized combination of process parameters is validated by the application in a practical process. The parametric study reveals that a reasonable combination of process parameters considering the flow resistance, flow localization and the effects of deformation and friction heating is crucial for the titanium alloy blade forging with uniformity. This work can provide a significant guidance for the design and optimization of blade forging processes.

  15. Forging of Advanced Disk Alloy LSHR

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Falsey, John

    2005-01-01

    The powder metallurgy disk alloy LSHR was designed with a relatively low gamma precipitate solvus temperature and high refractory element content to allow versatile heat treatment processing combined with high tensile, creep and fatigue properties. Grain size can be chiefly controlled through proper selection of solution heat treatment temperatures relative to the gamma precipitate solvus temperature. However, forging process conditions can also significantly influence solution heat treatment-grain size response. Therefore, it is necessary to understand the relationships between forging process conditions and the eventual grain size of solution heat treated material. A series of forging experiments were performed with subsequent subsolvus and supersolvus heat treatments, in search of suitable forging conditions for producing uniform fine grain and coarse grain microstructures. Subsolvus, supersolvus, and combined subsolvus plus supersolvus heat treatments were then applied. Forging and subsequent heat treatment conditions were identified allowing uniform fine and coarse grain microstructures.

  16. Development of powder-forged connecting rods

    SciTech Connect

    Imahashi, K.; Tsumuki, C.; Nagare, I.

    1984-01-01

    In comparison with conventional hot forging process, powder forging process has much advantage such as good dimensional accuracy, minimum scattering of weight, etc. In spite of much advantage, the powder forged parts have not been mass-produced except for relatively simple shape parts because of technical and economic problems such as low productivity. Solving these problems, powder forging process was applied to connecting rods which required fatigue strength and minimum scattering of weight, and which were complex in shape. As a result, for the first time in the world, mass-production of powder forged connecting rods was carried out, and its properties are as follows: (1) Sufficient fatigue strength; (2) Minimum scattering of weight; and (3) Good dimensional accuracy.

  17. Ceramic bearings with bilayer coating in cementless total hip arthroplasty. A safe solution. A retrospective study of one hundred and twenty six cases with more than ten years' follow-up.

    PubMed

    Ferreira, André; Aslanian, Thierry; Dalin, Thibaud; Picaud, Jean

    2017-05-01

    Using a ceramic-ceramic bearings, cementless total hip arthroplasty (THA) has provided good clinical results. To ensure longevity a good quality fixation of the implants is mandatory. Different surface treatments had been used, with inconsistent results. We hypothesized that a "bilayer coating" applied to both THA components using validated technology will provide a long-lasting and reliable bone fixation. We studied the survival and bone integration of a continuous, single-surgeon, retrospective series of 126 THA cases (116 patients) with an average follow-up of 12.2 years (minimum 10 years). The THA consisted of cementless implants with a bilayer coating of titanium and hydroxyapatite and used a ceramic-ceramic bearing. With surgical revision for any cause (except infection) as the end point, THA survival was 95.1 % at 13 years. Stem (98.8 %) and cup (98.6 %) survival was similar at 13 years. Bone integration was confirmed in 100 % of implants (Engh-Massin score of 17.42 and ARA score of 5.94). There were no instances of loosening. Revisions were performed because of instability (1.6 %), prosthetic impingement or material-related issues. A bilayer titanium and hydroxyapatite coating provides strong, fast, reliable osseo integration, without deterioration at the interface or release of damaging particles. The good clinical outcomes expected of ceramic bearings were achieved, as were equally reliable stem and cup fixation.

  18. Bone ingrowth and wear debris in well-fixed cementless porous-coated tibial components removed from patients.

    PubMed

    Sumner, D R; Kienapfel, H; Jacobs, J J; Urban, R M; Turner, T M; Galante, J O

    1995-04-01

    Bone ingrowth and the distribution of wear debris within the porous coating of 13 primary cementless porous-coated tibial components removed for reasons unrelated to fixation or infection were quantitatively described. The average length of implantation was 15.3 months (range, 3-30 months). The implants were all of the same design, made for Ti6A14V with a commercially pure titanium fiber-metal porous coating, which covered the undersurface of the tray and the four fixation pegs. In all but one component, supplemental screw fixation was used. The average extent of bone ingrowth within the tray was 27.1 +/- 16.1%, and the average volume fraction was 9.5 +/- 7.5%. There was significantly more bone ingrowth within the fixation pegs than within the tray and also more bone ingrowth in the anterior half of the tray than posteriorly. There was no correlation between the amount of bone ingrowth and the length of implantation, age, or sex of the patient; however, the depth and orientation of the resection plane were found to correlate with the topographic distribution of bone ingrowth. Particulate debris appeared to gain access to the interface via soft tissue pathways both at the periphery and through the holes for adjuvant screw fixation.

  19. Cementless versus cemented Oxford unicompartmental knee arthroplasty: early results of a non-designer user group.

    PubMed

    Kerens, B; Schotanus, M G M; Boonen, B; Boog, P; Emans, P J; Lacroix, H; Kort, N P

    2017-03-01

    Although fewer tibial radiolucent lines are observed in cementless Oxford unicompartmental knee arthroplasty (UKA) compared with cemented Oxford UKA, an independent comparative study on this topic is lacking. In this multicentre retrospective study, a cohort of 60 consecutive cases of cementless Oxford UKA is compared with a cohort of 60 consecutive cases of cemented Oxford UKA. Radiolucent lines, survival, perioperative data and clinical results were compared. No complete tibial radiolucent lines were observed in either group. Seventeen per cent of partial tibial radiolucent lines were observed in the cementless group versus 21 % in the cemented group (n.s.). The percentage of tibial radiolucent zones was 4 versus 9 %, respectively (p = 0.036). Survival rates were 90 % at 34 months for the cementless group and 84 % at 54 months for the cemented group (n.s.). Mean operation time was 10 min shorter in the cementless group (p < 0.001), and clinical results were not significantly different. Although no significant differences in radiolucent lines were found between both groups, they appear to be more common in the cemented group. This confirms previous results from reports by prosthesis designers. The presence of radiolucent lines after cemented Oxford UKA does not correlate with clinical outcome or survival. III.

  20. NON-MELT PROCESSING OF "LOW-COST", ARMSTRONG TITANIUM AND TITANIUM ALLOY POWDERS

    SciTech Connect

    Peter, William H; Blue, Craig A; Clive, Scorey; Ernst, Bill; McKernan, John; Kiggans, Jim; Rivard, John D; Yu, Dr. Charlie

    2007-01-01

    In the last decade, a considerable effort has been made to develop new methods for producing low cost titanium and titanium powders. The Armstrong process is a new method of producing titanium powder via reducing TiCl4 vapor in molten sodium. The process is scalable, and can be used to produce pre-alloyed powders. Non-melt processing and powder metallurgy approaches are economically viable with the commercially pure powders. In this investigation, several non-melt processing technologies, including vacuum hot pressing, extrusion, roll compaction, and forging techniques, will be evaluated using the Armstrong titanium powders. The metallurgical, chemical, and mechanical properties of the processed titanium samples will be discussed.

  1. [Custom cementless stem for osteoarthritis following developmental hip dysplasia].

    PubMed

    Flecher, X; Argenson, J N; Parratte, S; Ryembault, E; Aubaniac, J M

    2006-06-01

    Arthroplasty in developmental dysplasia of the hip joint raises technical problems related to the anatomy and age of the young patient. The purpose of this work was to report results obtained with a custom-designed cementless stem. This study included 257 hips reviewed at mean 82 months (range 43-162 months). Mean patient age was 55 years (17-78), mean weight 67 kg (42-118), and mean height 164 cm (147-190). A standard imaging protocol was performed for all patients: AP pelvis in reclining position, AP and lateral views of healthy and pathological hip, AP view of entire lower limb in standing position, computed tomography of lower limb. La position of the greater trochanter and the lengthening necessary was determined from the preoperative films. Stem integration and migration as well as osteolysis were studied postoperatively. Femoral anteversion and the anteroposterior diameter of the paleoacetabulum were measured on the superposed computed tomographic images. Surgery was performed via a Watson-Jones approach to insert a noncemented cup hooked in the obturator foramen and implanted in the paleoacetabulum. The femur endomedullary cavity was prepared with a ream having the form of the definitive stem and the prosthetic neck was custom fit to match the desired lever arm and anteversion. The series included 174 cases of dysplasia and 83 dislocations, 39% stage 1, 30% stage 2, 14% stage 3 and 17% stage 4. Mean lengthening was 39 mm. The mean helitorsion was 28 +/- 16 degrees and the mean anteroposterior diameter of the acetabulum was 51 mm. On average, the alpha correction in the prosthetic neck was -13.4 degrees (-71 degrees to +37 degrees). The Postel-Merle-d'Aubigné score improved from 10.4 points preoperatively to 16.7 points at last follow-up. Postoperative x-rays showed signs of osteointegration in 88% of cases, osteolysis in 5% and one case of stem impaction. Ten hips (3.9%) required revision for replacement (7 for an aseptic problem and 3 for sepsis

  2. Design of forging process variables under uncertainties

    NASA Astrophysics Data System (ADS)

    Repalle, Jalaja; Grandhi, Ramana V.

    2005-02-01

    Forging is a complex nonlinear process that is vulnerable to various manufacturing anomalies, such as variations in billet geometry, billet/die temperatures, material properties, and workpiece and forging equipment positional errors. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion, and reduced productivity. Identifying, quantifying, and controlling the uncertainties will reduce variability risk in a manufacturing environment, which will minimize the overall production cost. In this article, various uncertainties that affect the forging process are identified, and their cumulative effect on the forging tool life is evaluated. Because the forging process simulation is time-consuming, a response surface model is used to reduce computation time by establishing a relationship between the process performance and the critical process variables. A robust design methodology is developed by incorporating reliability-based optimization techniques to obtain sound forging components. A case study of an automotive-component forging-process design is presented to demonstrate the applicability of the method.

  3. Study of bone remodeling of two models of femoral cementless stems by means of DEXA and finite elements

    PubMed Central

    2010-01-01

    Background A hip replacement with a cemented or cementless femoral stem produces an effect on the bone called adaptive remodelling, attributable to mechanical and biological factors. All of the cementless prostheses designs try to achieve an optimal load transfer in order to avoid stress-shielding, which produces an osteopenia. Long-term densitometric studies taken after implanting ABG-I and ABG-II stems confirm that the changes made to the design and alloy of the ABG-II stem help produce less proximal atrophy of the femur. The simulation with FE allowed us to study the biomechanical behaviour of two stems. The aim of this study was, if possible, to correlate the biological and mechanical findings. Methods Both models with prostheses ABG-I and II have been simulated in five different moments of time which coincide with the DEXA measurements: postoperative, 6 months, 1, 3 and 5 years, in addition to the healthy femur as the initial reference. For the complete comparative analysis of both stems, all of the possible combinations of bone mass (group I and group II of pacients in two controlled studies for ABG-I and II stems, respectively), prosthetic geometry (ABG-I and ABG-II) and stem material (Wrought Titanium or TMZF) were simulated. Results and Discussion In both groups of bone mass an increase of stress in the area of the cancellous bone is produced, which coincides with the end of the HA coating, as a consequence of the bottleneck effect which is produced in the transmission of loads, and corresponds to Gruen zones 2 and 6, where no osteopenia can be seen in contrast to zones 1 and 7. Conclusions In this study it is shown that the ABG-II stem is more effective than the ABG-I given that it generates higher tensional values on the bone, due to which proximal bone atrophy diminishes. This biomechanical behaviour with an improved transmission of loads confirmed by means of FE simulation corresponds to the biological findings obtained with Dual-Energy X

  4. Near Net Shape Manufacturing of New Titanium Powders for Industry

    SciTech Connect

    2009-05-01

    This factsheet describes a research project whose goal is to develop a manufacturing technology to process new titanium powders into fully consolidated near net shape components for industrial applications. This will be achieved using various technologies, including press and sinter, pneumatic isostatic forging (PIF), hot isostatic pressing (HIP), and adiabatic compaction.

  5. Results after Cementless Medial Oxford Unicompartmental Knee Replacement - Incidence of Radiolucent Lines

    PubMed Central

    Panzram, Benjamin; Bertlich, Ines; Reiner, Tobias; Walker, Tilman; Hagmann, Sébastien; Weber, Marc-André; Gotterbarm, Tobias

    2017-01-01

    Purpose Tibial radiolucent lines (RL) are commonly seen in cemented unicompartmental knee replacement (UKR). In the postoperative course, they can be misinterpreted as signs of loosening, thus leading to unnecessary revision. Since 2004, a cementless OUKR is available. First studies and registry data have shown equally good clinical results of cementless OUKR compared to the cemented version and a significantly reduced incidence of RL in cementless implants. Methods This single-centre retrospective cohort study includes the first 30 UKR (27 patients) implanted between 2007 and 2009 with a mean follow-up of 5 years. Clinical outcome was evaluated using the OKS, AKS, range of movement (ROM) and level of pain (VAS). Standard radiologic evaluation was performed at three months, one and five years after surgery. The results five years after implantation were compared to a group of 27 cemented Oxford UKR (OUKR) in a matched-pair-analysis. Results Tibial RL were seen in 10 implants three months after operation, which significantly decreased to five after one year and to three after five years (p = 0.02). RL did not have a significant influence on revision (p = 1.0) or clinical outcome after five years. RL were always partial, never progressive and strictly limited to the tibia. There was no significant difference in the incidence of tibial RL five years after implantation between cemented and cementless implants (cemented: 4, cementless: 3, p = 1.0). Conclusions After cementless implantation RL were limited to the tibia, partial and never progressive. During short term follow-up the incidence of RL decreased significantly. RL seem to have no influence on clinical outcome and revision. PMID:28103308

  6. Processing and Characterization of Sub-delta Solvus Forged Hemispherical Forgings of Inconel 718

    NASA Astrophysics Data System (ADS)

    Chenna Krishna, S.; Rao, G. Sudarasana; Singh, Satish Kumar; Narayana Murty, S. V. S.; Venkatanarayana, G.; Jha, Abhay K.; Pant, Bhanu; Venkitakrishnan, P. V.

    2016-12-01

    In this paper, microstructure and mechanical properties of 200 mm diameter Inconel 718 hemispherical domes processed at 1025 °C through closed die hammer forging have been investigated. Microstructure and mechanical properties of the forgings in radial and tangential directions were characterized using optical microscopy, scanning electron microscopy, impact testing, and tensile testing. Grain size of the forgings at three different locations was fine with an average grain size of ASTM No. 8-9. The typical tensile properties of the forgings in solution-treated and aged condition were ultimate tensile strength-1450 MPa, yield strength-1240 MPa, and ductility-25%. The fine grain size achieved in forgings has been attributed to delta phase present at grain boundaries which pinned the grains during forging and prevented grain coarsening.

  7. Microstructural Evaluation of Forging Parameters for Superalloy Disks

    NASA Technical Reports Server (NTRS)

    Falsey, John R.

    2004-01-01

    Forgings of nickel base superalloy were formed under several different strain rates and forging temperatures. Samples were taken from each forging condition to find the ASTM grain size, and the as large as grain (ALA). The specimens were mounted in bakelite, polished, etched and then optical microscopy was used to determine grain size. The specimens ASTM grain sizes from each forging condition were plotted against strain rate, forging temperature, and presoak time. Grain sizes increased with increasing forging temperature. Grain sizes also increased with decreasing strain rates and increasing forging presoak time. The ALA had been determined from each forging condition using the ASTM standard method. Each ALA was compared with the ASTM grain size of each forging condition to determine if the grain sizes were uniform or not. The forging condition of a strain rate of .03/sec and supersolvus heat treatment produced non uniform grains indicated by critical grain growth. Other anomalies are noted as well.

  8. Case Report: Cementless Stem Stabilization after Intraoperative Fracture: A Radiostereometric Analysis

    PubMed Central

    Mercer, Graham; Nilsson, Kjell G.; Callary, Stuart A.

    2009-01-01

    We present the case of a patient with intraoperative femoral fracture during THA, which was repaired using cerclage fixation and insertion of an hydroxyapatite-coated cementless stem. The patient was evaluated postoperatively using radiostereometry during a 2-year course, and despite a large amount of subsidence and rotation, stabilization occurred and was maintained by 6 months. By evaluating the pattern of stem migration after intraoperative fracture, this case shows, even in the presence of instability, a successful clinical outcome can be achieved using an hydroxyapatite-coated cementless stem. PMID:19760467

  9. Case report: Cementless stem stabilization after intraoperative fracture: a radiostereometric analysis.

    PubMed

    Campbell, David; Mercer, Graham; Nilsson, Kjell G; Callary, Stuart A

    2010-03-01

    We present the case of a patient with intraoperative femoral fracture during THA, which was repaired using cerclage fixation and insertion of an hydroxyapatite-coated cementless stem. The patient was evaluated postoperatively using radiostereometry during a 2-year course, and despite a large amount of subsidence and rotation, stabilization occurred and was maintained by 6 months. By evaluating the pattern of stem migration after intraoperative fracture, this case shows, even in the presence of instability, a successful clinical outcome can be achieved using an hydroxyapatite-coated cementless stem.

  10. The investigation of ultrasonic mechanical forging influence on the structure and mechanical properties of VT23 welded joints by methods of laser and electron beam welding

    NASA Astrophysics Data System (ADS)

    Smirnova, A. S.; Pochivalov, Yu. I.; Panin, V. E.; Orishich, A. M.; Malikov, A. G.; Fomin, V. M.

    2016-11-01

    The structure and mechanical properties of welded joints of VT23 titanium alloy received by methods of laser and electron beam welding with subsequent thermomechanical treatment (TMP1 and TMP2) including ultrasonic mechanical forging are investigated. X-ray structure analysis, scanning electron and transmission electron microscopy have revealed the features of phase structure, microstructure and fractography of welded joints after electron beam and laser welding with subsequent ultrasonic mechanical forging. Application of ultrasonic mechanical forging of welded joints produced by electron beam and laser welding has allowed increasing fatigue life of samples of welded joints after laser welding from 6369 to 19 569 cycles and from 54 616 cycles to 77 126 cycles for electron beam welding. Thus, the application of ultrasonic mechanical forging can significantly raise fatigue and mechanical characteristics of welded connections.

  11. Dynamic material modeling in hot forging

    SciTech Connect

    El-Gizawy, A.S. )

    1992-03-01

    A dynamic material model that characterized flow behavior in the workpiece under forging conditions was required to optimize the process and produce defect-free product at minimum cost. Constitutive equations describe the relationship between stress, strain rate, and temperature under forging conditions. Using aluminum alloy 7050, numerous deformation experiments were conducted to fully characterize constitutive equation variables. A thorough description of the experimental arrangement was provided. Flow data and efficiency data were assembled into a three-dimensional plot of temperature vs. strain rate vs. deformation efficiency to produce an efficiency map. The efficiency map provided the information required for optimization of forging process design. The results of dynamic modeling of the material were used in simulating the isothermal forging of a particular part. Recommendations concerning optimum preform design and processing conditions were reported.

  12. Mechanical Testing Development for Reservoir Forgings

    SciTech Connect

    Wenski, E.G.

    2000-05-22

    The goal of this project was to determine the machining techniques and testing capabilities required for mechanical property evaluation of commercially procured reservoir forgings. Due to the small size of these specific forgings, specialized methods are required to adequately machine and test these sub-miniature samples in accordance with the requirements of ASTM-E8 and ASTM-E9. At the time of project initiation, no capability existed at Federal Manufacturing & Technologies (FM&T) to verify the physical properties of these reservoirs as required on the drawing specifications. The project determined the sample definitions, machining processes, and testing procedures to verify the physical properties of the reservoir forgings; specifically, tensile strength, yield strength, reduction of area, and elongation. In addition, a compression test method was also developed to minimize sample preparation time and provide a more easily machined test sample while maintaining the physical validation of the forging.

  13. Forging of FeAl intermetallic compounds

    SciTech Connect

    Flores, O.; Juarez, J.; Campillo, B.; Martinez, L.; Schneibel, J.H.

    1994-09-01

    Much activity has been concentrated on the development of intermetallic compounds with the aim of improving tensile ductility, fracture toughness and high notch sensitivity in order to develop an attractive combination of properties for high and low temperature applications. This paper reports experience in processing and forging of FeAl intermetallic of B2 type. During the experiments two different temperatures were employed, and the specimens were forged after annealing in air, 10{sup {minus}2} torr vacuum and argon. From the results it was learned that annealing FeAl in argon atmosphere prior to forging resulted in better deformation behavior than for the other two environments. For the higher forging temperature used in the experiments (700C), the as-cast microstructure becomes partially recrystallized.

  14. Developments in Titanium Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Froes, F. H.; Eylon, D.; Eichelman, G. E.; Burte, H. M.

    1980-02-01

    The high buy-to-fly ratio associated with many titanium components, combined with forging and machining difficulties, and recent availability problems, has led to a strong drive for near-net titanium shape fabrication. A very promising method of attaining this goal is powder metallurgy. Two major approaches are considered in this article: the "elemental" and "pre-alloyed" powder methods. Shape-making capability and mechanical properties of both technologies are presented. Consideration is given to the cost-effectiveness of the processes and mechanical performance compared to conventional fabrication methods. Design philosophies, modified to include the presence of foreign particles in the compacted article, are discussed. Emerging advances in the technology are presented and future developments forecast.

  15. Metallurgical modelling of superalloy disc isothermal forgings

    NASA Astrophysics Data System (ADS)

    Evans, R. W.

    1988-08-01

    The metallurgical structure of superalloy aeroengine disc forgings is a complex function of the forging operation parameters and the post forging heat treatment. It is often desirable to obtain certain specific structures in parts of the disc which are, for instance, resistant to crack propagation and this has traditionally been accomplished by means of a series of production trials. This expensive and time consuming procedure can be considerably shortened if the development of microstructure during the forging can be accurately modelled by a suitable computer code. Described here is such a model and its use in the design of isothermal forged components. The model discribed is a fully thermally coupled viscoplasticity finite element algorithm. It treats nodal velocities as the basic unknowns and both the mesh geometry and the various metallurgical structural terms are updated by a single step Euler scheme. Facilities are available for ensuring that surface nodes follow die shapes after impingement, that flow is incompressible and that suitable surface friction forces are applied. Throughout the whole forging process (which may involve the re-meshing of severely distorted elements), the metallurgical history of elements is retained so that the effects of subsequent heat treatments can be assessed.

  16. New Nomenclatures for Heat Treatments of Additively Manufactured Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Baker, Andrew H.; Collins, Peter C.; Williams, James C.

    2017-07-01

    The heat-treatment designations and microstructure nomenclatures for many structural metallic alloys were established for traditional metals processing, such as casting, hot rolling or forging. These terms do not necessarily apply for additively manufactured (i.e., three-dimensionally printed or "3D printed") metallic structures. The heat-treatment terminology for titanium alloys generally implies the heat-treatment temperatures and their sequence relative to a thermomechanical processing step (e.g., forging, rolling). These designations include: β-processing, α + β-processing, β-annealing, duplex annealing and mill annealing. Owing to the absence of a thermomechanical processing step, these traditional designations can pose a problem when titanium alloys are first produced via additive manufacturing, and then heat-treated. This communication proposes new nomenclatures for heat treatments of additively manufactured titanium alloys, and uses the distinct microstructural features to provide a correlation between traditional nomenclature and the proposed nomenclature.

  17. Compressed Air System Optimization Project Improves Production at a Metal Forging Plant (Modern Forge, TN, Plant)

    SciTech Connect

    2000-12-01

    In 1995, Modern Forge of Tennessee implemented a compressed air system improvement project at its Piney Flats, Tennessee, forging plant. Due to the project’s implementation, the plant was able to operate with fewer compressors and improve its product quality, thus allowing it to increase productivity. The project also resulted in considerable energy and maintenance savings.

  18. Microstructural and mechanical evolutions during the forging step of the COBAPRESS, a casting/forging process

    NASA Astrophysics Data System (ADS)

    Perrier, Frédéric; Desrayaud, Christophe; Bouvier, Véronique

    Aluminum casting/forging processes are used to produce parts for the automotive industry. In this study, we examined the influence of the forging step on the microstructure and the mechanical properties of an A356 aluminum alloy modified with strontium. Firstly, a design of samples which allows us to test mechanically the alloy before and after forging was created. A finite element analysis with the ABAQUS software predicts a maximum of strain in the core of the specimens. Observations with the EBSD technique confirm a more intense sub-structuration of the dendrite cells in this zone. Yield strength, ultimate tensile strength, elongation and fatigue lives were then improved for the casting/forging samples compared to the only cast specimens. The closure of the porosities and the improvement of the surface quality during the forging step enhance also the fatigue resistance of the samples.

  19. An integrated CAD/CAM/robotic milling method for custom cementless femoral prostheses.

    PubMed

    Wen-ming, Xi; Ai-min, Wang; Qi, Wu; Chang-hua, Liu; Jian-fei, Zhu; Fang-fang, Xia

    2015-09-01

    Aseptic loosening is the primary cause of cementless femoral prosthesis failure and is related to the primary stability of the cementless femoral prosthesis in the femoral cavity. The primary stability affects both the osseointegration and the long-term stability of cementless femoral prostheses. A custom cementless femoral prosthesis can improve the fit and fill of the prosthesis in the femoral cavity and decrease the micromotion of the proximal prosthesis such that the primary stability of the custom prosthesis can be improved, and osseointegration of the proximal prosthesis is achieved. These results will help to achieve long-term stability in total hip arthroplasty (THA). In this paper, we introduce an integrated CAD/CAM/robotic method of milling custom cementless femoral prostheses. The 3D reconstruction model uses femoral CT images and 3D design software to design a CAD model of the custom prosthesis. After the transformation matrices between two units of the robotic system are calibrated, consistency between the CAM software and the robotic system can be achieved, and errors in the robotic milling can be limited. According to the CAD model of the custom prosthesis, the positions of the robotic tool points are produced by the CAM software of the CNC machine. The normal vector of the three adjacent robotic tool point positions determines the pose of the robotic tool point. In conclusion, the fit rate of custom pig femur stems in the femoral cavities was 90.84%. After custom femoral prostheses were inserted into the femoral cavities, the maximum gaps between the prostheses and the cavities measured less than 1 mm at the diaphysis and 1.3 mm at the metaphysis. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Cementless acetabular fixation in patients 50 years and younger at 10 to 18 years of follow-up.

    PubMed

    Teusink, Matthew J; Callaghan, John J; Warth, Lucian C; Goetz, Devon D; Pedersen, Douglas R; Johnston, Richard C

    2012-08-01

    The purpose of the study was to evaluate the 10- to 18-year follow-up of cementless acetabular fixation in patients 50 years and younger. We retrospectively reviewed a consecutive group of 118 patients (144 hips) in whom primary total hip arthroplasty had been performed by 2 surgeons using a cementless acetabular component. Two (1.4%) cementless acetabular components were revised because of aseptic loosening. Twenty-four hips (16.7%) were revised for any mechanical failure of the acetabular component mostly related to acetabular liner wear and osteolysis. The average linear wear rate was 0.19 mm per year, which was higher than our previous reports with cemented acetabular fixation. The fiber mesh ingrowth surface of the cementless acetabular component in this study was superior to cemented acetabular components in terms of fixation. However, the high rates of wear and osteolysis have led to poor overall acetabular component construct survivorship.

  1. No difference between cemented and cementless total knee arthroplasty in young patients: a review of the evidence.

    PubMed

    Franceschetti, Edoardo; Torre, Guglielmo; Palumbo, Alessio; Papalia, Rocco; Karlsson, Jón; Ayeni, Olufemi R; Samuelsson, Kristian; Franceschi, Francesco

    2017-06-01

    The present piece of work provides improved knowledge about the evidence related to TKA in patients 60 years of age or younger, with special focus on fixation methods. Main concern of the review is to analyse the difference of survival rate and complications of cemented and cementless implants. An electronic search was carried out between October and December 2015, through CINAHL, PubMed and the Cochrane Central Registry of Controlled Trials web databases. Articles in English, Italian, French and Spanish were considered for inclusion. Only peer-reviewed studies with adult patients aged 60 years or less, with diagnosis of osteoarthritis in more than 90% of the subjects, were considered for inclusion. All studies had to report outcomes after TKA with either cemented or cementless fixation technique. No significant differences in terms of clinical, functional and radiological outcomes were found between cemented and cementless implants. Good clinical and functional results were obtained in terms of the Knee Society score and Western Ontario and McMaster Universities Osteoarthritis Index for both techniques. Radiographic results showed that radiolucent lines of <2 mm in width were detected at radiographs, without difference between cemented or cementless implants. Well-conducted trials on cemented versus cementless TKA were carried out in few papers. A survival rate of over 90% was reported in the majority of the studies at a mean follow-up of 8.6 years (range 5-18 years). Similar results were observed in terms of functional outcome and survival rates for both cemented and cementless TKAs. High survival rates were reported for both operative techniques and cemented TKA did not offer additional benefit. Assuming that cementless prosthesis allows a stable fixation and reduces the time of operation, the authors recommend the cementless fixation as a primary choice in the investigated patient population. However, evidence is low, and further research is needed. IV.

  2. Cementless total hip arthroplasty in patients with ankylosing spondylitis

    PubMed Central

    Xu, Jun; Zeng, Min; Xie, Jie; Wen, Ting; Hu, Yihe

    2017-01-01

    Abstract Controversies on the surgical protocols and efficacies of total hip arthroplasty (THA) in ankylosing spondylitis (AS) still exist. The aim of this study was to retrospectively analyze the perioperative managements and their outcomes related to performing THA on patients with AS. Data of 54 AS patients who underwent 81 THAs between 2008 and 2014 were retrospectively analyzed. Clinical and imaging data were collected preoperatively, postoperatively, and during the follow-up period for surgical efficacy. Using posterolateral approach, cementless prostheses were selected in all cases. Mean follow-up period was 3.6 years (range, 2–8 years). Inclinations and anteversions of acetabular cups were 36.3°±4.5° (range, 30°–50°) and 12.3°±4.9° (range, 0°–25°) respectively. Mean visual analog scale (VAS) score decreased from 6.7 ± 2.1 (range, 4–10) preoperatively to 1.5 ± 1.0 (range, 0–4) at final follow-up, and mean Harris hip score (HHS) improved from 31.2 ± 11.6 (range, 15–45) to 86.1 ± 4.3 (range, 80–95) (P < 0.05). Postoperative range of motion (ROM) in flexion was improved from 6.7°±13.5° (range, 0°–50°) preoperatively to 82.5°±6.4° (range, 70°–100°) at final follow-up, and ROM in extension was improved from 1.8°±5.7°(range, 0°–15°) to 15.4°±2.6° (range, 10°–20°) (P < 0.05). Heterotopic ossification (HO) was documented in 9 hips (11.1%). Signs of stable fibrous ingrowth and bone ingrowth were detected in 52 and 29 hips, respectively. Sciatic never injury was occurred in 3 cases, and treated conservatively. There were no signs of periprosthetic fractures, dislocation, or prosthesis loosening. Surgical efficacies of THA for AS patients with severe hip involvement are satisfactory. PMID:28121928

  3. Initial experience with a newly developed cementless hip endoprosthesis.

    PubMed

    Hach, V; Delfs, G

    2009-01-01

    The HELICA-Endoprosthesis is a newly developed cementless hip prosthesis for dogs. It was implanted in 39 dogs that had severe hip osteoarthritis and a history of hip pain, as well as in one dog that had chronic hip luxation. One dog had a bilateral arthroplasty. The body weight of the patients ranged between 22 and 54 kg and their ages between nine months and 10 years. Both the femoral stem and acetabular component of the prosthesis were screwed into position following bony preparation. Additional fixation was not necessary as the components remain fixed in position until osteointegration is complete. There are currently five sizes of prosthesis available, and the various components such as the stem, cup and head are readily interchangeable. Although it appeared that good osseous anchorage of the prostheses in the bone on the surgery table had been obtained, three patients experienced both stem and cup loosening (one week, three weeks and six months after surgery). In one animal, stem loosening was observed six weeks after surgery, and another dog experienced a cup loosening two weeks postoperatively. Most of the complications were due to technical errors that occurred during the learning phase. Surgical revisions were successful in three out of five animals. In two animals we had to perform a femoral head and neck excision. Two other animals experienced radiographic bone resorption underneath the segmented collar of the femoral prosthesis but did not show any significant clinical signs of lameness. Another dog that showed signs of ischial neuropraxy after surgery, recovered completely within six weeks after surgery. All of the dogs were capable of weight bearing on the operated leg one day after surgery. The main advantage of the HELICA-Endoprosthesis is the relatively easy surgical technique and short surgery time. The initial clinical results in these 40 cases have been very encouraging. The aim of this study was to assess the early clinical results in these 39

  4. 1. MIDDLE FORGE DISPLAY, ACROSS FROM BUILDING NO. 114 on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. MIDDLE FORGE DISPLAY, ACROSS FROM BUILDING NO. 114 on FARLEY AVE. MARKER ON DISPLAY ITSELF READS: FORGE AND TOOLS, USED AT MIDDLE FORGE LOCATED AT PICATINNY LAKE OUTLETS 1749 TO 1880. NEARBY MARKER READS: THE MIDDLE FORGE. THE MT. HOPE IRONWORKS INCLUDING A TRACT CALLED THE MIDDLE FORGE, SUPPLIED ORDNANCE MATERIAL TO THE CONTINENTAL ARMY IN THE AMERICAN REVOLUTION. GENERAL WASHINGTON INSPECTED THE FACILITY. THE WAR DEPARTMENT PURCHASED THE MIDDLE FORGE PORPERTY FOR AN ARMY POWDER DEPOT IN 1879-80. THE FORGE AND TOOLS WERE RECOVERED AT THE ACTUAL SITE NEAR PICATINNY PEAK. THROUGH THE YEARS, THE MIDDLE FORGE DISPLAY CAME TO BE THE UNOFFICIAL SYMBOL OF PICATINNY ARSENAL. -- HISTORICAL OFFICE NO DATE - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

  5. Stainless-steel elbows formed by spin forging

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Large seamless austenitic stainless steel elbows are fabricated by spin forging /rotary shear forming/. A specially designed spin forging tool for mounting on a hydrospin machine has been built for this purpose.

  6. 4. FORGE, ANVIL, PEDESTAL GRINDER, AND BELT DRIVES. NOTE WATERWHEEL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. FORGE, ANVIL, PEDESTAL GRINDER, AND BELT DRIVES. NOTE WATERWHEEL NEEDLE VALVE CASTING HANGING ON THE WALL ABOVE THE FORGE. VIEW TO NORTH. - Santa Ana River Hydroelectric System, SAR-1 Machine Shop, Redlands, San Bernardino County, CA

  7. Impact of Temperature on Cooling Structural Variation of Forging Dies

    NASA Astrophysics Data System (ADS)

    Piesova, Marianna; Czan, Andrej

    2014-12-01

    The article is focused on the issue of die forging in the automotive industry. The cooling effect of temperature on the structure of forged die are under review. In the article, there is elaborated the analysis of theoretical knowledge in the field, focusing on die forging and experimentally proven effect of the cooling rate on the final structure of forged dies made of hypoeutectic carbon steel C56E2.

  8. Titanium 2013

    USGS Publications Warehouse

    2014-01-01

    Titanium is the ninth most abundant element in the earth's crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that the metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  9. Near-Net Forging Technology Demonstration Program

    NASA Technical Reports Server (NTRS)

    Hall, I. Keith

    1996-01-01

    Significant advantages in specific mechanical properties, when compared to conventional aluminum (Al) alloys, make aluminum-lithium (Al-Li) alloys attractive candidate materials for use in cryogenic propellant tanks and dry bay structures. However, the cost of Al-Li alloys is typically five times that of 2219 aluminum. If conventional fabrication processes are employed to fabricate launch vehicle structure, the material costs will restrict their utilization. In order to fully exploit the potential cost and performance benefits of Al-Li alloys, it is necessary that near-net manufacturing methods be developed to off-set or reduce raw material costs. Near-net forging is an advanced manufacturing method that uses elevated temperature metal movement (forging) to fabricate a single piece, near-net shape, structure. This process is termed 'near-net' because only a minimal amount of post-forge machining is required. The near-net forging process was developed to reduce the material scrap rate (buy-to-fly ratio) and fabrication costs associated with conventional manufacturing methods. The goal for the near-net forging process, when mature, is to achieve an overall cost reduction of approximately 50 percent compared with conventional manufacturing options for producing structures fabricated from Al-Li alloys. This NASA Marshall Space Flight Center (MSFC) sponsored program has been a part of a unique government / industry partnership, coordinated to develop and demonstrate near-net forging technology. The objective of this program was to demonstrate scale-up of the near-net forging process. This objective was successfully achieved by fabricating four integrally stiffened, 170- inch diameter by 20-inch tall, Al-Li alloy 2195, Y-ring adapters. Initially, two 2195 Al-Li ingots were converted and back extruded to produce four cylindrical blockers. Conventional ring rolling of the blockers was performed to produce ring preforms, which were then contour ring rolled to produce

  10. Electrical heating of forging billets. Final report

    SciTech Connect

    Keith, R.E.; Weldon, W.F.

    1982-11-01

    Recent and ongoing research concerned with homopolar generators operated in a pulse mode and making use of kinetic energy storage principles has led to the application of these techniques to forging billet heating. Most forging billet heating is done using fuel-fired furnaces, but use of electric induction heating is increasing. The homopolar pulse billet heating (HPBH) process is described and its capabilities are evaluated relative to furnace and induction heating. Conclusions are that applications for this new process will most likely be in the heating of stainless steel and superalloy billets, particularly if present research efforts are successful in reducing costs.

  11. The thermal modeling of large axisymmetric forgings

    NASA Astrophysics Data System (ADS)

    van Tyne, C. J.; Focht, R. B.; Nelson, T. D.; Reese, W.

    1994-09-01

    Three thermal models for simulating the heating cycles used for large forgings were developed. They were designed for accuracy, user friendliness, and rapid calculation on a personal computer. The results that are obtained from these models are the temperature profiles that occur within the ingot, forging or roll at various depths from the surface. The values for these temperature versus time curves can be used to examine several features about the heat treatment process. The example presented in this paper showed the effect of heating rate and hold at 704 °C on the surface-to-center temperature difference that occurs in a medium carbon steel ingot.

  12. Co-Operative Training in the Sheffield Forging Industry

    ERIC Educational Resources Information Center

    Duncan, R.

    2008-01-01

    Purpose: The purpose of this paper is to give details of an operation carried out in Sheffield to increase the recruitment of young men into the steel forging industry. Design/methodology/approach: The Sheffield Forges Co-operative Training Scheme was designed to encourage boys to enter the forging industry and to provide them with training and…

  13. 76 FR 50755 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... COMMISSION Heavy Forged Hand Tools From China Determinations On the basis of the record \\1\\ developed in the... antidumping duty orders on heavy forged hand tools from China would be likely to lead to continuation or... Forged Hand Tools From China: Investigation Nos. 731-TA-457-A-D (Third Review). Issued: August 10, 2011...

  14. Co-Operative Training in the Sheffield Forging Industry

    ERIC Educational Resources Information Center

    Duncan, R.

    2008-01-01

    Purpose: The purpose of this paper is to give details of an operation carried out in Sheffield to increase the recruitment of young men into the steel forging industry. Design/methodology/approach: The Sheffield Forges Co-operative Training Scheme was designed to encourage boys to enter the forging industry and to provide them with training and…

  15. Comparison of Clinical Efficacy Between Modular Cementless Stem Prostheses and Coated Cementless Long-Stem Prostheses on Bone Defect in Hip Revision Arthroplasty

    PubMed Central

    Li, Huibin; Chen, Fang; Wang, Zhe; Chen, Qian

    2016-01-01

    Background The aim of this study was to investigate and compare the clinical efficacy of modular cementless stem and coated cementless long-stem prostheses in hip revision arthroplasty. Material/Methods Sixty-five patients with complete hip revision surgery data during January 2005 to March 2015 were selected from the People’s Hospital of Linyi City and randomly divided into a S-ROM group (implanted with cementless modular stem prostheses, n=32) and a SLR-PLUS group (implanted with cementless coated long-stem prostheses, n=33). Harris score was used to evaluate the hip function of the patients in order to measure the clinical efficacy of the prostheses in total hip arthroplasty. Anteroposterior pelvic radiographs and lateral pelvic radiographs were taken and each patient’s hip arthroplasty condition was recorded. Kaplan-Meier method was applied to compare the cumulative 5-year non-revision rate between the 2 prostheses and log-rank method was used to inspect the statistical data. Results The Harris scores of both the S-ROM group and the SLR-PLUS group were significantly higher at 12 months after the operation than those before the operation (both P<0.05). The Harris scores of the patients with type I/II bone defects in the S-ROM group were not significantly different from those of the same types in the SLR-PLUS group at all time points (all P>0.05), while the Harris scores of the patients with type IIIA/IIIB in the S-ROM group were both significantly higher than those of the same types in the SLR-PLUS group at 3 months, 6 months, and 12 months after the operation (all P<0.05). No significant difference was found in the cumulative 5-year non-revision rate between the type I/II patients in the S-ROM group (92.31%) and the patients of the same types in the SLR-PLUS group (85.71%) (P>0.05). However, the cumulative 5-year non-revision rate of the type IIIA/IIIB patients in the S-ROM group (89.47%) was significantly different from the patients of the same types in

  16. Forging Collaborative Partnerships: The Waterloo Neighborhood Project.

    ERIC Educational Resources Information Center

    Gruenewald, Anne

    The Forging Collaborative Partnerships Project in Waterloo, Iowa is a collaborative venture to assist voluntary agencies in developing tools and strategies to strengthen collaborative relationships among public and nonprofit child welfare agencies and other key stakeholders as they adopt a family-focused philosophy. This monograph details how the…

  17. Forging Inclusive Solutions: Experiential Earth Charter Education

    ERIC Educational Resources Information Center

    Hill, Linda D.

    2010-01-01

    Forging Inclusive Solutions describes the aims, methodology and outcomes of Inclusive Leadership Adventures, an experiential education curriculum for exploring the Earth Charter. Experiential education builds meaningful relationships, skills, awareness and an inclusive community based on the Earth Charter principles. When we meet people where they…

  18. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, R.; Glatzmaier, G.C.

    1995-05-23

    A process is disclosed for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  19. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, Rasit; Glatzmaier, Gregory C.

    1995-01-01

    A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  20. Cavitary acetabular defects treated with morselized cancellous bone graft and cementless cups

    PubMed Central

    Pereira, G. C.T.; Kubiak, E. N.; Levine, B.; Chen, F. S.

    2006-01-01

    The use of impacted morselized cancellous bone grafts in conjunction with cementless hemispherical acetabular cups for treatment of AAOS type II acetabular cavitary deficiencies was evaluated in a retrospective study of 23 primary and 24 revision total hip arthroplasties, at a mean follow-up of 7.9 and 8.1 years, respectively. All primary hips received autografts, while all revision hips received allografts. Modified Harris Hip Scores for primary and revision hip replacements increased from a pre-operative mean of 37 and 47 to a postoperative mean of 90 and 86, respectively. All 23 autografts and 23 out of 24 cancellous allografts were radiographically incorporated without evidence of resorption. There were no instances of infection, component migration, or cases requiring subsequent acetabular revision. We conclude that impacted morselized cancellous bone-graft augmentation of cementless cups is a viable surgical option for AAOS type II cavitary acetabular defects. PMID:16988799

  1. Cementless two-stage exchange arthroplasty for infection after total hip arthroplasty.

    PubMed

    Masri, Bassam A; Panagiotopoulos, Kostas P; Greidanus, Nelson V; Garbuz, Donald S; Duncan, Clive P

    2007-01-01

    We retrospectively reviewed all patients at one center with an infected total hip arthroplasty treated with 2-stage revision using cementless components for the second stage and the PROSTALAC articulated spacer at the first stage. Twenty-nine patients were reviewed and followed for at least 2 years postoperatively. An isolated Staphylococcus species was cultured in 76% (22/29) of patients. Three (10.3%) of 29 patients had recurrent infection at the site of the prosthesis. One of the 3 patients ultimately underwent a Girdlestone arthroplasty. Another patient was managed with irrigation and debridement, whereas the final patient was treated with intravenous antibiotics alone. Treatment of infection at the site of a hip arthroplasty with 2-stage revision using cementless components and an articulated spacer yields recurrence rates similar to revisions where at least one of the components at the second stage is fixed with antibiotic-loaded cement.

  2. Bone scans after total knee arthroplasty in asymptomatic patients. Cemented versus cementless

    SciTech Connect

    Hofmann, A.A.; Wyatt, R.W.; Daniels, A.U.; Armstrong, L.; Alazraki, N.; Taylor, A. Jr. )

    1990-02-01

    The natural history of bone scans after total knee arthroplasty (TKA) was studied in 26 patients with 28 cemented TKAs and 29 patients with 31 cementless TKAs. The bone scans were examined at specified postoperative intervals. Radionuclide activity of the femoral, tibial, and patellar regions was measured. Six patients who developed pain postoperatively were excluded. Bone scans immediately postoperative and at three months demonstrated increased uptake, which gradually decreased to baseline levels at ten to 12 months. Radioisotope uptake was comparable in the cemented and cementless groups, but was highly variable in individual patients and in each of the follow-up periods. A single postoperative bone scan cannot differentiate component loosening from early bone remodeling. Sequential bone scans, as a supplement to the clinical examination and conventional radiography, may prove useful in the diagnosis of TKA failure.

  3. Comparative Fixation and Subsidence Profiles of Cementless Unicompartmental Knee Arthroplasty Implants.

    PubMed

    Yildirim, Gokce; Gopalakrishnan, Ananthkrishnan; Davignon, Robert A; Parker, John W; Chawla, Harshvardhan; Pearle, Andrew D

    2016-09-01

    Aseptic loosening is the primary cause of failure for both cemented and cementless unicondylar knee replacements (UKRs). Micromotion and subsidence of tibial baseplate are two causes of failure, due to poor fixation and misalignment, respectively. Stair ascent activity profiles from Bergmann et al and Li et al were used. Biphasic Sawbones models were prepared according to the surgical techniques of traditional and novel cementless UKRs. Implants were tested for 10,000 cycles representing post-operative bone interdigitation period, and micromotion was observed using speckle pattern measurements, which demonstrated sufficient resolution. Additionally, the test method proposed by Liddle et al was used to measure subsidence with pressure sensors under increasingly lateralized loading. Mean displacement due to micromotion for mediolateral and anteroposterior plane was consistently greater for traditional cementless UKR. Mean displacement for axial micromotion was significantly higher for traditional UKR at the anterior aspect of the implant; however, values were lower for the medial periphery of the implant. Subsidence was significantly lower for the novel design with increasingly lateralized loading, and indentation was not observed on the test substrate, when compared to the traditional design. Our findings demonstrate that the novel cementless design is capable of fixation and elimination of subsidence in laboratory test settings. Both designs limit micromotion to below the established loosening micromotion value of 150 μm. The L-shaped keel design resists both micromotion and subsidence and may prevent failure modes that can lead to aseptic loosening for UKRs. These findings are highly relevant for clinical application. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Cementless Oxford medial unicompartimental knee replacement: an independent series with a 5-year-follow-up.

    PubMed

    Panzram, Benjamin; Bertlich, Ines; Reiner, Tobias; Walker, Tilman; Hagmann, Sébastien; Gotterbarm, Tobias

    2017-07-01

    Cemented unicompartmental knee replacement (UKR) has proven excellent long-term survival rates and functional scores in Price et al. (Clin Orthop Relat Res 435:171-180, 2005), Price and Svard (Clin Orthop Relat Res 469(1):174-179, 2011) and Murray et al. (Bone Joint Surg Br 80(6):983-989, 1998). The main causes for revision, aseptic loosening and pain of unknown origin might be addressed by cementless UKR in Liddle et al. (Bone Joint J 95-B(2):181-187, 2013), Pandit et al. (J Bone Joint Surg Am 95(15):1365-1372, 2013), National Joint Registry for England, Wales and Northern Ireland: 10th Annual Report 2013 ( http://www.njrcentre.org.uk/njrcentre/Portals/0/Documents/England/Reports/10th_annual_report/NJR%2010th%20Annual%20Report%202013%20B.pdf , 2013), Swedish Knee Arthroplasty Register: Annual Report 2013 ( http://www.myknee.se/pdf/SKAR2013_Eng.pdf , 2013). This single-centre retrospective cohort study reports the 5-year follow-up results of our first 30 consecutively implanted cementless Oxford UKR (OUKR). Clinical outcome was measured using the OKS, AKSS, range of movement and level of pain (visual analogue scale). The results were compared to cemented OUKR in a matched-pair analysis. Implant survival was 89.7%. One revision each was performed due to tibial fracture, progression of osteoarthritis (OA) and inlay dislocation. The 5-year survival rate of the cementless group was 89.7% and of the cemented group 94.1%. Both groups showed excellent postoperative clinical scores. Cementless fixation shows good survival rates and clinical outcome compared to cemented fixation.

  5. Total hip replacement: A meta-analysis to evaluate survival of cemented, cementless and hybrid implants

    PubMed Central

    Phedy, Phedy; Ismail, H Dilogo; Hoo, Charles; Djaja, Yoshi P

    2017-01-01

    AIM To determine whether cemented, cementless, or hybrid implant was superior to the other in terms of survival rate. METHODS Systematic searches across MEDLINE, CINAHL, and Cochrane that compared cemented, cementless and hybrid total hip replacement (THR) were performed. Two independent reviewers evaluated the risk ratios of revision due to any cause, aseptic loosening, infection, and dislocation rate of each implants with a pre-determined form. The risk ratios were pooled separately for clinical trials, cohorts and registers before pooled altogether using fixed-effect model. Meta-regressions were performed to identify the source of heterogeneity. Funnel plots were analyzed. RESULTS Twenty-seven studies comprising 5 clinical trials, 9 cohorts, and 13 registers fulfilled the research criteria and analyzed. Compared to cementless THR, cemented THR have pooled RR of 0.47 (95%CI: 0.45-0.48), 0.9 (0.84-0.95), 1.29 (1.06-1.57) and 0.69 (0.6-0.79) for revision due to any reason, revision due to aseptic loosening, revision due to infection, and dislocation respectively. Compared to hybrid THR, the pooled RRs of cemented THR were 0.82 (0.76-0.89), 2.65 (1.14-6.17), 0.98 (0.7-1.38), and 0.67 (0.57-0.79) respectively. Compared to hybrid THR, cementless THR had RRs of 0.7 (0.65-0.75), 0.85 (0.49-1.5), 1.47 (0.93-2.34) and 1.13 (0.98-1.3). CONCLUSION Despite the limitations in this study, there was some tendency that cemented fixation was still superior than other types of fixation in terms of implant survival. PMID:28251071

  6. Wrought processing of ingot-metallurgy gamma titanium aluminide alloys

    SciTech Connect

    Semiatin, S.L.

    1995-12-31

    The wrought processing of ingot-metallurgy, gamma titanium aluminide alloys is reviewed. Attention is focused on five major areas in the development of thermomechanical processes for these materials: (1) ingot structure and homogenization, (2) ingot breakdown via existing techniques, (3) novel processes for ingot breakdown, (4) secondary processing, and (5) process scaleup considerations. The nature of the cast microstructure and the influence of composition and ingot size on grain size and segregation are described. The design of existing processes for ingot breakdown deals with the selection of process variables and the design of cans for nonisothermal metalworking techniques. Novel breakdown processes, including smart forging, alpha forging, controlled dwell extrusion, and equal channel angular extrusion, are reviewed. In the area of secondary processing, developments related to pack rolling of sheet, superplastic sheet forming, and isothermal, closed-die forging are summarized. Lastly, scaleup considerations such as thermal cracking during ingot production are addressed.

  7. Greater trochanter osteotomy with cementless THA for Crowe type IV DDH.

    PubMed

    Lei, Pengfei; Hu, Yihe; Cai, PengDe; Xie, Jie; Yang, XuCheng; Wang, Long

    2013-05-01

    This study explored the surgical method and short-term clinical effect of a greater trochanter osteotomy along with cementless artificial total hip arthroplasty in the treatment of Crowe type IV developmental dysplasia of the hip. The authors conducted a retrospective analysis of 18 patients (22 hips) with Crowe type IV dysplasia who were seen between June 2008 and August 2010. After undergoing cementless artificial total hip arthroplasty using a posterolateral approach, a greater trochanter osteotomy was used to adjust the tension of the gluteal muscle, and an acetabular cup was placed. Average preoperative length shortening of the affected limb was 4.5 cm (range, 3.4-6 cm), and average postoperative length increase was 4.0 cm (range, 3.2-4.8 cm). Average postoperative Harris Hip Score was 87 (range, 79-91), which was higher than the average preoperative score of 38 (range, 32-51). Intraoperatively, 3 hips (3 patients) sustained a proximal femur fracture. Due to the stability of the femoral prosthesis, either no treatment or wire fixation only was given; by 2 months postoperatively, radiographs indicated that all fractures had healed. One patient had symptoms of sciatic nerve paralysis that resolved 3 months postoperatively. Performing a greater trochanter osteotomy after cementless artificial total hip arthroplasty is effective for the treatment of Crowe type IV dysplasia and can rebuild the complex biology and biomechanics of hip dysplasia without increasing the complication risk. Copyright 2013, SLACK Incorporated.

  8. Comparative Study of Bipolar Hemiarthroplasty for Femur Neck Fractures Treated with Cemented versus Cementless Stem

    PubMed Central

    Choi, Jung-Yun; Kim, Joo-Hyung

    2016-01-01

    Purpose To compare and analyze clinical and radiologic outcomes of cemented versus cementless bipolar hemiarthroplasty for treatment of femur neck fractures. Materials and Methods A total of 180 patients aged 65 years and over older who underwent bipolar hemiarthroplasty for treatment of displaced femur neck fractures (Garden stage III, IV) from March 2009 to February 2014 were included in this study. Among the 180 patients, 115 were treated with cemented stems and 65 patients with cementless stems. Clinical outcomes assessed were: i) postoperative ambulatory status, ii) inguinal and thigh pain, and iii) complications. The radiologic outcome was femoral stem subsidence measured using postoperative simple X-ray. Results The cemented group had significantly lower occurrence of complications (postoperative infection, P=0.04) compared to the cementless group. There was no significant difference in postoperative ambulatory status, inguinal and thigh pain, and femoral stem subsidence. Conclusion For patients undergoing bipolar hemiarthroplasty, other than complications, there was no statistically significant difference in clinical or radiologic outcomes in our study. Selective use of cemented stem in bipolar hemiarthroplasty may be a desirable treatment method for patients with poor bone quality and higher risk of infections. PMID:28097110

  9. Research to Develop Process Models for Producing a Dual Property Titanium Alloy Compressor Disk.

    DTIC Science & Technology

    1981-10-01

    81 -4130 - RESEARCH TO DEVELOP PROCESS MODELS FOR PRODUCING A DUAL PROPERTY TITANIUM ALLOY COMPRESSOR DISK G. D. Lahoti T. Altan Battelle’s Columbus...COVERED INTERIM ANNUAL TECHNICAL RESEARCH TO DEVELOP PROCESS MODELS FOR PRODUCING A DUAL PROPERTY TITANIUM ALLOY REPORT, 8/1/80 to 7/31/81 COMPRESSOR DISK...validity and application of this approach will be demonstrated by developing forging process for a compressor disk from Ti-6242 alloy, as an example. VD

  10. Promising short-term clinical results of the cementless Oxford phase III medial unicondylar knee prosthesis.

    PubMed

    van Dorp, Karin B; Breugem, Stefan Jm; Bruijn, Daniël J; Driessen, Marcel Jm

    2016-04-18

    To investigate the short-term clinical results of the Oxford phase III cementless medial unicondylar knee prosthesis (UKP) compared to the cemented medial UKP. We conducted a cross-sectional study in a tertairy orthopedic centre between the period of May 2010 and September 2012. We included 99 medial UKP in 97 patients and of these UKP, 53 were cemented and 46 were cementless. Clinical outcome was measured using a questionnaire, containing a visual analogue scale (VAS) for pain, Oxford Knee score, Kujala score and SF-12 score. Knee function was tested using the American Knee Society score. Complications, reoperations and revisions were recorded. Statistical significance was defined as a P value < 0.05. In a mean follow-up time of 19.5 mo, three cemented medial UKP were revised to a total knee prosthesis. Reasons for revision were malrotation of the tibial component, aseptic loosening of the tibial component and progression of osteoarthritis in the lateral- and patellofemoral compartment. In five patients a successful reoperation was performed, because of impingement or (sub)luxation of the polyethylene bearing. Patients with a reoperation were significant younger than patients in the primary group (56.7 vs 64.0, P = 0.01) and were more likely to be male (85.7% vs 38.8%, P = 0.015). Overall the cementless medial UKP seems to perform better, but the differences in clinical outcome are not significant; a VAS pain score of 7.4 vs 11.7 (P = 0.22), an Oxford Knee score of 43.3 vs 41.7 (P = 0.27) and a Kujala score of 79.6 vs 78.0 (P = 0.63). The American Knee Society scores were slightly better in the cementless group with 94.5 vs 90.2 (P = 0.055) for the objective score and 91.2 vs 87.8 (P = 0.25) for the subjective score. The cementless Oxford phase III medial UKP shows good short-term clinical results, when used in a specialist clinic by an experienced surgeon.

  11. Second-generation cementless total hip arthroplasty. Eight to eleven-year results.

    PubMed

    Archibeck, M J; Berger, R A; Jacobs, J J; Quigley, L R; Gitelis, S; Rosenberg, A G; Galante, J O

    2001-11-01

    Second-generation cementless femoral components were designed to provide more reliable ingrowth and to limit distal osteolysis by incorporating circumferential proximal ingrowth surfaces. We examined the eight to eleven-year results of total hip arthroplasty with a cementless, anatomically designed femoral component and a cementless hemispheric acetabular component. Ninety-two consecutive primary total hip arthroplasties with implantation of a femoral component with a circumferential proximal porous coating (Anatomic Hip) and a cementless hemispheric porous-coated acetabular component (Harris-Galante II) were performed in eighty-five patients. These patients were prospectively followed clinically and radiographically. Six patients (seven hips) died and five patients (seven hips) were lost to follow-up, leaving seventy-four patients (seventy-eight hips) who had been followed for a mean of ten years (range, eight to eleven years). The mean age at the time of the arthroplasty was fifty-two years. The mean preoperative Harris hip score of 51 points improved to 94 points at the time of final follow-up; 86% of the hips had a good or excellent result. Thigh pain was reported as mild to severe after seven hip arthroplasties. No femoral component was revised for any reason, and none were loose radiographically at the time of the last follow-up. Two hips underwent acetabular revision (one because of dislocation and one because of loosening). Kaplan-Meier survivorship analysis was performed with revision or loosening of any component as the end point. The ten-year survival rate was 96.4% +/- 2.1% for the total hip prosthesis, 100% for the femoral component, and 96.4% +/- 2.1% for the acetabular component. Radiolucencies adjacent to the nonporous portion of the femoral component were seen in sixty-eight (93%) of the -seventy-three hips with complete radiographic follow-up. Femoral osteolysis proximal to the lesser trochanter was noted in four hips (5%). No osteolysis was

  12. 2014 Accomplishments-Tritium aging studies on stainless steel: Fracture toughness properties of forged stainless steels-Effect of hydrogen, forging strain rate, and forging temperature

    SciTech Connect

    Morgan, Michael J.

    2015-02-01

    Forged stainless steels are used as the materials of construction for tritium reservoirs. During service, tritium diffuses into the reservoir walls and radioactively decays to helium-3. Tritium and decay helium cause a higher propensity for cracking which could lead to a tritium leak or delayed failure of a tritium reservoir. The factors that affect the tendency for crack formation and propagation include: Environment; steel type and microstructure; and, vessel configuration (geometry, pressure, residual stress). Fracture toughness properties are needed for evaluating the long-term effects of tritium on their structural properties. Until now, these effects have been characterized by measuring the effects of tritium on the tensile and fracture toughness properties of specimens fabricated from experimental forgings in the form of forward-extruded cylinders. A key result of those studies is that the long-term cracking resistance of stainless steels in tritium service depends greatly on the interaction between decay helium and the steels’ forged microstructure. New experimental research programs are underway and are designed to measure tritium and decay helium effects on the cracking properties of stainless steels using actual tritium reservoir forgings instead of the experimental forgings of past programs. The properties measured should be more representative of actual reservoir properties because the microstructure of the specimens tested will be more like that of the tritium reservoirs. The programs are designed to measure the effects of key forging variables on tritium compatibility and include three stainless steels, multiple yield strengths, and four different forging processes. The effects on fracture toughness of hydrogen and crack orientation were measured for type 316L forgings. In addition, hydrogen effects on toughness were measured for Type 304L block forgings having two different yield strengths. Finally, fracture toughness properties of type 304L

  13. Improvements in the process of boss bar upset forging into a horizontal forging machine with the aim of joint knuckle forging quality improvement

    NASA Astrophysics Data System (ADS)

    Pankratov, D. L.; Nizamov, R. S.; Kharisov, I. Zh

    2016-06-01

    A new technique for tapered composing transition shaping has been put forward in the process of upset forging with the use of an experimental tool. The results of the upset forging process with the use of a new composing transition has been computer simulated.

  14. Experimental study of multiple scattering in anisotropic titanium alloys

    NASA Astrophysics Data System (ADS)

    Baelde, Aurelien; Laurent, Jérôme; Coulette, Richard; Khalifa, Warida Ben; Duclos, Daniel; Jenson, Frédéric; Fink, Mathias; Prada, Claire

    2017-02-01

    Ultrasonic testing of jet engine titanium alloys is of high importance for the aircraft manufacturing industry. The quality of ultrasonic non-destructive testing is severely impacted by the titanium complex microstructure. These alloys have been extensively studied and single scattering models are now well known and implemented in ultrasonic propagation simulators. In addition, titanium billets and forged parts have been known to exhibit a highly anisotropic microstructure. We studied ultrasonic wave scattering in Ti17 forged disk, through statistical analysis of the backscattered noise generated by the microstructure. More specifically, we focused on the quantification of multiple scattering relative to single scattering in the backscattered wave. To that end, we used the full matrix capture acquisition with a linear transducer array. Two phenomena were used to quantify the proportion of single scattering with respect to multiple scattering. The first is the coherent backscattering effect, used as a binary indicator of multiple scattering. The second is a repurposed version of the multiple scattering filter, recently developed on random rod forest and applied on Inconel alloys. With these methods, significant level of multiple scattering was consistently measured in Ti17 forged disks, showing that ultrasonic testing could be enhanced by filtering the multiple scattering contribution.

  15. Enhancement of Aluminum Alloy Forgings through Rapid Billet Heating

    SciTech Connect

    Kervick, R.; Blue, C. A.; Kadolkar, P. B.; Ando, T.; Lu, H.; Nakazawa, K.; Mayer, H.; Mochnal, G.

    2006-06-01

    Forging is a manufacturing process in which metal is pressed, pounded or squeezed under great pressure and, often, under high strain rates into high-strength parts known as forgings. The process is typically performed hot by preheating the metal to a desired temperature before it is worked. The forging process can create parts that are stronger than those manufactured by any other metal working process. Forgings are almost always used where reliability and human safety are critical. Forgings are normally component parts contained inside assembled items such airplanes, automobiles, tractors, ships, oil drilling equipment, engines missiles, and all kinds of capital equipment Forgings are stronger than castings and surpass them in predictable strength properties, producing superior strength that is assured, part to part.

  16. Forging of helical gears: Upper bound analyses and experiments

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Choi, J. C.

    1998-08-01

    In this paper, forging of helical gears has been investigated. The forging process of helical gears has been classified into two types of operations: guiding and clamping. The two types of forging of helical gears have been analyzed by using the upper-bound method. Kinematically admissible velocity fields have been developed in which an involute curve has been introduced to represent the tooth profile of the gear. Numerical calculations have been carried out to investigate the effects of various parameters such as module, number of teeth, helix angle and friction factors on the forging of helical gears. Some forging experiments were carried out with commercial aluminum alloy to show the validity of the analysis. Good agreements were found between the predicted values of the forging load and those obtained from the experimental results.

  17. The Otto Aufranc Award: Enhanced Biocompatibility of Stainless Steel Implants by Titanium Coating and Microarc Oxidation

    PubMed Central

    Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon

    2010-01-01

    Background Stainless steel is one of the most widely used biomaterials for internal fixation devices, but is not used in cementless arthroplasty implants because a stable oxide layer essential for biocompatibility cannot be formed on the surface. We applied a Ti electron beam coating, to form oxide layer on the stainless steel surface. To form a thicker oxide layer, we used a microarc oxidation process on the surface of Ti coated stainless steel. Modification of the surface using Ti electron beam coating and microarc oxidation could improve the ability of stainless steel implants to osseointegrate. Questions/purposes The ability of cells to adhere to grit-blasted, titanium-coated, microarc-oxidated stainless steel in vitro was compared with that of two different types of surface modifications, machined and titanium-coated, and microarc-oxidated. Methods We performed energy-dispersive x-ray spectroscopy and scanning electron microscopy investigations to assess the chemical composition and structure of the stainless steel surfaces and cell morphology. The biologic responses of an osteoblastlike cell line (SaOS-2) were examined by measuring proliferation (cell proliferation assay), differentiation (alkaline phosphatase activity), and attraction ability (cell migration assay). Results Cell proliferation, alkaline phosphatase activity, migration, and adhesion were increased in the grit-blasted, titanium-coated, microarc-oxidated group compared to the two other groups. Osteoblastlike cells on the grit-blasted, titanium-coated, microarc-oxidated surface were strongly adhered, and proliferated well compared to those on the other surfaces. Conclusions The surface modifications we used (grit blasting, titanium coating, microarc oxidation) enhanced the biocompatibility (proliferation and migration of osteoblastlike cells) of stainless steel. Clinical Relevance This process is not unique to stainless steel; it can be applied to many metals to improve their biocompatibility

  18. Comparison of Biocompatibility of Cemented vs. Cementless Hip Joint Endoprostheses Based on Postoperative Evaluation of Proinflammatory Cytokine Levels

    PubMed Central

    Szypuła, Jan; Cabak, Anna; Kiljański, Marek; Boguszewski, Dariusz; Tomaszewski, Wiesław

    2016-01-01

    Background The yearly increase in the number of procedures involving implantation of hip joint endoprostheses forces prosthetics manufacturers to search for biologically neutral implants. The goal of this study was to assess the concentration of Interleukin-6 (IL-6) and its correlation with C-reactive protein (CRP), depending on the type of hip joint endoprosthesis (cemented or cementless endoprosthesis) in order to determine implant biotolerance during the early postoperative period. Material/Methods The sample comprised 200 patients [mean age=64 (31–81) years] with coxarthrosis. All patients underwent hip joint arthroplasty using a cemented or cementless endoprosthesis. Blood samples were collected 3 times: before the procedure, on the first day after the procedure, and after 6 weeks. IL-6 and CRP levels were assayed using immunoenzymatic methods. The results were subjected to statistical analysis using the Shapiro-Wilk test. Results On the 1st day after the procedure, CRP and IL-6 concentration increased rapidly after implantation of both cemented and cementless endoprostheses. At 6 weeks postoperatively, the CRP value remained at a similar level in patients after cemented arthroplasty and was almost 2-fold lower in patients who underwent cementless arthroplasty. The IL-6 value returned to the baseline level in patients after cementless arthroplasty and showed an ongoing increasing tendency in patients after cemented arthroplasty. Conclusions 1. The measurement of C-reactive protein and Interleukin-6 is a high-sensitivity test, assessing implant biotolerance. 2. The implantation of a cemented endoprosthesis induces a higher increase in the level of proinflammatory cytokines as compared with a cementless endoprosthesis. 3. For a complete assessment of both early and later body responses to implantation and the related surgical procedure, further studies using available approaches and tools are recommended. PMID:27935873

  19. [2- to 5-year follow-up of cementless implantable knee joint prosthesis of the Miller-Galante type].

    PubMed

    Kienapfel, H; Griss, P; Orth, J; Roloff, K; Malzer, U

    1991-06-01

    Based on a prospective study protocol, the two- to five-year results of the Miller-Galante cementless total knee arthroplasty are presented. Sixty-four implants were placed in 59 patients: 60 implantations were cementless and 4 cemented. Clinically, the scores for pain, range of motion, walking and stair climbing improved significantly. Radiographically, the uncemented components displayed no signs of definite or possible loosening, whereas one of the cemented components was found to be definitely loose. On histological evaluation of the retrieved implants, all components had bone ingrowth.

  20. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are clearly... components, accessories, attachments and parts) then the particular forging, casting, extrusion,...

  1. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are clearly... components, accessories, attachments and parts) then the particular forging, casting, extrusion,...

  2. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are clearly... components, accessories, attachments and parts) then the particular forging, casting, extrusion,...

  3. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are clearly... components, accessories, attachments and parts) then the particular forging, casting, extrusion,...

  4. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are clearly... components, accessories, attachments and parts) then the particular forging, casting, extrusion,...

  5. 77 FR 23496 - Boundary Revision of Valley Forge National Historical Park

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-19

    ... National Park Service Boundary Revision of Valley Forge National Historical Park AGENCY: National Park... to the boundary of Valley Forge National Historical Park, pursuant to the authority specified below... ``Valley Forge National Historical Park Proposed Boundary Expansion, Montgomery County, Pennsylvania...

  6. Performance of Porous Tantalum vs. Titanium Cup in Total Hip Arthroplasty: Randomized Trial with Minimum 10-Year Follow-Up.

    PubMed

    Wegrzyn, Julien; Kaufman, Kenton R; Hanssen, Arlen D; Lewallen, David G

    2015-06-01

    Porous tantalum monoblock cups have been proposed to improve survivorship of cementless primary THA. However, there are few direct comparative trials to established implants such as porous-coated titanium cups. 113 patients were randomized into two groups according to the cup: a porous tantalum monoblock cup (TM) or a porous-coated titanium monoblock cup (control). At a mean of 12 years after THA, no implants migrated in both groups. Two TM patients (4%) and 13 control patients (33%) presented with radiolucency around the cup (P<0.001). In the control group, 1 cup (2%) was revised for aseptic loosening. At 12 years post-implantation, porous tantalum monoblock cups demonstrated 100% survivorship, and significantly less radiolucency as compared to porous-coated titanium monoblock cups. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Cementless Total Hip Arthroplasty Involving Trochanteric Osteotomy without Subtrochanteric Shortening for High Hip Dislocation

    PubMed Central

    Lee, Soong Joon; Kim, Hee Joong

    2017-01-01

    Background Total hip arthroplasty with subtrochanteric shortening osteotomy is widely performed for high hip dislocation. However, suboptimal leg length discrepancy correction and nonunion of the osteotomy site remain concerns. Although total hip arthroplasty using trochanteric osteotomy without subtrochanteric osteotomy was introduced, cemented implants have been more commonly used than contemporary cementless implants in this procedure. We evaluated the long-term results of cementless total hip arthroplasty with trochanteric osteotomy without subtrochanteric osteotomy for high hip dislocation. Methods From 1990 to 2002, 27 cementless total hip arthroplasties using trochanteric osteotomy without subtrochanteric osteotomy were performed in 26 patients with Crowe III or IV high hip dislocation and a mean age of 36.4 ± 12.9 years. Seven ceramic-on-ceramic, 8 ceramic-on-polyethylene, 10 metal-on-polyethylene, and 2 metal-on-metal bearings were inserted. Mean follow-up was 15.1 ± 3.7 years. We retrospectively reviewed medical records and radiographic data and evaluated the clinical and radiological results including the Harris hip score, implant survival, correction of leg length discrepancy, and occurrence of complications. Results The mean Harris hip score and leg length discrepancy improved significantly from 73.3 to 94.9 points and from 4.3 cm to 1.0 cm, respectively. With revision for loosening set as the end point, implant survival rates at 10 and 15 years postoperatively were 96.0% and 90.9% for stems and 74.1% and 52.3% for cups. In 8 of 10 hips with the metal-on-polyethylene bearing and 4 of 8 hips with the ceramic-on-polyethylene bearing, revision surgery was performed for aseptic loosening. However, no revision was performed in hips with the ceramic-on-ceramic bearing or the metal-on-metal bearing. Implant survival was significantly different by the type of bearing surface. Two permanent neurologic complications occurred in patients with a limb lengthening

  8. Does osteoporosis reduce the primary tilting stability of cementless acetabular cups?

    PubMed

    von Schulze Pellengahr, Christoph; von Engelhardt, Lars V; Wegener, Bernd; Müller, Peter E; Fottner, Andreas; Weber, Patrick; Ackermann, Ole; Lahner, Matthias; Teske, Wolfram

    2015-04-21

    Cementless hip cups need sufficient primary tilting stability to achieve osseointegration. The aim of the study was to assess differences of the primary implant stability in osteoporotic bone and in bone with normal bone density. To assess the influence of different cup designs, two types of threaded and two types of press-fit cups were tested. The maximum tilting moment for two different cementless threaded cups and two different cementless press-fit cups was determined in macerated human hip acetabuli with reduced (n=20) and normal bone density (n=20), determined using Q-CT. The tilting moments for each cup were determined five times in the group with reduced bone density and five times in the group with normal bone density, and the respective average values were calculated. The mean maximum extrusion force of the threaded cup Zintra was 5670.5 N (max. tilting moment 141.8 Nm) in bone with normal density and.5748.3 N (max. tilting moment 143.7 Nm) in osteoporotic bone. For the Hofer Imhof (HI) threaded cup it was 7681.5 N (192.0 Nm) in bone with normal density and 6828.9 N (max. tilting moment 170.7 Nm) in the group with osteoporotic bone. The mean maximum extrusion force of the macro-textured press-fit cup Metallsockel CL was 3824.6 N (max. tilting moment 95.6 Nm) in bone with normal and 2246.2 N (max. tilting moment 56.2 Nm) in osteoporotic bone. For the Monoblock it was 1303.8 N (max. tilting moment 32.6 Nm) in normal and 1317 N (max. tilting moment 32.9 Nm) in osteoporotic bone. There was no significance. A reduction of the maximum tilting moment in osteoporotic bone of the ESKA press-fit cup Metallsockel CL was noticed. Results on macerated bone specimens showed no statistically significant reduction of the maximum tilting moment in specimens with osteoporotic bone density compared to normal bone, neither for threaded nor for the press-fit cups. With the limitation that the results were obtained using macerated bone, we could not detect any restrictions for

  9. Fallon FORGE 3D Geologic Model

    SciTech Connect

    Doug Blankenship

    2016-03-01

    An x,y,z scattered data file for the 3D geologic model of the Fallon FORGE site. Model created in Earthvision by Dynamic Graphic Inc. The model was constructed with a grid spacing of 100 m. Geologic surfaces were extrapolated from the input data using a minimum tension gridding algorithm. The data file is tabular data in a text file, with lithology data associated with X,Y,Z grid points. All the relevant information is in the file header (the spatial reference, the projection etc.) In addition all the fields in the data file are identified in the header.

  10. West Flank Coso, CA FORGE Seismic Reflection

    SciTech Connect

    Doug Blankenship

    2016-05-16

    PDFs of seismic reflection profiles 101,110, 111 local to the West Flank FORGE site. 45 line kilometers of seismic reflection data are processed data collected in 2001 through the use of vibroseis trucks. The initial analysis and interpretation of these data was performed by Unruh et al. (2001). Optim processed these data by inverting the P-wave first arrivals to create a 2-D velocity structure. Kirchhoff images were then created for each line using velocity tomograms (Unruh et al., 2001).

  11. Forging Oxide-Dispersion-Strengthened Superalloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.; Glasgow, T. K.; Moracz, D. J.; Austin, C. M.

    1986-01-01

    Cladding of mild steel prevents surface cracking when alloy contacts die. Continual need for improvements in properties of alloys capable of withstanding elevated temperatures. Accomplished by using oxide-dispersion-strengthed superalloys such as Inconel Alloy MA 6000. Elevated tensile properties of forged alloy equal those of hot-rolled MA 6000 bar. Stress-rupture properties somewhat lower than those of bar stock but, at 1,100 degrees C, exceed those of strongest commercial single crystal, directionally solidified and conventionally cast superalloys.

  12. Titanium Cranioplasty

    PubMed Central

    Gordon, D. S.; Blair, G. A. S.

    1974-01-01

    The technique of repairing defects of the skull with titanium is described. The skull contour can be accurately reproduced. The technique is simpler than wiring or suturing methods. The material is inert, radiolucent, and rigid. ImagesFIG. 1FIG. 2FIG. 3FIG. 5FIG. 6FIG. 7 PMID:4834099

  13. View west of small tooling and forging dies in Blacksmith ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View west of small tooling and forging dies in Blacksmith Shop, Boilermakers Department, east side of building 57; during World War II approximately forty women were employed as blacksmith's forging a variety of small tools; these may be the tools they used. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

  14. 17. Forge building, fuel storage shed, and foundry, 1906 Photocopied ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    17. Forge building, fuel storage shed, and foundry, 1906 Photocopied from a photograph by Thomas S. Bronson, 'Group at Whitney Factory, 5 November 1906,' NHCHSL. The most reliable view of the fuel storage sheds and foundry, together with a view of the forge building. - Eli Whitney Armory, West of Whitney Avenue, Armory Street Vicinity, Hamden, New Haven County, CT

  15. 22 CFR 121.10 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 22 Foreign Relations 1 2014-04-01 2014-04-01 false Forgings, castings, and machined bodies. 121.10 Section 121.10 Foreign Relations DEPARTMENT OF STATE INTERNATIONAL TRAFFIC IN ARMS REGULATIONS THE UNITED STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings, and machined bodies. The...

  16. 18. INTERIOR VIEW OF ROUGH FORGED TOOLS (FOREGROUND) WHICH ARE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    18. INTERIOR VIEW OF ROUGH FORGED TOOLS (FOREGROUND) WHICH ARE PRE-HEATED IN THE FURNACE (REAR RIGHT) AND THEN FORGED WITH THE BRADLEY HAMMER (LEFT) AS SHOWN BY JAMES GLASPELL - Warwood Tool Company, Foot of Nineteenth Street, Wheeling, Ohio County, WV

  17. Intra-operative evaluation of cementless hip implant stability: a prototype device based on vibration analysis.

    PubMed

    Lannocca, Maurizio; Varini, Elena; Cappello, Angelo; Cristofolini, Luca; Bialoblocka, Ewa

    2007-10-01

    Cementless implants are mechanically stabilized during surgery by a press-fitting procedure. Good initial stability is crucial to avoid stem loosening and bone cracking, therefore, the surgeon must achieve optimal press-fitting. A possible approach to solve this problem and assist the surgeon in achieving the optimal compromise, involves the use of vibration analysis. The present study aimed to design and test a prototype device able to evaluate the primary mechanical stability of a cementless prosthesis, based on vibration analysis. In particular, the goal was to discriminate between stable and quasi-stable implants; thus the stem-bone system was assumed to be linear in both cases. For that reason, it was decided to study the frequency responses of the system, instead of the harmonic distortion. The prototype developed consists of a piezoelectric exciter connected to the stem and an accelerometer attached to the femur. Preliminary tests were performed on four composite femurs implanted with a conventional stem. The results showed that the input signal was repeatable and the output could be recorded accurately. The most sensitive parameter to stability was the shift in resonance frequency of the stem-bone system, which was highly correlated with residual micromotion on all four specimens.

  18. Retaining well-fixed cementless stem in the treatment of infected hip arthroplasty

    PubMed Central

    2013-01-01

    Background and purpose Two-stage reconstruction, reimplantation after removal of an infected prosthesis, has been considered to be the gold standard for treatment of infected hip arthroplasty. However, during the removal of a well-fixed femoral stem, the proximal femur can be damaged and a sequestrum can be formed, which might lead to chronic osteomyelitis and difficulty in reimplantation. We wanted to determine whether infection after hip arthroplasty can be treated without removal of a well-fixed stem. Methods We treated 19 patients who had an infection after hip replacement, but a well-fixed cementless stem, with 2-stage reconstruction. At the first stage, we removed the acetabular cup, the liner and the head, but not the stem. We then implanted a cup of cement spacer. After control of infection, we reimplanted the acetabular component and head. Results 2 patients did not undergo second-stage reconstruction because they were satisfied with the pain relief and the activity that they had with the cement-spacer implantation. The remaining 17 patients underwent the second-stage of the reconstruction using cementless arthroplasty. At a mean follow-up time of 4 (2–8) years, 15 of the patients had no recurrence of infection, with satisfactory clinical and radiographic outcome. Interpretation This second-stage reconstruction after retention of the stem could be an alternative treatment option for periprosthetic infection with a well-fixed stem. PMID:23621807

  19. A genetic algorithm based multi-objective shape optimization scheme for cementless femoral implant.

    PubMed

    Chanda, Souptick; Gupta, Sanjay; Kumar Pratihar, Dilip

    2015-03-01

    The shape and geometry of femoral implant influence implant-induced periprosthetic bone resorption and implant-bone interface stresses, which are potential causes of aseptic loosening in cementless total hip arthroplasty (THA). Development of a shape optimization scheme is necessary to achieve a trade-off between these two conflicting objectives. The objective of this study was to develop a novel multi-objective custom-based shape optimization scheme for cementless femoral implant by integrating finite element (FE) analysis and a multi-objective genetic algorithm (GA). The FE model of a proximal femur was based on a subject-specific CT-scan dataset. Eighteen parameters describing the nature of four key sections of the implant were identified as design variables. Two objective functions, one based on implant-bone interface failure criterion, and the other based on resorbed proximal bone mass fraction (BMF), were formulated. The results predicted by the two objective functions were found to be contradictory; a reduction in the proximal bone resorption was accompanied by a greater chance of interface failure. The resorbed proximal BMF was found to be between 23% and 27% for the trade-off geometries as compared to ∼39% for a generic implant. Moreover, the overall chances of interface failure have been minimized for the optimal designs, compared to the generic implant. The adaptive bone remodeling was also found to be minimal for the optimally designed implants and, further with remodeling, the chances of interface debonding increased only marginally.

  20. Reliability of system for precise cold forging

    NASA Astrophysics Data System (ADS)

    Krušič, Vid; Rodič, Tomaž

    2017-06-01

    The influence of scatter of principal input parameters of the forging system on the dimensional accuracy of product and on the tool life for closed-die forging process is presented in this paper. Scatter of the essential input parameters for the closed-die upsetting process was adjusted to the maximal values that enabled the reliable production of a dimensionally accurate product at optimal tool life. An operating window was created in which exists the maximal scatter of principal input parameters for the closed-die upsetting process that still ensures the desired dimensional accuracy of the product and the optimal tool life. Application of the adjustment of the process input parameters is shown on the example of making an inner race of homokinetic joint from mass production. High productivity in manufacture of elements by cold massive extrusion is often achieved by multiple forming operations that are performed simultaneously on the same press. By redesigning the time sequences of forming operations at multistage forming process of starter barrel during the working stroke the course of the resultant force is optimized.

  1. Advanced numerical models for the thermo-mechanical-metallurgical analysis in hot forging processes

    NASA Astrophysics Data System (ADS)

    Ducato, Antonino; Fratini, Livan; Micari, Fabrizio

    2013-05-01

    In the paper a literature review of the numerical modeling of thermo-mechanical-metallurgical evolutions of a metal in hot forging operations is presented. In particular models of multiaxial loading tests are considered for carbon steels. The collected examples from literature regard phases transformations, also martensitic transformations, morphologies evolutions and transformation plasticity phenomena. The purpose of the tests is to show the correlation between the mechanical and the metallurgical behavior of a carbon steel during a combination of several types of loads. In particular a few mechanical tests with heat treatment are analyzed. Furthermore, Ti-6Al-4V titanium alloy is considered. Such material is a multi-phasic alloy, at room temperature made of two main different phases, namely Alpha and Beta, which evolve during both cooling and heating stages. Several numerical applications, conducted using a commercial implicit lagrangian FEM code are presented too. This code can conduct tri-coupled thermo-mechanical-metallurgical simulations of forming processes. The numerical model has been used to carry out a 3D simulation of a forging process of a complex shape part. The model is able to take into account the effects of all the phenomena resulting from the coupling of thermal, mechanical and metallurgical events. As simulation results strongly depend on the accuracy of input data, physical simulation experiments on real-material samples are carried out to characterize material behavior during phase transformation.

  2. Low-temperature superplasticity of submicrocrystalline Ti-48Al-2Nb-2Cr alloy produced by multiple forging

    SciTech Connect

    Imayev, V.M.; Salishchev, G.A.; Shagiev, M.R.; Kuznetsov, A.V.; Imayev, R.M.; Senkov, O.N.; Froes, F.H.

    1998-12-18

    Gamma titanium aluminides are attractive for elevated temperature applications because of their high specific strength, modulus retention, good oxidation and creep resistance. However they are inherently brittle at temperatures below 600 C due to their strong covalent interatomic bonding, which makes fabrication difficult and has restricted commercial applications. In this research work the authors have studied superplastic (SP) forming of a gamma alloy. Grain refinement is the most common method of decreasing the temperature at which superplasticity is observed, while the second approach is applicable only to gamma alloys containing less than 47 at.% Al. In the present work, a low-temperature superplasticity of a gamma TiAl-based alloy was achieved by producing a submicrocrystalline structure via multistep forging. Mechanical behavior and microstructural evolution of the submicrocrystalline gamma titanium aluminide were studied and possible mechanisms of the low-temperature superplasticity were discussed.

  3. Processing and structure of high-energy-rate-forged 21-6-9 and 304L forgings

    SciTech Connect

    Mataya, M.C.; Carr, M.J.; Krenzer, R.W.; Krauss, G.

    1981-08-10

    Two 304L and three Nitronic 40 (21-6-9) high energy rate processed forgings were studied to determine interrelationships that exist between forging history, mechanical properties, microstructure, macrostructure, and substructure. A striking observation is the wide variation in properties and structure between different forgings and also between different locations within an individual forging. Variations were related to either finishing temperature of the last forming stage or to the forming sequence. For example, lower finishing temperatures resulted in higher dislocation densities and therefore higher strengths. Higher finishing temperatures promoted dynamic recrystallization, lower dislocation densities, and lower strengths. With respect to forming sequence, locations in the forging which are formed first undergo a number of additional thermal cycles while the rest of the part is being formed. These areas are usually recrystallized and have lower dislocation densities, and therefore lower strengths relative to locations formed later in the sequence.

  4. Preparation of titanium diboride powder

    DOEpatents

    Brynestad, Jorulf; Bamberger, Carlos E.

    1985-01-01

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  5. Metal Bonded Titanium Diboride

    DTIC Science & Technology

    1952-03-01

    of specimens made from titanium diboride plus 10 percent titanium and 30 percent zirconium . X 100. 22 6. Microstructures of specimens made from...chromium. X 1000 26 10. Microstructures of specimens made from titanium diboride plus 10 percent titanium and 30 percent zirconium . X 1200 27 11. Gain in...shock resistance and oxidation resistance of titanium diboride but zirconium diboride which is isomorphous with titanium diboride has been reported6

  6. Titanium metals form direct bonding to bone after alkali and heat treatments.

    PubMed

    Nishiguchi, S; Kato, H; Fujita, H; Oka, M; Kim, H M; Kokubo, T; Nakamura, T

    2001-09-01

    In this article we evaluated the bone-bonding strengths of titanium and titanium alloy implants with and without alkali and heat treatments using the conventional canine femur push-out model. Four kinds of smooth cylindrical implants, made of pure titanium or three titanium alloys, were prepared with and without alkali and heat treatments. The implants were inserted hemitranscortically into canine femora. The bone-bonding shear strengths of the implants were measured using push-out test. At 4 weeks all types of the alkali- and heat-treated implants showed significantly higher bonding strength (2.4-4.5 MPa) than their untreated counterparts (0.3-0.6 MPa). At 12 weeks the bonding strengths of the treated implants showed no further increase, while those of the untreated implants had increased to 0.6-1.2MPa. Histologically, alkali- and heat-treated implants showed direct bonding to bony tissue without intervening fibrous tissue. On the other hand, untreated implants usually had intervening fibrous tissue at the interface between bone and the implant. The early and strong bonding to bone of alkali- and heat-treated titanium and its alloys without intervening fibrous tissue may be useful in establishing cementless stable fixation of orthopedic implants.

  7. Initial billet and forging dies shape optimization: Application on an axisymetrical forging with a hammer

    NASA Astrophysics Data System (ADS)

    Meng, Fanjuan; Labergere, Carl; Lafon, Pascal

    2011-05-01

    In metal forming process, the forging die design is the most important step for products quality control. Reasonable dies shape can not only reduce raw material cost but also improving material flow and eliminating defects. The main objective of this paper is to obtain some optimal parameters of the initial billet and forging dies shape according to the simulation results of a two-step metal forming process (platting step and forging step). To develop this metal forming process optimization system several numerical tools are required: geometric modelling (CATIA V5™), FEM analysis (ABAQUS®), work-flow control and optimization computation (MODEFRONTIER®). This study is done in three stages: simulating the two-step metal forming process, building surrogate meta-models to relate response and variables and optimizing the process by using advanced optimization algorithms. In this paper, a two-step axisymmetric metal forming project was studied as an example. By using our simulation model, we get 581 correct real simulation results totally. According to all these real values, we build the surrogate meta-models and obtain Pareto points for a two-objective optimization process. The choice of a solution in all Pareto points will be done by the engineer who can choose his best values according to their criterions of project.

  8. Forging of compressor blades: Temperature and ram velocity effects

    SciTech Connect

    Saigal, A.; Zhen, K.; Chan, T.S.

    1995-07-01

    Forging is one of the most widely used manufacturing process for making high-strength, structurally integrated, impact and creep-resistant Ti-6Al-4V compressor blades for jet engines. In addition, in modern metal forming technology, finite element analysis method and computer modeling are being extensively employed for initial evaluation and optimization of various processes, including forging. In this study, DEFORM, a rigid viscoplastic two-dimensional finite element code was used to study the effects of initial die temperature and initial ram velocity on the forging process. For a given billet, die temperature and ram velocity influence the strain rate, temperature distribution,and thus the flow stress of the material. The die temperature and the ram velocity were varied over the range 300 to 700 F and 15--25 in./sec, respectively, to estimate the maximum forging load and the total energy required to forge compressor blades. The ram velocity was assumed to vary linearly as a function of stroke. Based on the analysis,it was found the increasing the die temperature from 300 to 700 F decreases the forging loads by 19.9 percent and increases the average temperature of the workpiece by 43 F. Similarly, increasing the initial ram velocity from 15 to 25 in./sec decreases the forging loads by 25.2 percent and increases the average temperature of the workpiece by 36 F. The nodal temperature distribution is bimodal in each case. The forging energy required to forge the blades is approximately 18 kips *in./in.

  9. Increased risk of revision of cementless stemmed total hip arthroplasty with metal-on-metal bearings

    PubMed Central

    Pedersen, Alma B; Mäkelä, Keijo; Eskelinen, Antti; Havelin, Leif Ivar; Furnes, Ove; Kärrholm, Johan; Garellick, Göran; Overgaard, Søren

    2015-01-01

    Background and purpose Data from the national joint registries in Australia and England and Wales have revealed inferior medium-term survivorship for metal-on-metal (MoM) total hip arthroplasty (THA) than for metal-on-polyethylene (MoP) THA. Based on data from the Nordic Arthroplasty Register Association (NARA), we compared the revision risk of cementless stemmed THA with MoM and MoP bearings and we also compared MoM THA to each other. Patients and methods We identified 32,678 patients who were operated from 2002 through 2010 with cementless stemmed THA with either MoM bearings (11,567 patients, 35%) or MoP bearings (21,111 patients, 65%). The patients were followed until revision, death, emigration, or the end of the study period (December 31, 2011), and median follow-up was 3.6 (interquartile range (IQR): 2.4–4.8) years for MoM bearings and 3.4 (IQR: 2.0–5.8) years for MoP bearings. Multivariable regression in the presence of competing risk of death was used to assess the relative risk (RR) of revision for any reason (with 95% confidence interval (CI)). Results The cumulative incidence of revision at 8 years of follow-up was 7.0% (CI: 6.0–8.1) for MoM bearings and 5.1% (CI: 4.7–5.6) for MoP bearings. At 6 years of follow-up, the RR of revision for any reason was 1.5 (CI: 1.3–1.7) for MoM bearings compared to MoP bearings. The RR of revision for any reason was higher for the ASR (adjusted RR = 6.4, CI: 5.0–8.1), the Conserve Plus (adjusted RR = 1.7, CI: 1.1–2.5) and “other” acetabular components (adjusted RR = 2.4, CI: 1.5–3.9) than for MoP THA at 6 years of follow-up. Interpretation At medium-term follow-up, the survivorship for cementless stemmed MoM THA was inferior to that for MoP THA, and metal-related problems may cause higher revision rates for MoM bearings with longer follow-up. PMID:25715878

  10. Low BMD affects initial stability and delays stem osseointegration in cementless total hip arthroplasty in women

    PubMed Central

    2012-01-01

    Background and purpose Immediate implant stability is a key factor for success in cementless total hip arthroplasty (THA). Low bone mineral density (BMD) and age-related geometric changes of the proximal femur may jeopardize initial stability and osseointegration. We compared migration of hydroxyapatite-coated femoral stems in women with or without low systemic BMD. Patients and methods 61 female patients with hip osteoarthritis were treated with cementless THA with anatomically designed hydroxyapatite-coated femoral stems and ceramic-ceramic bearing surfaces (ABG-II). Of the 39 eligible patients between the ages of 41 and 78 years, 12 had normal systemic BMD and 27 had osteopenia or osteoporosis. According to the Dorr classification, 21 had type A bone and 18 had type B. Translational and rotational migration of the stems was evaluated with radiostereometric analysis (RSA) up to 2 years after surgery. Results Patients with low systemic BMD showed higher subsidence of the femoral stem during the first 3 months after surgery than did those with normal BMD (difference = 0.6, 95% CI: 0.1–1.1; p = 0.03). Low systemic BMD (odds ratio (OR) = 0.1, CI: 0.006–1.0; p = 0.02), low local hip BMD (OR = 0.3, CI: 0.1–0.7; p = 0.005) and ageing (OR = 1.1, CI: 1.0–1.2; p = 0.02) were risk factors for delayed translational stability. Ageing and low canal flare index were risk factors for delayed rotational stabilization (OR = 3, CI: 1.1–9; p = 0.04 and OR = 1.1, CI: 1.0–1.2; p = 0.02, respectively). Harris hip score and WOMAC score were similar in patients with normal systemic BMD and low systemic BMD. Interpretation Low BMD, changes in intraosseous dimensions of the proximal femur, and ageing adversely affected initial stability and delayed osseointegration of cementless stems in women. PMID:22489886

  11. Mid-term outcome of a modular, cementless, proximally hydroxyapatite-coated, anatomic femoral stem.

    PubMed

    Cossetto, David J; Goudar, Anil

    2012-12-01

    To report the mid-term outcome of a modular, cementless, proximally hydroxyapatitecoated, anatomic femoral stem in total hip arthroplasty (THA). 160 consecutive patients aged 42 to 92 (mean, 70) years underwent 185 cementless THAs for primary osteoarthritis or femoral neck fractures. All procedures were performed by a single surgeon using the same modular, cementless, proximally hydroxyapatite-coated, anatomic femoral stem, regardless of age and bone quality. Clinical evaluation (pain, range of movement, and ability to walk) was based on the Merle d'Aubigne and Postel scores. Radiological assessment was based on criteria by Engh et al. in the 7 Gruen zones with regard to the presence of radiolucent lines, osteolysis, cancellous condensation, cortical hypertrophy or atrophy, reactive lines, and pedestal formation. Failure of the stem was defined as revision or impending revision because of aseptic loosening or pain. Of the 160 patients, 21 died and none were lost to follow-up. In 3 of the 21 patients, the femoral stems were revised for periprosthetic fractures after a fall at 6 weeks, 10 months, and 3.8 years. 138 patients (162 THAs) completed a mean follow-up of 7.8 (range, 5.5-10.4) years. Their overall mean Merle d'Aubigne and Postel scores increased from 7.09 preoperatively to 16.36 postoperatively. The mean Engh score was 24.9 out of 27, with the mean score for femoral stem fixation 10 out of 10 and 14.9 out of 17 for femoral stem stability. No reactive lines at the bone-stem interfaces and no subsidence or osteolysis were evident in any of the radiographs. There were 5 periprosthetic femoral fractures, 2 deep infections, 3 dislocations, and 2 aseptic loosening (one each for the femoral stem and acetabular socket). Survivorship of the femoral stem at 10 years was 99% when revision secondary to only aseptic loosening of the stem was the endpoint. It was 96% when failures due to all causes (infection, periprosthetic fracture, and aseptic loosening) were the

  12. Long-term outcome of a metal-on-polyethylene cementless hip resurfacing.

    PubMed

    Tan, Timothy L; Ebramzadeh, Edward; Campbell, Patricia A; Al-Hamad, Mariam; Amstutz, Harlan C

    2014-04-01

    Due to the well-documented problems surrounding metal-on-metal bearings, the use of hip resurfacing has declined. Since the potential benefits of hip resurfacing remain desirable, it may be beneficial to investigate the long-term outcome of hip resurfacings using metal-on-polyethylene in the 1980's. We report the long-term survivorship and modes of failure of a cementless metal-on-polyethylene resurfacing (n = 178) with different porous ingrowth surfaces. While acetabular loosening was absent, a high incidence of femoral failures (femoral loosening = 18.1%, osteolytic neck fracture = 21%) occurred despite using the same ingrowth surface for both components. Ongoing developments using the lessons learned from these previous generation components and utilizing modern low wear materials, e.g., cross-linked polyethylene, may lead to improved implants for future hip resurfacings. © 2014 Elsevier Inc. All rights reserved.

  13. A second-generation cementless total hip arthroplasty mean 9-year results.

    PubMed

    Surdam, Jonathan W; Archibeck, Michael J; Schultz, Steven C; Junick, Daniel W; White, Richard E

    2007-02-01

    Two hundred fifty-eight primary total hip arthroplasties in 231 patients were implanted using a circumferentially, proximally porous-coated, collared femoral component and a cementless, hemispherical, porous-coated acetabular component and followed up for a mean of 9 years (5-14 years). Four femoral components were revised (2 stems for infection and 2 stems for aseptic loosening). One additional femoral component was radiographically loose at last follow-up. Nine hips underwent acetabular revision (4 for instability, 2 for infection, 2 for loosening, and 1 for osteolysis). Ten-year survivorship with revision or loosening of any component as the end point was 92%; with femoral component aseptic loosening as end point, survivorship was 98%; with acetabular aseptic loosening as the end point, survivorship was 99%. Osteolysis was identified in 26 hips (13%).

  14. Radiographic wear measurements in a cementless metal-backed modular cobalt-chromium acetabular component.

    PubMed

    Barrack, R L; Lavernia, C; Szuszczewicz, E S; Sawhney, J

    2001-10-01

    Linear polyethylene wear was measured radiographically and correlated with direct measurements of wear from 21 of 24 liners retrieved at revision. An optical comparator was used to assess linear wear using the shadowgraph technique. Postoperative and prerevision radiographs were reviewed to measure the amount of linear wear radiographically. Seven radiographic methods described in the literature were used: 5 were manual techniques, and 2 techniques used a computer-assisted digitizer. Linear regression analysis showed that there was a statistically significant correlation between the radiographic measurements compared with the direct measurement for 4 of the 5 manual techniques but only 1 of the 2 computerized techniques. Based on these results, radiographic wear measurements of cementless, modular components should be considered qualitative rather than quantitative. There is a significant difference in the measurements obtained among various published techniques. The addition of computer digitization to enhance manual methodology does not improve accuracy.

  15. Total hip arthroplasty using a cylindrical cementless stem in patients with a small physique.

    PubMed

    Nakamura, Yoshihide; Mitsui, Hiromasa; Kikuchi, Akira; Toh, Satoshi; Katano, Hiroshi

    2011-01-01

    We performed total hip arthroplasty using an anatomic medullary locking cementless stem for small-physique patients from 1988 to 1995. We conducted a retrospective study of 50 joints in 44 cases, including 40 developmentally dysplastic hips followed for 12 to 20 years (average, 15.1 years). Average height and body weight were 152 cm and 56 kg (5.0 ft and 124 lb), respectively, with an average body mass index of 24.2. Twelve joints (24%) were revised for acetabular-sided failures. Forty-eight stems (96%) showed bone ingrowth fixation, and there were no unstable stems. The simple cylindrical shape of the distal portion of the AML stem was less affected by deformity of the proximal femur of developmental dysplasia of the hip in patients with a small physique, and both clinically and radiologically good results were confirmed at long-term follow-up.

  16. Computationally efficient prediction of bone-implant interface micromotion of a cementless tibial tray during gait.

    PubMed

    Fitzpatrick, Clare K; Hemelaar, Pleun; Taylor, Mark

    2014-05-07

    Cementless tibial fixation in total knee replacement (TKR) has potential for improved fixation and ease of revision. Achieving primary stability in cementless TKR is critical to the performance of the components. Excessive micromotion may prevent osseointegration at the bone-implant interface. Computational finite element (FE) studies have been used to predict micromotion at the interface, but analysis of an entire activity cycle is computational expensive, prohibiting large numbers of analyses. Surrogate modeling methods can be used to train a numerical model to predict the response of an FE model. These models are computationally efficient and are suitable for high-volume or iterative analyses requiring probabilistic, statistical or optimization methods. The objective of this work was to train a surrogate model capable of predicting micromotion over the entire bone-implant interface. A proximal tibial bone with mapped material properties was virtually implanted with a tibial tray. A FE model, with six-degree-of-freedom loads sampled from telemetric patients during walking, was used to generate training data for the surrogate model. The linear response surrogate model was evaluated for six full gait cycles; the average and peak micromotion across the interface, and the percentage of bone-implant interface surface area experiencing micromotions less than 50 and greater than 150µm were calculated both as a function of the activity cycle and as the composite peak micromotion throughout the cycle. Differences in root-mean-square (RMS) micromotion between FE and surrogate models were less than 14µm. FE analysis time for a complete gait cycle was 15h, compared to 30s for the surrogate model. Surrogate models have significant potential to rapidly predict micromotion over the entire bone-implant interface, allowing greater range in loading conditions to be explored than is possible through conventional methods. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Acoustic pattern evaluation during cementless hip arthroplasty surgery may be a new method for predicting complications

    PubMed Central

    Morohashi, Itaru; Iwase, Hideaki; Kanda, Akio; Sato, Taichi; Homma, Yasuhiro; Mogami, Atsuhiko; Obayashi, Osamu; Kaneko, Kazuo

    2017-01-01

    Background: Although surgeons must perform implantation of the cementless stem during total hip arthroplasty (THA) without complications, assessment is left to the surgeon’s intuitive judgement, which could contain inter/intra-observer bias variety. We therefore asked (1) whether the sound created during the stem implantation could be evaluated objectively and (2) whether those sounds are correlate to the complication specific to the cementless stems. Our hypothesis is that the sounds produced during stem insertion could be quantified and related to the complications. Patients and method: In 71 THAs, we quantified the sound produced during stem insertion and investigated the relationship between these sounds and the occurrence of intraoperative fracture and subsidence. Results: The sound data were divided into two patterns: Patterns A and B. The difference between the peak value (dB) at the most common frequency (near 7 kHz) and the second most common frequency (near 4 kHz) of strikes during the final phase of implantation in Patterns A and B showed a significant difference. Adverse events on intraoperative fracture and subsidence were significantly less common in patients with Pattern A than in those with Pattern B (six of 42 hips with Pattern A and 13 of 29 hips with Pattern B, p = 0.004). Pattern A in predicting a clinical course without those adverse events was 69.2% and the specificity was 68.4%. Positive and negative predictive values were 85.7% and 44.8%, respectively. Conclusion: The sound generated during stem insertion was quantified. Those sound patterns were associated with complications. PMID:28186872

  18. Mesh morphing for finite element analysis of implant positioning in cementless total hip replacements.

    PubMed

    Bah, Mamadou T; Nair, Prasanth B; Browne, Martin

    2009-12-01

    Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 degrees between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements.

  19. A biodegradable gentamicin-hydroxyapatite-coating for infection prophylaxis in cementless hip prostheses.

    PubMed

    Neut, D; Dijkstra, R J; Thompson, J I; Kavanagh, C; van der Mei, H C; Busscher, H J

    2015-01-02

    A degradable, poly (lactic-co-glycolic acid) (PLGA), gentamicin-loaded prophylactic coating for hydroxyapatite (HA)-coated cementless hip prostheses is developed with similar antibacterial efficacy as offered by gentamicin-loaded cements for fixing traditional, cemented prostheses in bone. We describe the development pathway, from in vitro investigation of antibiotic release and antibacterial properties of this PLGA-gentamicin-HA-coating in different in vitro models to an evaluation of its efficacy in preventing implant-related infection in rabbits. Bone in-growth in the absence and presence of the coating was investigated in a canine model. The PLGA-gentamicin-HA-coating showed high-burst release, with antibacterial efficacy in agar-assays completely disappearing after 4 days, minimising risk of inducing antibiotic resistance. Gentamicin-sensitive and gentamicin-resistant staphylococci were killed by the antibiotic-loaded coating, in a simulated prosthesis-related interfacial gap. PLGA-gentamicin-HA-coatings prevented growth of bioluminescent staphylococci around a miniature-stem mounted in bacterially contaminated agar, as observed using bio-optical imaging. PLGA-gentamicin-HA-coated pins inserted in bacterially contaminated medullary canals in rabbits caused a statistically significant reduction in infection rates compared to HA-coated pins without gentamicin. Bone ingrowth to PLGA-gentamicin-HA-coated pins, in condylar defects of Beagle dogs was not impaired by the presence of the degradable, gentamicin-loaded coating. In conclusion, the PLGA-gentamicin-HA-coating constitutes an effective strategy for infection prophylaxis in cementless prostheses.

  20. Forging and Stamping Nonferrous Metals. Handbook.

    DTIC Science & Technology

    1984-05-10

    C) in cal/cm-s*0 C. (12). Specific resistance (200C) in wQ*cm. (13). f Temperature of allotropic change in *C periods of grate in A. (14). a-titanium...Page 204. The surface layer, contaminated by iron, is etched at the depth of 0.025-0.05 mm in 5-% sulfuric acid. During stamping of powder in t

  1. View northeast of tooling for forging marine hardware in blacksmith ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View northeast of tooling for forging marine hardware in blacksmith shop, east side of building 57. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Structure Shop, League Island, Philadelphia, Philadelphia County, PA

  2. Dynamic material modeling in hot forging. Progress report 4

    SciTech Connect

    El-Gizawy, A.S.

    1992-03-01

    A dynamic material model that characterized flow behavior in the workpiece under forging conditions was required to optimize the process and produce defect-free product at minimum cost. Constitutive equations describe the relationship between stress, strain rate, and temperature under forging conditions. Using aluminum alloy 7050, numerous deformation experiments were conducted to fully characterize constitutive equation variables. A thorough description of the experimental arrangement was provided. Flow data and efficiency data were assembled into a three-dimensional plot of temperature vs. strain rate vs. deformation efficiency to produce an efficiency map. The efficiency map provided the information required for optimization of forging process design. The results of dynamic modeling of the material were used in simulating the isothermal forging of a particular part. Recommendations concerning optimum preform design and processing conditions were reported.

  3. DETAIL VIEW OF BLACKSMITH'S FORGE AND WORK AREA ON WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL VIEW OF BLACKSMITH'S FORGE AND WORK AREA ON WEST SIDE OF UPPER TRAM TERMINAL, LOOKING EAST. FORGE IS IN FOREGROUND, WITH THE ANVIL BLOCK JUST TO THE RIGHT AND BEHIND IT. A TRAM CAR IS UPSIDE DOWN TO THE LEFT OF THE FORGE. THE PIPE GOING INTO THE FORGE ON THE RIGHT CARRIED COMPRESSED AIR TO BLOW THE COALS. AT CENTER RIGHT ON THE TRAM TERMINAL ARE THE OPENING AND CLOSING MECHANISMS FOR THE ORE BUCKETS. AT CENTER LEFT IS A BRAKE WHEEL. THE ANCHOR POINTS FOR THE STATIONARY TRAM CABLES ARE JUST BELOW THIS WHEEL. THE FRONT END OF THE TERMINAL IS JUST OFF FRAME ON THE RIGHT. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  4. Critical current densities in Bi-2223 sinter forgings.

    SciTech Connect

    Balachandran, U.; Fisher, B. L.; Goretta, K. C.; Harris, N. C.; Murayama, N.

    1999-07-23

    (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (Bi-2223) bars, prepared by sinter forging, exhibited good phase purity and strong textures with the c axes of the Bi-2223 grains parallel to the forging direction. The initial zero-field critical current density (J{sub c}) of the bars was 10{sup 3} A/cm{sup 2}, but because the forged bars were uncoated, this value decreased with repeated thermal cycling. J{sub c} as a function of applied magnetic field magnitude and direction roughly followed the dependencies exhibited by Ag-sheathed Bi-2223 tapes, but the forged bars were more strongly dependent on field strength and less strongly dependent on field angle.

  5. Modeling microstructural development during the forging of Waspaloy

    SciTech Connect

    Shen, G.; Shivpuri, R.; Semiatin, S.L.

    1995-07-01

    A model for predicting the evolution of microstructure in Waspaloy during thermomechanical processing was developed in terms of dynamic recrystallization (DRX), metadynamic recrystallization, and grain growth phenomena. Three sets of experiments were conducted to develop the model: (1) preheating tests to model grain growth prior to hot deformation; (2) compression tests in a Gleeble testing machine with different deformation and cooling conditions to model DRX, metadynamic recrystallization, and short time grain growth during the post deformation dwell period and cooling; and (3) pancake and closed die forging tests conducted in a manufacturing environment to verify and refine the model. The microstructural model was combined with finite element modeling (FEM) to predict microstructure development during forging of Waspaloy. Model predictions showed good agreement with microstructures obtained in actual isothermal and hammer forgings carried out at a forging shop.

  6. View facing east of top of quarry wall with forge ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View facing east of top of quarry wall with forge site in foreground - Granite Hill Plantation, Quarry No. 4, South side of State Route 16, 1.3 miles northeast east of Sparta, Sparta, Hancock County, GA

  7. Total quality management of forged products through finite element simulation

    NASA Astrophysics Data System (ADS)

    Chandra, U.; Rachakonda, S.; Chandrasekharan, S.

    The paper reviews the entire thermo-mechanical history experienced by a complex shaped, high strength forged part during all stages of its manufacturing process, i.e. forging, heat treatment, and machining. It examines the current practice of selecting the process parameters using finite element simulation of forging and quenching operations on an individual basis. Some recent work related to the simulation of aging and machining operations is summarized. The capabilities of several well-known finite element codes for these individual simulations are compared. Then, an integrated simulation approach is presented which will permit the optimization of process parameters for all operations, as opposed to a single operation. This approach will ensure a total quality management of forged products by avoiding costly problems which, under the current practice, are detected only at the end of the manufacturing cycle, i.e. after final machining.

  8. 6. NORTH END OF MACHINE SHOP. FORGE SHOP (HAER No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. NORTH END OF MACHINE SHOP. FORGE SHOP (HAER No. CA-326-K) ON LEFT, FORD PLANT IN DISTANCE, NE BY 60. - Rosie the Riveter National Historical Park, Machine Shop, 1311 Canal Boulevard, Richmond, Contra Costa County, CA

  9. [Joint prostheses components of warm-forged and surface treated Ti-6Al-7Nb alloy].

    PubMed

    Semlitsch, M; Weber, H; Streicher, R M; Schön, R

    1991-05-01

    In 1978 development of a TiAl alloy with the inert alloying element niobium was initiated. In 1984, the optimal composition was found to be Ti-6Al-7Nb (Protasul-100). This custom-made alloy for implants has the same alpha/beta micro-structure and equally good mechanical properties as Ti-6Al-4V. The corrosion resistance of Ti-6Al-7Nb is better than that of pure titanium and Ti-6Al-4V, due to the very dense and stable passive layer. Since 1985, highly stressed anchoring stems of various hip prosthesis designs have been manufactured from hot-forged Ti-6Al-7Nb/Protasul-100. Polished surfaces of hip, knee or wrist joints made of Ti-6Al-7Nb intended to articulate with polyethylene are surface-treated by the application of a very hard, 3-5 microns thick titanium nitride coating (Tribosul-TiN), or by oxygen diffusion hardening (Tribosul-ODH) to a depth of 30 microns.

  10. Titanium "irons" and titanium "steels"

    NASA Astrophysics Data System (ADS)

    Firstov, S. A.; Tkachenko, S. V.; Kuz'menko, N. N.

    2009-01-01

    Special features of the structure and properties of promising structural alloys based on the Ti-Si system are described. The similarity of the diagrams of phase equilibria of the Fe-Si and Fe-C systems makes it possible to classify the alloys of the Ti-Si system into titanium "steels" and "irons" depending on the silicon content. Results of studies of the effects of alloying, heat treatment, and thermomechanical treatment on the phase and structural transformations and on some properties of alloys based on the Ti-Si system are presented.

  11. Hydriding of Titanium.

    DTIC Science & Technology

    1998-03-01

    hole. The metals used to make these couples with titanium included HY80 steel , 316 stainless steel , five-nines aluminum, 6061 aluminum, and zinc. All...the other surfaces. Titanium Coupled With Other Metals The corrosion potentials of grade 2 titanium galvanically coupled with naval brass, HY80 steel ...2 titanium; naval brass caused titanium to become an anode. At room temperature, HY80 steel and 316 stainless steel couples exhibited corrosion

  12. Total Knee Arthroplasty Using Cementless Porous Tantalum Monoblock Tibial Component: A Minimum 10-Year Follow-Up.

    PubMed

    De Martino, Ivan; D'Apolito, Rocco; Sculco, Peter K; Poultsides, Lazaros A; Gasparini, Giorgio

    2016-10-01

    Cementless fixation in total knee arthroplasty (TKA) was introduced to improve the longevity of implants but has yet to be widely adopted because of reports of higher failure rates in some series. The cementless tantalum monoblock tibial component, in contrast, has shown successful short-term results, but long-term survivorship with this design is still lacking. The purpose of this study was to investigate the minimum 10-year clinical and radiographic results of the cementless tantalum monoblock tibial component in primary TKA. From March 2002 to March 2005, 33 patients (33 knees) underwent primary TKA with a cementless tantalum monoblock tibial component. All patients were followed clinically and radiographically for a minimum of 10 years (mean 11.5 years, range 10-13 years). No patients were lost to follow-up. The underlying diagnosis that led to the primary TKA was primary osteoarthritis in 31 knees and post-traumatic osteoarthritis in 2 knees. None of the components was revised. At a minimum 10-year follow-up, the survivorship with reoperation for any reason as end point was 96.9%. With tibial component revision for aseptic loosening or osteolysis as the end point survivorship was 100%. There was no radiographic evidence of tibial component loosening, subsidence, osteolysis, or migration at the time of the latest follow-up. The mean Knee Society knee scores improved from 56 points preoperatively to 93 points at the last clinical visit. The porous tantalum tibial monoblock component demonstrated excellent clinical and radiographic outcomes with no component revisions for aseptic loosening at a minimum follow-up of 10 years. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Alumina Delta-on-Alumina Delta Bearing in Cementless Total Hip Arthroplasty in Patients Aged <50 Years.

    PubMed

    Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

    2016-10-01

    There are limited studies to evaluate long-term clinical and radiographic outcomes of alumina delta ceramic-on-ceramic bearings in cementless total hip arthroplasty (THA). The purpose of this study was to evaluate the clinical and radiographic results, prevalence of osteolysis, squeaking, and fracture of ceramic material associated with the use of the alumina delta ceramic-on-alumina delta ceramic bearing in cementless THA in patients aged <50 years. We reviewed the cases of 277 patients (334 hips) who underwent a cementless THA using alumina delta ceramic-on-alumina delta ceramic when they were 50 years or younger at the time of surgery. Demographic data; Harris Hip Score; Western Ontario McMaster Universities Osteoarthritis Index; and University of California, Los Angeles activity score were recorded. Radiographic and computerized tomographic evaluations were used to evaluate implant fixation and osteolysis. Squeaking sound and ceramic fracture were documented. The mean follow-up was 13.1 years (range, 10-14). The mean postoperative Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index score, University of California, Los Angeles activity score were 93 points, 15 points, and 8.6 points, respectively. Two patients had thigh pain (grade 7 points). All acetabular components and all but 2 femoral components were well fixed. Thirty-three hips (10%) exhibited clicking sound, and 2 hips (0.6%) exhibited squeaking sound. No hip had osteolysis or ceramic head or liner fracture. Our minimum 10-year follow-up results with the use of alumina delta ceramic-on-alumina delta ceramic bearings in patients aged <50 years suggest that cementless THA provides a high rate of survivorship without evidence of osteolysis or fracture of ceramic material. Copyright © 2016. Published by Elsevier Inc.

  14. Migration pattern of cementless press fit cups in the presence of stabilizing screws in total hip arthroplasty

    PubMed Central

    2011-01-01

    The aim of this study was to evaluate the initial acetabular implant stability and late acetabular implant migration in press fit cups combined with screw fixation of the acetabular component in order to answer the question whether screws are necessary for the fixation of the acetabular component in cementless primary total hip arthroplasty. One hundred and seven hips were available for follow-up after primary THA using a cementless, porous-coated acetabular component. A total of 631 standardized radiographs were analyzed digitally by the "single-film-x-ray-analysis" method (EBRA). One hundred 'and one (94.4%) acetabular components did not show significant migration of more than 1 mm. Six (5.6%) implants showed migration of more than 1 mm. Statistical analysis did not reveal preoperative patterns that would identify predictors for future migration. Our findings suggest that the use of screw fixation for cementless porous- coated acetabular components for primary THA does not prevent cup migration. PMID:21486725

  15. New titanium and titanium/hydroxyapatite coatings on ultra-high-molecular-weight polyethylene-in vitro osteoblastic performance.

    PubMed

    Silva, M A; Gomes, P S; Vila, M; Lopes, M A; Santos, J D; Silva, R F; Fernandes, M H

    2010-06-01

    The development of optimized hip joint materials is one of the most challenging opportunities in prosthetic technologies. In current approaches, ultra-high-molecular-weight polyethylene(UHMWPE) has been a favorite material for the acetabular component and, regarding the cementless technique, several coating options may be considered to contain and stabilize bearing surfaces and establish an improved interface with bone. In this work, newly developed constructs of UHMWPE coated with either commercially pure titanium (cpTi-UHMWPE), by DC magnetron sputtering, or with commercially pure titanium and hydroxyapatite(cpTi/HA-UHMWPE), by DC/RF magnetron co-sputtering, have been prepared and biologically characterized with human bone marrow-derived osteoblastic cultures. The cpTi-UHMWPE samples allowed a high cell growth and the expression of the complete osteoblastic phenotype, with high alkaline phosphatase activity, expression of osteogenic-associated genes and evident cell-mediated mineralization of the extracellular matrix. In comparison, the cpTi/HA-UHMWPE samples reported lower cell proliferation but earlier cell-mediated matrix mineralization. Accordingly, these newly developed systems maybe suitable candidates to improve the osteointegration process in arthroplastic devices;nevertheless, further biological evaluation should be conducted.

  16. Snake River Plain FORGE Site Characterization Data

    DOE Data Explorer

    Robert Podgorney

    2016-04-18

    The site characterization data used to develop the conceptual geologic model for the Snake River Plain site in Idaho, as part of phase 1 of the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative. This collection includes data on seismic events, groundwater, geomechanical models, gravity surveys, magnetics, resistivity, magnetotellurics (MT), rock physics, stress, the geologic setting, and supporting documentation, including several papers. Also included are 3D models (Petrel and Jewelsuite) of the proposed site. Data for wells INEL-1, WO-2, and USGS-142 have been included as links to separate data collections. These data have been assembled by the Snake River Geothermal Consortium (SRGC), a team of collaborators that includes members from national laboratories, universities, industry, and federal agencies, lead by the Idaho National Laboratory (INL). Other contributors include the National Renewable Energy Laboratory (NREL), Lawrence Livermore National Laboratory (LLNL), the Center for Advanced Energy Studies (CEAS), the University of Idaho, Idaho State University, Boise State University, University of Wyoming, University of Oklahoma, Energy and Geoscience Institute-University of Utah, US Geothermal, Baker Hughes Campbell Scientific Inc., Chena Power, US Geological Survey (USGS), Idaho Department of Water Resources, Idaho Geological Survey, and Mink GeoHydro.

  17. West Flank Coso, CA FORGE Magnetotelluric Inversion

    DOE Data Explorer

    Doug Blankenship

    2016-05-16

    The Coso Magnetotelluric (MT) dataset of which the West Flank FORGE MT data is a subset, was collected by Schlumberger / WesternGeco and initially processed by the WesternGeco GeoSolutions Integrated EM Center of Excellence in Milan, Italy. The 2011 data was based on 99 soundings that were centered on the West Flank geothermal prospect. The new soundings along with previous data from 2003 and 2006 were incorporated into a 3D inversion. Full impedance tensor data were inverted in the 1-3000 Hz range. The modelling report notes several noise sources, specifically the DC powerline that is 20,000 feet west of the survey area, and may have affected data in the 0.02 to 10 Hz range. Model cell dimensions of 450 x 450 x 65 feet were used to avoid computational instability in the 3D model. The fit between calculated and observed MT values for the final model run had an RMS value of 1.807. The included figure from the WesternGeco report shows the sounding locations from the 2011, 2006 and 2003 surveys.

  18. Enhanced Cell Integration to Titanium Alloy by Surface Treatment with Microarc Oxidation: A Pilot Study

    PubMed Central

    Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon; Kim, Hyoun Ee

    2009-01-01

    Microarc oxidation (MAO) is a surface treatment that provides nanoporous pits, and thick oxide layers, and incorporates calcium and phosphorus into the coating layer of titanium alloy. We presumed such modification on the surface of titanium alloy by MAO would improve the ability of cementless stems to osseointegrate. We therefore compared the in vitro ability of cells to adhere to MAOed titanium alloy to that of two different types of surface modifications: machined and grit-blasted. We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines (SaOS-2) were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and αvβ3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups. The osteoblast cell lines of the MAO group were also homogeneously spread on the surface, strongly adhered, and well differentiated when compared to the other groups. This method could be a reasonable option for treating the surfaces of titanium alloy for better osseointegration. PMID:19434468

  19. Osseointegration into a Novel Titanium Foam Implant in the Distal Femur of a Rabbit

    PubMed Central

    Willie, Bettina M.; Yang, Xu; Kelly, Natalie H.; Merkow, Justin; Gagne, Shawn; Ware, Robin; Wright, Timothy M.; Bostrom, Mathias P.G.

    2010-01-01

    A novel porous titanium foam implant has recently been developed to enhance biological fixation of orthopaedic implants to bone. The aim of this study was to examine the mechanical and histological characteristics of bone apposition into two different pore sizes of this titanium foam (565 and 464 micron mean void intercept length) and to compare these characteristics to those obtained with a fully porous conventionally sintered titanium bead implant. Cylindrical implants were studied in a rabbit distal femoral intramedullary osseointegration model at time zero and at 3, 6, and 12 weeks. The amount of bone ingrowth, amount of periprosthetic bone, and mineral apposition rate of periprosthetic bone measured did not differ among the three implant designs at 3, 6, or 12 weeks. By 12 weeks, the interface stiffness and maximum load of the beaded implant was significantly greater than either foam implant. No significant difference was found in the interface stiffness or maximum load between the two foam implant designs at 3, 6, or 12 weeks. The lower compressive modulus of the foam compared to the more dense sintered beaded implants likely contributed to the difference in failure mode. However, the foam implants have a similar compressive modulus to other clinically successful coatings, suggesting they are nonetheless clinically adequate. Additional studies are required to confirm this in weight-bearing models. Histological data suggest that these novel titanium foam implants are a promising alternative to current porous coatings and should be further investigated for clinical application in cementless joint replacement. PMID:20024964

  20. Computational modeling in the primary processing of titanium: A review

    NASA Astrophysics Data System (ADS)

    Venkatesh, Vasisht; Wilson, Andrew; Kamal, Manish; Thomas, Matthew; Lambert, Dave

    2009-05-01

    Process modeling is increasingly becoming a vital tool for modern metals manufacturing. This paper reviews process modeling initiatives started at TIMET over the last decade for the primary processing of titanium alloys. SOLAR, a finite volume-based numerical model developed at the Ecole de Mine at Nancy, has been successfully utilized to optimize vacuum arc remelting process parameters, such as electromagnetic stirring profiles in order to minimize macrosegregation and improve ingot quality. Thermo-mechanical modeling of heat treating, billet forging, and slab rolling is accomplished via the commercial finite element analysis model, DEFORM, to determine heating times, cooling rates, strain distributions, etc.

  1. Flaw Growth of 6Al-4V Titanium in a Freon TF Environment

    NASA Technical Reports Server (NTRS)

    Tiffany, C. F.; Masters, J. N.; Bixler, W. D.

    1969-01-01

    The plane strain threshold stress intensity and sustained stress flaw growth rates were experimentally determined for 6AI-4V S.T.A. titanium forging and weldments in environments of Freon TF at room temperature. Sustained load tests of surface flawed specimens were conducted with the experimental approach based on linear elastic fracture mechanics. It was concluded that sustained stress flaw growth rates, in conjunction with threshold stress intensities, can be used in assessing the service life of pressure vessels.

  2. The roles of rare earth dispersoids and process route on the low cycle fatigue behavior of a rapidly solidified powder metallurgy titanium alloy

    SciTech Connect

    Gigliotti, M.F.X. ); Woodfield, A.P. )

    1993-08-01

    Low cycle fatigue tests were conducted at 482C (900F) on forgings and extrusions of a rapidly solidified powder metallurgy titanium base alloy with and without rare earth additions. The variables studied were process temperature and heat treatment. Rare earth dispersions reduced fatigue life, and fracture surfaces indicated internal fatigue crack initiation at rare earth particles.

  3. Development of high purity large forgings for nuclear power plants

    NASA Astrophysics Data System (ADS)

    Tanaka, Yasuhiko; Sato, Ikuo

    2011-10-01

    The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

  4. Bioresorbable devices made of forged composites of hydroxyapatite (HA) particles and poly L-lactide (PLLA). Part II: practical properties of miniscrews and miniplates.

    PubMed

    Shikinami, Y; Okuno, M

    2001-12-01

    Miniscrews and miniplates made of forged composites composed of raw hydroxyapatite (u-HA) particles (particle size 0.2-20 microm, averaging 3.0 microm, Ca/p = 1.69 and containing CO3(2-)) and a poly L-lactide (PLLA, Mv: about 180 kDa, containing residual 0.05 wt% lactide) with osteological bioactivity such as direct bonding to bone and osteoconductivity, total resorbability and radiopacity were examined for various mechanical properties in order to evaluate their usefulness for cranio-, oral and maxillo-facial as well as plastic and reconstructive surgeries with PLLA-only or titanium devices. The composites containing u-HA particles at 30wt% for miniscrews and 40wt% for miniplates were selected based on total mechanical strengths and bioactivity, respectively. It was found that the composite devices generally had slightly different mechanical properties than forged PLLA-only devices of which strengths are ranked the highest among the reinforced PLLA-only ones that having been used in many clinical cases to date, in spite of their approximate 2 or 3 times lower absolute strengths than those of titanium ones. However, a remarkable distinction that makes the composite miniplates stand above the titanium ones was confirmed on their fatigue resistance to alternate bendings such that they retained 70% of their initial strength even after 60 times without revealing any damage, whereas the metallic devices fully broke off at only 8 times. This behavior was similar to that of forged PLLA-only devices but is unique as composites made of organic polymers divided by inorganic particles. In addition, profile plates such as L-, T-, X, T, C-, Mesh-, Box-, and Barhole types which were processed by forging twice exhibited nearly directional isotropy in strength and could be deformed in situ at ordinary temperatures to adjust their shapes along the surface undulations of the skull, mandible, maxilla, zygomatic bone and the like without thermoforming and did not return to their

  5. Bilaterally Primary Cementless Total Hip Arthroplasty for Severe Hip Ankylosis with Ankylosing Spondylitis.

    PubMed

    Feng, Dong-Xu; Zhang, Kun; Zhang, Yu-Min; Nian, Yue-Wen; Zhang, Jun; Kang, Xiao-Min; Wu, Shu-Fang; Zhu, Yang-Jun

    2016-08-01

    Total hip arthroplasty is a reliable therapeutic intervention in patients with ankylosing spondylitis, in whom the aims of surgery are to reduce pain, restore hip function and improve quality of life. The current study is a retrospective analysis of the clinical and radiographic findings in a consecutive series of patients with hip ankylosis associated with severe ankylosing spondylitis who underwent bilateral primary total hip arthroplasty using non-cemented components. From June 2008 to May 2012, total hip arthroplasty was performed on 34 hips in 17 patients with bilateral ankylosis caused by ankylosing spondylitis. The study patients included 13 men and 4 women with a mean age of 24.2 years. The mean duration of disease was 8.3 years and the average duration of hip involvement was 7.6 years. All patients had severe hip pain and dysfunction with bilateral bony ankylosis and no range of motion preoperatively and all underwent bilateral cementless total hip arthroplasty performed by a single surgeon. Joint pain, range of motion (ROM), and Harris hip scores were assessed to evaluate the postoperative results. At a mean follow-up of 31.7 months, all patients had experienced significant clinical improvement in function, ROM, posture and ambulation. At the final follow-up, the mean postoperative flexion ROM was 134.4° compared with 0° preoperatively. Similar improvements were seen in hip abduction, adduction, internal rotation and external rotation. Postoperatively, 23 hips were completely pain-free, six had only occasional discomfort, three mild to moderate pain and two severe pain. The average Harris Hip Score improved from 23.7 preoperatively to 65.8 postoperatively. No stems had loosened at the final follow-up in any patient, nor had any revision surgery been required. Bilateral severe hip ankylosis in patients with ankylosing spondylitis can be treated with cementless bilateral synchronous total hip arthroplasty, which can greatly improve hip joint function and

  6. Preparation of the femoral bone cavity in cementless stems: broaching versus compaction

    PubMed Central

    Hjorth, Mette H; Stilling, Maiken; Søballe, Kjeld; Nielsen, Poul Torben; Christensen, Poul H; Kold, Søren

    2016-01-01

    Background and purpose — Short-term experimental studies have confirmed that there is superior fixation of cementless implants inserted with compaction compared to broaching of the cancellous bone. Patients and methods — 1-stage, bilateral primary THA was performed in 28 patients between May 2001 and September 2007. The patients were randomized to femoral bone preparation with broaching on 1 side and compaction on the other side. 8 patients declined to attend the postoperative follow-up, leaving 20 patients (13 male) with a mean age of 58 (36–70) years for evaluation. The patients were followed with radiostereometric analysis (RSA) at baseline, at 6 and 12 weeks, and at 1, 2, and 5 years, and measurements of periprosthetic bone mineral density (BMD) at baseline and at 1, 2, and 5 years. The subjective part of the Harris hip score (HHS) and details of complications throughout the observation period were obtained at a mean interval of 6.3 (3.0–9.5) years after surgery. Results — Femoral stems in the compaction group had a higher degree of medio-lateral migration (0.21 mm, 95% CI: 0.03–0.40) than femoral stems in the broaching group at 5 years (p = 0.02). No other significant differences in translations or rotations were found between the 2 surgical techniques at 2 years (p > 0.4) and 5 years (p > 0.7) postoperatively. There were no individual stems with continuous migration. Periprosthetic BMD in the 7 Gruen zones was similar at 2 years and at 5 years. Intraoperative femoral fractures occurred in 2 of 20 compacted hips, but there were none in the 20 broached hips. The HHS and dislocations were similar in the 2 groups at 6.3 (3.0–9.5) years after surgery. Interpretation — Bone compaction as a surgical technique with the Bi-Metric stem did not show the superior outcomes expected compared to conventional broaching. Furthermore, 2 periprosthetic fractures occurred using the compaction technique, so we cannot recommend compaction for insertion of the

  7. Joint replacement components made of hot-forged and surface-treated Ti-6Al-7Nb alloy.

    PubMed

    Semlitsch, M F; Weber, H; Streicher, R M; Schön, R

    1992-01-01

    We have developed a titanium-aluminium alloy with the inert alloying element niobium. The optimal composition was found to be Ti-6Al-7Nb (Protasul-100). This custom-made alloy designed for implants shows the same alpha/beta structure as Ti-6Al-4V and exhibits equally good mechanical properties. The corrosion resistance of Ti-6Al-7Nb in sodium chloride solution is equivalent to that of pure titanium and Ti-6Al-4V. This is due to a very dense and stable passive layer. Highly stressed anchorage stems of different hip prosthesis designs have been made from hot-forged Ti-6Al-7Nb. The polished surfaces of hip, knee and wrist joints made of Ti-6Al-7Nb and articulating against polyethylene are surface-treated by means of a very hard and 3-5 microns thick titanium nitride coating (Tribosul-TiN) or by oxygen diffusion hardening (Tribosul-ODH) to a depth of 30 microns.

  8. Prediction of Microstructure in High-Strength Ductile Forging Parts

    SciTech Connect

    Urban, M.; Back, A.; Hirt, G.; Keul, C.; Bleck, W.

    2010-06-15

    Governmental, environmental and economic demands call for lighter, stiffer and at the same time cheaper products in the vehicle industry. Especially safety relevant parts have to be stiff and at the same time ductile. The strategy of this project was to improve the mechanical properties of forging steel alloys by employing a high-strength and ductile bainitic microstructure in the parts while maintaining cost effective process chains to reach these goals for high stressed forged parts. Therefore, a new steel alloy combined with an optimized process chain has been developed. To optimize the process chain with a minimum of expensive experiments, a numerical approach was developed to predict the microstructure of the steel alloy after the process chain based on FEM simulations of the forging and cooling combined with deformation-time-temperature-transformation-diagrams.

  9. Long-term results using the straight tapered femoral cementless hip stem in total hip arthroplasty: a minimum of twenty-year follow-up.

    PubMed

    Ateschrang, Atesch; Weise, Kuno; Weller, Siegfried; Stöckle, Ulrich; de Zwart, Peter; Ochs, Björn Gunnar

    2014-08-01

    We report the first long-term results of a prospective cohort study after total hip arthroplasty using the cementless Bicontact hip stem. Between 1987 and 1990, 250 total hip arthroplasties in 236 patients were performed using the cementless Bicontact hip stem. The average follow-up was 22.8 years (20.4-24.8) and average age at index surgery was 58.1 years. Eighty-one patients died and 9 were lost to follow-up. We noted 11 stem revisions revealing an overall Kaplan Meier survival rate of 95.0% (CI 95%: 91.1-97.2%). The average Harris Hip Score revealed 81 points (range 24-93). The Bicontact hip stem demonstrated high survival rates despite high ages and osteopenic changes, which are equivalent to other long-term reports of cementless stem fixation.

  10. Biomechanical evaluation of adjunctive cerclage wire fixation for the prevention of periprosthetic femur fractures using cementless press-fit total hip replacement.

    PubMed

    Christopher, Scott A; Kim, Stanley E; Roe, Simon; Pozzi, Antonio

    2016-08-01

    Periprosthetic femoral fractures are a common complication associated with cementless press-fit total hip arthroplasty. The use of prophylactic cerclage wire fixation has been advocated to reduce this complication. The objective of this study was to evaluate whether a double loop cerclage wire, used as adjunctive fixation, increased the peak torsional load to failure in femora implanted with press-fit cementless stems. Peak torsional load to failure was compared between femora without adjunctive fixation and femora receiving a 1 mm double loop cerclage wire placed proximally to the lesser trochanter. Femora treated with adjunctive cerclage wire fixation failed at 20% greater peak torque (P = 0.0001). In conclusion, a double loop cerclage wire may aid in the prevention of periprosthetic fractures associated with press-fit cementless femoral stems.

  11. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-07-04

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  12. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  13. Acceleration of Intended Pozzolanic Reaction under Initial Thermal Treatment for Developing Cementless Fly Ash Based Mortar

    PubMed Central

    Kwon, Yang-Hee; Kang, Sung-Hoon; Hong, Sung-Gul; Moon, Juhyuk

    2017-01-01

    Without using strong alkaline solution or ordinary Portland cement, a new structural binder consisting of fly ash and hydrated lime was hardened through an intensified pozzolanic reaction. The main experimental variables are the addition of silica fume and initial thermal treatment (60 °C for 3 days). A series of experiments consisting of mechanical testing (compressive and flexural strength, modulus of elasticity), X-ray diffraction, and measurements of the heat of hydration, pore structure, and shrinkage were conducted. These tests show that this new fly ash-based mortar has a compressive strength of 15 MPa at 91 days without any silica fume addition or initial thermal treatment. The strength increased to over 50 MPa based on the acceleration of the intensified pozzolanic reaction from the silica fume addition and initial thermal treatment. This is explained by a significant synergistic effect induced by the silica fume. It intensifies the pozzolanic reaction under thermal treatment and provides a space filling effect. This improved material performance can open a new pathway to utilize the industrial by-product of fly ash in cementless construction materials. PMID:28772585

  14. The impact of subsidence on straight and curved modular cementless revision stems in hip revision surgery.

    PubMed

    Fraile Suari, A; Gil González, S; Pérez Prieto, D; León García, A; Mestre Cortadellas, C; Tey Pons, M; Marqués López, F

    Subsidence is one of the potential complications in femoral stem revision total hip arthroplasty surgery, and can affect stability and osseointegration. A retrospective study was conducted on the outcomes at one year and 5 years (specifically subsidence and clinical relevance) of 40 consecutive femoral total hip arthroplasty revisions, comparing two modular cementless revision stems, Straight vs. Curved, with 20 patients in each group. No mechanical failure was observed, and there was an improvement in functional outcomes. Mean radiological subsidence was 9.9±4.9mm (straight=10.75mm vs. curved=9.03mm), with no statistically significant difference between groups (p=0,076). Fourteen patients (35%) had ≥10mm of subsidence, up to a maximum of 22mm. The subsidence found in this study is similar to published series, with no short-term clinical manifestations, or an increased number of complications or stem loosening in either the Straight or Curved group. No differences in subsidence were observed at one year and 5 years after surgery between the 2 types of stems. Copyright © 2017 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Cementless Gustilo-Kyle and BIAS total hip arthroplasty: 2- to 5-year results.

    PubMed

    Kienapfel, H; Martell, J; Rosenberg, A; Galante, J

    1991-01-01

    We conducted extensive radiographic and clinical examination of 58 cementless total hip arthroplasties. Forty BIAS femoral stems had heads made of Co-base F 75 alloy and 18 Gustilo-Kyle femoral stems had Ti6A14V alloy heads. The cross-sectional geometry and location of the porous coating pads of the two stem types was identical, the BIAS component being slightly shorter. At the last follow-up, 27.8% of the Gustilo-Kyle femoral components and 2.5% of the BIAS femoral components were unstable. None of the acetabular components in the BIAS group as against 38.9% of the acetabular components in the Gustilo-Kyle group demonstrated wear of more than 1 mm. All unstable components which did not suffer intraoperative fracture had also acetabular wear of more than 1 mm. The only case with endosteal erosion was seen in a patient with an unstable implant displaying the most extensive wear. Nonparametric statistical analysis showed that the patients with Ti6A14V/polyethylene bearing surfaces had a statistically significantly higher extent of wear and a statistically significant higher incidence of femoral component loosening than patients with CrCoMo/polyethylene bearing surfaces.

  16. Short-term wear of Japanese highly cross-linked polyethylene in cementless THA.

    PubMed

    Miyanishi, Keita; Hara, Toshihiko; Kaminomachi, Shigekazu; Maekawa, Masayuki; Iwamoto, Mikio; Torisu, Takehiko

    2008-09-01

    Production of polyethylene wear from acetabular liners is thought, in part, to mediate the periprosthetic osteolysis. This study examined the in vivo wear performance of Japanese highly cross-linked polyethylene (Aeonian) in cementless total hip arthroplasty. Ninety-five hips received a highly cross-linked polyethylene liner, while 20 hips were implanted with conventional polyethylene. Two-dimensional linear wear was measured on radiographs and volumetric wear was then calculated. Both linear and volumetric wear rates were examined for the 1-year postoperative period as well as for the time frame beginning after 1 year ending with the final follow-up. The amount of linear wear was significantly lower in the cross-linked group at 3 and 5 years postoperatively (P < 0.01 and < 0.001, respectively). Linear and volumetric wear rates after 1 year postoperatively for hips with the cross-linked polyethylene were significantly reduced by 57 and 59%, respectively, when compared to rates for those who received conventional polyethylene (P < 0.01). A multiple logistic regression analysis revealed that cross-linking was a significant factor influencing linear wear rate after 1 year postoperatively with an odds ratio, exp(ss) = 10.033 (P < 0.001). These results suggest that the highly cross-linked polyethylene reduces penetration of the femoral head and may be an optimal bearing surface for patients receiving total hip arthroplasty.

  17. Design process of cementless femoral stem using a nonlinear three dimensional finite element analysis

    PubMed Central

    2014-01-01

    Background Minimal available information concerning hip morphology is the motivation for several researchers to study the difference between Asian and Western populations. Current use of a universal hip stem of variable size is not the best option for all femur types. This present study proposed a new design process of the cementless femoral stem using a three dimensional model which provided more information and accurate analysis compared to conventional methods. Methods This complete design cycle began with morphological analysis, followed by femoral stem design, fit and fill analysis, and nonlinear finite element analysis (FEA). Various femur parameters for periosteal and endosteal canal diameters are measured from the osteotomy level to 150 mm below to determine the isthmus position. Results The results showed better total fit (53.7%) and fill (76.7%) canal, with more load distributed proximally to prevent stress shielding at calcar region. The stem demonstrated lower displacement and micromotion (less than 40 μm) promoting osseointegration between the stem–bone and providing primary fixation stability. Conclusion This new design process could be used as a preclinical assessment tool and will shorten the design cycle by identifying the major steps which must be taken while designing the femoral stem. PMID:24484753

  18. A finite element analysis of the vibration behaviour of a cementless hip system.

    PubMed

    Pérez, M A; Seral-García, B

    2013-01-01

    An early diagnosis of aseptic loosening of a total hip replacement (THR) by plain radiography, scintigraphy or arthography has been shown to be less reliable than using a vibration technique. However, it has been suggested that it may be possible to distinguish between a secure and a loose prosthesis using a vibration technique. In fact, vibration analysis methods have been successfully used to assess dental implant stability, to monitor fracture healing and to measure bone mechanical properties. Several studies have combined the vibration technique with the finite element (FE) method in order to better understand the events involved in the experimental technique. In the present study, the main goal is to simulate the change in the resonance frequency during the osseointegration process of a cementless THR (Zweymüller). The FE method was used and a numerical modal analysis was conducted to obtain the natural frequencies and mode shapes under vibration. The effects were studied of different bone and stem material properties, and different contact conditions at the bone-implant interface. The results were in agreement with previous experimental and computational observations, and differences among the different cases studied were detected. As the osseointegration process at the bone-implant interface evolved, the resonance frequency values of the femur-prosthesis system also increased. In summary, vibration analysis combined with the FE method was able to detect different boundary conditions at the bone-implant interface in cases of both osseointegration and loosening.

  19. The use of a constrained cementless acetabular component for instability in total hip replacement.

    PubMed

    Rady, Ahmad Emad; Asal, Mohammed Kamal; Bassiony, Ayman Abdelaziz

    2010-01-01

    Recurrent dislocation after total hip arthroplasty is a disabling complication that can be difficult to treat. We evaluated the early clinical and radiographic outcome associated with the use of a constrained acetabular component for instability in total hip arthroplasty. Fifteen patients underwent either primary or revision total hip arthroplasty with a cementless constrained acetabular component for different indications. The mean patient age at surgery was 57.4 years and the mean clinical and radiological follow-up period was 26.4 months. Clinical assessment was performed by the Harris hip score and at the latest follow up patients reported outcome using the Oxford hip score questionnaire. All radiographs were evaluated for evidence of loosening. Only one patient experienced redislocation with the constrained prosthesis. The average Harris hip score increased from a preoperative mean of 22 (range, 16 - 36) to a postoperative mean of 85 (range, 66-94). Preoperatively, the mean Oxford Hip Score was 48.6, which decreased to 20.5 at the final examination. All but one of the 15 hips had a well-fixed, stable cup. Femoral component stability with bone ingrowth was achieved in 10 cases. A constrained acetabular component is an effective option for the treatment of hip instability in primary and revision arthroplasty in those at high risk of dislocation. The potential for aseptic loosening requires evaluation by long term studies.

  20. Fabrication of low-cost, cementless femoral stem 316L stainless steel using investment casting technique.

    PubMed

    Baharuddin, Mohd Yusof; Salleh, Sh-Hussain; Suhasril, Andril Arafat; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Omar, Mohd Afian; Abd Kader, Ab Saman; Mohd Noor, Alias; A Harris, Arief Ruhullah; Abdul Majid, Norazman

    2014-07-01

    Total hip arthroplasty is a flourishing orthopedic surgery, generating billions of dollars of revenue. The cost associated with the fabrication of implants has been increasing year by year, and this phenomenon has burdened the patient with extra charges. Consequently, this study will focus on designing an accurate implant via implementing the reverse engineering of three-dimensional morphological study based on a particular population. By using finite element analysis, this study will assist to predict the outcome and could become a useful tool for preclinical testing of newly designed implants. A prototype is then fabricated using 316L stainless steel by applying investment casting techniques that reduce manufacturing cost without jeopardizing implant quality. The finite element analysis showed that the maximum von Mises stress was 66.88 MPa proximally with a safety factor of 2.39 against endosteal fracture, and micromotion was 4.73 μm, which promotes osseointegration. This method offers a fabrication process of cementless femoral stems with lower cost, subsequently helping patients, particularly those from nondeveloped countries.

  1. Metallosis with pseudotumour formation: Long-term complication following cementless total hip replacement in a dog

    PubMed Central

    Volstad, Nicola J.; Schaefer, Susan L.; Snyder, Laura A.; Meinen, Jeffrey B.; Sample, Susannah J.

    2017-01-01

    Summary Case description A 10-year-old female Belgian Teruven dog was presented to our clinic for total hip revision following a diagnosis of implant (cup) failure with metallosis and abdominal pseudotumour formation. The patient had a cementless metal-on-polyethylene total hip replacement performed nine years prior to presentation. Clinical findings The clinical findings, including pseudotumour formation locally and at sites distant from the implant and pain associated with the joint replacement, were similar to those described in human patients with this condition. Histopathological, surgical, and radiographic findings additionally supported the diagnosis of metallosis and pseudotumour formation. Treatment and outcome Distant site pseudo tumours were surgically removed and the total hip replacement was explanted due to poor bone quality. The patient recovered uneventfully and has since resumed normal activity. Conclusion In veterinary patients with metal-on-polyethylene total hip implants, cup failure leading to metallosis and pseudotumour formation should be considered as a potential cause of ipsilateral hindlimb lameness, intra-pelvic abdominal tumours, or a combination of both. These clinical findings may occur years after total hip replacement surgery. PMID:27189390

  2. West Flank Coso FORGE Magnetotelluric 3D Data

    SciTech Connect

    Doug Blankenship

    2016-01-01

    This is the 3D version of the MT data for the West Flank FORGE area.The Coso geothermal field has had three Magnetotelluric (MT) datasets collected including surveys in 2003, 2006, and 2011. The final collection, in 2011, expanded the survey to the west and covers the West Flank of FORGE area.This most recent data set was collected by Schlumberger/WesternGeco and inverted by the WesternGeco GeoSolutions Integrated EM Center of Excellence in Milan, Italy; the 2003 and 2006 data were integrated for these inversions in the present study.

  3. A New Definition of Shape Complexity Factor in Forging

    NASA Astrophysics Data System (ADS)

    Ara, R. Hosseini; Poursina, M.; Golastanian, H.

    2007-04-01

    One of the main objectives of forging process design is to ensure adequate metal flow in the dies so that the desired finished part geometry can be obtained without any internal or external defects. This paper presents a preform design method which employs a new criterion based on shape complexity factor to determine the necessity of preform stages for axisymmetric forging parts. The presented criterion was tested on several examples using finite element method to verify the models. Comparison of the new shape complexity factor with the other ones shows that the new criterion is more accurate in estimating the number of preform stages.

  4. Isothermal Roll Forging of T55 Compressor Blades

    DTIC Science & Technology

    1977-12-01

    VI LIST OF FIGURES Figure Page 1 Some Stages in Cold Roll-Forging of Compressor Blade 4 in 17 - 4PH Steel 2 Single Pass Isothermal Rolling of 0.375...operations in blade manufacture by this method are shown in Figure 1 for a cold-rolled compressor blade in 17 - 4PH steel used in a Solar turbine. In the...34’■ ’y^ at ̂ ^PP Figure 1, Some Stages in Cold Steel (#76-2679) Roll-Forging of Compressor Blade in 17 - 4PH 2.2 THE ISOTHERMAL ROLL

  5. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; Watkins, R.D.

    1988-01-21

    Glass compositions containing CaO, Al/sub 2/O/sub 3/, B/sub 2/O/sub 3/, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  6. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1992-01-01

    Glass compositions containing CaO, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  7. Cytotoxicity of titanium and titanium alloying elements.

    PubMed

    Li, Y; Wong, C; Xiong, J; Hodgson, P; Wen, C

    2010-05-01

    It is commonly accepted that titanium and the titanium alloying elements of tantalum, niobium, zirconium, molybdenum, tin, and silicon are biocompatible. However, our research in the development of new titanium alloys for biomedical applications indicated that some titanium alloys containing molybdenum, niobium, and silicon produced by powder metallurgy show a certain degree of cytotoxicity. We hypothesized that the cytotoxicity is linked to the ion release from the metals. To prove this hypothesis, we assessed the cytotoxicity of titanium and titanium alloying elements in both forms of powder and bulk, using osteoblast-like SaOS(2) cells. Results indicated that the metal powders of titanium, niobium, molybdenum, and silicon are cytotoxic, and the bulk metals of silicon and molybdenum also showed cytotoxicity. Meanwhile, we established that the safe ion concentrations (below which the ion concentration is non-toxic) are 8.5, 15.5, 172.0, and 37,000.0 microg/L for molybdenum, titanium, niobium, and silicon, respectively.

  8. Titanium sponge on titanium substrate for titanium electrolytic capacitor anodes

    NASA Astrophysics Data System (ADS)

    Ki, Jun-Wan

    2005-07-01

    Capacitors are energy storage devices capable of supplying electric energy. Volumetric and gravimetric energy storage efficiencies are some of the important criteria for evaluating electrolytic capacitors as energy storage devices. High energy density capacitors can be achieved by anodic growth of a dielectric film on surface enhanced valve-metal. Electrodes with high surface area accessible along with wide and short conduction paths (electrolyte) have advantages as power devices. Surface-enhanced metal substrates can be made by various methods. One method is by oxidation followed by reduction. Oxidation of a metal and reduction of oxide are generally associated with volume changes. During growth of an oxide scale on a metal substrate, the volume expansion of an attached oxide scale can only occur in the thickness direction. During subsequent reduction of the oxide volume shrinkage occurs. It can take place along all directions, in particular in the plane of the oxide scale. This shrinkage leads to pores in the metal layer that is formed by the reduction of the oxide scale. Therefore, a layer of titanium sponge can be obtained by the oxidation plus reduction method. The titanium sponge layer can be anodized in order to grow a thin dielectric film on the surface of the sponge metal. In this way it is made into a capacitor anode. Reduction of titanium oxide scale with magnesium or calcium produces titanium sponge with different morphologies. Magnesium-reduced sponge has a higher degree of porosity than calcium-reduced sponge. The different morphologies of the reduced oxide scale result from different reduction behaviors in the presence of magnesium or calcium. Possible mechanisms are suggested to explain how magnesium and calcium affect the reduction behavior of titanium oxide. Because titanium anodic films tend to have high leakage current, titanium is not used for commercial electrolytic capacitor anodes. Nitrogen and oxygen doping of titanium surface layer enables

  9. 77 FR 14445 - Application for a License To Export Steel Forging

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION Application for a License To Export Steel Forging Pursuant to 10 CFR 110.70(b) ``Public Notice of... Spain. December 15, 2011 head steel head steel February 7, 2012 forging. forging will be XR175...

  10. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... Commission. ACTION: Institution of five-year reviews concerning the antidumping duty orders on forged... determine whether revocation of the antidumping duty orders on forged stainless steel flanges from India and... (``Commerce'') issued antidumping duty orders on imports of forged stainless steel flanges from India and...

  11. Influence of free forging conditions on austenitic grain growth in constructional steel

    NASA Astrophysics Data System (ADS)

    Zagulyaeva, S. V.; Potanina, V. S.; Vinograd, M. I.

    1984-02-01

    The initial period of austenitic grain growth in heating of a hot forged billet of 50G-SSh steel and of forgings after free forging is characterized by the formation of a mixed grain structure of No. 8 fine grains and No. 3-0 coarse.

  12. 76 FR 30200 - Forging Machines; Extension of the Office of Management and Budget's (OMB) Approval of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-24

    ... Occupational Safety and Health Administration Forging Machines; Extension of the Office of Management and... contained in the Forging Machines Standard (29 CFR 1910.218). The paperwork provisions of the Standard... ensuring that forging machines used by them are in safe operating condition, and employees are able...

  13. Modelling of the radial forging process of a hollow billet with the mandrel on the lever radial forging machine

    NASA Astrophysics Data System (ADS)

    Karamyshev, A. P.; Nekrasov, I. I.; Pugin, A. I.; Fedulov, A. A.

    2016-04-01

    The finite-element method (FEM) has been used in scientific research of forming technological process modelling. Among the others, the process of the multistage radial forging of hollow billets has been modelled. The model includes both the thermal problem, concerning preliminary heating of the billet taking into account thermal expansion, and the deformation problem, when the billet is forged in a special machine. The latter part of the model describes such features of the process as die calibration, die movement, initial die temperature, friction conditions, etc. The results obtained can be used to define the necessary process parameters and die calibration.

  14. Recent Advancement in Titanium Near-Net-Shape Technology

    NASA Astrophysics Data System (ADS)

    Chen, Charlie C.

    1982-11-01

    Significant advancements in near-net-shape technologies for titanium alloys have been achieved in 1970s. These technologies are now readily applicable as major manufacturing methods of producing structural and engine components for aerospace and defense industry applications. The cost effectiveness of the NNS technologies depends on the processing variables, part quantity, and shape and size of a particular component and alloy. These technologies possess major advantages over conventional methods, including reduced material and cost, reduced machining requirement and cost, improved shape-making capability, and precise control of processing variables and resultant microstructure and properties. Each of these technologies has specific advantages and limitations, and both technological and economic feasibilities must be analyzed before any of these technologies could be effectively implemented. Selection of NNS processes depends on part economics, performance, and quality standards; however, the hot-die forging approach is the most promising route for the manufacturing NNS critical titanium components. This approach by the strain-softening-forge process exhibits the greatest advantages in cost reduction, property upgrading, shape-making, and process flexibility. It provides the capability of precise control and selective use of processing variables to achieve the specific design property requirements.

  15. Cementless modular hip arthroplasty as a salvage operation for failed internal fixation of trochanteric fractures in elderly patients.

    PubMed

    Laffosse, Jean-Michel; Molinier, François; Tricoire, Jean-Louis; Bonnevialle, Nicolas; Chiron, Philippe; Puget, Jean

    2007-12-01

    Failure of internal fixation of trochanteric fractures requires repeat surgery in order to avoid the risks of complications affecting bedridden patients. This study was conducted to assess the results of hemi- or total hip arthroplasty with a cementless modular femoral stem, as a salvage operation following early mechanical failure of internal fixation. Twenty nine patients with a mean age of 81.1 years (70-91) were included in the study. Fractures extending into the diaphysis and pathological fractures were excluded, as well as patients who presented late complications. A cementless modular stem designed for metaphyso-diaphyseal anchorage was used in all cases. Twenty-two patients underwent hemiarthroplasty and seven total hip arthroplasty. Four patients died within one year and two were lost to follow-up. The remaining 23 patients were followed for a mean of 20 months (range: 6-89). At the time of last follow-up, 20 were ambulatory with (11 cases) or without support (9 cases) and three were bedridden. There were no intra- or postoperative femoral fractures. Two patients presented an early dislocation after bipolar hemiarthroplasty. One was successfully treated by closed reduction; the other underwent revision with a dual mobility acetabular component because of recurrent dislocation. All the patients reported significant pain relief and functional improvement. Subsidence of the stem greater than 5 mm was noted in three cases, without clinical consequences. The cementless modular femoral stem used in this study appeared as a reliable implant. Primary arthroplasty with such an implant could be considered in selected cases such as markedly unstable fractures and in osteoporotic elderly patients.

  16. A multicenter approach evaluating the impact of vitamin e-blended polyethylene in cementless total hip replacement.

    PubMed

    Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, Vitas

    2014-04-22

    Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant

  17. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem.

    PubMed

    Oba, M; Inaba, Y; Kobayashi, N; Ike, H; Tezuka, T; Saito, T

    2016-09-01

    In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject-specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year. Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively. The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding.Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362-369. DOI: 10.1302/2046-3758.59.2000525. © 2016 Yutaka et al.

  18. Cementless Tapered Wedge Femoral Stems Decrease Subsidence in Obese Patients Compared to Traditional Fit-and-Fill Stems.

    PubMed

    Grant, Tanner W; Lovro, Luke R; Licini, David J; Warth, Lucian C; Ziemba-Davis, Mary; Meneghini, Robert M

    2017-03-01

    Femoral component stability and resistance to subsidence is critical for osseointegration and clinical success in cementless total hip arthroplasty. The purpose of this study was to radiographically evaluate the anatomic fit and subsidence of 2 different proximally tapered, porous-coated modern cementless femoral component designs. A retrospective cohort study of 126 consecutive cementless total hip arthroplasties was performed. Traditional fit-and-fill stems were implanted in the first 61 hips with the remaining 65 receiving morphometric tapered wedge stems. Preoperative bone morphology was radiographically assessed by the canal flare index. Canal fill in the coronal plane, subsidence, and the sagittal alignment of stems was measured digitally on immediate and 1-month postoperative radiographs. Demographics and canal flare indices were similar between groups. The percentage of femoral canal fill was greater in the tapered wedge compared to the fit-and-fill stem (P = .001). There was significantly less subsidence in the tapered wedge design (0.3 mm) compared to the fit-and-fill design (1.1 mm) (P = .001). Subsidence significantly increased as body mass index (BMI) increased in the fit-and-fill stems, a finding not observed in the tapered wedge design (P = .013). An anatomically designed morphometric tapered wedge femoral stem demonstrated greater axial stability and decreased subsidence with increasing BMI than a traditional fit-and-fill stem. The resistance to subsidence, irrespective of BMI, is likely due to the inherent axial stability of a tapered wedge design and may be the optimal stem design for obese patients. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem

    PubMed Central

    Oba, M.; Kobayashi, N.; Ike, H.; Tezuka, T.; Saito, T.

    2016-01-01

    Objectives In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. Patients and Methods We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject–specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year. Results Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively. Conclusions The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding. Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362–369. DOI: 10.1302/2046-3758.59.2000525. PMID:27601435

  20. Long-Term Results of Third-Generation Ceramic-on-Ceramic Bearing Cementless Total Hip Arthroplasty in Young Patients.

    PubMed

    Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

    2016-11-01

    The results of third-generation of alumina-on-alumina ceramic bearing in a large number of patient cohorts are limited. The purpose of this study was to determine clinical and radiologic outcome, prevalence of osteolysis detected with radiographs and computerized tomographic scan, and survivorship of a cementless total hip arthroplasty using a third-generation of alumina-on-alumina ceramic bearing in a large number of active patients aged younger than 65 years. We reviewed the cases of 871 patients (1131 hips) who underwent a cementless total hip arthroplasty when they were aged 65 years or younger at the time of surgery. The most common diagnoses were osteonecrosis (53%) and osteoarthritis (20%). Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index, and University of California, Los Angeles activity scores were recorded. Radiographic and computerized tomographic evaluations were used to evaluate implant fixation and osteolysis. The mean follow-up interval was 18.8 years (range, 15-20 years). At the time of final follow-up, the mean Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index score, and University of California, Los Angeles activity score were 90 points, 15 points, and 8 points, respectively. All the femoral stem and acetabular components were well-fixed at the time of final follow-up. No hip had aseptic loosening or osteolysis or fracture of ceramic material at the time of the final follow-up. The current results with the use of the third-generation of alumina-on-alumina ceramic bearings in young patients suggest that cementless acetabular and femoral components provide outstanding long-term fixation and provide a high rate of survivorship without evidence of osteolysis. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. A Multicenter Approach Evaluating the Impact of Vitamin E-Blended Polyethylene in Cementless Total Hip Replacement

    PubMed Central

    Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, VITAS

    2014-01-01

    Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant

  2. Removing a well-fixed nonmodular large-bearing cementless acetabular component: a simple modification of an existing removal device.

    PubMed

    Blumenfeld, Thomas J

    2010-04-01

    Removing well-fixed cementless acetabular components while minimizing bone loss has been facilitated by the use of a removal device featuring sharp curved gouges, specific to the outside diameter of the existing acetabular shell, mated to a femoral head designed to sit inside the acetabular liner. Nonmodular acetabular components with inner bearing diameters greater than 36 mm are to date not accommodated by femoral head sizes in this system. A simple modification, placement of a bipolar head matching the inner diameter of the fixed shell, allows use of this removal device for nonmodular shells. (c) 2010 Elsevier Inc. All rights reserved.

  3. Electronic Portfolios in Teacher Education: Forging a Middle Ground

    ERIC Educational Resources Information Center

    Strudler, Neal; Wetzel, Keith

    2012-01-01

    At a time when implementation of electronic portfolios (EPs) is expanding, the issues of clarifying their purposes continue to plague teacher education programs. Are student-centered uses of EPs compatible with program assessment and accreditation efforts? Is this an either/or situation, or can a productive middle ground be forged? This article…

  4. Consolidation and Forging Methods for a Cryomilled Al Alloy

    NASA Astrophysics Data System (ADS)

    Newbery, A. P.; Ahn, B.; Hayes, R. W.; Pao, P. S.; Nutt, S. R.; Lavernia, E. J.

    2008-09-01

    The method used to consolidate a cryogenically ball-milled powder is critical to the retention of superior strength along with acceptable tensile ductility in the bulk product. In this study, gas-atomized Al 5083 powder was cryomilled, hot vacuum degassed, and consolidated by hot isostatic pressing (HIP) or by quasi-isostatic (QI) forging to produce low-porosity billets. The billets were then forged, either at high strain rate (without a die) or quasi-isostatically, and subsequently hot rolled to produce three 6.5-mm-thick plates. Despite extended periods at elevated temperatures and differences between the consolidation/deformation methods, a similar predominantly ultrafine grain microstructure was obtained in all three plates. The plates possessed similar ultimate tensile strengths, about 50 pct greater than standard work-hardened Al 5083. However, in terms of fracture toughness, there were significant differences between the plates. Debonding at prior cryomilled powder particle surfaces was an important fracture mechanism for “HIPped” material, leading to low toughness for crack surfaces in the plane of the plate. This effect was minimized by the implementation of double QI forging, producing plate with good isotropic fracture toughness. The type of particle boundary deformation during forging and the influence of impurities appeared to be more important in determining fracture toughness than the presence of ˜10 vol pct coarser micron-sized grains.

  5. 16. Forge building and fuel storage shed from the southwest, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Forge building and fuel storage shed from the southwest, c.1918 Photocopied from a photograph in the collection of William F. Applegate, 43 Grandview Avenue, Wallingford, Connecticut. - Eli Whitney Armory, West of Whitney Avenue, Armory Street Vicinity, Hamden, New Haven County, CT

  6. Forging an Identity over the Life-Course

    ERIC Educational Resources Information Center

    Spiteri, Damian

    2009-01-01

    Using a social constructionist approach, this study explores the self-perceptions of young men who, when at school, were classed as boys with social, emotional and behavioural difficulties (SEBD). The aim is to understand how these perceptions were forged throughout the young men's life-courses resulting in changing self-identities. The study also…

  7. Sinter-forging of nanophase TiO sub 2

    SciTech Connect

    Uchic, M.; Hofler, H.J.; Flick, W.J.; Tao, R.; Averback, R.S. . Dept. of Materials Science and Engineering); Kurath, P. . Dept. of Mechanical Engineering)

    1992-03-01

    Considerable effort has been directed in recent years to developing ceramic materials that can be both sintered to full density at low temperatures and processed by superplastic forming. One strategy for achieving this goal has been to reduce the particle size of the starting powder, and by anaphase processing, particles of sizes less than {approx}10 nm can now be realized. Indeed, recent studies on nanophase ceramics have demonstrated that sintering temperatures can be reduced dramatically and that nanophase ceramics have excellent potential for superplastic forming. Nevertheless, the grain growth that occurs during the processing of these new materials restricts their applicability. In nanophase (n-) TiO{sub 2}, some progress in controlling grain size has been achieved by using dopants or hot pressing. Sinter-forging offers another means to achieve this goal, although this method has been applied mostly to materials with larger grains. Studies of sinter-forging are also useful for elucidating the mechanisms of sintering and creep in ceramic materials. In the present paper, the authors examine the characteristics of sinter-forging in n-TiO{sub 2}. Only limited studies of sinter-forging have thus far been performed on well characterized powders of comparable size, and even these had a somewhat larger grain size.

  8. Family Health and Financial Literacy--Forging the Connection

    ERIC Educational Resources Information Center

    Braun, Bonnie; Kim, Jinhee; Anderson, Elaine A.

    2009-01-01

    Families are at-risk of or experiencing a diminished quality of living and life in current economic times and difficult decisions are required. Health and financial literacy are the basis for wise personal and public decision making. Family and consumer sciences (FCS) professionals can forge connections between health and financial literacy to…

  9. Forging Consensus for Implementing Youth Socialization Policy in Northwest China

    ERIC Educational Resources Information Center

    Fairbrother, Gregory P.

    2011-01-01

    The goal of this article is to examine how the provincial education media in China play a role of forging consensus among local actors responsible for the implementation of new centrally-promulgated youth socialization policy. In doing so, it also explores the tension among three of the Chinese state's claims to legitimacy: economic development,…

  10. Forging an Identity over the Life-Course

    ERIC Educational Resources Information Center

    Spiteri, Damian

    2009-01-01

    Using a social constructionist approach, this study explores the self-perceptions of young men who, when at school, were classed as boys with social, emotional and behavioural difficulties (SEBD). The aim is to understand how these perceptions were forged throughout the young men's life-courses resulting in changing self-identities. The study also…

  11. The Valley Forge Encampment: Epic on the Schuylkill.

    ERIC Educational Resources Information Center

    Trussell, John B. B., Jr.

    Valley Forge, outside Philadelphia (Pennsylvania), has long been recognized as the site of a great victory of the human spirit. Eleven thousand men including Blacks and Indians resided there during the winter of 1777-78 and triumphed over cold, starvation, nakedness, disease, and uncertainty. The encampment site was unprepared for the tattered,…

  12. The Valley Forge Encampment: Epic on the Schuylkill.

    ERIC Educational Resources Information Center

    Trussell, John B. B., Jr.

    Valley Forge, outside Philadelphia (Pennsylvania), has long been recognized as the site of a great victory of the human spirit. Eleven thousand men including Blacks and Indians resided there during the winter of 1777-78 and triumphed over cold, starvation, nakedness, disease, and uncertainty. The encampment site was unprepared for the tattered,…

  13. Evaluation of Lubrication Systems for Isothermal Forging of Alpha-Beta and Beta Titanium Alloys.

    DTIC Science & Technology

    1977-11-01

    U R FS , C o n t i n u e d Fliure 19a Closeup t o p view of s t r u c t u r a l compo — nent fore ~ ni s produced by I sot hernia Ifori inq at I t...a 1 Po~~c- ’t i p t j on of iso t hernia l !~-o t ; in ~ Li tb r ican t s Sel e c t e d fo i - Phase I ( ‘ t a sk I I ) i- t I I o t t f o...K20) 24 gm of TiC 457 gin of xylene 78.1 gin of acrylic binder Acheson Delta_ ** water—based silicate glass compound Colloids g laze Company 69 TRW

  14. A comparison of the sintering of various titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-02-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press- and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics; with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  15. Parameter Optimization During Forging Process of a Novel High-Speed-Steel Cold Work Roll

    NASA Astrophysics Data System (ADS)

    Guo, Jing; Liu, Ligang; Sun, Yanliang; Li, Qiang; Ren, Xuejun; Yang, Qingxiang

    2016-01-01

    The forging of high-speed-steel (HSS) roll has always been a technical problem in manufacturing industry. In this study, the forging process of a novel HSS cold work roll was simulated by deform-3D on the basis of rigid-viscoplastic finite element model. The effect of heating temperature and forging speed on temperature and stress fields during forging process was simulated too. The results show that during forging process, the temperature of the contact region with anvils increases. The stress of the forging region increases and distributes un-uniformly, while that of the non-forging region is almost zero. With increasing forging time, Z load on anvil increases gradually. With increasing heating temperature or decreasing forging speed, the temperature of the whole billet increases, while the stress and Z load on anvil decrease. In order to ensure the high efficiency and safety of the forging process, the heating temperature and the forging speed are chosen as 1160 °C and 16.667 mm/s, respectively.

  16. A large scale finite element study of a cementless osseointegrated tibial tray.

    PubMed

    Galloway, Francis; Kahnt, Max; Ramm, Heiko; Worsley, Peter; Zachow, Stefan; Nair, Prasanth; Taylor, Mark

    2013-07-26

    The aim of this study was to investigate the performance of a cementless osseointegrated tibial tray (P.F.C. ® Sigma®, Depuy® Inc, USA) in a general population using finite element (FE) analysis. Computational testing of total knee replacements (TKRs) typically only use a model of a single patient and assume the results can be extrapolated to the general population. In this study, two statistical models (SMs) were used; one of the shape and elastic modulus of the tibia, and one of the tibiofemoral joint loads over a gait cycle, to generate a population of FE models. A method was developed to automatically size, position and implant the tibial tray in each tibia, and 328 models were successfully implanted and analysed. The peak strain in the bone of the resected surface was examined and the percentage surface area of bone above yield strain (PSAY) was used to determine the risk of failure of a model. Using an arbitrary threshold of 10% PSAY, the models were divided into two groups ('higher risk' and 'lower risk') in order to explore factors that may influence potential failure. In this study, 17% of models were in the 'higher risk' group and it was found that these models had a lower elastic modulus (mean 275.7MPa), a higher weight (mean 85.3kg), and larger peak loads, of which the axial force was the most significant. This study showed the mean peak strain of the resected surface and PSAY were not significantly different between implant sizes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Radiologic bone adaptations on a cementless short-stem shoulder prosthesis.

    PubMed

    Schnetzke, Marc; Coda, Sebastian; Raiss, Patric; Walch, Gilles; Loew, Markus

    2016-04-01

    This study evaluated the timing and location of radiologic bone adaptations related to shoulder arthroplasty using a single type of cementless short-stem shoulder prosthesis. Uncemented short-stem shoulder arthroplasties were evaluated in 52 patients at a mean age of 71.6 years (range, 58.1-86.6) with a minimum clinical and radiologic follow-up of 2 years (mean, 32 months; range, 23-52 months). All radiographs were analyzed for inclination of the stem, filling ratio of metaphysis and diaphysis, bone remodeling around the stem, radiolucent lines around the glenoid, and subsidence of the humeral stem. Finally, the radiographic and clinical findings were compared between patients with low and high bone adaptations. At final follow-up, no loosening, subsidence, or osteolysis was seen. High bone adaptations were present in 27 patients (51.9%). Cortical thinning and osteopenia in the medial cortex (82.7%) and spot welds in the lateral cortex (78.6%) were the most frequently occurring bone adaptations. Patients with high bone adaptations had significantly higher metaphyseal (0.60 ± 0.05 vs. 0.56 ± 0.06; P = .024) and diaphyseal filling ratio (0.66 ± 0.04 vs. 0.61 ± 0.06; P = .019) at 2-year follow-up than patients with low bone adaptations. Clinical outcome was not influenced by the radiographic changes. The clinical and radiologic results of the short-stem shoulder arthroplasty are comparable to those with the third and fourth generations of standard stem arthroplasty. Higher filling ratios in the metaphysis and the diaphysis were significantly associated with the occurrence of high bone adaptations. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  18. The dimensional accuracy of preparation of femoral cavity in cementless total hip arthroplasty*

    PubMed Central

    Wu, Li-dong; Hahne, HJ; Hassenpflug, J

    2004-01-01

    Objective: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. Methods: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3 mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface, the gap width and the percentage of gap and bone contact area were measured in every slice. Results: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81 mm and the average gap width was only 0.20 mm. While in the conventional group, the average percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97 mm and the average gap width was 0.77 mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% higher bone contact than the manual group. Conclusion: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty. PMID:15362200

  19. Sustained load crack growth design data for Ti-6Al-4V titanium alloy tanks containing hydrazine

    NASA Technical Reports Server (NTRS)

    Lewis, J. C.; Kenny, J. T.

    1976-01-01

    Sustained load crack growth data for Ti-6Al-4V titanium alloy in hydrazine per MIL-P-26536 and refined hydrazine are presented. Fracture mechanics data on crack growth thresholds for heat-treated forgings, aged and unaged welds, and aged and unaged heat-affected zones are reported. Fracture mechanics design curves of crack growth threshold stress intensity versus temperature are generated from 40 to 71 C.

  20. Sports and physical activity after cementless total hip arthroplasty with a minimum follow-up of 10 years.

    PubMed

    Innmann, M M; Weiss, S; Andreas, F; Merle, C; Streit, M R

    2016-05-01

    The present retrospective cohort study was conducted to compare sporting activity levels before and a minimum of 10 years after primary cementless total hip arthroplasty (THA). A consecutive series of 86 patients with a mean age at surgery of 52 years (range, 21-60 years) was evaluated 11 years after surgery (range, 10-12 years). Pre- and post-operative sporting activities were assessed at routine follow-up using the University of California, Los Angeles activity score and the Schulthess Clinic sports and activity questionnaire. Post-operative health-related quality of life was measured using the Short-Form 36 (SF-36) questionnaire and compared with age-matched reference populations from the SF-36 database. Eleven years after THA, 89% of preoperatively active patients had returned to sport. Comparing sports activity preoperatively (before the onset of symptoms) and 11 years after THA, no significant difference was found for the mean number of disciplines or session length. A significant decline in high-impact activities was observed, while participation in low-impact activities significantly increased. Health-related quality of life compared well against a healthy age-matched reference population and was significantly higher than in a reference group of patients with osteoarthritis. The majority of patients were able to maintain their physical activity level in the long term after primary cementless THA, compared with the activity level before the onset of restricting osteoarthritis symptoms. However, a change in disciplines toward low-impact activities was observed.

  1. Midterm Outcome of Cementless Total Hip Arthroplasty in Crowe IV-Hartofilakidis Type III Developmental Dysplasia of the Hip.

    PubMed

    Mu, Wenbo; Yang, Desheng; Xu, Boyong; Mamtimin, Askar; Guo, Wentao; Cao, Li

    2016-03-01

    Developmental dysplasia of the hip (DDH) is widespread in developing countries, and treating Crowe IV-Hartofilakidis Type III DDH in adults requires the use of a highly demanding technique. We sought to determine the outcome of cementless total hip arthroplasty using Zweymüller components to treat Crowe IV-Hartofilakidis Type III DDH. Fifty-eight patients (71 hips) with a mean age of 35.8 years at time of index operation were included in our study. The average duration of follow-up was 70.5 months. The acetabular component was placed in the true acetabulum in all cases, and subtrochanteric shortening osteotomy was performed in 61 hips. With any component revision for any reason as the end point, Kaplan-Meier survivorship analysis at 98 months revealed a cumulative survival rate for implanted components of 91.40%. The mean Harris Hip Score improved from 35.6 preoperatively to 82.9 postoperatively. There were 20 cases of intraoperative fracture, 1 case of complete nerve palsy, and 7 cases of transient nerve palsy. Revision surgery was performed in 7 patients because of cup loosening in 1, severe polyethylene wear in 4, cup breakage in 1, and dislocation in 1. Midterm results for cementless total hip arthroplasty in patients with Crowe IV-Hartofilakidis Type III DDH was satisfactory; however, intraoperative fracture and polyethylene wear were major complications. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Development of the Dynamic Globularization Prediction Model for Ti-17 Titanium Alloy Using Finite Element Method

    NASA Astrophysics Data System (ADS)

    Jia, Zhiqiang; Zeng, Weidong; Xu, Jianwei; Zhou, Jianhua; Wang, Xiaoying

    2015-04-01

    In this work, a finite element method (FEM) model for predicting dynamic globularization of Ti-17 titanium alloy is established. For obtaining the microstructure evolution during dynamic globularization under varying processing parameters, isothermal hot compression tests and quantitative metallographic analysis were conducted on Ti-17 titanium alloy with initial lamellar microstructure. The prediction model, which quantitatively described the non-linear relationship between the dynamic globularization fraction and the deformation strain, temperature, and strain rate, was developed on the basis of the Avrami equation. Then the developed model was incorporated into DEFORM software as a user subroutine. Finally, the large-sized step-shaped workpiece was isothermally forged and corresponding FEM simulation was conducted to verify the reliability and accuracy of the integrated FEM model. The reasonable coincidence of the predicted results with experimental ones indicated that the established FEM model provides an easy and a practical method to predict dynamic globularization for Ti-17 titanium alloy with complex shape.

  3. Titanium Nitride Cermets

    DTIC Science & Technology

    1952-07-01

    7696i ’-Brewer, L., et al. Thermodynamic and Physical Properties of Nitrides. Carbides, Sulfides, i1licides, and Phosphides, Chemistry and Metallurgy of...12 Referen eCs 0 . ...................... • • • 14 WADC TR 52-155 iv LIST OF TABLES I Properties of Titanium Nitride Bodies...15 II Properties of Titanium Nitride-Nickel Bodies............16 III Properties of Titanium Nitride Cermets with Nickel,..... 17 Cobalt, and

  4. Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

    PubMed Central

    Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R

    2015-01-01

    Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617

  5. First Results of Energy Saving at Process Redesign of Die Forging Al-Alloys

    SciTech Connect

    Pepelnjak, Tomaz; Kuzman, Karl; Kokol, Anton

    2011-05-04

    The contribution deals with eco-friendly solutions for shortened production chains of forging light alloys. During the die forging operations a remarkable amount of material goes into the flash and later on into chips during finish machining. These low value side products are rich with embedded energy therefore recycling or reprocessing could be very energy saving procedure.In cooperation with a die forging company a shortened reprocessing cycle has been studied starting from re-melting the forging flash and without additional heating to cast preforms for subsequent die forging. As such preforms have not as good formability characteristics as those done from extruded billets the isothermal forging process has been adopted. First results showed that without cracks and other defects the formability is sufficient for a broad spectrum of forgings.To improve the formability a homogenization process of cast preforms has been implemented. As the process started immediately after casting, amount of additional energy for heating was minimized. To reduce voids forging process was redesigned in a way to assure greater hydrostatic pressures in parts during forging. First results were promising therefore research is going towards improving processes without adding significantly more energy as it is needed for casting with homogenization and die forging.

  6. Crack toughness evaluation of hot pressed and forged beryllium.

    NASA Technical Reports Server (NTRS)

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

    1973-01-01

    Fracture toughness tests at room temperature were made on three-point loaded beryllium bend specimens cut from hot pressed block and a forged disk. These specimens had plane proportions conforming to ASTM E 399 and covered a thickness range of from 1/32 to 1/2 in. Two sets of bend specimens were tested, one having fatigue cracks and the other 0.5 mil radius notches. One objective of the investigation was the development of techniques to produce fatigue cracks in accordance with the procedures specified in ASTM E 399. This objective was achieved for the hot pressed material. In plane cracks were not consistently produced in the specimens cut from forged stock.

  7. West Flank Coso, CA FORGE ArcGIS data 2

    SciTech Connect

    Doug Blankenship

    2016-03-01

    archive of ArcGIS data from the West Flank FORGE site located in Coso, California. Archive contains: 8 shapefiles polygon of the 3D geologic model polylines of the traces 3D modeled faults polylines of the fault traces from Duffield and Bacon, 1980 polygon of the West Flank FORGE site polylines of the traces of the geologic cross-sections (cross-sections in a separate archive in the GDR) polylines of the traces of the seismic reflection profiles through and adjacent to the West Flank site (seismic reflection profiles in a separate archive in the GDR) points of the well collars in and around the West Flank site polylines of the surface expression of the West Flank well paths

  8. Crack toughness evaluation of hot pressed and forged beryllium.

    NASA Technical Reports Server (NTRS)

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

    1973-01-01

    Fracture toughness tests at room temperature were made on three-point loaded beryllium bend specimens cut from hot pressed block and a forged disk. These specimens had plane proportions conforming to ASTM E 399 and covered a thickness range of from 1/32 to 1/2 in. Two sets of bend specimens were tested, one having fatigue cracks and the other 0.5 mil radius notches. One objective of the investigation was the development of techniques to produce fatigue cracks in accordance with the procedures specified in ASTM E 399. This objective was achieved for the hot pressed material. In plane cracks were not consistently produced in the specimens cut from forged stock.

  9. Process modeling and development for three axisymmetric net shape forgings

    SciTech Connect

    El-Gizawy, A.S. . Dept. of Mechanical Aerospace Engineering)

    1992-03-01

    The results of dynamic material modeling experiments are reported on aluminum alloys 6061 and 7050, and steel alloy 4340. This information was used to accurately describe the variables in the various constitutive equations used in computer modeling programs. A description of the experimental equipment used to deform the specimens and gather data was given. Previously reported work regarding computer modeling of interface friction and the forging process was reviewed. Using dynamic flow models, three different axisymmetric parts were analyzed for their potential for being produced by net shape or near net shape forging processes. Two aluminum alloy parts were recommended as potential candidates while the steel part was not a potential candidate. Recommendations for processing conditions were also given. 18 refs.

  10. Process modelings and simulations of heavy castings and forgings

    NASA Astrophysics Data System (ADS)

    Li, Dianzhong; Sun, Mingyue; Wang, Pei; Kang, Xiuhong; Fu, Paixian; Li, Yiyi

    2013-05-01

    The Materials Process Modeling Division, IMR, CAS has been promoting for more than 10 years research activities on modeling and experimental studies on heavy castings and forgings. In this report, we highlight some selected achievements and impacts in this area: To satisfy domestic strategic requirements, such as nuclear and hydraulic power, marine projects and high speed rail, we have developed a number of casting and forging technologies, which combine advanced computing simulations, X-ray real time observation techniques and industrial-scaled trial experiments. These technologies have been successfully applied in various industrial areas and yielded a series of scientific and technological breakthroughs and innovation. Important examples of this strategic research include the hot-processing technologies of the Three Gorge water turbine runner, marine crankshaft manufacturers, backup rolls for hot rolling mills and the production of hundreds-ton steel ingot.

  11. Performance Assessment Method for a Forged Fingerprint Detection Algorithm

    NASA Astrophysics Data System (ADS)

    Shin, Yong Nyuo; Jun, In-Kyung; Kim, Hyun; Shin, Woochang

    The threat of invasion of privacy and of the illegal appropriation of information both increase with the expansion of the biometrics service environment to open systems. However, while certificates or smart cards can easily be cancelled and reissued if found to be missing, there is no way to recover the unique biometric information of an individual following a security breach. With the recognition that this threat factor may disrupt the large-scale civil service operations approaching implementation, such as electronic ID cards and e-Government systems, many agencies and vendors around the world continue to develop forged fingerprint detection technology, but no objective performance assessment method has, to date, been reported. Therefore, in this paper, we propose a methodology designed to evaluate the objective performance of the forged fingerprint detection technology that is currently attracting a great deal of attention.

  12. Isothermal Roll Forging of T55 Compressor Blades. Phase 2

    DTIC Science & Technology

    1980-06-01

    Forge Deformation on Delta Ferrite Bonding 11 Microstructure of Molybdenum Alloy MT-104 Die Facings 19 12 Chemical Analysis of MT-104 Powder and...dark etching islands of delta ferrite , containing finely precipitated austenite, in a lighter etching matrix of martensite . Carbide precipitation...able as it consists of tempered martensite with discontinuous delta ferrite , and there is no evidence of heavy grain boundary carbides. All surface

  13. Internal Shear Forging Processes for Missile Primary Structures.

    DTIC Science & Technology

    1981-07-20

    34Roll Extruding Precision Seamless Pipe and Tubing ," Metal Progress, June 1977, pp. 28-31. See also "Recent Advances m in Roll Extrusion ," in Rotary...15 14 Internal roll extrusion of ribs using moving inner mandrel. 16 15 Test setup to subject tubes to continuously increasing wall...angles in extrusion , drawing, and shear forging, shown here for cold tube extrusion . .. .. . ... .. ... . .. 23 19 Buildup in various stages of shear

  14. Occurrence of shear bands in isothermal, hot forging

    SciTech Connect

    Semiatin, S.L.; Lahoti, G.D.

    1982-02-01

    The paper is a continuation of previously reported work on deformation and unstable flow in hot forging and hot torsion. The instability criterion is employed to interpret data and shear band observations. In addition, computer simulations were run to obtain detailed strain, strain rate, and stress histories. This analysis formed the basis for workability maps which delineate safe regimes for hot working in terms of strain rate and temperature. 34 refs.

  15. Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR): A Logic Model.

    PubMed

    Gill, Simone V; Khetani, Mary A; Yinusa-Nyahkoon, Leanne; McManus, Beth; Gardiner, Paula M; Tickle-Degnen, Linda

    2017-07-01

    In a patient-centered care era, rehabilitation can benefit from researcher-clinician collaboration to effectively and efficiently produce the interdisciplinary science that is needed to improve patient-centered outcomes. The authors propose the use of the Forging Alliances in Interdisciplinary Rehabilitation Research (FAIRR) logic model to provide guidance to rehabilitation scientists and clinicians who are committed to growing their involvement in interdisciplinary rehabilitation research. We describe the importance and key characteristics of the FAIRR model for conducting interdisciplinary rehabilitation research.

  16. A Short Study of Large Rotary Forged Cylinders

    DTIC Science & Technology

    1979-06-01

    Bottom) 7 Microstructure at mid-wall of reheat treated rotary 25 forged cylinders - Martensite- Bainite 8 Martensitic microstructure of (a) normalized...also was unsatisfactory (Table 2). The microstructure at the mid-wall of both the top and bottom showed evidence of ferrite and bainite (Figs. 1 and...austenitized, and of bainite , showing that the material transformed to austenite had been in- adequately quenched, since martensite is the desired product

  17. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  18. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-07-15

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B{sub 2}O{sub 3}), barium oxide (BaO), lanthanum oxide (La{sub 2}O{sub 3}), and at least one other oxide selected from the group consisting of aluminum oxide (Al{sub 2}O{sub 3}), calcium oxide (CaO), lithium oxide (Li{sub 2}O), sodium oxide (Na{sub 2}O), silicon dioxide (SiO{sub 2}), or titanium dioxide (TiO{sub 2}). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900 C, and generally about 700--800 C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 1 fig.

  19. Open-die forging of structurally porous sandwich panels

    SciTech Connect

    Elzey, D.M.; Wadley, H.N.G.

    1999-10-01

    Structurally porous metal sandwich panels consisting of dense face sheets and porous cores of controlled relative density can be manufactured by trapping inert gas during hot isostatic pressing and modifying its distribution via subsequent thermomechanical forming. A plane-strain solution for analyzing the open-die forging of such a plastically compressible sandwich panel is developed. An effective yield potential for the face sheet/core sandwich is constructed from the Mises yield criterion for the rigid-plastic face sheet and Doraivelu et al's density-dependent yield function for the compressible core. This effective constitutive response is used in a classical slab analysis of open-die forging. The analysis predicts the upsetting force and the distributions of pressure, core relative density, and average stresses within both the face sheet and the core. During upsetting, a zone of fully constrained material (i.e., with zero lateral strain) is predicted to occur at the center of the workpiece, and this densifies first. A densification front then advances laterally from the panel center toward the outer edges. The nonuniform densification complicates the use of forging for the production of components requiring a uniform density core.

  20. Fracture behavior of warm forged and CVD tungsten

    SciTech Connect

    Lassila, D.H.; Connor, A.

    1991-02-14

    The fracture behavior of warm forged and chemical vapor deposition (CVD) tungsten was studied. Three-point bend tests were used to determine ductile-brittle transition temperatures (DBTT) of the materials using a strain based criterion for the DBTT which was arrived at by analysis of computer code modelling results of the three-point bend test. The DBTT's of the warm forged materials were found to be considerably lower than those of the CVD materials. Scanning electron microscopy (SEM), scanning Auger electron spectroscopy (SAES) and X-ray photoelectron spectroscopy (XPS) were performed to characterize the fracture morphologies and fracture surface compositions of the materials. All fracture surfaces were found to be comprised entirely of tungsten with significant and varying amounts of oxygen and carbon segregation. A large portion of the fracture surfaces of the warm forged materials is intergranular, although this is not always directly evident from SEM observations. The fracture surfaces of the CVD materials were clearly 100% intergranular. Results of the study suggest that the fracture paths of the different materials were related to the DBTTs. 22 refs., 8 figs., 2 tabs.

  1. High yttria ferritic ODS steels through powder forging

    NASA Astrophysics Data System (ADS)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-05-01

    Oxide dispersion strengthened (ODS) steels are being developed for future nuclear reactors. ODS Fe-18%Cr-2%W-0.2%Ti steels with 0, 0.35, 0.5, 1 and 1.5% Y2O3 (all compositions in weight%) dispersion were fabricated by mechanical alloying of elemental powders. The powders were placed in a mild steel can and forged in a stream of hydrogen gas at 1473 K. The steels were forged again to final density. The strength of ODS steel increased with yttria content. Though this was accompanied by a decrease in tensile elongation, all the steels showed significant ductility. The ductility in high yttria alloys may be attributed to improved inter-particle bonding between milled powders due to reduction of surface oxides by hydrogen. This may permit development of ODS steels with yttria contents higher than the conventional limit of 0.5%. It is suggested that powder forging is a promising route to fabricate ODS steels with high yttria contents and improved ductility.

  2. Material morphological characteristics in laser ablation of alpha case from titanium alloy

    NASA Astrophysics Data System (ADS)

    Yue, Liyang; Wang, Zengbo; Li, Lin

    2012-08-01

    Alpha case (an oxygen enriched alloy layer) is commonly formed in forged titanium alloys during the manufacturing process and it reduces the service life of the materials. This layer is normally removed mechanically or chemically. This paper reports the feasibility and characteristics of using a short pulsed laser to remove oxygen-enriched alpha case layer from a titanium alloy (Ti6Al4V) substrate. The material removal rate, i.e., ablation rate, and ablation threshold of the alpha case titanium were experimentally determined, and compared with those for the removal of bulk Ti6Al4V. Surface morphologies of laser processed alpha case titanium layer, especially that of cracks at different ablated depths, were carefully examined, and also compared with those for Ti6Al4V. It has been shown that in the alpha case layer, laser ablation has always resulted in crack formation while for laser ablation of alpha case free Ti6Al4V layers, cracking was not present. In addition, the surface is rougher within the alpha case layer and becomes smoother (Ra - 110 nm) once the substrate Ti-alloy is reached. The work has demonstrated that laser is a feasible processing tool for removing alpha case titanium, and could also be used for the rapid detection of the presence of alpha case titanium on Ti6Al4V surfaces in aerospace applications.

  3. Cementless total hip arthroplasty in patients with ankylosing spondylitis: A retrospective observational study.

    PubMed

    Xu, Jun; Zeng, Min; Xie, Jie; Wen, Ting; Hu, Yihe

    2017-01-01

    Controversies on the surgical protocols and efficacies of total hip arthroplasty (THA) in ankylosing spondylitis (AS) still exist. The aim of this study was to retrospectively analyze the perioperative managements and their outcomes related to performing THA on patients with AS.Data of 54 AS patients who underwent 81 THAs between 2008 and 2014 were retrospectively analyzed. Clinical and imaging data were collected preoperatively, postoperatively, and during the follow-up period for surgical efficacy.Using posterolateral approach, cementless prostheses were selected in all cases. Mean follow-up period was 3.6 years (range, 2-8 years). Inclinations and anteversions of acetabular cups were 36.3°±4.5° (range, 30°-50°) and 12.3°±4.9° (range, 0°-25°) respectively. Mean visual analog scale (VAS) score decreased from 6.7 ± 2.1 (range, 4-10) preoperatively to 1.5 ± 1.0 (range, 0-4) at final follow-up, and mean Harris hip score (HHS) improved from 31.2 ± 11.6 (range, 15-45) to 86.1 ± 4.3 (range, 80-95) (P < 0.05). Postoperative range of motion (ROM) in flexion was improved from 6.7°±13.5° (range, 0°-50°) preoperatively to 82.5°±6.4° (range, 70°-100°) at final follow-up, and ROM in extension was improved from 1.8°±5.7°(range, 0°-15°) to 15.4°±2.6° (range, 10°-20°) (P < 0.05). Heterotopic ossification (HO) was documented in 9 hips (11.1%). Signs of stable fibrous ingrowth and bone ingrowth were detected in 52 and 29 hips, respectively. Sciatic never injury was occurred in 3 cases, and treated conservatively. There were no signs of periprosthetic fractures, dislocation, or prosthesis loosening.Surgical efficacies of THA for AS patients with severe hip involvement are satisfactory.

  4. Cementless surface replacement arthroplasty (Copeland CSRA) for osteoarthritis of the shoulder.

    PubMed

    Levy, Ofer; Copeland, Stephen A

    2004-01-01

    Clinical experience with the Copeland cementless surface replacement arthroplasty (CSRA) of the shoulder now spans 17 years. Between 1986 and 1997, 79 CSRAs (42 total shoulder replacements and 37 hemiarthroplasties) were performed for primary osteoarthritis of the shoulder. Total shoulder replacement was done in 12 men and 30 women with a mean age of 71.5 years (range, 50-87 years). Hemiarthroplasty was used in 9 men and 28 women; 5 patients had bilateral hemiarthroplasty. The mean age was 73.4 years (range, 53-88 years). Thirty-nine total shoulder arthroplasties and thirty hemiarthroplasties with a follow-up of more than 2 years were available for review. The mean follow-up was 7.6 years (range, 48 months to 13 years) for total shoulder replacement and 4.4 years (range, 24 months to 6.5 years) for hemiarthroplasty. The Constant scores improved from an age-adjusted Constant score of 33.8% (20.0 points) to 94% (61.9 points) for total shoulder replacement and from an age-adjusted Constant score 40.0% (25.3 points) to 91% (58.1 points) for hemiarthroplasty. Active elevation improved by a mean of 59.9 degrees to a mean of 128 degrees for total shoulder replacement and to a mean of 124 degrees for hemiarthroplasty. Of the patients, 89.9% considered the shoulder to be much better or better as a result of the operation. Radiographically, one humeral implant and three glenoid implants had evidence of loosening. Four revisions were performed in the total shoulder replacement group. No revision surgery was needed in the hemiarthroplasty group. The results of this series are at least comparable to those reported for stemmed prostheses with a comparable length of follow-up. The results of total shoulder replacement and hemiarthroplasty in osteoarthritis of the shoulder seem to be comparable. With use of the CSRA prosthesis, several severe complications mainly concerning the humeral shaft and periprosthetic fractures can be avoided. Should the need for revision surgery or

  5. Five-year clinical and radiological outcomes in 257 consecutive cementless Oxford medial unicompartmental knee arthroplasties.

    PubMed

    Blaney, J; Harty, H; Doran, E; O'Brien, S; Hill, J; Dobie, I; Beverland, D

    2017-05-01

    Our aim was to examine the clinical and radiographic outcomes in 257 consecutive Oxford unicompartmental knee arthroplasties (OUKAs) (238 patients), five years post-operatively. A retrospective evaluation was undertaken of patients treated between April 2008 and October 2010 in a regional centre by two non-designing surgeons with no previous experience of UKAs. The Oxford Knee Scores (OKSs) were recorded and fluoroscopically aligned radiographs were assessed post-operatively at one and five years. The median age of the 238 patients was 65.0 years (interquartile range (IQR) 59.0 to 73.0), the median body mas index was 30.0 (IQR 27.5 to 33.0) and 51.7% were male. There were no intra-operative complications. There was a significant improvement in the median OKS at six weeks (34, IQR 31.0 to 37.0), one year (38, IQR 29.0 to 43.0) and five years (37, IQR 27.0 to 42.0) when compared with the pre-operative scores (16, IQR 13.0 to 19.0) (all p = < 0.01). No patient had progressive radiolucent lines or loosening. A total of 16 patients had died by five years. The cumulative survival at five years was 98.8% and the mean survival time was 5.8 years (95% confidence interval 5.6 to 5.9). A total of seven OUKAs (2.7%) were revised; three within five years and four thereafter, between 5.1 and 5.7 years post-operatively. Five (1.9%) had re-operations within five years. The proportion of patients requiring revision at five years is lower than that generally reported for UKA. These findings add support for the use of the cementless OUKA outside the design centre. Longer follow-up is required. Cite this article: Bone Joint J 2017;99-B:623-31. ©2017 The British Editorial Society of Bone & Joint Surgery.

  6. Sprayable titanium composition

    DOEpatents

    Tracy, Chester E.; Kern, Werner; Vibronek, Robert D.

    1980-01-01

    The addition of 2-ethyl-1-hexanol to an organometallic titanium compound dissolved in a diluent and optionally containing a lower aliphatic alcohol spreading modifier, produces a solution that can be sprayed onto a substrate and cured to form an antireflection titanium oxide coating having a refractive index of from about 2.0 to 2.2.

  7. Influence of Processing Parameters on Grain Size Evolution of a Forged Superalloy

    NASA Astrophysics Data System (ADS)

    Reyes, L. A.; Páramo, P.; Salas Zamarripa, A.; de la Garza, M.; Guerrero-Mata, M. P.

    2016-01-01

    The microstructure evolution of nickel-based superalloys has a great influence on the mechanical behavior during service conditions. Microstructure modification and the effect of process variables such as forging temperature, die-speed, and tool heating were evaluated after hot die forging of a heat-resistant nickel-based alloy. Forging sequences in a temperature range from 1253 to 1323 K were considered through experimental trials. An Avrami model was applied using finite element data to evaluate the average grain size and recrystallization at different evolution zones. It was observed that sequential forging at final temperatures below 1273 K provided greater grain refinement through time-dependent recrystallization phenomena. This investigation was aim to explore the influence of forging parameters on grain size evolution in order to design a fully homogenous and refined microstructure after hot die forging.

  8. High-energy rate forgings of wedges. Characterization of processing conditions

    SciTech Connect

    Reynolds, Thomas Bither; Everhart, Wesley; Switzner, Nathan T; Balch, Dorian K.; San Marchi, Christopher W.

    2014-05-01

    The wedge geometry is a simple geometry for establishing a relatively constant gradient of strain in a forged part. The geometry is used to establish gradients in microstructure and strength as a function of strain, forging temperature, and quenching time after forging. This geometry has previously been used to benchmark predictions of strength and recrystallization using Sandias materials model for type 304L austenitic stainless steel. In this report, the processing conditions, in particular the times to forge and quench the forged parts, are summarized based on information recorded during forging on June 18, 2013 of the so-called wedge geometry from type 316L and 21Cr-6Ni-9Mn austenitic stainless steels.

  9. Corrosion Fatigue Mechanism on Hot-Forged AA6082 Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Saleema, N.; Gauthier, P.; Chen, X.-G.

    An attempt has been made to understand the corrosion fatigue phenomenon in AA6082 aluminum hot-forged parts. Fatigue and corrosion fatigue experiments of forged parts produced by two different feedstock materials have been performed in the lab air and in a corrosive 3.5% NaCl solution under different stress levels. The scanning electron microscopy was used to study the rupture and to identify failure modes. With corrosion and mechanical stress working together, the failure occurred earlier in the specimens subjected to a 3.5% NaCl solution as compared to those subjected to the lab air irrespective of the material forms (cast-forged or extruded-forged). The corrosion fatigue performance of these specimens with different stress levels as well as the crack initiation and propagation were elaborated. It was found that there is no significant variation in corrosion fatigue resistance for final cast-forged and extruded-forged products.

  10. Netcast™ Shape Casting Technology: A Technological Breakthrough that Enhances the Cost Effectiveness of Aluminum Forgings

    NASA Astrophysics Data System (ADS)

    Anderson, Mark; Bruski, Richard; Groszkiewicz, Daniel; Wagstaff, Bob

    A new Direct Chill (DC) casting process is introduced to semi-continuous casting where near net shaped ingots are solidified. This process is currently being used at Alcan Engineered Cast Products (ECP) facility in Jonquiere, Canada, sectioned, then forged at Alcoa Automotive, Kentucky Casting Center (KCC). Finished forgings are machined and assembled into the Ford D/EW98 platform as suspension components. A brief description of the process and the implications on the forging process are presented.

  11. Determination of Optimal Forging Conditions for Void Elimination in Large Steel Ingots =

    NASA Astrophysics Data System (ADS)

    Harris, Nathan

    The presence of internal voids is commonly observed throughout the casting and solidification of large size ingots. Their mechanical closure is generally achieved during the initial deformation of a hot forming process. The present work focuses on the determination of optimal forging conditions for void elimination in large steel ingots with respect to the involved materials and industrial processes. A state of the art is compiled as initial research in order to develop a solid background in void elimination theory. An extensive review of void closure models is presented and characterisation techniques are discussed. It is shown that current void closure models lack application to industrial scale forgings. An analysis of the industrial partner's open die forging procedure ensues and characteristic forging sequences are introduced. Feasibility for further forging analysis using experimental data is evaluated and successfully proposed. A novel method for fast calculating void closure models is developed. Rational polynomial functions are established for the calculation of material dependant constants. 3D mapping is used to evaluate the influence of the triaxiality state and material parameters. The void closure model is validated for use on high strength steels from the industrial partner. Void closure is modeled and simulated during an open die forging sequence. The effect of in-billet void positioning is studied and the forging sequence effectiveness for void closure is validated and characterized for different zones. An original combination of data from relative void closure and volumetric strain rate provides a way for forging optimisation. Novel software for successful open die slab forging, Forge Calculus, is developed based on large amounts of experimental data. The in-house code provides fundamental information for setting forging standards. Future development concerning real time prediction of forging quality is discussed.

  12. Manufacturing Methods and Technology for Production Hot Forging of Alkali Halide Lenses.

    DTIC Science & Technology

    1981-06-30

    Figure Page 1 Diagram of SU-103/UA IR Imager and KBr Lens 2 2 Block Diagram of Forging Process 4 3 Polariscopic Strain Photographs of 10 KBr Starting...Crystals 6 4 Polariscopic Strain Photographs of First Stage Forging 7 Numbers 084, 085, 091, 092, and 093 Polariscopic Strain Photographs of First Stage...starting configaration. It was originally thought that the amount of strain in the starting crystal would reflect the amount of strain in the forged lens

  13. Mechanical-Property Data Ti-10V-2Fe-3Al Alloy. Isothermally Forged

    DTIC Science & Technology

    1982-06-01

    mm) RCS, reheated to 1700 F (1200 K) and forged to a 5-inch (127 mm) RCS, reheated to 1500 F ( 1089 K) and forged to a 4-inch (102 mm) octagon. A final...pass at RMI was performed in a rotary forging machine at 1500 F ( 1089 K) transfoiming the octagon 4 "to a 3-1/4-inch (8.26 mm) diameter round bar. At

  14. Titanium and titanium alloys as dental materials.

    PubMed

    Lautenschlager, E P; Monaghan, P

    1993-06-01

    Because of light weight, high strength to weight ratio, low modulus of elasticity, and excellent corrosion resistance, titanium and some of its alloys have been important materials for the aerospace industry since the 1950s. Now, with the additional advantages of excellent biocompatibility, good local spot weldability, and easy shaping and finishing by a number of mechanical and electrochemical processes, these materials are finding uses in dental applications, such as implants and restorative castings. Although more research is still needed in areas such as development of optimal casting investments, porcelain veneering systems, device designs, and controlled biological responses, the present and future uses of titanium appear bright for dentistry.

  15. Residual Stresses in 21-6-9 Stainless Steel Warm Forgings

    SciTech Connect

    Everhart, Wesley A.; Lee, Jordan D.; Broecker, Daniel J.; Bartow, John P.; McQueen, Jamie M.; Switzner, Nathan T.; Neidt, Tod M.; Sisneros, Thomas A.; Brown, Donald W.

    2012-11-14

    Forging residual stresses are detrimental to the production and performance of derived machined parts due to machining distortions, corrosion drivers and fatigue crack drivers. Residual strains in a 21-6-9 stainless steel warm High Energy Rate Forging (HERF) were measured via neutron diffraction. The finite element analysis (FEA) method was used to predict the residual stresses that occur during forging and water quenching. The experimentally measured residual strains were used to calibrate simulations of the three-dimensional residual stress state of the forging. ABAQUS simulation tools predicted residual strains that tend to match with experimental results when varying yield strength is considered.

  16. Opacity and Mass Emission Relationship in Forging Areas of Large Caliber Metal Parts Facilities,

    DTIC Science & Technology

    1981-11-01

    was tested to he 0.0058 gr/dscf. The lubricating oil used at Flinchbaugh is designated as Hot Forging Agent 201 (HF 201), manufactured by E. F. Houghton...at the New Bedford forgi, shop are designated as MacForge 599 and MacForge-, 958. MacForge 958 is water, based, containing 1? percent oil and 24...determine mass emissions from optical density at another plant, the particulate characteristics and the ptrocess imu t be very siwilar to the plant

  17. The Harris-Galante cementless acetabular component: results in 190 cases with at least 3 years follow-up.

    PubMed

    Claus, B; Van Innis, B; De Witte, E; Van Overschelde, J; Magotteaux, B; Fatemi, F; Vandepaer, F

    1993-01-01

    The results of 190 primary total hip arthroplasties with a Harris-Galante cementless acetabular cup were reviewed. All patients had a minimum follow-up of 3 years (range, 3 to 5.5 years, mean 46 months). Clinical and radiographical analysis was performed. Inguinal pain was recorded in five cases. We noted a fracture of a screw in four cases without further implications. There was no evidence of acetabular loosening. There was no migration of the acetabular cup. No acetabular component showed measurable wear of the polyethylene liner. Non-progressive radiolucent lines were recorded in 14% of the patients: among these patients, radiolucent lines were noted in zone 1 in 46%, in zone 2 in 4% and in zone 3 in 86%. Two socket revisions became necessary. One patient suffered a deep-seated infection. Another revision was necessary because of recurrent dislocation.

  18. Three- to five-year results with the cementless Harris-Galante acetabular component used in hybrid total hip arthroplasty.

    PubMed

    Kienapfel, H; Pitzer, W; Griss, P

    1992-01-01

    In this paper we present our 3- to 5-year results after hybrid total hip replacement using the cementless porous coated Harris-Galante acetabular component and the cemented Griss femoral component in 39 patients with 40 implantations. Postoperatively, mild to moderate pain was experienced by 16.1% of patients, mostly following hard activity. A slight to moderate limp occurred in 24.2%. All patients were able to walk more than 1000 m. Full-time use of support was required by 2.8%. The postoperative range of motion was increased in 93.9%. Radiographically, none of the acetabular or femoral components had to be classified as unstable. Only one acetabular component displayed complete (i.e., along all interface zones) radiolucency and was therefore classified as possibly unstable.

  19. In vitro osteogenic capacity of bone marrow MSCs from postmenopausal women reflect the osseointegration of their cementless hip stems.

    PubMed

    Alm, Jessica J; Moritz, Niko; Aro, Hannu T

    2016-12-01

    Age-related dysfunction of mesenchymal stromal cells (MSCs) is suggested as a main cause of altered bone repair with aging. We recently showed that in postmenopausal women undergoing cementless total hip arthroplasty (THA) aging, low bone mineral density (BMD) and age-related geometric changes of the proximal femur are risk factors for increased early migration and delayed osseointegration of the femoral stems. Extending these analyses, we have here explored how the in vitro osteogenic capacity of bone marrow MSCs from these patients reflects implant osseointegration, representing the patient's in vivo bone healing capacity. A total of 19 postmenopausal women with primary hip osteoarthritis (mean age 65 years, range 50-78) and well-defined bone quality underwent successful preoperative in vitro analysis of osteogenic capacity of iliac crest bone marrow MSCs as well as two-year radiostereometric (RSA) follow-up of femoral stem migration after cementless THA. In patients with MSCs of low osteogenic capacity, the magnitude of cumulative stem subsidence after the settling period of three months was greater (p = 0.028) and the time point for translational osseointegration was significantly delayed (p = 0.030) compared to patients with MSCs of high osteogenic capacity. This study suggests that patients with MSCs of low in vitro osteogenic capacity may display increased stem subsidence after the settling period of 3 months and thereby delayed osseointegration. Our study presents a novel approach for studying the biological progress of hip implant osseointegration and to verify the impact of decreased MSCs function, especially in patients with age-related dysfunction of MSCs and bone healing capacity.

  20. Forge Welding of Magnesium Alloy to Aluminum Alloy Using a Cu, Ni, or Ti Interlayer

    NASA Astrophysics Data System (ADS)

    Yamagishi, Hideki; Sumioka, Junji; Kakiuchi, Shigeki; Tomida, Shogo; Takeda, Kouichi; Shimazaki, Kouichi

    2015-08-01

    The forge-welding process was examined to develop a high-strength bonding application of magnesium (Mg) alloy to aluminum (Al) alloy under high-productivity conditions. The effect of the insert material on the tensile strength of the joints, under various preheat temperatures and pressures, was investigated by analyzing the reaction layers of the bonded interface. The tensile strengths resulting from direct bonding, using pure copper (Cu), pure nickel (Ni), and pure titanium (Ti) inserts were 56, 100, 119, and 151 MPa, respectively. The maximum joint strength reached 93 pct with respect to the Mg cast billet. During high-pressure bonding, a microscopic plastic flow occurred that contributed to an anchor effect and the generation of a newly formed surface at the interface, particularly prominent with the Ti insert in the form of an oxide layer. The bonded interfaces of the maximum-strength inserts were investigated using scanning electron microscopy-energy-dispersive spectroscopy and electron probe microanalysis. The diffusion reaction layer at the bonded interface consisted of brittle Al-Mg intermetallics having a thickness of approximately 30 μm. In contrast, for the three inserts, the thicknesses of the diffusion reaction layer were infinitely thin. For the pure Ti insert, exhibiting the maximum tensile strength value among the inserts tested, focused ion beam-transmission electron microscopy-EDS analysis revealed a 60-nm-thick Al-Ti reaction layer, which had formed at the bonded interface on the Mg alloy side. Thus, a high-strength Al-Mg bonding method in air was demonstrated, suitable for mass production.

  1. Friction and wear in hot forging of steels

    SciTech Connect

    Daouben, E.; Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A.; Truong-Dinh, N.; Lazzarotto, L.

    2007-04-07

    In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200 deg. C. A nitrided contactor representing the tool is heated at 200 deg. C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants.

  2. Friction and wear in hot forging of steels

    NASA Astrophysics Data System (ADS)

    Daouben, E.; Dubar, L.; Dubar, M.; Deltombe, R.; Dubois, A.; Truong-Dinh, N.; Lazzarotto, L.

    2007-04-01

    In the field of hot forging of steels, the mastering of wear phenomena enables to save cost production, especially concerning tools. Surfaces of tools are protected thanks to graphite. The existing lubrication processes are not very well known: amount and quality of lubricant, lubrication techniques have to be strongly optimized to delay wear phenomena occurrence. This optimization is linked with hot forging processes, the lubricant layers must be tested according to representative friction conditions. This paper presents the first part of a global study focused on wear phenomena encountered in hot forging of steels. The goal is the identification of reliable parameters, in order to bring knowledge and models of wear. A prototype testing stand developed in the authors' laboratory is involved in this experimental analysis. This test is called Warm and Hot Upsetting Sliding Test (WHUST). The stand is composed of a heating induction system and a servo-hydraulic system. Workpieces taken from production can be heated until 1200°C. A nitrided contactor representing the tool is heated at 200°C. The contactor is then coated with graphite and rubs against the workpiece, leaving a residual track on it. Friction coefficient and surface parameters on the contactor and the workpiece are the most representative test results. The surface parameters are mainly the sliding length before defects occurrence, and the amplitude of surface profile of the contactor. The developed methodology will be first presented followed by the different parts of the experimental prototype. The results of experiment show clearly different levels of performance according to different lubricants.

  3. Aerospace applications of beta titanium alloys

    NASA Astrophysics Data System (ADS)

    Boyer, Rodney R.

    1994-07-01

    Beta alloys are beginning to play a significant role in both military and commercial aircraft. Ti-10V-2Fe-3Al forgings, for example, play major roles in the McDonnell Douglas C-17 and the Boeing 777. The attractive properties of Beta-C are increasing the use of titanium, rather than steel, in aircraft springs. Ti-15V-3Cr-3Al-3Sn is subject to increasing usage primarily because of its strip producibility and formability. Beta-21S is gaining importance for high-temperature applications. New alloys such as β-CEZ, SP-700, and Timetal® LCB could become important because of advantageous costs, processing, and/or properties. In the past, the use of beta alloys has largely been driven by their superior properties and weight-savings potential. In the future, cost will become more important. As a result, a greater emphasis will be placed on lower cost alloys and/or taking advantage of the improved processing capabilities of these alloys to minimize final component costs.

  4. Electroplating on titanium alloy

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1971-01-01

    Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

  5. West Flank Coso, CA FORGE 3D geologic model

    SciTech Connect

    Doug Blankenship

    2016-03-01

    This is an x,y,z file of the West Flank FORGE 3D geologic model. Model created in Earthvision by Dynamic Graphic Inc. The model was constructed with a grid spacing of 100 m. Geologic surfaces were extrapolated from the input data using a minimum tension gridding algorithm. The data file is tabular data in a text file, with lithology data associated with X,Y,Z grid points. All the relevant information is in the file header (the spatial reference, the projection etc.) In addition all the fields in the data file are identified in the header.

  6. Performance of hot stacked-sinter forged Bi2223 ceramics

    NASA Astrophysics Data System (ADS)

    Noudem, J. G.; Guilmeau, E.; Chateigner, D.; Ouladdiaf, B.; Bourgault, D.

    2004-08-01

    Dense Bi2223 superconductors have been successfully formed by hot stacking-forging process (HSF). Neutron diffraction measurements were used to investigate the bulk textures of HSF-Bi2223 samples. Angular dependence of transport critical current density, Jc values were measured at various temperatures and different applied magnetic fields. Several textured pieces were hot-stacked. This procedure leads to an increase of both the sample thickness and the nominal engineering critical current ( Ic), favourable hints for use of textured-Bi2223 in power generation supplies.

  7. Snake River Plain FORGE Well Data for USGS-142

    DOE Data Explorer

    Robert Podgorney

    2015-11-23

    Well data for the USGS-142 well located in eastern Snake River Plain, Idaho. This data collection includes lithology reports, borehole logs, and photos of rhyolite core samples. This collection of data has been assembled as part of the site characterization data used to develop the conceptual geologic model for the Snake River Plain site in Idaho, as part of phase 1 of the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative. They were assembled by the Snake River Geothermal Consortium (SRGC), a team of collaborators that includes members from national laboratories, universities, industry, and federal agencies, lead by the Idaho National Laboratory (INL).

  8. Cold Rotary Forging of Small Caliber Gun Barrels

    DTIC Science & Technology

    1975-12-01

    COMPONENTS SUPPORTED. (1) 7.62mm M219 machine gun barrel (2) 7.62mm M134 mini gun ( Gau barrel) (3) .30 caliber machine gun barrel (4) 5.56=m MI6Al rifle ...barrel (5) 50 cal. M8C spotting rifle barrel (6) 7.62mm Ml4 National Match rifle bw’rel (7) other small arms weapon barrels K -. 1. FACILITIES SUPPORTED... rifle barrels was made in conjunction with the rotary forging process. From this, a purchase description was written and submitted for bid for a

  9. Research of annealing mode for high accuracy stamped parts production from titanium alloy 83Ti-5Al-5Cr-5Mo after tooling

    NASA Astrophysics Data System (ADS)

    Balaykin, A. V.; Nosova, E. A.; Galkina, N. V.

    2016-11-01

    The aim of the work is to solve question of accuracy increase in tolled and annealed parts made from forged rod of titanium alloy. Plate pieces were cut from cross-section, annealed at 800°C during 1, 2, 3, 4 and 5 hours. The criterion combining minimum bending radius and spring back angle was found. This criterion shows the maximum values after tooling and annealing for 3 hours.

  10. Vibration control in forge hammers. [by shock wave damping in foundation platform

    NASA Technical Reports Server (NTRS)

    Moise, F.; Lazarescu, C.

    1974-01-01

    Special measures are discussed for calculating, designing and executing a forge hammer foundation, so that the vibrations that occur during its working will not be transmitted to neighboring machinery, workrooms and offices. These vibrations are harmful to the workers near the forge hammer.

  11. Microstructure Modeling of a Ni-Fe-Based Superalloy During the Rotary Forging Process

    NASA Astrophysics Data System (ADS)

    Loyda, A.; Hernández-Muñoz, G. M.; Reyes, L. A.; Zambrano-Robledo, P.

    2016-06-01

    The microstructure evolution of Ni-Fe superalloys has a great influence on the mechanical behavior during service conditions. The rotary forging process offers an alternative to conventional bulk forming processes where the parts can be rotary forged with a fraction of the force commonly needed by conventional forging techniques. In this investigation, a numerical modeling of microstructure evolution for design and optimization of the hot forging operations has been used to manufacture a heat-resistant nickel-based superalloy. An Avrami model was implemented into finite element commercial platform DEFORM 3D to evaluate the average grain size and recrystallization during the rotary forging process. The simulations were carried out considering three initial temperatures, 980, 1000, and 1050 °C, to obtain the microstructure behavior after rotary forging. The final average grain size of one case was validated by comparing with results of previous experimental work of disk forging operation. This investigation was aimed to explore the influence of the rotary forging process on microstructure evolution in order to obtain a homogenous and refined grain size in the final component.

  12. A New Method for Controlling Billet Temperature During Isothermal Die Forging of a Complex Superalloy Casing

    NASA Astrophysics Data System (ADS)

    Lin, Y. C.; Wu, Xian-Yang

    2015-09-01

    Isothermal die forging is one of near net-shape metal-forming technologies. Strict control of billet temperature during isothermal die forging is a guarantee for the excellent properties of final product. In this study, a new method is proposed to accurately control the billet temperature of complex superalloy casing, based on the finite element simulation and response surface methodology (RSM). The proposed method is accomplished by the following two steps. Firstly, the thermal compensation process is designed and optimized to overcome the inevitable heat loss of dies during hot forging. i.e., the layout and opening time of heaters assembled on die sleeves are optimized. Then, the effects of forging speed (the pressing velocity of hydraulic machine) and its changing time on the maximum billet temperature are discussed. Furthermore, the optimized forging speed and its changing time are obtained by RSM. Comparisons between the optimized and conventional die forging processes indicate that the proposed method can effectively control the billet temperature within the optimal forming temperature range. So, the optimized die forging processes can guarantee the high volume fraction of dynamic recrystallization, and restrict the rapid growth of grains in the forged superalloy casing.

  13. Sand Abrasive Wear Behavior of Hot Forged Al 6061-TiO2 Composites

    NASA Astrophysics Data System (ADS)

    Ramesh, C. S.; Bharathesh, T. P.; Verma, S. M.; Keshavamurthy, R.

    2012-01-01

    Nickel-coated TiO2 particulate reinforced Al6061 matrix composites developed using the vortex technique were hot forged at a temperature of 500 °C. A constant deformation ratio of 6:1 was adopted. Hot forged Al6061 alloy and Al6061-TiO2 composites were then subjected to heat treatment by solutionizing at a temperature of 530 °C for duration of 2 h followed by ice quenching. Both natural and artificial aging at 175 °C were performed on the quenched samples from 2 to 8 h duration in steps of 2. Microstructure, microhardness, and dry sand abrasive wear behavior of both matrix alloy and developed composites in both as-forged and heat-treated conditions have been evaluated. Worn surface studies have been carried out using scanning electron microscope. Results have revealed that nickel-coated TiO2 particles are uniformly distributed through out the matrix alloy. Microhardness of Al6061-TiO2 composites increases with increase in percentage of reinforcement. Heat-treated forged alloy and its composites possesses higher hardness when compared with the forged composites. Forged Al6061-TiO2 composites exhibited lower abrasive wear loss when compared with the forged matrix alloy. Heat treatment has a profound effect on the abrasive wear resistance of both as-forged Al6061 alloy and Al6061-TiO2 composites.

  14. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site leased... are engaged in the production of aluminum alloy forgings. Information shows that on July 28, 2010...

  15. [Research on the inner wall condition monitoring method of ring forgings based on infrared spectra].

    PubMed

    Fu, Xian-bin; Liu, Bin; Wei, Bin; Zhang, Yu-cun; Liu, Zhao-lun

    2015-01-01

    In order to grasp the inner wall condition of ring forgings, an inner wall condition monitoring method based on infrared spectra for ring forgings is proposed in the present paper. Firstly, using infrared spectroscopy the forgings temperature measurement system was built based on the three-level FP-cavity LCTF. The two single radiation spectra from the forgings' surface were got using the three-level FP-cavity LCTF. And the temperature measuring of the surface forgings was achieved according to the infrared double-color temperature measuring principle. The measuring accuracy can be greatly improved by this temperature measurement method. Secondly, on the basis of the Laplace heat conduction differential equation the inner wall condition monitoring model was established by the method of separating variables. The inner wall condition monitoring of ring forgings was realized via combining the temperature data and the forgings own parameter information. Finally, this method is feasible according to the simulation experiment. The inner wall condition monitoring method can provide the theoretical basis for the normal operating of the ring forgings.

  16. Forging; Heat Treating and Testing; Technically Oriented Industrial Materials and Process 1: 5898.05.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    The course provides students with advanced and exploratory experience in the area of plastic deformation of metals and in the changing of the physical characteristics of metals by the controlled application and timed removal of heat. Course content includes goals, specific objectives, safety in forge work, forging tools and equipment, industrial…

  17. Investigations on Forging Dies with Ceramic Inserts by means of Finite-Element-Analysis

    SciTech Connect

    Behrens, B.-A.; Schaefer, F.; Bistron, M.

    2007-05-17

    The tools in hot forging processes are exposed to high thermal and mechanical loadings. Tempering of the tool edge layer occurs as a result of thermal loadings. This leads to a gradual hardness loss of the tool material and increase of wear over forging cycles. Hence, the tool life in hot forging is mainly limited by wear. An extension of the die service life can be achieved by the use of ceramic inserts. The integration of ceramics into the die base plate made of hot-work steel is realised by active brazing, whereby it possible to apply ceramic in region with high wear. It has to be ensured in the design process of ceramic inserts for forging dies that no critical tensile stresses occur in the ceramics. A reliable design of the ceramic inserts is possible only through consideration of brazing and forming process. The development of a Finite-Element-model for the design of forging dies with ceramic inserts is the intention of the work presented in this paper. At first the forging process with a conventional die is analyzed concerning abrasive die wear to identify regions with high wear risk applying a modified Archard model. Based on the results of wear calculation, a forging die with ceramic inserts is investigated in terms of joint stresses at the end of the active brazing process. Subsequently, the forging process considering the residual stresses caused by joining is simulated in order to obtain the die stress in use.

  18. 76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ...; Forging Machines ACTION: Notice. SUMMARY: The Department of Labor (DOL) is submitting the Occupational... Machines,'' to the Office of Management and Budget (OMB) for review and approval for continued use in... employers to conduct and to document periodic inspections of forging machines, guards, and...

  19. Low Temperature Superplasticity of Ti-6Al-4V Processed by Warm Multidirectional Forging (Preprint)

    DTIC Science & Technology

    2012-07-01

    temperature superplasticity, multidirectional forging , ultrafine grain structure , microstructure evolution 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...mail.ru, dLee.Semiatin@wpafb.af.mil Keywords: Low-temperature superplasticity, Multidirectional forging , Ultrafine grain structure , Microstructure... Metals Branch Structural Materials Division G.A. Salishchev, E.A. Kudrjavtsev, and S.V. Zherebtsov Belgorod State University July

  20. A prospective comparative study of cementless total hip arthroplasty and hip resurfacing in patients under the age of 55 years: a ten-year follow-up.

    PubMed

    Haddad, F S; Konan, S; Tahmassebi, J

    2015-05-01

    The aim of this study was to evaluate the ten-year clinical and functional outcome of hip resurfacing and to compare it with that of cementless hip arthroplasty in patients under the age of 55 years. Between 1999 and 2002, 80 patients were enrolled into the study: 24 were randomised (11 to hip resurfacing, 13 to total hip arthroplasty), 18 refused hip resurfacing and chose cementless total hip arthroplasty with a 32 mm bearing, and 38 insisted on resurfacing. The mean follow-up for all patients was 12.1 years (10 to 14). Patients were assessed clinically and radiologically at one year, five years and ten years. Outcome measures included EuroQol EQ5D, Oxford, Harris hip, University of California Los Angeles and University College Hospital functional scores. No differences were seen between the two groups in the Oxford or Harris hip scores or in the quality of life scores. Despite a similar aspiration to activity pre-operatively, a higher proportion of patients with a hip resurfacing were running and involved in sport and heavy manual labour after ten years. We found significantly higher function scores in patients who had undergone hip resurfacing than in those with a cementless hip arthroplasty at ten years. This suggests a functional advantage for hip resurfacing. There were no other attendant problems. ©2015 The British Editorial Society of Bone & Joint Surgery.

  1. Study of the Ti-5Al-5Mo-5V-1Cr-1Fe titanium alloy grain structure uniformity after bending and annealing

    NASA Astrophysics Data System (ADS)

    Balaykin, A. V.; Nosova, E. A.; Galkina, N. V.

    2017-02-01

    The uniform grain structure of titanium alloys is required to enhance the product manufacturability and precision. For the research, flat blanks cut out of the BT-22 titanium alloy forged bar were used. Bending tests with the subsequent annealing were carried out at the temperature of 800°C during 1–5 h. The grain size change and its uniformity depending on the annealing duration were analysed. The possibility of obtaining the uniform fine-grained structure after deformation and annealing for 4 hours was established.

  2. HYDROGEN-ASSISTED FRACTURE IN FORGED TYPE 304L AUSTENITIC STAINLESS STEEL

    SciTech Connect

    Switzner, Nathan; Neidt, Ted; Hollenbeck, John; Knutson, J.; Everhart, Wes; Hanlin, R.; Bergen, R.; Balch, D. K.

    2012-09-06

    Austenitic stainless steels generally have good resistance to hydrogen-assisted fracture; however, structural designs for high-pressure gaseous hydrogen are constrained by the low strength of this class of material. Forging is used to increase the low strength of austenitic stainless steels, thus improving the efficiency of structural designs. Hydrogen-assisted racture, however, depends on microstructural details associated with manufacturing. In this study, hydrogen-assisted fracture of forged type 304L austenitic stainless steel is investigated. Microstructural variation in multi-step forged 304L was achieved by forging at different rates and temperatures, and by process annealing. High internal hydrogen content in forged type 304L austenitic stainless steel is achieved by thermal precharging in gaseous hydrogen and results in as much as 50% reduction of tensile ductility.

  3. Improved Thermoelectric Performance of p-Type Bismuth Antimony Telluride Bulk Alloys Prepared by Hot Forging

    NASA Astrophysics Data System (ADS)

    Shen, J. J.; Yin, Z. Z.; Yang, S. H.; Yu, C.; Zhu, T. J.; Zhao, X. B.

    2011-05-01

    The thermoelectric (TE) performance of Bi0.5Sb1.5Te3 polycrystalline alloys has been improved by a simple hot-forging process. No obvious texture was observed in the x-ray diffraction (XRD) patterns of the hot-forged samples. Transport property measurements indicated that the hot-forged samples possessed extremely low thermal conductivities. A maximum ZT value of ˜1.1 at room temperature was obtained for the sample forged under 30 MPa pressure, being almost 50% more than that of the initial unforged alloy. High-resolution transmission electron microscopy (HRTEM) observations suggested that the high density of lattice defects of the hot-forged samples could be responsible for the extremely low thermal conductivities.

  4. Simulation and analysis of hot forging process for industrial locking gear elevators

    NASA Astrophysics Data System (ADS)

    Maarefdoust, M.; Kadkhodayan, M.

    2010-06-01

    In this paper hot forging process for industrial locking gear elevators is simulated and analyzed. An increase in demand of industrial locking gear elevators with better quality and lower price caused the machining process to be replaced by hot forging process. Production of industrial locking gear elevators by means of hot forging process is affected by many parameters such as billet temperature, geometry of die and geometry of pre-formatted billet. In this study the influences of billet temperature on effective plastic strain, radius of die corners on internal stress of billet and thickness of flash on required force of press are investigated by means of computer simulation. Three-dimensional modeling of initial material and die are performed by Solid Edge, while simulation and analysis of forging are performed by Super Forge. Based on the computer simulation the required dies are designed and the workpieces are formed. Comparison of simulation results with experimental data demonstrates great compatibility.

  5. Research into Oil-based Colloidal-Graphite Lubricants for Forging of Al-based Alloys

    SciTech Connect

    Petrov, A.; Petrov, P.; Petrov, M.

    2011-05-04

    The presented paper describes the topical problem in metal forging production. It deals with the choice of an optimal lubricant for forging of Al-based alloys. Within the scope of the paper, the properties of several oil-based colloidal-graphite lubricants were investigated. The physicochemical and technological properties of these lubricants are presented. It was found that physicochemical properties of lubricant compositions have an influence on friction coefficient value and quality of forgings.The ring compression method was used to estimate the friction coefficient value. Hydraulic press was used for the test. The comparative analysis of the investigated lubricants was carried out. The forging quality was estimated on the basis of production test. The practical recommendations were given to choose an optimal oil-based colloidal-graphite lubricant for isothermal forging of Al-based alloy.

  6. Sensitivity Analysis and Optimization Algorithms for 3D Forging Process Design

    NASA Astrophysics Data System (ADS)

    Do, T. T.; Fourment, L.; Laroussi, M.

    2004-06-01

    This paper presents several approaches for preform shape optimization in 3D forging. The process simulation is carried out using the FORGE3® finite element software, and the optimization problem regards the shape of initial axisymmetrical preforms. Several objective functions are considered, like the forging energy, the forging force or a surface defect criterion. Both deterministic and stochastic optimization algorithms are tested for 3D applications. The deterministic approach uses the sensitivity analysis that provides the gradient of the objective function. It is obtained by the adjoint-state method and semi-analytical differentiation. The study of stochastic approaches aims at comparing genetic algorithms and evolution strategies. Numerical results show the feasibility of such approaches, i.e. the achieving of satisfactory solutions within a limited number of 3D simulations, less than fifty. For a more industrial problem, the forging of a gear, encouraging optimization results are obtained.

  7. The development and production of thermo-mechanically forged tool steel spur gears

    NASA Technical Reports Server (NTRS)

    Bamberger, E. N.

    1973-01-01

    A development program to establish the feasibility and applicability of high energy rate forging procedures to tool steel spur gears was performed. Included in the study were relatively standard forging procedures as well as a thermo-mechanical process termed ausforming. The subject gear configuration utilized was essentially a standard spur gear having 28 teeth, a pitch diameter of 3.5 inches and a diametral pitch of 8. Initially it had been planned to use a high contact ratio gear design, however, a comprehensive evaluation indicated that severe forging problems would be encountered as a result of the extremely small teeth required by this type of design. The forging studies were successful in achieving gear blanks having integrally formed teeth using both standard and thermo-mechanical forging procedures.

  8. Titanium by design: TRIP titanium alloy

    NASA Astrophysics Data System (ADS)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  9. Fracture Mechanical Measurements with Commercial Stainless Steels at 4 K and with Cp-Titanium at 173 K

    NASA Astrophysics Data System (ADS)

    Nyilas, A.; Mitterbacher, H.

    2010-04-01

    Using the JETT (J-Evaluation on Tensile Test) technique, measurements have been performed with commercial stainless steels in forged and cast condition for the reason of an assessment for low temperature service down to 4 K. These steels frequently used for industrial applications are designated by German Werkstoff (WNr) 1.4308 and 1.4408 cast stainless steels and a forged material with the number 1.4307. The fracture toughness tests at 4 K with forged material 1.4307 comprised apart from the base metal also the weld zone and additionally the 5% and 8% pre-strained conditions of the base metal. Fracture toughness reduced slightly for cold worked condition gradually as well as for the weld joint. The Reliability of the JETT measurements has been also checked using the ASTM E 1820—99a standard. In addition, to these measurements, commercial pure ASTM grade 2 titanium (WNr 3.7035) has been also examined using the same JETT method for the reason of industrial application and the requirement of minimum fracture toughness of 100 MPa√m was fulfilled at 173 K. Furthermore, test results performed at 7 K of pure titanium plate material (ASTM grade 1) with respect to fracture mechanical JETT method are presented.

  10. Research on the Microstructure and Mechanical Property of Ti-7Cu Alloy after Semi-Solid Forging

    NASA Astrophysics Data System (ADS)

    Chen, Yongnan; Huo, Yazhou; Zhao, Yongqing; Sun, Zhiping; Bai, Fan

    2016-06-01

    The present work is focused on the development of microstructure of Ti-7Cu alloy as a function of forging temperature and forging ratio in semi-solid state and the influence of resulting microstructure on the mechanical properties. The experimental results showed that the dynamic recrystallization occurred during semi-solid forging and the grain refinement was attained which is considered to be favorable for improving the semi-solid formability. The grain size increased with forging temperature and decreased with forging ratio. Forging temperature has a significant effect on the precipitation behavior in grain boundary regions during the semi-solid processing. More acicular-Ti2Cu tended to precipitate in grain boundary regions with higher forging temperature and finally formed precipitates zones adjacent to grain boundaries after forged at 1,100°C. High ultimate tensile strengths and low elongation have been achieved after semi-solid forging. The strength and hardness decreased with increase of forging temperature, while the ductility increased with increase of forging ratio. The relative contributions of tensile properties were attributed to the varieties of grain size and the distribution of Ti2Cu precipitates obtained by semi-solid forging.

  11. 77 FR 39997 - Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles From the People's...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-06

    ... International Trade Administration Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles From... and is amending the final results of the antidumping duty review on heavy forged hand tools, finished... Heavy Forged Hand Tools, Finished or Unfinished, With or Without Handles, From the People's Republic...

  12. 76 FR 31631 - Heavy Forged Hand Tools From China; Scheduling of Expedited Five-Year Reviews Concerning the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... COMMISSION Heavy Forged Hand Tools From China; Scheduling of Expedited Five- Year Reviews Concerning the Antidumping Duty Orders on Heavy Forged Hand Tools From China. AGENCY: United States International Trade... determine whether revocation of the antidumping duty orders on heavy forged hand tools from China would be...

  13. Anisotropie embrittlement in high-hardness ESR 4340 steel forgings

    NASA Astrophysics Data System (ADS)

    Olson, G. B.; Anctil, A. A.; Desisto, T. S.; Kula, E. B.

    1983-08-01

    ESR 4340 steel forgings tempered to a hardness of HRC 55 exhibit a severe loss of tensile ductility in the short transverse direction which is strain-rate and humidity dependent. The anisotropy is also reflected in blunt-notch Charpy impact energy, but is absent in the sharp-crack fracture toughness. Brittle behavior is associated with regions of smooth intergranular fracture which are aligned with microstructural banding. Scanning Auger microprobe analysis indicates some intergranular segregation of phosphorus and sulfur in these regions. The anisotropic embrittlement is attributed to an interaction of nonequilibrium segregation on solidification with local equilibrium segregation at grain boundaries during austenitizing. This produces defective regions of enhanced intergranular impurity segregation which are oriented during forging. The regions are prone to brittle fracture under impact conditions and abnormal sensitivity to environmental attack during low strain-rate deformation. A relatively sparse distribution of these defects (˜10cm-3) accounts for the discrepancy between smooth bar and blunt-notch tests vs sharp-crack tests. Isotropie properties are restored by homogenization treatment. For application of these steels at extreme hardness levels, homogenization treatment is essential.

  14. Ultrasonic phased arrays for nondestructive inspection of forgings

    SciTech Connect

    Wuestenberg, H.; Rotter, B. ); Klanke, H.P. ); Harbecke, D. )

    1993-06-01

    Ultrasonic examinations on large forgings like rotor shafts for turbines or components for nuclear reactors are carried out at various manufacturing stages and during in-service inspections. During the manufacture, most of the inspections are carried out manually. Special in-service conditions, such as those at nuclear pressure vessels, have resulted in the development of mechanized scanning equipment. Ultrasonic probes have improved, and well-adapted sound fields and pulse shapes and based on special imaging procedures for the representation of the reportable reflectors have been applied. Since the geometry of many forgings requires the use of a multitude of angles for the inspections in-service and during manufacture, phased-array probes can be used successfully. The main advantages of the phased-array concept, e.g. the generation of a multitude of angles with the typical increase of redundancy in detection and quantitative evaluation and the possibility to produce pictures of defect situations, will be described in this contribution.

  15. Characterization of a Viking Blade Fabricated by Traditional Forging Techniques

    NASA Astrophysics Data System (ADS)

    Vo, H.; Frazer, D.; Bailey, N.; Traylor, R.; Austin, J.; Pringle, J.; Bickel, J.; Connick, R.; Connick, W.; Hosemann, P.

    2016-12-01

    A team of students from the University of California, Berkeley, participated in a blade-smithing competition hosted by the Minerals, Metals, and Materials Society at the TMS 2015 144th annual meeting and exhibition. Motivated by ancient forging methods, the UC Berkeley team chose to fabricate our blade from historical smithing techniques utilizing naturally-occurring deposits of iron ore. This approach resulted in receiving the "Best Example of a Traditional Blade Process/Ore Smelting Technique" award for our blade named "Berkelium." First, iron-enriched sand was collected from local beaches. Magnetite (Fe3O4) was then extracted from the sand and smelted into individual high- and low-carbon steel ingots. Layers of high- and low-carbon steels were forge-welded together, predominantly by hand, to form a composite material. Optical microscopy, energy dispersive spectroscopy, and Vickers hardness mechanical testing were conducted at different stages throughout the blade-making process to evaluate the microstructure and hardness evolution during formation. It was found that the pre-heat-treated blade microstructure was composed of ferrite and pearlite, and contained many nonmetallic inclusions. A final heat treatment was performed, which caused the average hardness of the blade edge to increase by more than a factor of two, indicating a martensitic transformation.

  16. Cuprate superconductors on titanium substrates

    NASA Astrophysics Data System (ADS)

    Mitterbauer, Christina; Gritzner, Gerhard

    2007-09-01

    The applicability of titanium as substrate material for coated conductors was investigated. Titanium metal was rolled to a thickness of 1 mm and mechanically polished. The titanium sheets were oxidized in air at 1000 °C for 1 h. A dense oxide layer was formed. YBCO superconducting layers were applied to the oxidized titanium surface via screen printing from a suspension in acetone-terpineol. The YBCO layers were characterized by X-ray diffraction and by scanning electron microscopy.

  17. Weld-bonded titanium structures

    NASA Technical Reports Server (NTRS)

    Vaughan, R. W.; Creedon, J. F. (Inventor)

    1976-01-01

    Structurally stronger titanium articles are produced by a weld-bonding technique comprising fastening at least two plates of titanium together using spotwelding and curing an adhesive interspersed between the spot-weld nuggets. This weld-bonding may be employed to form lap joints or to stiffen titanium metal plates.

  18. Titanium metal: extraction to application

    SciTech Connect

    Gambogi, Joseph; Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  19. Mineral of the month: titanium

    USGS Publications Warehouse

    Gambogi, Joseph

    2004-01-01

    From paint to airplanes, titanium is important in a number of applications. Commercial production comes from titanium-bearing ilmenite, rutile and leucoxene (altered ilmenite). These minerals are used to produce titanium dioxide pigment, as well as an assortment of metal and chemical products.

  20. Using of material-technological modelling for designing production of closed die forgings

    NASA Astrophysics Data System (ADS)

    Ibrahim, K.; Vorel, I.; Jeníček, Š.; Káňa, J.; Aišman, D.; Kotěšovec, V.

    2017-02-01

    Production of forgings is a complex and demanding process which consists of a number of forging operations and, in many cases, includes post-forge heat treatment. An optimized manufacturing line is a prerequisite for obtaining prime-quality products which in turn are essential to profitable operation of a forging company. Problems may, however, arise from modifications to the manufacturing route due to changing customer needs. As a result, the production may have to be suspended temporarily to enable changeover and optimization. Using material-technological modelling, the required modifications can be tested and optimized under laboratory conditions outside the plant without disrupting the production. Thanks to material-technological modelling, the process parameters can be varied rapidly in response to changes in market requirements. Outcomes of the modelling runs include optimum parameters for the forging part’s manufacturing route, values of mechanical properties, and results of microstructure analysis. This article describes the use of material-technological modelling for exploring the impact of the amount of deformation and the rate of cooling of a particular forged part from the finish-forging temperature on its microstructure and related mechanical properties.

  1. 3D Finite Element Analysis of Spider Non-isothermal Forging Process

    NASA Astrophysics Data System (ADS)

    Niu, Ling; Wei, Wei; Wei, Kun Xia; Alexandrov, Igor V.; Hu, Jing

    2016-06-01

    The differences of effective stress, effective strain, velocity field, and the load-time curves between the spider isothermal and non-isothermal forging processes are investigated by making full use of 3D FEA, and verified by the production experiment of spider forging. Effective stress is mainly concentrated on the pin, and becomes lower closer to the front of the pin. The maximum effective strain in the non-isothermal forging is lower than that in the isothermal. The great majority of strain in the non-isothermal forging process is 1.76, which is larger than the strain of 1.31 in the isothermal forging. The maximum load required in the isothermal forging is higher than that in the non-isothermal. The maximum experimental load and deformation temperature in the spider production are in good agreement with those in the non-isothermal FEA. The results indicate that the non-isothermal 3D FEA results can guide the design of the spider forging process.

  2. Optimum Design of Forging Process Parameters and Preform Shape under Uncertainties

    NASA Astrophysics Data System (ADS)

    Repalle, Jalaja; Grandhi, Ramana V.

    2004-06-01

    Forging is a highly complex non-linear process that is vulnerable to various uncertainties, such as variations in billet geometry, die temperature, material properties, workpiece and forging equipment positional errors and process parameters. A combination of these uncertainties could induce heavy manufacturing losses through premature die failure, final part geometric distortion and production risk. Identifying the sources of uncertainties, quantifying and controlling them will reduce risk in the manufacturing environment, which will minimize the overall cost of production. In this paper, various uncertainties that affect forging tool life and preform design are identified, and their cumulative effect on the forging process is evaluated. Since the forging process simulation is computationally intensive, the response surface approach is used to reduce time by establishing a relationship between the system performance and the critical process design parameters. Variability in system performance due to randomness in the parameters is computed by applying Monte Carlo Simulations (MCS) on generated Response Surface Models (RSM). Finally, a Robust Methodology is developed to optimize forging process parameters and preform shape. The developed method is demonstrated by applying it to an axisymmetric H-cross section disk forging to improve the product quality and robustness.

  3. Development of Oxide Dispersion Strengthened (ODS) Ferritic Steel Through Powder Forging

    NASA Astrophysics Data System (ADS)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-02-01

    Oxide dispersion strengthened (ODS) ferritic steels are candidates for cladding tubes in fast breeder nuclear reactors. In this study, an 18%Cr ODS ferritic steel was prepared through powder forging route. Elemental powders with a nominal composition of Fe-18Cr-2 W-0.2Ti (composition in wt.%) with 0 and 0.35% yttria were prepared by mechanical alloying in a Simoloyer attritor under argon atmosphere. The alloyed powders were heated in a mild steel can to 1473 K under flowing hydrogen atmosphere. The can was then hot forged. Steps of sealing, degassing and evacuation are eliminated by using powder forging. Heating ODS powder in hydrogen atmosphere ensures good bonding between alloy powders. A dense ODS alloy with an attractive combination of strength and ductility was obtained after re-forging. On testing at 973 K, a loss in ductility was observed in yttria-containing alloy. The strength and ductility increased with increase in strain rate at 973 K. Reasons for this are discussed. The ODS alloy exhibited a recrystallized microstructure which is difficult to achieve by extrusion. No prior particle boundaries were observed after forging. The forged compacts exhibited isotropic mechanical properties. It is suggested that powder forging may offer several advantages over the traditional extrusion/HIP routes for fabrication of ODS alloys.

  4. Development of Oxide Dispersion Strengthened (ODS) Ferritic Steel Through Powder Forging

    NASA Astrophysics Data System (ADS)

    Kumar, Deepak; Prakash, Ujjwal; Dabhade, Vikram V.; Laha, K.; Sakthivel, T.

    2017-04-01

    Oxide dispersion strengthened (ODS) ferritic steels are candidates for cladding tubes in fast breeder nuclear reactors. In this study, an 18%Cr ODS ferritic steel was prepared through powder forging route. Elemental powders with a nominal composition of Fe-18Cr-2 W-0.2Ti (composition in wt.%) with 0 and 0.35% yttria were prepared by mechanical alloying in a Simoloyer attritor under argon atmosphere. The alloyed powders were heated in a mild steel can to 1473 K under flowing hydrogen atmosphere. The can was then hot forged. Steps of sealing, degassing and evacuation are eliminated by using powder forging. Heating ODS powder in hydrogen atmosphere ensures good bonding between alloy powders. A dense ODS alloy with an attractive combination of strength and ductility was obtained after re-forging. On testing at 973 K, a loss in ductility was observed in yttria-containing alloy. The strength and ductility increased with increase in strain rate at 973 K. Reasons for this are discussed. The ODS alloy exhibited a recrystallized microstructure which is difficult to achieve by extrusion. No prior particle boundaries were observed after forging. The forged compacts exhibited isotropic mechanical properties. It is suggested that powder forging may offer several advantages over the traditional extrusion/HIP routes for fabrication of ODS alloys.

  5. Effect of Forging on Microstructure, Texture, and Uniaxial Properties of Cast AZ31B Alloy

    NASA Astrophysics Data System (ADS)

    Toscano, D.; Shaha, S. K.; Behravesh, B.; Jahed, H.; Williams, B.

    2017-07-01

    The effect of open-die hot forging on cast AZ31B magnesium alloy was investigated in terms of the evolution of microstructure, texture, and mechanical properties. A refined microstructure with strong basal texture was developed in forged material. A significant increase in tensile yield and ultimate strengths by 143 and 23%, respectively, was determined as well. When tested in compression at room temperature, the forged alloy displayed significant in-plane asymmetry and unchanged yield strength compared to the cast alloy owing to the activation of 10\\bar{1}2} < 10\\bar{1}1 \\rangle extension twins in both the cast and forged conditions. However, the ultimate compressive strength for the forged material increased by 22 percent compared to the as-cast material. Microstructure and texture analysis of the fracture samples confirmed that the deformation of the forged samples was dominated by slip during tension and twin in compression. In comparison, both slip and twin were observed in the cast samples for similar testing conditions. The increase in strength of forging was attributed to the refinement of grains and the formation of strong basal texture, which activated the non-basal slip on the prismatic and pyramidal slip systems instead of extension twin.

  6. Design and Analysis of a Forging Die for Manufacturing of Multiple Connecting Rods

    NASA Astrophysics Data System (ADS)

    Megharaj, C. E.; Nagaraj, P. M.; Jeelan Pasha, K.

    2016-09-01

    This paper demonstrates to utilize the hammer capacity by modifying the die design such that forging hammer can manufacture more than one connecting rod in a given forging cycle time. To modify the die design study is carried out to understand the parameters that are required for forging die design. By considering these parameters, forging die is designed using design modelling tool solid edge. This new design now can produce two connecting rods in same capacity hammer. The new design is required to validate by verifying complete filing of metal in die cavities without any defects in it. To verify this, analysis tool DEFORM 3D is used in this project. Before start of validation process it is require to convert 3D generated models in to. STL file format to import the models into the analysis tool DEFORM 3D. After importing these designs they are analysed for material flow into the cavities and energy required to produce two connecting rods in new forging die design. It is found that the forging die design is proper without any defects and also energy graph shows that the forging energy required to produce two connecting rods is within the limit of that hammer capacity. Implementation of this project increases the production of connecting rods by 200% in less than previous cycle time.

  7. Surface modification of titanium and titanium alloys by ion implantation.

    PubMed

    Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

    2010-05-01

    Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation.

  8. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  9. Tracing Titanium Escape

    NASA Image and Video Library

    2015-05-07

    The plot of data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR (right), amounts to a "smoking gun" of evidence in the mystery of how massive stars explode. The observations indicate that supernovae belonging to a class called Type II or core-collapse blast apart in a lopsided fashion, with the core of the star hurtling in one direction, and the ejected material mostly expanding the other way (see diagram in Figure 1). NuSTAR made the most precise measurements yet of a radioactive element, called titanium-44, in the supernova remnant called 1987A. NuSTAR sees high-energy X-rays, as shown here in the plot ranging from 60 to more than 80 kiloelectron volts. The spectral signature of titanium-44 is apparent as the two tall peaks. The white line shows where one would expect to see these spectral signatures if the titanium were not moving. The fact that the spectral peaks have shifted to lower energies indicates that the titanium has "redshifted," and is moving way from us. This is similar to what happens to a train's whistle as the train leaves the station. The whistle's sound shifts to lower frequencies. NuSTAR's detection of redshifted titanium reveals that the bulk of material ejected in the 1987A supernova is flying way from us at a velocity of 1.6 million miles per hour (2.6 million kilometers per hour). Had the explosion been spherical in nature, the titanium would have been seen flying uniformly in all directions. This is proof that this explosion occurred in an asymmetrical fashion. http://photojournal.jpl.nasa.gov/catalog/PIA19335

  10. [Research on the temperature field detection method of large cylinder forgings during heat treatment process based on infrared spectra].

    PubMed

    Zhang, Yu-Cun; Fu, Xian-Bin; Liu, Bin; Qi, Yan-De; Zhou, Shan

    2013-01-01

    In order to grasp the changes of the forging's temperature field during heat treatment, a temperature field detection method based on infrared spectra for large cylinder forgings is proposed in the present paper. On the basis of heat transfer a temperature field model of large barrel forgings was established by the method of separating variables. Using infrared spectroscopy the large forgings temperature measurement system was built based on the three-level interference filter. The temperature field detection of forging was realized in its heat treatment by combining the temperature data and the forgings temperature field detection model. Finally, this method is feasible according to the simulation experiment. The heating forging temperature detection method can provide the theoretical basis for the correct implementation of the heat treatment process.

  11. Approximate-model based estimation method for dynamic response of forging processes

    NASA Astrophysics Data System (ADS)

    Lei, Jie; Lu, Xinjiang; Li, Yibo; Huang, Minghui; Zou, Wei

    2015-03-01

    Many high-quality forging productions require the large-sized hydraulic press machine (HPM) to have a desirable dynamic response. Since the forging process is complex under the low velocity, its response is difficult to estimate. And this often causes the desirable low-velocity forging condition difficult to obtain. So far little work has been found to estimate the dynamic response of the forging process under low velocity. In this paper, an approximate-model based estimation method is proposed to estimate the dynamic response of the forging process under low velocity. First, an approximate model is developed to represent the forging process of this complex HPM around the low-velocity working point. Under guaranteeing the modeling performance, the model may greatly ease the complexity of the subsequent estimation of the dynamic response because it has a good linear structure. On this basis, the dynamic response is estimated and the conditions for stability, vibration, and creep are derived according to the solution of the velocity. All these analytical results are further verified by both simulations and experiment. In the simulation verification for modeling, the original movement model and the derived approximate model always have the same dynamic responses with very small approximate error. The simulations and experiment finally demonstrate and test the effectiveness of the derived conditions for stability, vibration, and creep, and these conditions will benefit both the prediction of the dynamic response of the forging process and the design of the controller for the high-quality forging. The proposed method is an effective solution to achieve the desirable low-velocity forging condition.

  12. Analysis of the thermo-mechanical deformations in a hot forging tool by numerical simulation

    NASA Astrophysics Data System (ADS)

    L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.

    2016-03-01

    Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different mechanical properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the mechanical behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large deformations. The thermo-mechanical model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.

  13. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  14. Optimizing noise control strategy in a forging workshop.

    PubMed

    Razavi, Hamideh; Ramazanifar, Ehsan; Bagherzadeh, Jalal

    2014-01-01

    In this paper, a computer program based on a genetic algorithm is developed to find an economic solution for noise control in a forging workshop. Initially, input data, including characteristics of sound sources, human exposure, abatement techniques, and production plans are inserted into the model. Using sound pressure levels at working locations, the operators who are at higher risk are identified and picked out for the next step. The program is devised in MATLAB such that the parameters can be easily defined and changed for comparison. The final results are structured into 4 sections that specify an appropriate abatement method for each operator and machine, minimum allowance time for high-risk operators, required damping material for enclosures, and minimum total cost of these treatments. The validity of input data in addition to proper settings in the optimization model ensures the final solution is practical and economically reasonable.

  15. Snake River Plain FORGE Well Data for INEL-1

    DOE Data Explorer

    Robert Podgorney

    1979-03-01

    Well data for the INEL-1 well located in eastern Snake River Plain, Idaho. This data collection includes caliper logs, lithology reports, borehole logs, temperature at depth data, neutron density and gamma data, full color logs, fracture analysis, photos, and rock strength parameters for the INEL-1 well. This collection of data has been assembled as part of the site characterization data used to develop the conceptual geologic model for the Snake River Plain site in Idaho, as part of phase 1 of the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative. They were assembled by the Snake River Geothermal Consortium (SRGC), a team of collaborators that includes members from national laboratories, universities, industry, and federal agencies, lead by the Idaho National Laboratory (INL).

  16. Experimentation and numerical modeling of forging induced bending (FIB) process

    NASA Astrophysics Data System (ADS)

    Naseem, S.; van den Boogaard, A. H.

    2016-10-01

    Accurate prediction of the final shape using numerical modeling has been a top priority in the field of sheet and bulk forming. Better shape prediction is the result of a better estimation of the physical stress and strain state. For experimental and numerical investigations of such estimations, simple benchmark processes are used. In this paper a benchmark process involving forging (flattening) of sheet metal between punch and die with negative clearance is proposed. The introduced material flow results in bending. Easy measurability of the angle of this bend makes this process suitable for validation purpose. Physical experiments are performed to characterize this bending angle due to flattening. Furthermore a numerical model is developed to capture this phenomenon. The main focus of this paper is the validation of the numerical model in terms of accurate prediction of the physical results.

  17. Crack toughness evaluation of hot pressed and forged beryllium

    NASA Technical Reports Server (NTRS)

    Jones, M. H.; Bubsey, R. T.; Brown, W. F., Jr.

    1971-01-01

    Beryllium fracture toughness test specimens were fatigue cracked using reversed cycling with a compression load two to three times the tension load. In worked beryllium, textures may be produced which result in fatigue cracks that are out of plane with the starter notch. Specimens of hot pressed stock exhibited load displacement records which were nonlinear throughout their course. Fracture specimens of both hot pressed and forged stock showed essentially no reduction of thickness and the fracture surfaces were flat and normal to the load axis. However, the stress intensity factor at maximum load increased with decreasing thickness. Load-displacement and electric potential records for the hot pressed beryllium specimens exhibited several anomalies such as negative residual crack mouth displacements and a decrease in electrical potential with increasing load.

  18. Snake River Plain FORGE Well Data for WO-2

    DOE Data Explorer

    Robert Podgorney

    1991-07-29

    Well data for the WO-2 well located in eastern Snake River Plain, Idaho. This data collection includes lithology reports, borehole logs, temperature at depth data, neutron density and gamma data, and rock strength parameters for the WO-2 well. This collection of data has been assembled as part of the site characterization data used to develop the conceptual geologic model for the Snake River Plain site in Idaho, as part of phase 1 of the Frontier Observatory for Research in Geothermal Energy (FORGE) initiative. They were assembled by the Snake River Geothermal Consortium (SRGC), a team of collaborators that includes members from national laboratories, universities, industry, and federal agencies, lead by the Idaho National Laboratory (INL).

  19. Science Education and Outreach: Forging a Path to the Future

    NASA Astrophysics Data System (ADS)

    Manning, James G.

    2009-05-01

    The International Year of Astronomy and the Year of Science provide singular opportunities to focus public attention on science in general and the universe in particular in 2009. But what happens on January 1, 2010? How can the science and science education communities build on the initiatives and successes of 2009 to create sustainable programs and efforts to continue to advance science education and literacy objectives for the longer term? The presenter will relate how these questions will be addressed at the annual meeting of the Astronomical Society of the Pacific in Millbrae, California, September 12-16, and how the meeting will provide an opportunity for the science, astronomy, and science education and outreach communities to contribute to the discussion and to share their answers and perspectives with the larger community, and to identify ways in which we can forge that future path together.

  20. Physics and Technological Training in Bulgarian Forge Craft

    NASA Astrophysics Data System (ADS)

    Petkova, Petya N.; Velcheva, Keranka G.

    2010-01-01

    The contemporary world regenerates and preserves the traditions of decorative—applied art and the national crafts. This brings up young generation and helps them to uncover the sources of national culture. In the commonly educational system the technological training realizes succession of new methods for national and applied art. The aim is examination of the national crafts as technological processes for cultivation of different metal constructions. There are enforced physical laws here. Seven basic groups of forging methods consider in Bulgarian tradition craft as heat treatment, plastic deformation and applying of different tensions. This gives information about morphology of construction after applying of stress, enlarging or decreasing of the linear sizes, structure change and the change of physical and mechanical properties.

  1. Follow-up of hearing thresholds among forge hammering workers

    SciTech Connect

    Kamal, A.A.; Mikael, R.A.; Faris, R. )

    1989-01-01

    Hearing threshold was reexamined in a group of forge hammering workers investigated 8 years ago with consideration of the age effect and of auditory symptoms. Workers were exposed to impact noise that ranged from 112 to 139 dB(A)--at an irregular rate of 20 to 50 drop/minute--and a continuous background noise that ranged from 90 to 94 dB(A). Similar to what was observed 8 years ago, the present permanent threshold shift (PTS) showed a maximum notch at the frequency of 6 kHz and considerable elevations at the frequencies of 0.25-1 kHz. The age-corrected PTS and the postexposure hearing threshold were significantly higher than the corresponding previous values at the frequencies 0.25, 0.5, 1, and 8 kHz only. The rise was more evident at the low than at the high frequencies. Temporary threshold shift (TTS) values were significantly less than those 8 years ago. Contrary to the previous TTS, the present TTS were higher at low than at high frequencies. Although progression of PTS at the frequencies 0.25 and 0.5 kHz was continuous throughout the observed durations of exposure, progression at higher frequencies occurred essentially in the first 10 to 15 years of exposure. Thereafter, it followed a much slower rate. Tinnitus was significantly associated with difficulty in hearing the human voice and with elevation of PTS at all the tested frequencies, while acoustic after-image was significantly associated with increment of PTS at the frequencies 0.25-2 kHz. No relation between PTS and smoking was found. PTS at low frequencies may provide an indication of progression of hearing damage when the sensitivity at 6 and 4 kHz diminishes after prolonged years of exposure. Tinnitus and acoustic after-image are related to the auditory effect of forge hammering noise.

  2. Hot Superplastic Powder Forging for Transparent nanocrystalline Ceramics

    SciTech Connect

    Cannon, W. Roger

    2006-05-22

    The program explored a completely new, economical method of manufacturing nanocrystalline ceramics, Hot Superplastic Powder Forging (HSPF). The goal of the work was the development of nanocrystalline/low porosity optically transparent zirconia/alumina. The high optical transparency should result from lack of grain boundary scattering since grains will be smaller than one tenth the wavelength of light and from elimination of porosity. An important technological potential for this process is manufacturing of envelopes for high-pressure sodium vapor lamps. The technique for fabricating monolithic nanocrystalline material does not begin with powder whose particle diameter is <100 nm as is commonly done. Instead it begins with powder whose particle diameter is on the order of 10-100 microns but contains nanocrystalline crystallites <<100 nm. Spherical particles are quenched from a melt and heat treated to achieve the desired microstructure. Under a moderate pressure within a die or a mold at temperatures of 1100C to 1300C densification is by plastic flow of superplastic particles. A nanocrystalline microstructure results, though some features are greater than 100nm. It was found, for instance, that in the fully dense Al2O3-ZrO2 eutectic specimens that a bicontinuous microstructure exists containing <100 nm ZrO2 particles in a matrix of Al2O3 grains extending over 1-2 microns. Crystallization, growth, phase development and creep during hot pressing and forging were studied for several compositions and so provided some details on development of polycrystalline microstructure from heating quenched ceramics.

  3. Assessment of NASA Dual Microstructure Heat Treatment Method for Multiple Forging Batch Heat Treatment

    NASA Technical Reports Server (NTRS)

    Gayda, John (Technical Monitor); Lemsky, Joe

    2004-01-01

    NASA dual microstructure heat treatment technology previously demonstrated on single forging heat treat batches of a generic disk shape was successfully demonstrated on a multiple disk batch of a production shape component. A group of four Rolls-Royce Corporation 3rd Stage AE2100 forgings produced from alloy ME209 were successfully dual microstructure heat treated as a single heat treat batch. The forgings responded uniformly as evidenced by part-to-part consistent thermocouple recordings and resultant macrostructures, and from ultrasonic examination. Multiple disk DMHT processing offers a low cost alternative to other published dual microstructure processing techniques.

  4. Laser-dispersing of forging tools using AlN-ceramics

    NASA Astrophysics Data System (ADS)

    Noelke, C.; Luecke, M.; Kaierle, S.; Wesling, V.; Overmeyer, L.

    2014-02-01

    Forging tools for aluminum work pieces show an increased adhesive wear due to cold welding during the forging process. Laser dispersing offers at this point a great potential to fabricate protective layers or tracks with tailored properties that reduce abrasive or adhesive wear at the surface of highly stressed components. Using different process strategies, four metal ceramic compounds applied on two substrate geometries were investigated regarding their structural and mechanical properties and their performance level. The subsequent forging tests have pointed out a positive effect and less adhesive residuals on the laser dispersed tool surface.

  5. Characterization of large 2219 aluminum alloy hand forgings for the space shuttle solid rocket booster

    NASA Technical Reports Server (NTRS)

    Brennecke, M. W.

    1978-01-01

    The mechanical properties, including fracture toughness, and stress corrosion properties of four types of 2219-T852 aluminum alloy hand forgings are presented. Weight of the forgings varied between 450 and 3500 lb at the time of heat treatment and dimensions exceeded the maximum covered in existing specifications. The forgings were destructively tested to develop reliable mechanical property data to replace estimates employed in the design of the Space Shuttle Solid Rocket Booster (SRB) and to establish minimum guaranteed properties for structural refinement and for entry into specification revisions. The report summarizes data required from the forgers and from the SRB Structures contractor.

  6. Non-isothermal deformation of gamma titanium aluminide

    SciTech Connect

    Mohan, B.; Srinivasan, R.; Weiss, I.

    1995-12-31

    Gamma titanium aluminide is being considered as a material for use in internal combustion (IC) engine valves. At the present time IC engine valves are made from steel by a combination of extrusion and forging operations using a heated workpiece and relatively cold dies. In order to develop similar deformation processing technologies for gamma titanium aluminide, limits of formability under different processing conditions need to be established. Non-isothermal deformation with heated dies were carried out on samples of materials which had been processed by different routes to yield microstructures with grain sizes in the range of 3 to 10,000 {micro}m. Processing parameters such as strain rate, specimen temperature, total strain, and type of lubricant were varied in order to establish processing windows for uniform deformation of the different materials. During non-isothermal forming, the highest strain rate for uniform deformation is about 0.1 s{sup {minus}1}. Strain rates slower than 0.01 s{sup {minus}1} result in extensive chilling of the workpiece resulting in fracture. The maximum amount of deformation that could be obtained was a 40% reduction in height (strain of 0.5). The type of lubricant used plays a significant role in the formation of cracks on the specimen at the specimen/die interfaces.

  7. Results of Total Elbow Arthroplasty with Cementless Implantation of an Alumina Ceramic Elbow Prosthesis for Patients with Rheumatoid Arthritis.

    PubMed

    Nishida, Keiichiro; Hashizume, Kenzo; Ozawa, Masatsugu; Takeshita, Ayumu; Kaneda, Daisuke; Nakahara, Ryuichi; Nasu, Yoshihisa; Shimamura, Yasunori; Inoue, Hajime; Ozaki, Toshifumi

    2017-02-01

    We investigated the long-term clinical results of total elbow arthroplasty (TEA) by cementless fixation of alumina ceramic unlinked elbow prostheses (J-alumina ceramic elbows: JACE) for the reconstruction of elbow joints with rheumatoid arthritis (RA). Seventeen elbows in 17 patients (aged 44-72 years, average 54.8) replaced by JACE TEA without bone cement were investigated. The average follow-up period was 10.7 (range, 1.0-19.3) years. Clinical conditions of each elbow before and after surgery were assessed according to the Mayo Elbow Performance Index (MEPI). Radiographic loosening was defined as a progressive radiolucent line of more than 1 mm that was completely circumferential around the intramedullary stem. The average MEPI significantly improved from 46.8 points preoperatively to 66.8 points at final follow-up (p=0.0226). However, aseptic loosening was noted in 10 of 17 elbows (58.8%) and revision surgery was required in 7 (41.2%). Most loosening was observed on the humeral side. With radiographic loosening and revision surgery defined as the end points, the likelihoods of prosthesis survival were 41.2% and 51.8%, respectively, up to 15 years by Kaplan-Meier analysis. The clinical results of JACE implantation without bone cement were disappointing, with high revision and loosening rates of the humeral component.

  8. Optimization of custom cementless stem using finite element analysis and elastic modulus distribution for reducing stress-shielding effect.

    PubMed

    Saravana Kumar, Gurunathan; George, Subin Philip

    2017-02-01

    This work proposes a methodology involving stiffness optimization for subject-specific cementless hip implant design based on finite element analysis for reducing stress-shielding effect. To assess the change in the stress-strain state of the femur and the resulting stress-shielding effect due to insertion of the implant, a finite element analysis of the resected femur with implant assembly is carried out for a clinically relevant loading condition. Selecting the von Mises stress as the criterion for discriminating regions for elastic modulus difference, a stiffness minimization method was employed by varying the elastic modulus distribution in custom implant stem. The stiffness minimization problem is formulated as material distribution problem without explicitly penalizing partial volume elements. This formulation enables designs that could be fabricated using additive manufacturing to make porous implant with varying levels of porosity. Stress-shielding effect, measured as difference between the von Mises stress in the intact and implanted femur, decreased as the elastic modulus distribution is optimized.

  9. Highly Cross-linked Polyethylene Liner Dissociation from a Cement-less Modular Acetabular Shell: Two Case Reports

    PubMed Central

    Kawano, Shunsuke; Sonohata, Motoki; Kitajima, Masaru; Mawatari, Masaaki

    2016-01-01

    Liner dissociation of polyethylene from a cementless acetabular socket following total hip arthroplasty (THA) is a rare complication. Cross-linked polyethylene liner dissociation from AMS-HA shell (KYOCERA Med, Osaka, Japan) occurred in 2 out of the 4153 (0.04%) cases approximately 10 years after undergoing surgery at our institute. First case was an 80-year-old female who underwent right THA along with subtrochanteric femoral shortening osteotomy due to complete dislocation hip, and second case was a 72-year-old male, who underwent right THA due to coxarthrosis. A 26 mm femoral head and CPE liner were used in both cases and the inclination degree of the acetabular socket was within 50°.There was no implant loosening in both cases. There was partial damage in the elevated rim on the alternative side and scratches on the back side in the both extracted CPE liner. It was surmised that liner dissociation was caused due to a problem in the liner fixing format of the push in type of the present model. PMID:28217197

  10. Prospective five-year subsidence analysis of a cementless fully hydroxyapatite-coated femoral hip arthroplasty component.

    PubMed

    Clauss, Martin; Van Der Straeten, Catherine; Goossens, Marc

    2014-01-01

    Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys stem (Mathys Ltd., Bettlach, Switzerland).This prospective single-surgeon series examined consecutive patients receiving a twinSys stem at Maria Middelares Hospital, Belgium. Patients aged >85 years or unable to come to follow-up were excluded. Subsidence was assessed using Ein Bild Roentgen Analyse--Femoral Component Analysis (EBRA-FCA). Additional clinical and radiographic assessments were performed. Follow-ups were prospectively scheduled at two, five, 12, 24, and 60 months.In total, 218 THA (211 patients) were included. At five years, mean subsidence was 0.66 mm (95% CI: 0.43-0.90). Of the 211 patients, 95.2% had an excellent or good Harris Hip Score. There were few radiological changes. Kaplan-Meier analysis indicated five-year stem survival to be 98.4% (95% CI: 97.6-100%).Subsidence levels of the twinSys femoral stem throughout the five years of follow-up were substantially lower than the 1.5 mm level predictive of aseptic loosening. This was reflected in the high five-year survival rate.

  11. Recrystallization behavior of Ti40 burn-resistant titanium alloy during hot working process

    NASA Astrophysics Data System (ADS)

    Lai, Yun-jin; Xin, She-wei; Zhang, Ping-xiang; Zhao, Yong-qing; Ma, Fan-jiao; Liu, Xiang-hong; Feng, Yong

    2016-05-01

    The recrystallization behavior of deformed Ti40 alloy during a heat-treatment process was studied using electron backscatter diffraction and optical microscopy. The results show that the microstructural evolution of Ti40 alloy is controlled by the growth behavior of grain-boundary small grains during the heating process. These small grains at the grain boundaries mostly originate during the forging process because of the alloy's inhomogeneous deformation. During forging, the deformation first occurs in the grain-boundary region. New small recrystallized grains are separated from the parent grains when the orientation between deformation zones and parent grains exceeds a certain threshold. During the heating process, the growth of these small recrystallized grains results in a uniform grain size and a decrease in the average grain size. The special recrystallization behavior of Ti40 alloy is mainly a consequence of the alloy's high β-stabilized elemental content and high solution strength of the β-grains, which partially explains the poor hot working ability of Ti-V-Cr-type burn-resistant titanium alloys. Notably, this study on Ti40 burn-resistant titanium alloy yields important information related to the optimization of the microstructures and mechanical properties.

  12. Carbon/PEEK composite materials as an alternative for stainless steel/titanium hip prosthesis: a finite element study.

    PubMed

    Rezaei, Farshid; Hassani, Kamran; Solhjoei, Nosratollah; Karimi, Alireza

    2015-12-01

    Total hip replacement (THR) has been ranked within the most typical surgical processes in the world. The durability of the prosthesis and loosening of prosthesis are the main concerns that mostly reported after THR surgeries. In THR, the femoral prosthesis can be fixed by either cement or cementless methods in the patient's bones. In both procedures, the stability of the prosthesis in the hosted bone has a key asset in its long-term durability and performance. This study aimed to execute a comparative finite element simulation to assess the load transfer between the prosthesis, which is made of carbon/PEEK composite and stainless steel/titanium, and the femur bone. The mechanical behavior of the cortical bone was assumed as a linear transverse isotropic while the spongy bone was modeled like a linear isotropic material. The implants were made of stainless steel (316L) and titanium alloy as they are common materials for implants. The results showed that the carbon/PEEK composites provide a flatter load transfer from the upper body to the leg compared to the stainless steel/titanium prosthesis. Furthermore, the results showed that the von Mises stress, principal stress, and the strain in the carbon/PEEK composites prosthesis were significantly lower than that made of the stainless steel/titanium. The results also imply that the carbon/PEEK composites can be applied to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease the stress shielding and interface stress. These findings will help clinicians and biomedical experts to increase their knowledge about the hip replacement.

  13. Sorting Titanium Welding Rods

    NASA Technical Reports Server (NTRS)

    Ross, W. D., Jr.; Brown, R. L.

    1985-01-01

    Three types of titanium welding wires identified by their resistance to current flow. Welding-wire tester quickly identifies unknown titaniumalloy wire by touching wire with test probe, and comparing meter response with standard response. Before touching wire, tip of test probe dipped into an electrolyte.

  14. [What effect does the hydroxyapatite coating have in cementless knee arthroplasty?].

    PubMed

    Hildebrand, R; Trappmann, D; Georg, C; Müller, H H; Koller, M; Klose, K J; Griss, P; Kienapfel, H

    2003-04-01

    The goal of this study was to compare the migration of noncemented diffusion sintered titanium fibermesh-coated tibial components with (HA group) and without (non-HA group) additional hydroxyapatite coating. For this purpose digital radiostereometry (DIRSA) was used to compare the migration after 2 and 9 years for the two groups. After 2 years the mean maximum subsidence of the HA-coated components (0.24+/-0.18 mm) was about one-half of the mean maximum subsidence of the non-HA-coated group (0.55+/-0.55 mm). After 9 years the maximum subsidence of the HA-coated components was still smaller, but not as pronounced as before. The same trend was also found for the endpoint maximum total point motion (MTPM). After 2 years the mean MTPM of the HA-coated components was 0.66+/-0.38 mm and of the non-HA group 0.73+/-0.50 mm. After 9 years the mean MTPM for the HA-coated components was 0.54+/-0.15 mm and for the non-HA-coated components 0.74+/-0.20 mm. None of the HA-coated tibial components but one of the non-HA group had to be revised and exchanged due to aseptic loosening.

  15. Early bone growth on the surface of titanium implants in rat femur is enhanced by an amorphous diamond coating

    PubMed Central

    2011-01-01

    Background and purpose Amorphous diamond (AD) is a durable and compatible biomaterial for joint prostheses. Knowledge regarding bone growth on AD-coated implants and their early-stage osseointegration is poor. We investigated bone growth on AD-coated cementless intramedullary implants implanted in rats. Titanium was chosen as a reference due to its well-known performance. Materials and methods We placed AD-coated and non-coated titanium implants (Ra ≈ 0.2 μm) into the femoral bone marrow of 25 rats. The animals were divided in 2 groups according to implant coating and they were killed after 4 or 12 weeks. The osseointegration of the implants was examined from hard tissue specimens by measuring the new bone formation on their surface. Results 4 weeks after the operation, the thickness of new bone in the AD-coated group was greater than that in the non-coated group (15.3 (SD 7.1) μm vs. 7.6 (SD 6.0) μm). 12 weeks after the operation, the thickness of new bone was similar in the non-coated group and in the AD-coated group. Interpretation We conclude that AD coating of femoral implants can enhance bone ongrowth in rats in the acute, early stage after the operation and might be an improvement over earlier coatings. PMID:21504369

  16. Calcium phosphate and fluorinated calcium phosphate coatings on titanium deposited by Nd:YAG laser at a high fluence.

    PubMed

    Ferro, Daniela; Barinov, Sergey M; Rau, Jiulietta V; Teghil, Roberto; Latini, Alessandro

    2005-03-01

    Calcium phosphate coatings are known to enhance long-term fixation, reliability and promote osteointegration of cementless titanium-based implant devices. This study was aimed at the pulsed laser deposition of calcium phosphate coatings onto titanium using hydroxyapatite and hydroxyapatite-fluorapatite targets. The deposition was carried out at the high laser beam fluence conditions, about 12 J/cm(2). The coatings were characterized with respect to their morphology, phase composition and hardness. X-ray energy dispersive analysis revealed the coatings retain their elemental composition, and fluoride content within the film is the same as in the initial target. However, unlike sintered targets, the deposited films contain no apatite-like phases. The hardness of the films, about 18 GPa, is surprisingly high compared to that of hydroxyapatite and hydroxyapatite-fluorapatite ceramic targets. The deposited coatings of 2.7-2.9 microm thickness have uniform and dense microstructure, containing the solidified droplets of the expulsed from the target phase. The uncommon structure and hardness of the films can be attributed to the melting and phase decomposition of the initial material in the laser plasma.

  17. Bioactive macroporous titanium surface layer on titanium substrate.

    PubMed

    Kim, H M; Kokubo, T; Fujibayashi, S; Nishiguchi, S; Nakamura, T

    2000-12-05

    A macroporous titanium surface layer is often formed on titanium and titanium alloy implants for morphological fixation of the implants to bone via bony ingrowth into the porous structure. The surface of titanium metal was recently shown to become highly bioactive by being subjected to 5.0 M-NaOH treatment at 60 degrees C for 24 h and subsequent heat treatment at 600 degrees C for 1 h. In the present study, the NaOH and heat treatments were applied to a macroporous titanium surface layer formed on titanium substrate by a plasma spraying method. The NaOH and heat treatments produced an uniform amorphous sodium titanate layer on the surface of the porous titanium. The sodium titanate induced a bonelike apatite formation in simulated body fluid at an early soaking period, whereby the apatite layer grew uniformly along the surface and cross-sectional macrotextures of the porous titanium. This indicates that the NaOH and heat treatments lead to a bioactive macroporous titanium surface layer on titanium substrate. Such a bioactive macroporous layer on an implant is expected not only to enhance bony ingrowth into the porous structure, but also to provide a chemical integration with bone via apatite formation on its surface in the body.

  18. Trial production of titanium orthodontic brackets fabricated by metal injection molding (MIM) with sintering.

    PubMed

    Deguchi, T; Ito, M; Obata, A; Koh, Y; Yamagishi, T; Oshida, Y

    1996-07-01

    Safety and esthetics are two indispensable factors to consider when fabricating orthodontic brackets. However, these factors are not easily achieved when conventional techniques (including forging and casting) are used in the mass production of titanium brackets, albeit the brackets exhibit excellent biocompatibility. In the present study, orthodontic brackets were manufactured by metal powder injection molding with sintering. Brackets with three different base designs were made and subjected to compression shear tests for evaluation of their bonding strength to enamel substrate. The shapes given to the dimple of the base were spherical, oval, and grooved. The maximum shear forces for each type were 11.1 kgf, 7.6 kgf, and 18.5 kgf, respectively. The bonding strengths of the titanium bracket were equivalent to those obtained with conventional stainless steel brackets. Moreover, uniform distribution of Vickers hardness values (average, 240 +/- 40 Hv) measured at three locations indicated that the titanium bracket was uniformly sintered. Accordingly, titanium brackets thus fabricated exhibit a potential for clinical application.

  19. A novel edge detection approach used for online dimensional measurement of heavy forging

    NASA Astrophysics Data System (ADS)

    Hu, Chunhai; Liu, Bin; Song, Xiaoxue

    2008-12-01

    An edge detection method was developed with capability of objectively detecting significant edges in images of high temperature forging. The issue of potential image degradation when viewing hot objects was serious concerned. The paper was absorbed in online dimensional measurement using stereovision technology. Particular characteristics of high temperature forging were described. A global self-adaptive thresholding preprocessing was used for eliminating most redundant mill scale regions and segmenting object from complex background. Then, the feature edges was detected and localized at single pixel scale. Post processing of surround suppression as final additional step was applied to improve edges detection performance by extracting genuine feature edges from edges map. The entire method was performed on a real hot forging image and the performance had been proved in experiment result. The approach was specifically designed for using in online dimensional measurement of heavy forging, but generally enough to be applied to other edge detection of any high-temperature object.

  20. 5. VIEW OF 20TON STEAMPOWERED FORGE HAMMER Manufactured by Chambersburg ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. VIEW OF 20-TON STEAM-POWERED FORGE HAMMER Manufactured by Chambersburg Engineering Company, Chambersburg, Pennsylvania - Juniata Shops, Blacksmith Shop No. 1, East of Fourth Avenue at Second Street, Altoona, Blair County, PA

  1. Calculation of recovery plasticity in multistage hot forging under isothermal conditions.

    PubMed

    Zhbankov, Iaroslav G; Perig, Alexander V; Aliieva, Leila I

    2016-01-01

    A widely used method for hot forming steels and alloys, especially heavy forging, is the process of multistage forging with pauses between stages. The well-known effect which accompanies multistage hot forging is metal plasticity recovery in comparison with monotonic deformation. A method which takes into consideration the recovery of plasticity in pauses between hot deformations of a billet under isothermal conditions is proposed. This method allows the prediction of billet forming limits as a function of deformation during the forging stage and the duration of the pause between the stages. This method takes into account the duration of pauses between deformations and the magnitude of subdivided deformations. A hot isothermal upsetting process with pauses was calculated by the proposed method. Results of the calculations have been confirmed with experimental data.

  2. Does cemented or cementless single-stage exchange arthroplasty of chronic periprosthetic hip infections provide similar infection rates to a two-stage? A systematic review.

    PubMed

    George, D A; Logoluso, N; Castellini, G; Gianola, S; Scarponi, S; Haddad, F S; Drago, L; Romano, C L

    2016-10-10

    The best surgical modality for treating chronic periprosthetic hip infections remains controversial, with a lack of randomised controlled studies. The aim of this systematic review is to compare the infection recurrence rate after a single-stage versus a two-stage exchange arthroplasty, and the rate of cemented versus cementless single-stage exchange arthroplasty for chronic periprosthetic hip infections. We searched for eligible studies published up to December 2015. Full text or abstract in English were reviewed. We included studies reporting the infection recurrence rate as the outcome of interest following single- or two-stage exchange arthroplasty, or both, with a minimum follow-up of 12 months. Two reviewers independently abstracted data and appraised quality assessment. After study selection, 90 observational studies were included. The majority of studies were focused on a two-stage hip exchange arthroplasty (65 %), 18 % on a single-stage exchange, and only a 17 % were comparative studies. There was no statistically significant difference between a single-stage versus a two-stage exchange in terms of recurrence of infection in controlled studies (pooled odds ratio of 1.37 [95 % CI = 0.68-2.74, I(2) = 45.5 %]). Similarly, the recurrence infection rate in cementless versus cemented single-stage hip exchanges failed to demonstrate a significant difference, due to the substantial heterogeneity among the studies. Despite the methodological limitations and the heterogeneity between single cohorts studies, if we considered only the available controlled studies no superiority was demonstrated between a single- and two-stage exchange at a minimum of 12 months follow-up. The overalapping of confidence intervals related to single-stage cementless and cemented hip exchanges, showed no superiority of either technique.

  3. Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study

    PubMed Central

    2011-01-01

    Background Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol. Methods Nineteen patients (20 hips) were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS]) and hip joint function (Harris Hip score). Results The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104) months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84) pre-operatively to 18 (range, 0 - 38) prior to spacer removal and to 8 (range, 0 - 15) at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment. Conclusions Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies. PMID:21575241

  4. Intra-articular injection of tranexamic acid via a drain plus drain-clamping to reduce blood loss in cementless total knee arthroplasty

    PubMed Central

    2012-01-01

    Background Patients undergoing cementless total knee arthroplasty (TKA) sometimes suffer large blood loss. In a retrospective study, we explored whether postoperative intra-articular retrograde injection of tranexamic acid (TA) and leaving a drain clamp in place for 1 h reduced blood loss. Patients and methods Patients (n = 140) treated with unilateral primary cementless TKA (posterior cruciate ligament retained) were divided into two groups: those who had an intra-articular injection of TA (1000 mg) and drain clamping for 1 h postoperatively (study group, n = 70) and those who were not given TA and did not undergo clamping of their drains (control group, n = 70). Postoperative total blood loss, volume of drainage, hemoglobin level, transfusion amounts and rates, D-dimer level at postoperative day (POD) 7, and complications were recorded. Results Total blood loss, total drainage, mean transfusion volume, and transfusion rates were lower in the study group than in controls (P < 0.001). Hemoglobin levels on PODs 1 and 14 were similar in the groups, but on POD 7 the hemoglobin level was higher in the study group than in controls (P < 0.001). D-dimer level on POD 7 was lower in the study group than in controls (P < 0.05). There were no complications in either group. Conclusions Immediately postoperative intra-articular retrograde injection of TA and 1 h of drain-clamping effectively reduced blood loss and blood transfusion after cementless TKA. We believe that this method is simple, easy, and suitable for these patients. PMID:23020868

  5. Long-term follow-up results of a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels.

    PubMed

    Han, Chang Wook; Yang, Ick Hwan; Lee, Hye Yeon; Han, Chang Dong

    2012-01-01

    We evaluated the results of more than 10 years of follow-up of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels. One hundred five patients (129 hips) who underwent surgery between 1991 and 1996 for primary total hip arthroplasty using cementless straight distal fluted femoral stems were followed for more than 10 years. Ninety-four hips in 80 patients were available for clinical and radiologic analysis. The mean age at the time of surgery was 47 years, and the mean duration of follow-up was 14.3 years. The mean Harris hip scores had improved from 58 points to 88 points at the time of the 10-year follow-up. Activity-related thigh pain was reported in nine hips (10%). At the last follow-up, 93 stems (99%) were biologically stable and one stem (1%) was revised because of loosening. No hip had distal diaphyseal osteolysis. Proximal femoral stress-shielding was reported in 86 hips (91%). We found no significant relationship between collar-calcar contact and thigh pain, stem fixation status, or stress-shielding. The cumulative survival of the femoral stem was 99% (95% confidence interval, 98-100%) after 10 years. The long-term results of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels were satisfactory; however, the high rate of proximal stress-shielding and the minimal effect of the collar indicate the need for some changes in the stem design.

  6. Cementless total hip arthroplasty using Biolox®delta ceramic-on-ceramic bearing in patients with osteonecrosis of the femoral head.

    PubMed

    Lim, Seung-Jae; Kim, Sang-Min; Kim, Dong-Wook; Moon, Young-Wan; Park, Youn-Soo

    2016-01-01

    The purpose of this study was to evaluate the results of cementless total hip arthroplasty (THA) using a 32 mm or larger Biolox®delta ceramic-on-ceramic (CoC) bearing in patients with osteonecrosis of the femoral head after a minimum of 5 years of follow-up. We retrospectively analysed 44 patients (53 hips) who underwent cementless THA using Biolox®delta CoC bearing. There were 33 men (40 hips) and 11 women (13 hips) with the mean age of 49 years. A 36 mm head was used in 42 (79%) of 53 hips and a 32 mm head was used in 11 hips with smaller acetabular shells. The mean duration of follow-up was 5.3 years (range 5-6 years). The mean Harris Hip Score improved from 50 points preoperatively to 97 points at final follow-up (p<0.001). All acetabular and femoral components showed radiographic evidence of osseointegration. No osteolysis was observed. No patients sustained ceramic fracture. An audible hip noise was identified in 2 (4%) of the 53 hips (1 squeaking and 1 clicking). Survivorship with revision for any reason at a minimum of 5 years was 100% in the best-case scenario and 95 % in the worst-case scenario. The minimum 5-year results of cementless THA using a 32 mm or larger Biolox®delta CoC bearing in patients with osteonecrosis of the femoral head were encouraging with excellent survivorship. However, it was also found that the risk of noise development remains even for the new alumina matrix composite ceramic.

  7. Comparison of the risk of revision in cementless total hip arthroplasty with ceramic-on-ceramic and metal-on-polyethylene bearings

    PubMed Central

    Varnum, Claus; Pedersen, Alma B; Kjærsgaard-Andersen, Per; Overgaard, Søren

    2015-01-01

    Background and purpose Ceramic-on-ceramic (CoC) bearings were introduced in total hip arthroplasty (THA) to reduce problems related to polyethylene wear. We compared the 9-year revision risk for cementless CoC THA and for cementless metal-on-polyethylene (MoP) THA. Patients and methods In this prospective, population-based study from the Danish Hip Arthroplasty Registry, we identified all the primary cementless THAs that had been performed from 2002 through 2009 (n = 25,656). Of these, 1,773 THAs with CoC bearings and 9,323 THAs with MoP bearings were included in the study. To estimate the relative risk (RR) of revision, we used regression with the pseudo-value approach and treated death as a competing risk. Results 444 revisions were identified: 4.0% for CoC THA (71 of 1,773) and 4.0% for MoP THA (373 of 9,323). No statistically significant difference in the risk of revision for any reason was found for CoC and MoP bearings after 9 years of follow-up (adjusted RR = 1.3, 95% CI: 0.72–2.4). Revision rates due to component failure were 0.5% (n = 8) for CoC bearings and 0.1% (n = 6) for MoP bearings (p < 0.001). 6 patients with CoC bearings (0.34%) underwent revision due to ceramic fracture. Interpretation When compared to the “standard” MoP bearings, CoC THA had a 33% higher (though not statistically significantly higher) risk of revision for any reason at 9 years. PMID:25637339

  8. Development of strategies for saving energy by temperature reduction in warm forging processes

    NASA Astrophysics Data System (ADS)

    Varela, Sonia; Santos, Maite; Vadillo, Leire; Idoyaga, Zuriñe; Valbuena, Óscar

    2016-10-01

    This paper is associated to the European policy of increasing efficiency in raw material and energy usage. This policy becomes even more important in sectors consuming high amount of resources, like hot forging industry, where material costs sums up to 50% of component price and energy ones are continuously raising. The warm forging shows a clear potential of raw material reduction (near-net-shape components) and also of energy saving (forging temperature under 1000°C). However and due to the increment of the energy costs, new solutions are required by the forging sector in order to reduce the temperature below 900°C. The reported research is based on several approaches to reduce the forging temperature applied to a flanged shaft of the automotive sector as demonstration case. The developed investigations have included several aspects: raw material, process parameters, tools and dies behavior during forging process and also metallographic evaluation of the forged parts. This paper summarizes analysis of the ductility and the admissible forces of the flanged shaft material Ck45 in as-supplied state (as-rolled) and also in two additional heat treated states. Hot compression and tensile tests using a GLEEBLE 3800C Thermo mechanical simulator have been performed pursuing this target. In the same way, a coupled numerical model based on Finite Element Method (FEM) has been developed to predict the material flow, the forging loads and the stresses on the tools at lower temperature with the new heat treatments of the raw material. In order to validate the previous development, experimental trials at 850 °C and 750 °C were carried out in a mechanical press and the results were very promising.

  9. Establishment of a Process for Creep Forging Aluminum Alloy Weapon Components

    DTIC Science & Technology

    1978-04-01

    the important powder particle character- istics are mean particle size and size distribution, dendritic cell size and pattern, internal voids , and...Geometry Forging No. 26 (Fig. 53) showed excellent die filling except for a slight underfill at the tallest rib. Minor cracking also occurred over a small...Much cracking and underfill In rib detal1. 0.2 750 400 1 Some cracking Trimmed weight, 3.0 lb. 0.1 830 150 - Forged

  10. Numerical analysis of rheological and tribological behavior influence on 16MnCr5 forging fibering

    NASA Astrophysics Data System (ADS)

    Gavrus, A.; Pintilie, D.; Nedelcu, R.

    2016-10-01

    The present research work is focus on the influence of the rheological constitutive equation and friction law formulation on 16MnCr5 forging fibering. Numerical analysis using FE Forge® and Abaqus code show the importance of the rheological softening terms on the metals fibers morphology and position coordinate. Calibration of friction law and sensitivity of softening parameters corresponding to a Hansel-Spittel rheological equation have been studied.

  11. Military Process Specification for Type 46XX Powder-Forged Weapon Components

    DTIC Science & Technology

    1985-08-20

    one with low carbon or carburizing steels (Figure 18). Fracture Toughness Only one paper contained fracture toughness data for P/F 10XX steels . The...201-213. 8. Brown, G. T., "The Core ’Properties of a Range of Powder-Forged Steels ’ for Carburizing Applications," Powder Metallurgy, vol. 20, no...621205H84001, Dover, NJ: ARRADC0M, October 1980. Smith, A. 0., "Hardenability of Forged Alloy Steel Powders for Carburizing Ap- plications," Inland

  12. Nine percent nickel steel heavy forging weld repair study. [National Transonic Wind Tunnel fan components

    NASA Technical Reports Server (NTRS)

    Young, C. P., Jr.; Gerringer, A. H.; Brooks, T. G.; Berry, R. F., Jr.

    1978-01-01

    The feasibility of making weld repairs on heavy section 9% nickel steel forgings such as those being manufactured for the National Transonic Facility fan disk and fan drive shaft components was evaluated. Results indicate that 9% nickel steel in heavy forgings has very good weldability characteristics for the particular weld rod and weld procedures used. A comparison of data for known similar work is included.

  13. Manufacturing Methods and Technology for Production Hot Forging of Alkali Halide Lenses

    DTIC Science & Technology

    1983-05-01

    Polariscopic strain photographs of 10 KBr starting crystals 12 7 Polariscopic strain photographs of first stage forging numbers 13 084, 085, 091, 092...and 093 8 Polariscopic strain photographs of first stage forging numbers 14 086, 087, 088, 089 and 090 9 Console containing electronic controls for...20 084 through 089 20 13 Double pass transmission wavefront distortion test 22 14 Lateral shearing interferometer 22 15 Polariscopic photographs of

  14. Prospective randomised clinical trial assessing subsidence and rotation, using radiostereometric analysis, of two modular cementless femoral stems (Global K2 and Apex)

    PubMed Central

    Edmondson, Mark; Ebert, Jay; Nivbrant, Oscar; Wood, David

    2014-01-01

    Aims To accurately assess subsidence, rotation and clinical scores in two cementless femoral stems. Methods 260 patients received either K2 or Apex femoral stems and were studied over 2y, with RSA and clinical scores. Results Mean Oxford Hip score for both stems was excellent (45.78 and 46.76). Very little subsidence or rotation were noted on RSA in either stem. There were no statistically significant differences in clinical scores, or radiological motion between stems. Revision rate was 0.8% over the study period. Conclusion Excellent clinical and RSA scores over the 2y study period predict good long term outcomes for these stems. PMID:25104894

  15. Cementless metaphyseal fitting anatomic total hip arthroplasty with a ceramic-on-ceramic bearing in patients thirty years of age or younger.

    PubMed

    Kim, Young-Hoo; Park, Jang-Won; Kim, Jun-Shik

    2012-09-05

    The number of midterm or long-term studies on the current generation of cementless total hip replacements with alumina-on-alumina ceramic bearings in patients younger than thirty years of age is limited. The purpose of this study was to evaluate the midterm results of the cementless metaphyseal fitting anatomic total hip prosthesis in patients younger than thirty years of age, with a particular emphasis on the prevalence of thigh pain, resorption of bone due to stress-shielding of the proximal part of the femur, aseptic loosening, and osteolysis. We reviewed the cases of ninety-six patients (127 hips) who had a cementless total hip arthroplasty when they were thirty years or younger at the time of surgery. All surgical procedures were performed by a single surgeon. The most common diagnoses were osteonecrosis (54.3%) and developmental dysplasia of the hip (20.5%). Demographic data, the Harris hip score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and University of California, Los Angeles (UCLA) activity scores were recorded. Radiographic evaluation was used to evaluate implant fixation and osteolysis. The minimum follow-up interval was ten years (mean, 14.6 years; range, ten to sixteen years). The mean preoperative Harris hip score, WOMAC score, and UCLA activity score were 41 points, 66 points, and 3 points, respectively. At the time of final follow-up, the mean Harris hip score, WOMAC score, and UCLA activity score were 95 points, 16 points, and 8 points, respectively. No patient had thigh pain after one year postoperatively. All of the femoral stems and all but one of the acetabular components were well-fixed at the time of final follow-up. No hip exhibited squeaking, ceramic fracture, loosening, or osteolysis at the time of the final follow-up. These results in patients thirty years of age or younger suggest that the cementless metaphyseal fitting anatomic total hip prosthesis provides outstanding midterm fixation and substantial

  16. Study on application of color filters in vision system of hot forgings

    NASA Astrophysics Data System (ADS)

    Bi, Chao; Fang, Jianguo; Li, Di; Qu, Xinghua

    2016-10-01

    In order to improve the quality and efficiency of forging process, it needs to execute on-line dimensional measurement of the forgings. In the paper, a laboratory color vision measuring system is set up and the combination of digital and physical filtering is adopted to improve the image quality based on the radiation characteristics of high-temperature forgings. The digital filtering technology is a kind of image processing methods, in which the R component of the forging image is removed. While, the physical filtering technology is achieved by optical filters installed in front of the CCD, in which strong self-emitted radiation from the hot parts can be filtered out. In order to evaluate the image quality, the image contrast is applied, which is generally defined as the difference value between average gray scale of object region and that of background region. In the experiments, image contrast derived with filters at different sample points set from 800°C to 1200°C is compared to determine the optimal scheme of filters to be selected. Results of experiments indicate that the application effect of filters is dissimilar when the forging is in different temperature ranges. Through comparison, the optimal selection scheme of filters is determined to derive high quality image of forgings at different temperatures, which lays a solid foundation for the subsequent image processing.

  17. Photogrammetry based system for the measurement of cylindrical forgings axis straightness

    NASA Astrophysics Data System (ADS)

    Zatočilová, Aneta; Poliščuk, Radek; Paloušek, David; Brandejs, Jan

    2013-04-01

    Dimension measurement of hot large forgings is necessary for manufacturing process and quality control. Conventional non-contact optical measurement methods are not applicable, mainly because of high temperature and large dimensions. A novel approach to the axis staightness measurement of the cylindrical forging, based on the principle of photogrammetry and edge detection, is described in this paper. Proposed system is developing under laboratory conditions, but the actual conditions of steel production are also considered. Demands on the measurement system were set by our industrial partner, producer of cylindrical forgings with length of 4 to 20 m and diameter up to 1.4 m. The system should be able to detect axis straightness deviations higher than 5 mm (system accuracy has to be better than 5 mm). Cylindrical forgings are 4 to 20 m long with diameter up to 1.4 m. The approach is based on the assumption that the actual shape of the cylindrical forging axis can be determined (in the simplest case) using four boundary curves which lie in two mutually perpendicular planes. Four boundary curves can be obtained by detecting the forgings edges in two images. The article provides results of first validation of proposed method in laboratory conditions. Measurement repeatability was validated by carrying out ten measurements of a deformed rod. Each measurement was compared with a measurement performed by industrial fringe projection scanner Atos III Triple Scan in order to verify the accuracy of the proposed method.

  18. Deformation, recrystallization, strength, and fracture of press-forged ceramic crystals.

    NASA Technical Reports Server (NTRS)

    Rice, R. W.

    1972-01-01

    Sapphire and ruby were very difficult to press-forge because they deformed without cracking only in a limited temperature range before they melted. Spinel crystals were somewhat easier and MgO, CaO, and TiC crystals much easier to forge. The degree of recrystallization that occurred during forging (which was related to the ease and type of slip intersections) varied from essentially zero in Al2O3 to complete (i.e., random polycrystalline bodies were produced) in CaO. Forging of bi- and polycrystalline bodies produced incoherent bodies as a result of grain-boundary sliding. Strengths of the forged crystals were comparable to those of dense polycrystalline bodies of similar grain size. However, forged and recrystallized CaO crystals were ductile at lower temperatures than dense hot-pressed CaO. This behavior is attributed to reduced grain-boundary impurities and porosity. Fracture origins could be located, indicating that fracture in the CaO occurs internally as a result of surface work hardening caused by machining.-

  19. Deformation, recrystallization, strength, and fracture of press-forged ceramic crystals.

    NASA Technical Reports Server (NTRS)

    Rice, R. W.

    1972-01-01

    Sapphire and ruby were very difficult to press-forge because they deformed without cracking only in a limited temperature range before they melted. Spinel crystals were somewhat easier and MgO, CaO, and TiC crystals much easier to forge. The degree of recrystallization that occurred during forging (which was related to the ease and type of slip intersections) varied from essentially zero in Al2O3 to complete (i.e., random polycrystalline bodies were produced) in CaO. Forging of bi- and polycrystalline bodies produced incoherent bodies as a result of grain-boundary sliding. Strengths of the forged crystals were comparable to those of dense polycrystalline bodies of similar grain size. However, forged and recrystallized CaO crystals were ductile at lower temperatures than dense hot-pressed CaO. This behavior is attributed to reduced grain-boundary impurities and porosity. Fracture origins could be located, indicating that fracture in the CaO occurs internally as a result of surface work hardening caused by machining.-

  20. FEM Analysis and Experimental Verification of the Integral Forging Process for AP1000 Primary Coolant Pipe

    NASA Astrophysics Data System (ADS)

    Wang, Shenglong; Yu, Xiaoyi; Yang, Bin; Zhang, Mingxian; Wu, Huanchun

    2016-10-01

    AP1000 primary coolant pipes must be manufactured by integral forging technology according to the designer—Westinghouse Electric Co. The characteristics of these large, special-shaped pipes create nonuniform temperatures, effective stress, and effective strain during shaping of the pipes. This paper presents a three-dimensional finite element simulation (3D FEM) of the integral forging process, and qualitatively evaluates the likelihood of forging defects. By analyzing the evolution histories of the three field variables, we concluded that the initial forging temperature should be strictly controlled within the interval 1123 K to 1423 K (850 °C to 1150 °C) to avoid second-phase precipitation. In the hard deformation zones, small strains do not contribute to recrystallization resulting in coarse grains. Conversely, in the free deformation zone, the large strains can contribute to the dynamic recrystallization, favoring grain refinement and closure of voids. Cracks are likely to appear, however, on the workpiece surface when forging leads to large deformations. Based on the simulation results, an eligible workpiece with good mechanical properties, few macroscopic defects, and favorable grain size has been successfully forged by experiments at an industrial scale, which validates the FEM simulation.

  1. West Flank Coso, CA FORGE 3D temperature model

    DOE Data Explorer

    Doug Blankenship

    2016-03-01

    x,y,z data of the 3D temperature model for the West Flank Coso FORGE site. Model grid spacing is 250m. The temperature model for the Coso geothermal field used over 100 geothermal production sized wells and intermediate-depth temperature holes. At the near surface of this model, two boundary temperatures were assumed: (1) areas with surface manifestations, including fumaroles along the northeast striking normal faults and northwest striking dextral faults with the hydrothermal field, a temperature of ~104˚C was applied to datum at +1066 meters above sea level elevation, and (2) a near-surface temperature at about 10 meters depth, of 20˚C was applied below the diurnal and annual conductive temperature perturbations. These assumptions were based on heat flow studies conducted at the CVF and for the Mojave Desert. On the edges of the hydrothermal system, a 73˚C/km (4˚F/100’) temperature gradient contour was established using conductive gradient data from shallow and intermediate-depth temperature holes. This contour was continued to all elevation datums between the 20˚C surface and -1520 meters below mean sea level. Because the West Flank is outside of the geothermal field footprint, during Phase 1, the three wells inside the FORGE site were incorporated into the preexisting temperature model. To ensure a complete model was built based on all the available data sets, measured bottom-hole temperature gradients in certain wells were downward extrapolated to the next deepest elevation datum (or a maximum of about 25% of the well depth where conductive gradients are evident in the lower portions of the wells). After assuring that the margins of the geothermal field were going to be adequately modelled, the data was contoured using the Kriging method algorithm. Although the extrapolated temperatures and boundary conditions are not rigorous, the calculated temperatures are anticipated to be within ~6˚C (20˚F), or one contour interval, of the

  2. Welded Titanium Case for Space-Probe Rocket Motor

    NASA Technical Reports Server (NTRS)

    Brothers, A. J.; Boundy, R. A.; Martens, H. E.; Jaffe, L. D.

    1959-01-01

    components used to make the stainless steel and the 6A1--4V titanium alloy cases. The forward dome and aft fitting for the stainless steel assembly were fabricated from a combination of forged, spun and machined parts.. In order to facilitate the fabrication of the titanium alloy motor ) these components were machined from a large-diameter billet.

  3. Implementation of state-of-the-art rotor forging evaluation to manage the oldest rotor fleet in the USA

    SciTech Connect

    Puri, A.; Steakley, M.; McCann, D.

    1995-12-31

    The average age of the Tennessee Valley Authority`s (TVA) fossil fleet is almost 40 years with a large population of ``C`` grade rotors manufactured in the 1950`s. Until 1991, TVA relied upon the OEM`s to support the rotor forging assessment and establish the reinspection intervals. Based on the OEM`s recommendations most turbine/generator overhauls were governed by the forging reinspection interval. In the spring of 1992, TVA initiated an engineered forging evaluation process that involved state-of-the-art amplitude independent, target-motion based Ultrasonic And Data Processing System (UDRPS) forging inspection, forging material sampling, and fracture mechanics analysis. This paper outlines TVA`s state-of-art rotor forging evaluation program, results achieved since its introduction and the long range benefits to TVA.

  4. Comparison of pitting fatigue life of ausforged and standard forged AISI M-50 and AISI 9310 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

    1975-01-01

    Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3.5 in.) in pitch diameter and had tip relief. The M-50 standard forged and ausforged test results were compared with each other. They were then compared with results for machined vacuum-arc-remelted AISI 9310 gears tested under identical conditions. Both types of M-50 gears had lives approximately five times that of the 9310 gears. The life at which 10 percent of the M-50 ausforged gears failed was slightly less than that at which the M-50 standard forged gears failed. The ausforged gears had a slightly greater tendency to fail by tooth fracture than did the standard forged gears, most likely because of the better forging and grain flow pattern of standard forged gears.

  5. Titanium Honeycomb Panel Testing

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance; Thompson, Randolph C.

    1996-01-01

    Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

  6. Intraoperative Femur Fracture Risk During Primary Direct Anterior Approach Cementless Total Hip Arthroplasty With and Without a Fracture Table.

    PubMed

    Cohen, Eric M; Vaughn, Joshua J; Ritterman, Scott A; Eisenson, Daniel L; Rubin, Lee E

    2017-09-01

    There is no study to date comparing intraoperative femur fractures (IFFs) in the direct anterior approach (DAA) with and without a fracture table. We hypothesize that there is no significant difference in the IFF with and without a fracture table when performed by experienced DAA hip surgeons. This study is a 1-year retrospective review of patients who underwent DAA total hip arthroplasty by 2 surgeons: one surgeon uses a flat table and manually elevates the femur with a large bone hook, while the other surgeon uses a fracture table and a mechanical femoral elevator. Exclusion criteria included cemented femoral implants, femoral neck fractures, and lack of 6-month follow-up. We identified 487 patients for analysis (220 male and 267 female, average age 66.55 years). There were 12 total IFFs (2.46%): 8 female and 4 male patients. The average age of IFF patients was 70.67 years and in nonfracture patients was 66.00 years. There was no difference in gender (P = .2981) or age (P = .2099) between IFF and nonfracture patients. In the fracture table group, there were 6 IFFs (2.22%) in 271 patients; in the nonfracture table group, there were 6 IFFs (2.76%) in 216 patients. There was no statistical difference in IFF between the 2 groups (P = .6973). We observed just 2 patients (0.4%) in this series where the IFFs changed management requiring a revision femoral stem. There was no statistical difference in IFF with or without the use of fracture table. Both DAA surgical technique variations are felt to be equivalent regarding the risk for IFF during DAA cementless total hip arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Acetabular screw head-induced ceramic acetabular liner fracture in cementless ceramic-on-ceramic total hip arthroplasty.

    PubMed

    Lee, Su Chan; Jung, Kwang Am; Nam, Chang Hyun; Kim, Tea Ho; Ahn, Nong Kyoum; Hwang, Seung Hyun

    2010-05-12

    Ceramic liner fractures are rare after ceramic-on-ceramic THA. This article describes a case of an early ceramic liner fracture caused by impingement with a tilted acetabular screw head 2 months after cementless ceramic-on-ceramic THA. A 59-year-old man underwent primary THA for avascular necrosis of his right femoral head. The implant used was an Osteonics Secur-Fit HA ceramic-on-ceramic bearing system. The metal shell was fixed with 1 cancellous bone screw. During the index procedure, the acetabular screw seemed tilted in the metal shell hole, but the liner was fully seated in the metal shell without difficulty. However, 2 months later he re-presented due to pain and crepitation in the right hip. Radiographs showed that the ceramic acetabular insert had fractured. At revision, ceramic insert had fractured into large and numerous comminuted fragments, and the acetabular screw head was slightly tilted and protruded over the inner surface of the metal shell, which had worn eccentrically. The ceramic inner head and metal shell were visibly intact. Because the metal shell-bone fixation was firm, a new identical design ceramic liner and head were fitted, and no adverse event has occurred since. This case suggests that a complete check of the inside of the shell should be made when using an acetabular screw and ceramic liner. In particular, the screw head must not be tilted or left proud of the inside surface of the shell. Correct acetabular screw direction and seating are essential to avoid detrimental clinical consequences. Copyright 2010, SLACK Incorporated.

  8. Texture Development During Equal Channel Angular Forging of BCC Metals

    SciTech Connect

    Agnew, S.R.

    1999-08-08

    Equal channel angular forging (ECAF) has been proposed as a severe plastic deformation technique for processing metals, alloys, and composites [e.g. Segal, 1995] (Fig. 1). The technique offers two capabilities of practical interest: a high degree of strain can be introduced with no change in the cross-sectional dimensions of the work-piece, hence, even greater strains can be introduced by re-inserting the work-piece for further deformation during subsequent passes through the ECAF die. Additionally, the deformation is accomplished by simple shear (like torsion of a short tube) on a plane whose orientation, with respect to prior deformations, can be controlled by varying the processing route. There is a nomenclature that has developed in the literature for the typical processing routes: A: no rotations; B{sub A}: 90 degrees CW (clockwise), 90 degrees CCW (counterclockwise), 9O degrees CW, 90 degrees CCW...; Bc: 90 degrees CW, 90 degrees CW, 90 degrees CW...; and C: 180 degrees, 18 0 degrees.... The impact of processing route on the subsequent microstructure [Ferasse, Segal, Hartwig and Goforth, 1997; Iwahashi, Horita, Nemoto and Langdon, 1996] and texture [Gibbs, Hartwig, Cornwell, Goforth and Payzant, 1998] has been the subject of numerous experimental studies.

  9. Anisotropic embrittlement in high-hardness ESR 4340 steel forgings

    SciTech Connect

    Olson, G.B.; Anctil, A.A.; DeSisto, T.S.; Kula, E.B.

    1983-08-01

    ESR 4340 steel forgings tempered to a hardness of HRC 55 exhibit a severe loss of tensile ductility in the short transverse direction which is strain-rate and humidity dependent. The anisotropy is also reflected in blunt-notch Charpy impact energy, but is absent in the sharp-crack fracture toughness. Brittle behavior is associated with regions of smooth intergranular fracture aligned with microstructural banding Scanning Auger microprobe analysis indicates intergranular segregation of phosphorus and sulfur. The anisotropic embrittlement is attributed to an interaction of nonequilibrium segregation on solidification with local equilibrium segregation at grain boundaries during austenitizing. The regions are prone to brittle fracture under impact conditions and abnormal sensitivity to environmental attack during low strain-rate deformation. A relatively sparse distribution of these defects accounts for the discrepancy between smooth bar and blunt-notch tests vs sharp-crack tests. Isotropic properties are restored by homogenization treatment. For application of these steels at extreme hardness levels, homogenization treatment is essential.

  10. Movement Synchrony Forges Social Bonds across Group Divides

    PubMed Central

    Tunçgenç, Bahar; Cohen, Emma

    2016-01-01

    Group dynamics play an important role in the social interactions of both children and adults. A large amount of research has shown that merely being allocated to arbitrarily defined groups can evoke disproportionately positive attitudes toward one's in-group and negative attitudes toward out-groups, and that these biases emerge in early childhood. This prompts important empirical questions with far-reaching theoretical and applied significance. How robust are these inter-group biases? Can biases be mitigated by behaviors known to bond individuals and groups together? How can bonds be forged across existing group divides? To explore these questions, we examined the bonding effects of interpersonal synchrony on minimally constructed groups in a controlled experiment. In-group and out-group bonding were assessed using questionnaires administered before and after a task in which groups performed movements either synchronously or non-synchronously in a between-participants design. We also developed an implicit behavioral measure, the Island Game, in which physical proximity was used as an indirect measure of interpersonal closeness. Self-report and behavioral measures showed increased bonding between groups after synchronous movement. Bonding with the out-group was significantly higher in the condition in which movements were performed synchronously than when movements were performed non-synchronously between groups. The findings are discussed in terms of their importance for the developmental social psychology of group dynamics as well as their implications for applied intervention programs. PMID:27303341

  11. Titanium: light, strong, and white

    USGS Publications Warehouse

    Woodruff, Laurel; Bedinger, George

    2013-01-01

    Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

  12. Titanium fasteners. [for aircraft industry

    NASA Technical Reports Server (NTRS)

    Phillips, J. L.

    1972-01-01

    Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

  13. DESIGN MECHANICAL PROPERTIES, FRACTURE TOUGHNESS, FATIGUE PROPERTIES, EXFOLIATION AND STRESS-CORROSION RESISTANCE OF 7050 SHEET, PLATE, HAND FORGINGS, DIE FORGINGS AND EXTRUSIONS

    DTIC Science & Technology

    1975-07-01

    Cracking, of Stress- Relieved Stretched Aluminum Alloy Extrusions", Technical Report AFML-TR-68-34, Fabruary 1968. 11. D. J. Brownhill, C. F. Babilon , 0. E...Rates of Stress-Relieved Aluminum Alloy Hand Forgings", Technical Report AFML-TR-70-10, February 1970. 12. C. F. Babilon , R. H. Wygonik, G. E

  14. Effect of Pressure and Temperature Factors on the Solidification of Cast Iron and Its Structure in Liquid Forging

    NASA Astrophysics Data System (ADS)

    Sosenushkin, E. N.; Frantsuzova, L. S.; Kozlova, E. M.

    2015-09-01

    This article examines the properties and microstructure of cast iron after fabrication of grinding balls by different kinds of casting and forging, with crystallization of the metal under pressure. A mathematical model of the process of solidification of a forging in a die is presented. Joint solution of two Fourier equations of heat conduction for the melt and for the solid skin is used to derive a kinetic equation of solidification and hence to determine the rate of solidification of the forging in the die. The effect of the pressure on the structure of the crystallizing metal and the quality of the forged grinding balls that are obtained is determined.

  15. Effect of impulse vibration and noise on vasomotor function of peripheral blood vessels among pneumatic forge hammer operators.

    PubMed

    Solecki, L

    1995-01-01

    An evaluation of the effect of impulse vibration and noise on vasomotor function of blood vessels among pneumatic forge hammer operators has been presented based on thermal tests (cooling). The study covered the following groups of workers; pneumatic forge hammer operators (I), pneumatic forging hammer operators (II), hammer operator's assistants (III), operators of forging presses and machines (IV) and the control group. The results of the study showed that in groups I and III it was impulse noise not vibration that caused changes in the functioning of peripheral blood vessels.

  16. Automatic simulation of a sequence of hot-former forging processes by a rigid-thermoviscoplastic finite element method

    SciTech Connect

    Joun, M.S.; Moon, H.K.; Shivpuri, R.

    1998-10-01

    A fully automatic forging simulation technique in hot-former forging is presented in this paper. A rigid-thermoviscoplastic finite element method is employed together with automatic simulation techniques. A realistic analysis model of the hot-former forging processes is given with emphasis on thermal analysis and simulation automation. The whole processes including forming, dwelling, ejecting, and transferring are considered in the analysis model and various cooling conditions are embedded in the analysis model. The approach is applied to a sequence of three-stage hot former forging process. Nonisothermal analysis results are compared with isothermal ones and the effect of heat transfer on predicted metal flows is discussed.

  17. Ibandronate and cementless total hip arthroplasty: densitometric measurement of periprosthetic bone mass and new therapeutic approach to the prevention of aseptic loosening

    PubMed Central

    Muratore, Maurizio; Quarta, Eugenio; Quarta, Laura; Calcagnile, Fabio; Grimaldi, Antonella; Orgiani, M. Antonio; Marsilio, Antonio; Rollo, Giuseppe

    2012-01-01

    Summary Studies of the mechanisms of periprosthetic bone loss have led to the development of pharmacologic strategies intended to enhance bone mass recovery after surgery and consequently prevent aseptic loosening and prolong the implant survival. Bisphosphonates, potent anti-resorptive drugs widely used in the treatment of osteoporosis and other disorders of bone metabolism, were shown to be particularly effective in reducing periprosthetic bone resorption in the first year after hip and knee arthroplasty, both cemented and cementless. Based on these results, we investigated the inhibitory effects of ibandronate on periprosthetic bone loss in a 2-year study of postmenopausal women that underwent cementless total hip arthroplasty. In the first 6 months both groups (A, treated with ibandronate 3 mg i.v. within five days after surgery and then with oral ibandronate 150 mg/month, plus calcium and vitamin D supplementation; and B, treated with calcium and vitamin D supplementation only) experienced bone loss, though to a lesser extent in group A. After 12 months, group A showed a remarkable BMD recovery, that was statistically significant versus baseline values (about +1, 74% of global BMD) and most evident in region R1 (+3, 81%) and R2 (+4, 12%); in group B, on the contrary, BMD values were unchanged compared with those at 6 months post-surgery. Quality of life scores also showed a greater improvement in group A, both at 6 and 12 months after surgery, likely because of the pain-reducing effects of ibandronate treatment. PMID:22783337

  18. Inter- and intra-observer variability of radiography and computed tomography for evaluation of Zurich cementless acetabular cup placement ex vivo.

    PubMed

    Leasure, Jessica O; Peck, Jeffrey N; Villamil, Armando; Fiore, Kara L; Tano, Cheryl A

    2016-11-23

    To evaluate the inter- and intra-observer variability in measurement of the angle of lateral opening (ALO) and version angle measurement using digital radiography and computed tomography (CT). Each hemipelvis was implanted with a cementless acetabular cup. Ventrodorsal and mediolateral radiographs were made of each pelvis, followed by CT imaging. After removal of the first cup, the pelves were implanted with an acetabular cup in the contralateral acetabulum and imaging was repeated. Three surgeons measured the ALO and version angles three times for each cup from the mediolateral radiographic projection. The same measurements were made using three-dimensional multiplanar reconstructions from CT images. Two anatomical axes were used to measure pelvic inclination in the sagittal plane, resulting in six measurements per cup. Two-way repeated measures analysis of variance evaluated inter- and intra-observer repeatability for radiographic and CT-based measurements. Version angle based on radiographic measurement did not differ within surgeons (p = 0.433), but differed between surgeons (p <0.001). Radiographic measurement of ALO differed within surgeons (p = 0.006) but not between surgeons (p = 0.989). The ALO and version angle measured on CT images did not differ with or between surgeons. Assessment of inter- and intra-observer measurement of ALO and version angle was more reproducible using CT images than conventional mediolateral radiography for a Zurich cementless acetabular cup.

  19. [Cementless total hip arthroplasty after acute femoral neck fracture in active patients. Prospective matched study with a minimum follow-up of 5 years].

    PubMed

    Lizaur-Utrilla, A; Sanz-Reig, J; Miralles-Muñoz, F A

    2014-01-01

    To evaluate outcomes of cementless total hip replacement after acute femoral neck fracture in active patients. A prospective matched study was conducted to compare the results between 76 patients with fractures and 76 patients with osteoarthritis. The Harris score, short-WOMAC and SF-12 were used for the clinical assessment. The mean follow-up was 7.3 years (range 5-11). There were no significant differences in medical or surgical complications between the 2 groups. Functional outcomes were similar, but more walking aids were used in fracture group. There were 6 revisions among the fractures group (one dislocation, 2 deep infections, 3 aseptic loosening), and 2 aseptic loosening among controls. There was no significant difference in arthroplasty survival at 10 years (88.7 vs. 96.1%, P=.15). The mortality rates at 2 and 10 years were similar. Cementless total hip replacement for treatment of acute femoral neck fracture showed similar results to those of elective surgery for osteoarthritis in these selected patients. Copyright © 2013 SECOT. Published by Elsevier Espana. All rights reserved.

  20. Primary cementless hip arthroplasty as a potential risk factor for non-union after long-stem revision arthroplasty in periprosthetic femoral fractures.

    PubMed

    Boesmueller, Sandra; Michel, Marc; Hofbauer, Marcus; Platzer, Patrick

    2015-04-01

    In case of stem loosening in periprosthetic femoral fractures (PPFF), revision arthroplasty should be performed. The first hypothesis of this study was that advanced patient age and female gender shows higher non-union rates. The second hypothesis was that primary cementless arthroplasty is associated with a higher non-union rate compared to cemented primary hip arthroplasty. All PPFF occurring between January 2000 and June 2010 treated by revision arthroplasty were included. Multiple regression analysis was performed to identify independent variables leading to fracture non-union. Eighty one patients (78 % female) met the inclusion criteria. In 20/81 patients (24.7 %) no adequate fracture healing could be determined on radiographs 12 months after revision surgery. Although age and female gender showed a positive correlation with bony non-union after PPFF as expected, the p-values were not statistically significant. Multiple regression analysis revealed primary cementless prosthesis (p = 0.001) to be the only independent variable associated with non-union. Non-cemented primary prosthesis might be a negative predicting factor for the development of non-union after long-stem revision arthroplasty in PPFF. We therefore recommend the thorough debridement of pannus tissue thus inducing bone healing before the implantation of revision prostheses.

  1. Cementless total hip arthroplasty with ceramic-on-ceramic bearing in patients younger than 45 years with femoral-head osteonecrosis.

    PubMed

    Kim, Young-Hoo; Choi, Yoowang; Kim, Jun-Shik

    2010-12-01

    Despite improvements in the quality of alumina ceramics, osteolysis has been reported anecdotally after total hip arthroplasty (THA) with use of a contemporary alumina-on-alumina ceramic bearing. The purpose of this study was to evaluate the clinical and radiographic outcomes of THA using alumina-on-alumina ceramic bearing and to determine osteolysis using radiographs and computed tomographic (CT) scans in young patients. Consecutive primary cementless THA using alumina-on-alumina ceramic bearing were performed in 64 patients (93 hips) who were younger than 45 years of age with femoral-head osteonecrosis. There were 55 men (84 hips) and nine women (nine hips). Average age was 38.2 (range 24-45) years. Average follow-up was 11.1 (range 10-13) years. Preoperative Harris Hip Score was 52.9 (range 22-58) points, which improved to 96 (range 85-100) points at the final follow-up examination. Two of 93 hips (2%) had clicking or squeaking sound. No hip had revision or aseptic loosening. Radiographs and CT scans demonstrated that no acetabular or femoral osteolysis was detected in any hip at the latest follow-up. Contemporary cementless acetabular and femoral components with alumina-on-alumina ceramic bearing couples function well with no osteolysis at a ten year minimum and average of 11.1-year follow-up in this series of young patients with femoral-head osteonecrosis.

  2. Making randomised trials more efficient: report of the first meeting to discuss the Trial Forge platform.

    PubMed

    Treweek, Shaun; Altman, Doug G; Bower, Peter; Campbell, Marion; Chalmers, Iain; Cotton, Seonaidh; Craig, Peter; Crosby, David; Davidson, Peter; Devane, Declan; Duley, Lelia; Dunn, Janet; Elbourne, Diana; Farrell, Barbara; Gamble, Carrol; Gillies, Katie; Hood, Kerry; Lang, Trudie; Littleford, Roberta; Loudon, Kirsty; McDonald, Alison; McPherson, Gladys; Nelson, Annmarie; Norrie, John; Ramsay, Craig; Sandercock, Peter; Shanahan, Daniel R; Summerskill, William; Sydes, Matt; Williamson, Paula; Clarke, Mike

    2015-06-05

    Randomised trials are at the heart of evidence-based healthcare, but the methods and infrastructure for conducting these sometimes complex studies are largely evidence free. Trial Forge ( www.trialforge.org ) is an initiative that aims to increase the evidence base for trial decision making and, in doing so, to improve trial efficiency.This paper summarises a one-day workshop held in Edinburgh on 10 July 2014 to discuss Trial Forge and how to advance this initiative. We first outline the problem of inefficiency in randomised trials and go on to describe Trial Forge. We present participants' views on the processes in the life of a randomised trial that should be covered by Trial Forge.General support existed at the workshop for the Trial Forge approach to increase the evidence base for making randomised trial decisions and for improving trial efficiency. Agreed upon key processes included choosing the right research question; logistical planning for delivery, training of staff, recruitment, and retention; data management and dissemination; and close down. The process of linking to existing initiatives where possible was considered crucial. Trial Forge will not be a guideline or a checklist but a 'go to' website for research on randomised trials methods, with a linked programme of applied methodology research, coupled to an effective evidence-dissemination process. Moreover, it will support an informal network of interested trialists who meet virtually (online) and occasionally in person to build capacity and knowledge in the design and conduct of efficient randomised trials.Some of the resources invested in randomised trials are wasted because of limited evidence upon which to base many aspects of design, conduct, analysis, and reporting of clinical trials. Trial Forge will help to address this lack of evidence.

  3. Inclusion engineering for improved fatigue response in forged AISI 4140 steel

    SciTech Connect

    Collins, S.R.; Michal, G.M.

    1995-12-31

    Small elemental additions to a steel melt can increase the flow stress of MnS inclusions, making them less deformable during hot working. This condition, called inclusion shape control, is a powerful tool for improving transverse fatigue life of 4140 steel. This research explored the effects of forging on changing the shape and distribution of MnS inclusions, and their role as fatigue initiation sites. The steels in the test matrix were chosen to examine forging effects on inclusions in steel with high and low sulfur levels. One heat had been treated for inclusion shape control. Billets, 127-mm (5-in.) in diameter and 248-mm (9.7-in) high, from bar stock of three heats of inert-gas-shielded/bottom poured (IGS) AISI 4140 steel were upset forged at 1,200 C (2,200 F) to a 50% reduction. A two-dimensional FEM program was used to model the forging process. FEM results at discrete elements were compared with the fatigue response of specimens machined from actual forgings to contain those elements in their gage sections. Both transverse and longitudinal fatigue specimens were machined, and heat treated to obtain a tempered martensite microstructure of approximately 38 HRC. The specimens were tested in tension cycling (R = 0.1) at {sigma}{sub max} = 825 to 965 MPa (120 to 140 ksi). Fatigue results were normalized to a single stress level using a modified Smith-Watson-Topper function. The normalized results were correlated with position in the forgings and calculated effective strains due to forging at those locations. Metallography and fractography were also used to examine inclusion morphologies in regions of low and high local effective strains.

  4. High survivorship with a titanium-encased alumina ceramic bearing for total hip arthroplasty.

    PubMed

    D'Antonio, James A; Capello, William N; Naughton, Marybeth

    2014-02-01

    Although ceramic-on-ceramic bearings for total hip arthroplasty (THA) show promising results in terms of bearing-surface wear, fracture of the bearing, insertional chips, and squeaking remain a concern. Our primary objective of this report was to determine overall survivorship of a titanium-encased ceramic-on-ceramic bearing couple. Our secondary objectives were to evaluate for ceramic fracture, insertional chips, osteolysis, and device squeaking. Six surgeons at six institutions implanted 194 patients (209 hips) with an average age of 52 years with cementless hips and alumina ceramic bearings. One hundred thirty-seven patients (146 hips) have 10-year followup (70%). We determined Kaplan-Meier survivorship of the bearing surface and implant system and collected radiographic and clinical data to evaluate for osteolysis and squeaking. Survivorship using revision for any reason as the end point was 97% at 10 years and survivorship end point bearing surface failure or aseptic loosening of 99%. There was one ceramic insert fracture (0.5%), there were no insertional chips, there was no visible osteolysis on AP and lateral radiographs, and there was a 1% patient-self-reported incidence of squeaking at the last clinical followup. Six hips underwent revision (3.7%). Ceramic bearings for THA with a titanium-encased insert have high survivorship at 10 years followup and a fracture risk of 0.5%. We found at last followup on routine radiographs no evidence of osteolysis, and no patient has been revised for squeaking or has reported dissatisfaction with the clinical result because of noise. IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

  5. Processing of titanium and titanium alloys by thermal spraying

    SciTech Connect

    Lugscheider, E.; Jokiel, P.

    1994-12-31

    Marine environments are generally known as aggressive corrosion atmospheres. Stainless steel applied as corrosion resistant material is very effective, but it is also an expensive solution since very often only localized areas may need protection. So, protective coatings such as aluminum, zinc, titanium or Cu/Ni alloys, organic paints and epoxies have been used to provide sufficient protection. Especially titanium and titanium alloys offer a high chemical resistance against various corrosive media due to a dense self healing oxide layer. Besides corrosion resistance, high mechanical strength combined with low specific weight are further advantages of titanium alloys. Economical restrictions still hinder titanium to be used as construction material outside of special applications in aircraft and medical technology. Generally most applications only deserve a thin protective coating. Thermal spray processes allow to combine cheap structural materials with a thin layer of high value material. The high affinity of titanium to oxygen has to be taken into account spraying this material. Therefore plasma spraying can be performed in vacuum or in inert atmosphere as well as using gas shrouds in order to shield the molten particles from reacting with the surrounding environment. This paper gives an overview on thermal spraying of titanium and titanium alloys. Coating formation as well as its characterization with regard to corrosion resistance and mechanical strength is examined.

  6. Characterization of residual stresses in heat treated Ti-6Al-4V forgings by machining induced distortion

    NASA Astrophysics Data System (ADS)

    Regener, B.; Krempaszky, C.; Werner, E.

    2010-06-01

    To provide a solid base for improved material exploitation in dimensioning calculations it is necessary to determine the stress state in the part prior to service loading. In order to achieve higher material strength at elevated temperatures, the surface temperature gradient with respect to time has to be sufficiently high during heat treatment. This results in non-negligable residual stresses that can reduce the allowable load level upon which yielding occurs. For titanium alloys there are two common heat treatments, namely solution treatment and mill annealing. The latter one is the method of choice within the presented project. Mill annealing is utilized in order to significantly reduce the residual stresses in the parts without loosing much of the improved strength at elevated temperatures. Quantification of residual stresses is done by solving an inverse problem. From the measurement of distortion, induced by dividing the investigated part, the residual stress state can be calculated via analytical modeling or correlation with finite element models. To assure a minimum perturbation of the residual stress state during specimen production, dividing of the part is accomplished by electric discharge machining. The parts of interest are v-shaped prisms with a length of approximatly 450 mm and a thickness in the cross sectional area from about 20 mm to 45 mm. Figure 1(a) shows the forged part and 1(b) the dimensions of the cross section in millimeters as well as the material properties considered in the finite element model. The heat exchange between the part and the environment is modelled as heat transfer by convection superimposed with heat radiation. Since the parts are exposed to air during forging and heat treatment, the surface develops a strongly adhesive oxide layer, the so called alpha-case. After forging the parts are cooled in air and heat treated at a temperature of 720° C for a duration of 120 min. Subsequent air cooling and removing the alpha-case by

  7. Titanium Optics for Ion Thrusters

    NASA Technical Reports Server (NTRS)

    Soulas, George C.; Haag, Thomas W.; Patterson, Michael J.; Rawlin, Vincent K.

    1999-01-01

    Ion thruster total impulse capability is limited, in part, by accelerator grid sputter erosion. A development effort was initiated to identify a material with a lower accelerator grid volumetric sputter erosion rate than molybdenum, but that could utilize the present NSTAR thruster grid design and fabrication techniques to keep development costs low, and perform as well as molybdenum optics. After comparing the sputter erosion rates of several atomic materials to that of molybdenum at accelerator voltages, titanium was found to offer a 45% reduction in volumetric erosion rates. To ensure that screen grid sputter erosion rates are not higher at discharge chamber potentials, titanium and molybdenum sputter erosion rates were measured at these potentials. Preliminary results showed only a slightly higher volumetric erosion rate for titanium, so that screen grid erosion is insignificant. A number of material, thermal, and mechanical properties were also examined to identify any fabrication, launch environment, and thruster operation issues. Several titanium grid sets were successfully fabricated. A titanium grid set was mounted onto an NSTAR 30 cm engineering model ion thruster and tested to determine optics performance. The titanium optics operated successfully over the entire NSTAR power range of 0.5 to 2.3 kW. Differences in impingement-limited perveances and electron backstreaming limits were found to be due to a larger cold gap for the titanium optics. Discharge losses for titanium grids were lower than those for molybdenum, likely due to a slightly larger titanium screen grid open area fraction. Radial distributions of beam current density with titanium optics were very similar to those with molybdenum optics at all power levels. Temporal electron backstreaming limit measurements showed that titanium optics achieved thermal equilibrium faster than molybdenum optics.

  8. Development of a dynamic recrystallization model for a β-solidifying titanium aluminide alloy using Kocks-Mecking plots

    NASA Astrophysics Data System (ADS)

    Bambach, Markus; Sizova, Irina; Bolz, Sebastian; Weiß, Sabine

    2016-10-01

    Intermetallic titanium aluminide alloys are of growing interest for aerospace and automotive industries due to their remarkable mechanical properties at elevated temperature. The present study focusses on the investigation of the high-temperature deformation behavior of an intermetallic alloy with the nominal composition Ti-44.5Al-6.25Nb-0.8Mo-0.1B. Isothermal compression tests were conducted on a Gleeble 3500 simulator. The flow curves were transformed into Kocks-Mecking plots, where remarkable features such as the absence of stage-III hardening and an inflection point marking the onset of dynamic recrystallization were observed. Based on these observations, a phenomenological flow stress model was devised which incorporates the observations revealed through the Kocks-Mecking plots and reproduces the course of flow stress up to the peak stress and towards the steady-state well. The model may hence be used in finite element simulations of isothermal forging of titanium aluminides.

  9. A comparative study of zinc, magnesium, strontium-incorporated hydroxyapatite-coated titanium implants for osseointegration of osteopenic rats.

    PubMed

    Tao, Zhou-Shan; Zhou, Wan-Shu; He, Xing-Wen; Liu, Wei; Bai, Bing-Li; Zhou, Qiang; Huang, Zheng-Liang; Tu, Kai-kai; Li, Hang; Sun, Tao; Lv, Yang-Xun; Cui, Wei; Yang, Lei

    2016-05-01

    Surface modification techniques have been applied to generate titanium implant surfaces that promote osseointegration for the implants in cementless arthroplasty. However, its effect is not sufficient for osteoporotic bone. Zinc (Zn), magnesium (Mg), and strontium (Sr) present a beneficial effect on bone growth, and positively affect bone regeneration. The aim of this study was to confirm the different effects of the fixation strength of Zn, Mg, Sr-substituted hydroxyapatite-coated (Zn-HA-coated, Mg-HA-coated, Sr-HA-coated) titanium implants via electrochemical deposition in the osteoporotic condition. Female Sprague-Dawley rats were used for this study. Twelve weeks after bilateral ovariectomy, all animals were randomly divided into four groups: group HA; group Zn-HA; group Mg-HA and group Sr-HA. Afterwards, all rats from groups HA, Zn-HA, Mg-HA and Sr-HA received implants with hydroxyapatite containing 0%, 10% Zn ions, 10% Mg ions, and 10% Sr ions. Implants were inserted bilaterally in all animals until death at 12 weeks. The bilateral femurs of rats were harvested for evaluation. All treatment groups increased new bone formation around the surface of titanium rods and push-out force; group Sr-HA showed the strongest effects on new bone formation and biomechanical strength. Additionally, there are significant differences in bone formation and push-out force was observed between groups Zn-HA and Mg-HA. This finding suggests that Zn, Mg, Sr-substituted hydroxyapatite coatings can improve implant osseointegration, and the 10% Sr coating exhibited the best properties for implant osseointegration among the tested coatings in osteoporosis rats.

  10. Forging New Links in the Asteroid-Meteorite Connection

    NASA Astrophysics Data System (ADS)

    Binzel, R. P.

    1995-09-01

    Historically, the path linking telescopic measurements of asteroids with laboratory measurements of meteorites has been an arduous one full of dead ends and dark passages. However some recent successes are beginning to clear and illuminate the path. Largely these successes have come about through advances in astronomical instrumentation and dedicated surveys of main-belt asteroids down to sizes substantially smaller than what had been previously observed. In addition, the most immediate precursor precursor population to meteorites, the near-Earth asteroids, are becoming more thoroughly studied. Three new links appear to have been forged. The strongest is the previously debated link between Vesta and the HED meteorites [1,2,3]. In a new survey of small (diameter < 20 km) main-belt asteroids, Binzel and Xu [4] found 20 which have visible spectra matching that which was previously unique to Vesta and the HED meteorites. While most appeared dynamically clustered around Vesta, eight of the discovered Vesta-like asteroids bridged the orbital space between Vesta and the 3:1 Jovian resonance -- a dynamical escape hatch to the inner solar system. Thus the observations demonstrate a complete delivery route for fragments from Vesta to the Earth, implying strong confidence that HED meteorites are derived from Vesta. The broad implications are that Vesta is now the fourth planetary body for which we have known samples, thus opening a new field for meteoritics and planetary science -- the geology of Vesta. A second, but more tentative link, is the discovery [5] of at least one small main-belt asteroid, 3628 Boznemcova, whose spectrum resembles ordinary chondrite meteorites. Previously, only one Earth-crossing asteroid (1862 Apollo) appeared to provide an asteroid spectral analog to these most common meteorites. Unfortunately the discovery of just one small main-belt ordinary chondrite-like asteroid out of about 1000 surveyed does not resolve issues such as whether space

  11. TDNiCr (ni-20Cr-2ThO2) forging studies

    NASA Technical Reports Server (NTRS)

    Filippi, A. M.

    1974-01-01

    Elevated temperature tensile and stress rupture properties were evaluated for forged TDNiCr (Ni-20Cr-2ThO2) and related to thermomechanical history and microstructure. Forging temperature and final annealed condition had pronounced influences on grain size which, in turn, was related to high temperature strength. Tensile strength improved by a factor of 8 as grain size changed from 1 to 150 microns. Stress-rupture strength was improved by a factor of 3 to 5 by a grain size increase from 10 to 1000 microns. Some contributions to the elevated temperature strength of very large grain material may also occur from the development of a strong texture and a preponderance of small twins. Other conditions promoting the improvement of high temperature strength were: an increase of total reduction, forging which continued the metal deformation inherent in the starting material, a low forging speed, and prior deformation by extrusion. The mechanical properties of optimally forged TDNiCr compared favorably to those of high strength sheet developed for space shuttle application.

  12. Modeling microstructure evolution in the delta process forging of superalloy IN718 turbine discs

    NASA Astrophysics Data System (ADS)

    Zhang, Haiyan; Zhang, Shihong; Cheng, Ming; Zhao, Zhong

    2013-05-01

    The microstructure development in the Delta Process (DP) forging of Superalloy IN718 turbine discs were predicted using the combined approach of axisymmetric finite element simulation and modeling for the dynamic recrystallization and grain growth. In order to establish the deformation constitutive equation and dynamic recrystallization models for the DP process of Superalloy IN718, the isothermal compression tests were carried out in the temperature range 950 to 1010 °C and strain rates range 0.001 to0.1s-1. Moreover, the isothermal heat treatment tests after hot deformation were conducted in the temperature range 950 to 1040°C to generate the grain growth model. The experimental results indicated the existence of the δ phase could make the activation energy of deformation increase. Furthermore, the existence of the δ phase could stimulate the occurrence of dynamic recrystallization, and the grain growth was restrained due to the pinning effect of δ phase. The predicted grain size and its distribution in the DP forging of Superalloy IN718 turbine discs were compared with the actual microstructures deformed by the hot die forging. It was found that the forging with uniform fine grains could be obtained by the application of DP process to the forging of the turbine disk, in which the alloy was pre-precipitated δ phase after the baiting in the original process.

  13. Test report: effect of specimen orientation and location on the tensile properties of GTS forging 1472859

    SciTech Connect

    Melcher, Ryan J

    2008-02-12

    ASTM standardized tensile tests were performed on GTS WR-quality 1472859 forging (21-6- 9 material) to determine the dependence of tensile properties on specimen orientation (longitudinal vs. transverse) with respect to forging ‘grain flow’ and location within the forging. Statistical analyses of the results show that location has a statistically measurable effect on the longitudinal tensile properties (as compared to the error involved in tensile testing). However, this dependence of the properties with location, especially in the circumferential orientation, causes large variability in the results that clouds the statistical determination of any orientation effect. As a result, this forging is determined to be inhomogeneous along the forging length, with a significant range in properties observed (e.g. yield strengths from 85 to 117 ksi) and highest strength/lowest ductility in the spherical region. Additional specimens should be tested to acquire a higher resolution view of this inhomogeneity if the end use of the data is structural integrity analyses using spatially dependent properties; however, sufficient data is provided in this study to extract a statistical lower bound for conservative, homogeneous structural analysis.

  14. [A method of temperature measurement for hot forging with surface oxide based on infrared spectroscopy].

    PubMed

    Zhang, Yu-cun; Qi, Yan-de; Fu, Xian-bin

    2012-05-01

    High temperature large forging is covered with a thick oxide during forging. It leads to a big measurement data error. In this paper, a method of measuring temperature based on infrared spectroscopy is presented. It can effectively eliminate the influence of surface oxide on the measurement of temperature. The method can measure the surface temperature and emissivity of the oxide directly using the infrared spectrum. The infrared spectrum is radiated from surface oxide of forging. Then it can derive the real temperature of hot forging covered with the oxide using the heat exchange equation. In order to greatly restrain interference spectroscopy through included in the received infrared radiation spectrum, three interference filter system was proposed, and a group of optimal gap parameter values using spectral simulation were obtained. The precision of temperature measurement was improved. The experimental results show that the method can accurately measure the surface temperature of high temperature forging covered with oxide. It meets the requirements of measurement accuracy, and the temperature measurement method is feasible according to the experiment result.

  15. Effect of Die Strength and Work Piece Strength on the Wear of Hot Forging Dies

    NASA Astrophysics Data System (ADS)

    Levy, B. S.; Van Tyne, C. J.

    2015-01-01

    The effect of the strength ratio extracted from an Archard model for wear is used to describe the wear rates expected in hot forging dies. In the current study, the strength ratio is the strength of the hot forging die to the strength of the work piece. Three hot forging die steels are evaluated. The three die steels are FX, 2714, and WF. To determine the strength of the forging die, a continuous function has been developed that describes the yield strength of three die steels for temperatures from 600 to 700 °C and for times up to 20 h (i.e., tempering times of up to 20 h). The work piece material is assumed to be AISI 1045. Based on the analysis, the wear resistance of WF should be superior and FX should be slightly better than 2714. Decreasing the forging temperature increases the strength ratio, because the strength of the die surface increases faster than the flow strength of AISI 1045. The increase in the strength ratio indicates a decrease in the expected wear rate.

  16. Identification of Forged Bank of England 20 Gbp Banknotes Using IR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sonnex, Emily

    2014-06-01

    Bank of England notes of 20 GBP denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. A principal aim of this work was to develop a method so that a small, compact ATR FTIR instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 wn from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine 20 GBP notes were observed in the ν(OH) (ca. 3500 wn), ν(C-H) (ca. 2900 wn) and ν(C=O) (ca. 1750 wn) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper. Further to this, with an announcement by the Bank of England to produce polymer banknotes in the future, the work has been extended using Australian polymer banknotes to show that the method would be transferable.

  17. Non-isothermal FEM analyses of large-strain back extrusion forging

    SciTech Connect

    Flower, E.C.; Hallquist, J.O.; Shapiro, A.B.

    1986-06-19

    Back extrusion forging is a complex metal forming operation dominated by large-strain, non-isothermal deformation. NIKE2D, a fully vectorized implicit finite-element program developed at Lawrence Livermore National Laboratory, was applied to a two-stage isothermal back extrusion forging process. Modeling of the forging process required special features in the FEM code such as friction and interactive rezoning that allows for remeshing of the distorted mesh while maintaining a complete history of all the state variables. To model conditions of the non-isothermal forging process required implementing TOPAZ2D, our LLNL-developed two-dimensional implicit finite element code for heat conduction analysis, as a subroutine into NIKE2D. The fully coupled version maintains all the original features of both codes and can account for the contribution of heat generation during plastic deformation. NIKE/TOPAZ-2D was applied to the piercing operation of the back extrusion forging process. The thermal deformation history of the die, punch, and workpiece and the effective plastic strains were calculated.

  18. Identification of forged Bank of England £20 banknotes using IR spectroscopy.

    PubMed

    Sonnex, Emily; Almond, Matthew J; Baum, John V; Bond, John W

    2014-01-24

    Bank of England notes of £20 denomination have been studied using infrared spectroscopy in order to generate a method to identify forged notes. An aim of this work was to develop a non-destructive method so that a small, compact Fourier transform infrared spectrometer (FT-IR) instrument could be used by bank workers, police departments or others such as shop assistants to identify forged notes in a non-lab setting. The ease of use of the instrument is the key to this method, as well as the relatively low cost. The presence of a peak at 1400 cm(-1) arising from νasym (CO3(2-)) from the blank paper section of a forged note proved to be a successful indicator of the note's illegality for the notes that we studied. Moreover, differences between the spectra of forged and genuine £20 notes were observed in the ν(OH) (ca. 3500 cm(-1)), ν(C-H) (ca. 2900 cm(-1)) and ν(C=O) (ca. 1750 cm(-1)) regions of the IR spectrum recorded for the polymer film covering the holographic strip. In cases where these simple tests fail, we have shown how an infrared microscope can be used to further differentiate genuine and forged banknotes by producing infrared maps of selected areas of the note contrasting inks with background paper.

  19. Forging of Naval Brass (ASTM B16) - Finite Element Analysis using Ls Dyna

    NASA Astrophysics Data System (ADS)

    Subha Sankari, T.; Sangavi, S.; Paneerselvam, T.; Venkatraman, R.; Venkatesan, M.

    2016-09-01

    Forging is one of the important manufacturing process in which products like connecting rod, transmission shaft, clutch hubs and gears are produced. Finite element analysis (FEA) in forming techniques is of recent interest for the optimal design and determination of right manufacturing forming process. The data from the numerical results can help in providing the information for selecting the ideal process conditions. Thus aside from experimental values, simulation by the finite element analysis software's such as LS DYNA can be used for the analysis of strain distribution in forging processes. In the present work, Finite element simulation of open die forging of naval brass (ASTM B16) is done at an optimal temperature. An advanced multi physics simulation software package by the Livermore software technology cooperation LSTC - LS DYNA is utilized for the simulation of forging process. For the forging validation, experiment is conducted with a cylindrical billet having height 45 mm and diameter of 40mm. The numerical results are compared with that of experimental results carried out at the same temperature and dimensions for validation. The distribution of strain is analyzed. Energy analysis due to impact load is detailed. The simulation results are found to be in good agreement with the experimental results.

  20. Controlled Forging of a Nb Containing Microalloyed Steel for Automotive Applications

    NASA Astrophysics Data System (ADS)

    Nakhaie, Davood; Hosseini Benhangi, Pooya; Fazeli, Fateh; Mazinani, Mohammad; Zohourvahid Karimi, Ebrahim; Ghandehari Ferdowsi, Mahmoud Reza

    2012-12-01

    Controlled forging of microalloyed steels is a viable economical process for the manufacture of automotive parts. Ferrite grain refinement and precipitation hardening are the major microstructural parameters to enhance the mechanical properties of the forged components. In the current study, a modified thermomechanical treatment for additional ferrite grain refinement is developed by exploiting the effect of Nb in increasing the T NR (no recrystallization temperature) and via phase transformation from a pancaked austenite. This is accomplished by performing the final passes of forging below the T NR temperature followed by a controlled cooling stage to produce a mixture of fine grained ferrite, small scaled acicular ferrite as well as a limited amount of martensite. The effect of processing parameters in terms of forging strain, cooling rate and aging condition on the microstructure and mechanical properties of a medium carbon, Nb containing microalloyed steel is investigated. An attempt is made to identify a suitable microstructure that provides a proper combination of high strength and good impact toughness. The processing-microstructure relationships for the proposed novel forging procedure are discussed, and directions for further improvements are outlined.

  1. Precision Cleaning Titanium Components

    SciTech Connect

    Hand, T.E.; Bohnert, G.W.

    2000-02-02

    Clean bond surfaces are critical to the operation of diffusion bonded titanium engine components. These components can be contaminated with machining coolant, shop dirt, and fingerprints during normal processing and handling. These contaminants must be removed to achieve acceptable bond quality. As environmental concerns become more important in manufacturing, elimination of the use of hazardous materials is desired. For this reason, another process (not using nitric-hydrofluoric acid solution) to clean titanium parts before bonding was sought. Initial cleaning trials were conducted at Honeywell to screen potential cleaning techniques and chemistries. During the initial cleaning process screening phase, Pratt and Whitney provided Honeywell with machined 3 inch x 3 inch x 1 inch titanium test blocks. These test blocks were machined with a water-based machining coolant and exposed to a normal shop environment and handling. (Honeywell sectioned one of these blocks into smaller samples to be used for additional cleanliness verification analyses.) The sample test blocks were ultrasonically cleaned in alkaline solutions and AUGER analysis was used by Honeywell FM and T to validate their cleanliness. This information enabled selection of final cleaning techniques and solutions to be used for the bonding trials. To validate Honeywell's AUGER data and to verify the cleaning processes in actual situations, additional sample blocks were cleaned (using the chosen processes) and then bonded. The bond quality of the test blocks was analyzed according to Pratt and Whitney's requirements. The Charpy impact testing was performed according to ASTM procedure {number_sign}E-23. Bond quality was determined by examining metallographic samples of the bonded test blocks for porosity along the bondline.

  2. Polyisocyanides of titanium.

    PubMed

    Rayón, Víctor M; Redondo, Pilar; Valdés, Haydee; Barrientos, Carmen; Largo, Antonio

    2009-02-26

    Neutral Ti[CN](n) complexes have been investigated with quantum chemistry techniques. According to our theoretical predictions, these complexes are shown to prefer isocyanide arrangements. Therefore, these compounds are good candidates to be the first polyisocyanides to be characterized. The theoretical calculations predict Ti(NC)(4), a methane-like tetrahedral structure with four isocyanide ligands, as the most stable neutral complex. The fact that the isocyanide ligand is a better pi-donor than the cyanide one seems to be the key factor for the preference for isocyanides in neutral titanium complexes.

  3. Process for stabilization of titanium silicide particulates within titanium aluminide containing metal matrix composites

    SciTech Connect

    Christodoulou, L.; Williams, J.C.; Riley, M.A.

    1990-04-10

    This paper describes a method for forming a final composite material comprising titanium silicide particles within a titanium aluminide containing matrix. It comprises: contacting titanium, silicon and aluminum at a temperature sufficient to initiate a reaction between the titanium and silicon to thereby form a first composite comprising titanium silicide particles dispersed within an aluminum matrix; admixing the first composite with titanium and zirconium to form a mixture; heating the mixture to a temperature sufficient to convert at least a portion of the aluminum matrix to titanium aluminide; and recovering a final composite material comprising titanium silicide particles dispersed within a titanium aluminide containing matrix.

  4. Hypersensitivity reactions to titanium: diagnosis and management.

    PubMed

    Wood, Megan M; Warshaw, Erin M

    2015-01-01

    Titanium is notable for its biocompatibility and is used as biologic implant material across surgical specialties, especially in metal-sensitive individuals. However, rare cases of titanium hypersensitivity reactions are reported in the literature. This article discusses the properties and biological behavior of titanium and provides a thorough review of the literature on reported cases, diagnostic techniques, and approach to management of titanium hypersensitivity.

  5. Computational Evaluation of the Effects of Bone Ingrowth on Bone Resorptive Remodeling after a Cementless Total Hip Arthroplasty

    NASA Astrophysics Data System (ADS)

    Jung, Duk-Young; Kang, Yu-Bong; Tsutsumi, Sadami; Nakai, Ryusuke; Ikeuchi, Ken; Sekel, Ron

    In this study, we simulated a wide cortex separation from a cementless hip prosthesis using the bone resorption remodeling method that is based on the generation of high compressive stress around the distal cortical bone. Thereafter, we estimated the effect on late migration quantities of the hip prosthesis produced by the interface state arising from bone ingrowth. This was accomplished using cortical bone remodeling over a long period of time. Two-dimensional natural hip and implanted hip FEM models were constructed with each of the following interface statements between the bone and prosthesis: (1) non-fixation, (2) proximal 1/3, (3) proximal 2/3 and (4) full-fixation. The fixation interfaces in the fully and partially porous coated regions were rigidly fixed by bony ingrowth. The non-fixation model was constructed as a critical situation, with the fibrous or bony tissue not integrated at all into the implant surface. The daily load history was generated using the three loading cases of a one-legged stance as well as abduction and adduction motions. With the natural hip and one-legged stance, the peak compressive principal stresses were found to be under the criteria value for causing bone resorption, while no implant movement occurred. The migration magnitude of the stem of the proximal 1/3 fixation model with adduction motion was much higher, reaching 6%, 11%and 21%greater than those of the non-fixation, proximal 2/3 fixation and all-fixation models, respectively. The full-fixation model showed the lowest compressive principal stress and implant movement. Thus, we concluded that the late loosening and subsequent movement of the stem in the long term could be estimated with the cortical bone remodeling method based on a high compressive stress at the bone-implant interface. The change caused at the bone-prosthesis interface by bony or fibrous tissue ingrowth constituted the major factor in determining the extent of cortical bone resorption occurring with

  6. Analysis Of Potentiometric Methods Used For Crack Detection In Forging Tools

    NASA Astrophysics Data System (ADS)

    Pilc, Jozef; Drbúl, Mário; Stančeková, Dana; Varga, Daniel; Martinček, Juraj; Kuždák, Viktor

    2015-12-01

    Increased use of forging tools in mass production causes their increased wear and creates pressure to design more efficient renovation process. Renovation is complicated because of the identification of cracks expanding from the surface to the core material. Given that the production of forging tools is expensive, caused by the cost of tool steels and the thermo-chemical treatment, it is important to design forging tool with its easy renovation in mind. It is important to choose the right renovation technology, which will be able to restore the instrument to its original state while maintaining financial rentability. Choosing the right technology is difficult because of nitrided and heat-treated surface for high hardness and wear resistance. Article discusses the use of non-destructive method of detecting cracks taking into account the size of the cracks formed during working process.

  7. Study on Carbide in Forged and Annealed H13 Hot Work Die Steel

    NASA Astrophysics Data System (ADS)

    Li, Ji; Li, Jing; Wang, Liangliang; Li, Longfei

    2015-10-01

    The present work studied the carbides in forged and annealed H13 hot work die steel. The carbides were examined by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD) and analyzed with quantitative chemical analysis method. The carbide types, qualities and compositions in dependence on temperatures were thermodynamically calculated by Thermo-Calc software and compared with the experimental results. In the final, methods for carbide improvement were discussed. The results are as follows. The primary carbides and the carbide segregation are improved after the hot-forging operation. The carbides in the hot-forged and annealed H13 steel are M7C3, M6(C, N) and M(C, N) which is accordance with the calculated results. Trace Mg added to the H13 steel leads to an increase of primary carbide nucleation and a decrease of primary carbide size.

  8. Simulation of 7050 Wrought Aluminum Alloy Wheel Die Forging and its Defects Analysis based on DEFORM

    SciTech Connect

    Huang Shiquan; Yi Youping; Zhang Yuxun

    2010-06-15

    Defects such as folding, intercrystalline cracking and flow lines outcrop are very likely to occur in the forging of aluminum alloy. Moreover, it is difficult to achieve the optimal set of process parameters just by trial and error within an industrial environment. In producing 7050 wrought aluminum alloy wheel, a rigid-plastic finite element method (FEM) analysis has been performed to optimize die forging process. Processing parameters were analyzed, focusing on the effects of punch speed, friction factor and temperature. Meanwhile, mechanism as well as the evolution with respect to the defects of the wrought wheel was studied in details. From an analysis of the results, isothermal die forging was proposed for producing 7050 aluminum alloy wheel with good mechanical properties. Finally, verification experiment was carried out on hydropress.

  9. Evaluation of Die Chilling Effects during Forging of Nimonic-80A Superalloy

    SciTech Connect

    Shahriari, D.; Sadeghi, M. H.; Amiri, A.; Cheraghzadeh, M.

    2010-06-15

    Nimonic-80A is a kind of nickel-based superalloys which is used in high temperature components of land gas turbines. In this paper, the influence of four design factors: die temperature, strain rate, friction coefficient and geometry size of ring sample over the variation of internal diameters (VID) and forging load (FL) was studied. It was done by means of design methodology based on DOE-designated full factorial and FE simulations. FEM and experimental results showed that the variation of internal diameters and forging load had inverse proportion to the die temperature. Regression models were developed by using the response surface methodology (RSM) for VID and FL. Rate of the dynamic recrystallization varied depending on different amounts of die temperature. The results can be used in the semi-isothermal forging of complex part of the Nimonic-80A.

  10. The effects of composition and thermal path on hot ductility of forging steels

    NASA Astrophysics Data System (ADS)

    Connolly, Brendan M.

    This work examines the effects of composition and thermal path on the hot ductility of several forging steels with varied aluminum and nitrogen content. The primary mechanisms and controlling factors related to hot ductility are identified with a focus on the role of precipitates and segregation. The unique thermal paths and solidification structures of large cross-section forging ingots are discussed. Hot ductility testing is performed in a manner that approximates industrial conditions experienced by large cross-section forging ingots. A computer model for precipitation of aluminum nitride and vanadium nitride in austenite is presented. Industrial material is examined for comparison to experimental findings. It is found that increased aluminum and nitrogen content coarsens the as-solidified structure. The combined effects of microsegregation and uphill diffusion during deformation allow for carbide precipitation at prior austenite grain boundaries which reduces the hot ductility.

  11. Hot forging to produce pore-free near-net-shape ceramic composites

    SciTech Connect

    Shulman, H.S.; Withers, J.C.; Loutfy, R.O.

    1988-08-01

    Researchers have demonstrated that it is possible to hot forge ceramic composites without damaging the whisker reinforcement and to reduce flaw size and population. Hot forging was investigated for the systems A1203, A1203/ZrO2, mullite, AlN, and SiC with reinforcements of SiCw and TiB2. The system Al203/SiCw was demonstrated to be forgeable at 1400 C which is 500 C lower than hot pressing temperatures. At high strain rates of greater than 0.1/sec, the density achieved was 99.7 percent with strength values comparable to hot pressing. The hot forging of ceramic-whisker composites offers the opportunity to produce low cost components and, because the process reduces the size and population of flaws, it can result in better mechanical properties with greater reliability.

  12. Simulation of 7050 Wrought Aluminum Alloy Wheel Die Forging and its Defects Analysis based on DEFORM

    NASA Astrophysics Data System (ADS)

    Shi-Quan, Huang; You-Ping, Yi; Yu-Xun, Zhang

    2010-06-01

    Defects such as folding, intercrystalline cracking and flow lines outcrop are very likely to occur in the forging of aluminum alloy. Moreover, it is difficult to achieve the optimal set of process parameters just by trial and error within an industrial environment. In producing 7050 wrought aluminum alloy wheel, a rigid-plastic finite element method (FEM) analysis has been performed to optimize die forging process. Processing parameters were analyzed, focusing on the effects of punch speed, friction factor and temperature. Meanwhile, mechanism as well as the evolution with respect to the defects of the wrought wheel was studied in details. From an analysis of the results, isothermal die forging was proposed for producing 7050 aluminum alloy wheel with good mechanical properties. Finally, verification experiment was carried out on hydropress.

  13. Ultrasonic attenuation measurements in sinter-forged YBa2Cu3O7-δ

    NASA Astrophysics Data System (ADS)

    Xu, M.-F.; Bein, D.; Wiegert, R. F.; Sarma, Bimal K.; Levy, M.; Zhao, Z.; Adenwalla, S.; Moreau, A.; Robinson, Q.; Johnson, D. L.; Hwu, S. J.; Poeppelmeier, K. R.; Ketterson, J. B.

    1989-01-01

    We report ultrasonic attenuation measurements on sinter-forged YBa2Cu2O7-δ material, which differs from ordinary sintered material in that the crystallites are preferentially oriented to form a uniaxial sample. Three peaks in attenuation, at temperatures of 250, 180, and 70 K, were observed for longitudinal waves propagating perpendicular to the forging axis, which is similar to that reported in ordinary (isotropic) polycrystalline samples. However, for both transverse and longitudinal sound propagated along the forging axis we have a different behavior, with only one peak at 180 K, showing a strong anisotropy. It is suggested that sound waves traveling parallel to and normal to the Cu-O planes may account for the anisotropic effect, and a relaxation mechanism may explain the increase in shear wave attenuation which was seen with decreasing temperature.

  14. Development of forging and heat treating practices for AMS 5737 for use at liquid helium temperatures

    SciTech Connect

    Dalder, E.N.C.; Greenlee, M.

    1981-08-10

    To achieve a combination of high yield-strength (sigma y), plane-strain fracture-toughness (K/sub IC/) and resistance to galling when turned against austenitic stainless steels in highly-loaded threaded turnbuckles in the M.F.T.F.-B (Mirror Fusion Test Facility), AMS 5737 (Fe-15Cr-25Ni-1Mo-V-Ti-Al-B), a heat-treatable Fe-base superalloy that is slightly-ferromagnetic under high magnetic fields at 4K, was chosen for large (approx. 340 kg) forged turn buckles. This report describes the forging and heat-treatment optimization program that resulted in good sigma y and K/sub IC/ over the 4 to 300K range of service-temperatures and the verification tests run on a pre-production forging and actual production parts.

  15. Titanium in 1980

    NASA Astrophysics Data System (ADS)

    Minkler, Ward W.

    1981-04-01

    Much attention is being focused on the availability and use of non-fuel minerals in the United States. Because of the rapid increase in demand since 1978, titanium has been one of the much-publicized metals in this group. Sponge producers are now expanding sponge manufacturing plants to meet this greater demand, and it now appears that there could be a surplus of sponge in 1981. A delay in airplane purchases caused by severe operating losses of the airlines could have a significant effect on mill product shipments in 1981. However, there is no reason to believe that titanium has reached maturity as a structural aerospace or industrial metal. While it is unreasonable to anticipate that demand will continue to grow at the same rate experienced between 1978 and 1980, new greenfield capacity will nevertheless be required in the early 1980s. Two basic issues must be resolved before such ventures become reality: 1) choice of process; and 2) method for financing, either public or private. Both will be the subject of study and debate in 1981.

  16. Compaction of Titanium Powders

    SciTech Connect

    Gerdemann, Stephen,J; Jablonski, Paul, J

    2011-05-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines<150 {micro}m,<75 {micro}m, and<45 {micro}m; two different sizes of a hydride-dehydride [HDH]<75 {micro}m and<45 {micro}m; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  17. Electrorotation of titanium microspheres.

    PubMed

    Arcenegui, Juan J; Ramos, Antonio; García-Sánchez, Pablo; Morgan, Hywel

    2013-04-01

    Electrorotation (ROT) data for solid titanium micrometer-sized spheres in an electrolyte are presented for three different ionic conductivities, over the frequency range of 10 Hz to 100 kHz. The direction of rotation was found to be opposite to the direction of rotation of the electric field vector (counterfield electrorotation), with a single rotation peak. The maximum rotation rate occurs at a frequency of the order of the reciprocal RC time constant for charging the particle double layer capacitance through the resistor of the electrolyte bulk. A model for the electrical torque acting on a metallic sphere is presented, using a constant phase element impedance to describe the metal/electrolyte interface. The titanium spheres are much denser than the electrolyte and rest on the bottom substrate. Therefore, the electrical and viscous torques near a wall are considered in the analysis. Good agreement is found between the predicted and measured rotational speed as a function of frequency. Theory shows that there is no effect of induced charge electroosmotic flow on the ROT, as observed experimentally.

  18. Compaction of Titanium Powders

    SciTech Connect

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  19. Queen City Forging Revitalized by Oak Ridge National Lab Partnership – U.S. Department of Energy

    SciTech Connect

    Mayer, Rob; Blue, Craig

    2016-05-11

    Oak Ridge National Laboratory, with support from the U.S. Department of Energy, teamed up with Queen City Forging, the U.S. Forging Industry, and Infrared Heating Technologies to develop a rapid-infrared heating furnace to produce aluminum turbochargers.

  20. Queen City Forging Revitalized by Oak Ridge National Lab Partnership – U.S. Department of Energy

    ScienceCinema

    Mayer, Rob; Blue, Craig

    2016-07-12

    Oak Ridge National Laboratory, with support from the U.S. Department of Energy, teamed up with Queen City Forging, the U.S. Forging Industry, and Infrared Heating Technologies to develop a rapid-infrared heating furnace to produce aluminum turbochargers.

  1. Multi-objective optimization of gear forging process based on adaptive surrogate meta-models

    NASA Astrophysics Data System (ADS)

    Meng, Fanjuan; Labergere, Carl; Lafon, Pascal; Daniel, Laurent

    2013-05-01

    In forging industry, net shape or near net shape forging of gears has been the subject of considerable research effort in the last few decades. So in this paper, a multi-objective optimization methodology of net shape gear forging process design has been discussed. The study is mainly done in four parts: building parametric CAD geometry model, simulating the forging process, fitting surrogate meta-models and optimizing the process by using an advanced algorithm. In order to maximally appropriate meta-models of the real response, an adaptive meta-model based design strategy has been applied. This is a continuous process: first, bui Id a preliminary version of the meta-models after the initial simulated calculations; second, improve the accuracy and update the meta-models by adding some new representative samplings. By using this iterative strategy, the number of the initial sample points for real numerical simulations is greatly decreased and the time for the forged gear design is significantly shortened. Finally, an optimal design for an industrial application of a 27-teeth gear forging process was introduced, which includes three optimization variables and two objective functions. A 3D FE nu merical simulation model is used to realize the process and an advanced thermo-elasto-visco-plastic constitutive equation is considered to represent the material behavior. The meta-model applied for this example is kriging and the optimization algorithm is NSGA-II. At last, a relatively better Pareto optimal front (POF) is gotten with gradually improving the obtained surrogate meta-models.

  2. A comparison of a conventional versus a short, anatomical metaphyseal-fitting cementless femoral stem in the treatment of patients with a fracture of the femoral neck.

    PubMed

    Kim, Y-H; Oh, J-H

    2012-06-01

    We compared the clinical and radiological outcomes of two cementless femoral stems in the treatment of patients with a Garden III or IV fracture of the femoral neck. A total of 70 patients (70 hips) in each group were enrolled into a prospective randomised study. One group received a short anatomical cementless stem and the other received a conventional cementless stem. Their mean age was 74.9 years (50 to 94) and 76.0 years (55 to 96), respectively (p = 0.328). The mean follow-up was 4.1 years (2 to 5) and 4.8 years (2 to 6), respectively. Perfusion lung scans and high resolution chest CTs were performed to detect pulmonary microemboli. At final follow-up there were no statistically significant differences between the short anatomical and the conventional stems with regard to the mean Harris hip score (85.7 (66 to 100) versus 86.5 (55 to 100); p = 0.791), the mean Western Ontario and McMaster Universities Osteoarthritis Index (17 (6 to 34) versus 16 (5 to 35); p = 0.13) or the mean University of California, Los Angeles activity score (5 (3 to 6) versus 4 (3 to 6); p = 0.032). No patient with a short stem had thigh pain, but 11 patients (16%) with a conventional stem had thigh pain. No patients with a short stem had symptomatic pulmonary microemboli, but 11 patients with a conventional stem had pulmonary microemboli (symptomatic in three patients and asymptomatic in eight patients). One hip (1.4%) in the short stem group and eight (11.4%) in the conventional group had an intra-operative undisplaced fracture of the calcar. No component was revised for aseptic loosening in either group. One acetabular component in the short stem group and two acetabular components in the conventional stem group were revised for recurrent dislocation. Our study demonstrated that despite the poor bone quality in these elderly patients with a fracture of the femoral neck, osseo-integration was obtained in all hips in both groups. However, the incidence of thigh pain, pulmonary

  3. Compressed Air System Optimization Project Saves Energy and Improves Production at a Citation Forging Plant

    SciTech Connect

    2003-05-01

    In the 1990s, a subsidiary of the Citation Corporation, Interstate Forging, implemented a compressed air system improvement project at its Milwaukee, Wisconsin, forging plant. This improvement enabled the plant to maintain an adequate and stable pressure level using fewer compressors, which led to improved product quality and lower production downtime. The project also yielded annual energy savings of 820,000 kWh and $45,000. With a total project cost of $67,000, the plant achieved a simple payback of just 1.5 years.

  4. The Development of a Ceramic Mold for Hot-Forging of Micro-Magnets

    SciTech Connect

    Christenson, Todd; Garino, Terry

    1999-06-25

    A new mold material has been developed for use in making rare-earth permanent magnet components with precise dimensions in the 10 to 1000 µm range by hot-forging. These molds are made from molds poly(methyl)methacrylate (PMMA) made by deep x-ray lithography (DXRL). An alumina bonded with colloidal silica has been developed for use in these molds. This material can be heated to 950°C without changing dimensions where it develops the strength needed to withstand the hot-fmging conditions (750°C, 100 MPa). In addition, it disintegrates in HF so that parts can be easily removed after forging.

  5. Computer modeling of wear in extrusion and forging of automotive exhaust valves

    NASA Astrophysics Data System (ADS)

    Tulsyan, R.; Shivpuri, R.

    1995-04-01

    In an automotive engine valve forging process, the billet is cold sheared, induction heated, and fed to a mechanical press for a two-stage forging operation with the first stage being extrusion. The main limiting factor in this operation is the wear of the dies during the first stage, extrusion. In this study. abrasive wear was identified as the primary mode of wear, and computer simulation was used to investigate the effect of process variables, such as press speed, initial billet temperature, and die preheat temperature upon abrasive wear. The result generated by this study should be applicable to other part geometry and not limited just to exhaust valves.

  6. Diffusion bonding of titanium-titanium aluminide-alumina sandwich

    SciTech Connect

    Wickman, H.A.; Chin, E.S.C.; Biederman, R.R.

    1995-12-31

    Diffusion bonding of a metallic-intermetallic-ceramic sandwich is of interest for potential armor applications. Low cost titanium, titanium diboride reinforced titanium aluminide (Ti-48at.%Al), and aluminum oxide are diffusion bonded in a vacuum furnace between 1,000 C and 1,400 C. Metallographic examination of the prior bonding interface showed excellent metallurgical coupling between the Ti-48at.%Al composite and the low cost Ti. A series of microstructures representative of phases consistent with a hypothetical Ti-Al-B phase diagram is visible. The alumina-Ti-48at.%Al interfacial bond is achieved through penetration of titanium-aluminum phases into the existing alumina porosity. A detailed microstructural analysis identifying mechanisms of interfacial bonding will be presented for each interfacial zone.

  7. Beta titanium alloys and their role in the titanium industry

    NASA Astrophysics Data System (ADS)

    Bania, Paul J.

    1994-07-01

    The class of titanium alloys generically referred to as the beta alloys is arguably the most versatile in the titanium family. Since these alloys offer the highest strength-to-weight ratios and deepest hardenability of all titanium alloys, one might expect them to compete favorably for a variety of aerospace applications. To the contrary, however, except for one very successful application (Ti-13V-11Cr-3Al on the SR-71), the beta alloys have remained a very small segment of the industry. As a perspective on this situation, this article reviews some past and present applications of titanium alloys. It also descibes some unique new alloys and applications that promise to reverse historical trends.

  8. Mid-Term Outcomes and Complications with Cementless Distal Locking Hip Revision Stem with Hydroxyapatite Coating for Proximal Bone Defects and Fractures.

    PubMed

    Carrera, Lluis; Haddad, Sleiman; Minguell, Joan; Amat, Carles; Corona, Pablo S

    2015-06-01

    We revised the first 100 revision total hip arthroplasties using a cementless distal locking revision stem conducted in our referral centre. Average follow-up was 9.2 years (range: 5.5-12 years). Harris Hip Score improved from 42.5 to 81.6, and none had thigh pain at last follow-up. No significant stress shielding, osteolysis, or radiologic loosening was found. All patients showed radiological evidence of secondary implant osseointegration. Overall survival was 97% with three patients being revised: two stem ruptures and one subsidence. We could trace these complications to technical errors. These findings suggest that a diaphyseal fixation of the revision stem with distal locking can provide the needed primary axial and rotational stability of the prosthesis. This would allow further bony ingrowth, enhanced by the hydroxyapatite coating.

  9. Hemocompatibility of titanium nitride.

    PubMed

    Dion, I; Baquey, C; Candelon, B; Monties, J R

    1992-10-01

    The left ventricular assist device is based on the principle of the Maillard-Wenkel rotative pump. The materials which make up the pump must present particular mechanical, tribological, thermal and chemical properties. Titanium nitride (TiN) because of its surface properties and graphite because of its bulk characteristics have been chosen. The present study evaluated the in vitro hemocompatibility of TiN coating deposited by the chemical vapor deposition process. Protein adsorption, platelet retention and hemolysis tests have been carried out. In spite of some disparities, the TiN behavior towards albumin and fibrinogen is interesting, compared with the one of a reference medical grade elastomer. The platelet retention test gives similar results as those achieved with the same elastomer. The hemolysis percentage is near to zero. TiN shows interesting characteristics, as far as mechanical and tribological problems are concerned, and presents very encouraging blood tolerability properties.

  10. Advanced titanium processing

    SciTech Connect

    Hartman, Alan D.; Gerdemann, Stephen J.; Schrems, Karol K.; Holcomb, Gordon R.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; Turner, Paul C.

    2001-01-01

    The Albany Research Center of the U.S. Department of Energy has been investigating a means to form useful wrought products by direct and continuous casting of titanium bars using cold-wall induction melting rather than current batch practices such as vacuum arc remelting. Continuous ingots produced by cold-wall induction melting, utilizing a bottomless water-cooled copper crucible, without slag (CaF2) additions had minor defects in the surface such as ''hot tears''. Slag additions as low as 0.5 weight percent were used to improve the surface finish. Therefore, a slag melted experimental Ti-6Al-4V alloy ingot was compared to a commercial Ti-6Al-4V alloy ingot in the areas of physical, chemical, mechanical, and corrosion attributes to address the question, ''Are any detrimental effects caused by slag addition''?

  11. Gamma titanium aluminide alloys

    SciTech Connect

    Yamaguchi, M.; Inui, H.; Kishida, K.; Matsumuro, M.; Shirai, Y.

    1995-08-01

    Extensive progress and improvements have been made in the science and technology of gamma titanium aluminide alloys within the last decade. In particular, the understanding of their microstructural characteristics and property/microstructure relationships has been substantially deepened. Based on these achievements, various engineering two-phase gamma alloys have been developed and their mechanical and chemical properties have been assessed. Aircraft and automotive industries arc pursuing their introduction for various structural components. At the same time, recent basic studies on the mechanical properties of two-phase gamma alloys, in particular with a controlled lamellar structure have provided a considerable amount of fundamental information on the deformation and fracture mechanisms of the two-phase gamma alloys. The results of such basic studies are incorporated in the recent alloy and microstructure design of two-phase gamma alloys. In this paper, such recent advances in the research and development of the two-phase gamma alloys and industrial involvement are summarized.

  12. Hydrogen in titanium alloys

    SciTech Connect

    Wille, G W; Davis, J W

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500/sup 0/C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150/sup 0/C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement.

  13. The effect of abductor muscle and anterior-posterior hip contact load simulation on the in-vitro primary stability of a cementless hip stem

    PubMed Central

    2010-01-01

    Background In-vitro mechanical tests are commonly performed to assess pre-clinically the effect of implant design on the stability of hip endoprostheses. There is no standard protocol for these tests, and the forces applied vary between studies. This study examines the effect of the abductor force with and without application of the anterior-posterior hip contact force in the in-vitro assessment of cementless hip implant stability. Methods Cementless stems (VerSys Fiber Metal) were implanted in twelve composite femurs which were divided into two groups: group 1 (N = 6) was loaded with the hip contact force only, whereas group 2 (N = 6) was additionally subjected to an abductor force. Both groups were subjected to the same cranial-caudal hip contact force component, 2.3 times body weight (BW) and each specimen was subjected to three levels of anterior-posterior hip contact load: 0, -0.1 to 0.3 BW (walking), and -0.1 to 0.6 BW (stair climbing). The implant migration and micromotion relative to the femur was measured using a custom-built system comprised of 6 LVDT sensors. Results Substantially higher implant motion was observed when the anterior-posterior force was 0.6BW compared to the lower anterior-posterior load levels, particularly distally and in retroversion. The abductor load had little effect on implant motion when simulating walking, but resulted in significantly less motion than the hip contact force alone when simulating stair climbing. Conclusions The anterior-posterior component of the hip contact load has a significant effect on the axial motion of the stem relative to the bone. Inclusion of the abductor force had a stabilizing effect on the implant motion when simulating stair climbing. PMID:20576151

  14. Congenital hip dysplasia treated by total hip arthroplasty using cementless tapered stem in patients younger than 50 years old: results after 12-years follow-up.

    PubMed

    Faldini, Cesare; Miscione, Maria Teresa; Chehrassan, Mohammadreza; Acri, Francesco; Pungetti, Camilla; d'Amato, Michele; Luciani, Deianira; Giannini, Sandro

    2011-12-01

    Congenital hip dysplasia may lead to severe acetabular and femoral abnormalities that can make total hip arthroplasty a challenging procedure. We assessed a series of patients affected by developmental hip dysplasia treated with total hip arthroplasty using cementless tapered stem and here we report the outcomes at long-term follow-up. Twenty-eight patients (24 women and 4 men) aged between 44 and 50 years (mean 47 years) were observed. Clinical evaluation was rated with the Harris Hip Score. Radiographic evaluation consisted in standard anteroposterior and axial view radiographs of the hip. According to Crowe's classification, 16 hips presented dysplasia grade 1, 14 grade 2, and 4 grade 3. All patients were treated with total hip arthroplasty using a cementless tapered stem (Wagner Cone Prosthesis). Six patients were operated bilaterally, with a totally of 34 hips operated. After surgery, the patients were clinically and radiographically checked at 3, 6, and 12 months and yearly thereafter until an average follow-up of 12 years (range 10-14 years). Average Harris Hip Score was 56 ± 9 (range 45-69) preoperatively, 90 ± 9 (range 81-100) 12 months after surgery, and 91 ± 8 (range 83-100) at last follow-up. Radiographic evaluation demonstrated excellent osteointegration of the implants. Signs of bone resorption were present in 6 hips, nevertheless no evidence of loosening was observed and none of the implants has been revised. Even in dysplasic femur, the tapered stem allowed adequate stability and orientation of the implant. We consider tapered stem a suitable option for total hip arthroplasty in developmental hip dysplasia, also in case of young patients, thanks to the favourable long-term results.

  15. Primary cementless total hip arthroplasty with an alumina ceramic-on-ceramic bearing: results after a minimum of twenty years of follow-up.

    PubMed

    Petsatodis, George E; Papadopoulos, Pericles P; Papavasiliou, Kyriakos A; Hatzokos, Ippokratis G; Agathangelidis, Filon G; Christodoulou, Anastasios G

    2010-03-01

    The biological problems related to wear debris after total hip arthroplasty have stimulated renewed interest in alternatives to metal-on-polyethylene bearing surfaces. We retrospectively evaluated the clinical and radiographic results of 100 patients who had undergone a total of 109 primary total hip arthroplasties with a cementless alumina ceramic-on-ceramic prosthesis between January 1985 and December 1989. The mean age of the patients at the time of the index arthroplasty was forty-six years. Clinical evaluation was performed with use of the Charnley modification of the Merle d'Aubigné-Postel scale. Seventy-eight patients who had had a total of eighty-five arthroplasties were available for follow-up evaluation at an average of 20.8 years. The patients' average age at the time of the latest follow-up was 66.8 years. Six hips (six acetabular cups and one femoral stem) in six patients underwent revision. Aseptic loosening of the cup combined with focal osteolysis was the cause of all six revisions. In one patient, the stem was also revised because of aseptic loosening. At the time of final follow-up, the result was excellent (according to the Merle d'Aubigné-Postel scale) in 68% of the hips, good in 19%, fair in 9%, and poor in 4%. The mean Merle d'Aubigné-Postel score improved from 7.9 points preoperatively to 16.9 points postoperatively (p < 0.001). The cumulative rate of survival of the prostheses was 84.4% at 20.8 years. The results of these cementless ceramic-on-ceramic total hip arthroplasties continued to be satisfactory at a minimum of twenty years postoperatively. The improved design of contemporary prostheses and the new generation of ceramic-on-ceramic bearing surfaces may lead to even better long-term results.

  16. The influence of contact ratio and its location on the primary stability of cementless total hip arthroplasty: A finite element analysis.

    PubMed

    Reimeringer, M; Nuño, N

    2016-05-03

    Cementless hip stems are fixed to the surrounding bone by means of press-fit. To ensure a good press-fit, current surgical technique specifies an under-reaming of the bone cavity using successively larger broaches. Nevertheless, this surgical technique is inaccurate. Several studies show that the contact ratio (percentage of stem interface in contact with bone) achieved after surgery can vary between 20% and 95%. Therefore, this study aimed to investigate the influence of the contact ratio and its location on the primary stability of a cementless total hip arthroplasty using finite element analysis. A straight tapered femoral stem implanted in a composite bone was subjected to stair climbing. Micromotion of 7600 nodes at the stem-bone interface was computed for different configurations of contact ratios between 2% and 98%) along the hip stem. Considering the 15 configurations evaluated, the average micromotion ranges between 27μm and 54μm. The percentage of the porous interface of the stem having micromotion below 40μm that allows bone ingrowth range between 25-57%. The present numerical study shows that full contact (100%) between stem and bone is not necessary to obtain a good primary stability. The stem primary stability is influenced by both the contact ratio and its location. Several configurations with contact ratio lower than 100% and involving either the proximal or the cortical contact provide better primary stability than the full contact configuration. However, with contact ratio lower than 40%, the stem should be in contact with cortical bone to ensure a good primary stability.

  17. Brazing titanium to stainless steel

    NASA Technical Reports Server (NTRS)

    Batista, R. I.

    1980-01-01

    Titanium and stainless-steel members are usually joined mechanically for lack of any other effective method. New approach using different brazing alloy and plating steel member with nickel resolves problem. Process must be carried out in inert atmosphere.

  18. Characterization of Cracking and Crack Growth Properties of the C5A Aircraft Tie-Box Forging

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Smith, Stephen W.; Newman, John A.; Willard, Scott A.

    2003-01-01

    Detailed destructive examinations were conducted to characterize the integrity and material properties of two aluminum alloy (7075-T6) horizontal stabilizer tie box forgings removed.from US. Air Force C5A and C5B transport aircraft. The C5B tie box forging was,found to contain no evidence of cracking. Thirteen cracks were found in the CSA,forging. All but one of the cracks observed in the C5A component were located along the top cap region (one crack was located in the bottom cap region). The cracks in the C5A component initiated at fastener holes and propagated along a highly tunneled intergranular crack path. The tunneled crack growth configuration is a likelv result of surface compressive stress produced during peening of the .forging suijace. The tie box forging ,fatigue crack growth, fracture and stress corrosion cracking (SCC) properties were characterized. Reported herein are the results of laboratory air ,fatigue crack growth tests and 95% relative humidity SCC tests conducted using specimens machined from the C5A ,forging. SCC test results revealed that the C5A ,forging material was susceptible to intergranular environmental assisted cracking: the C5A forging material exhibited a SCC crack-tip stress-intensity factor threshold of less than 6 MPadn. Fracture toughness tests revealed that the C5A forging material exhibited a fracture toughness that was 25% less than the C5B forging. The C5A forging exhibited rapid laboratory air fatigue crack growth rates having a threshold crack-tip stress-intensity factor range of less than 0.8 MPa sup m. Detailed fractographic examinations revealed that the ,fatigue crack intergranular growth crack path was similar to the cracking observed in the C5A tie box forging. Because both fatigue crack propagation and SCC exhibit similar intergranular crack path behavior, the damage mechanism resulting in multi-site cracking of tie box forgings cannot be determined unless local cyclic stresses can be quantified.

  19. Manufacturing of Advanced Titanium (Lined) Propellant Tanks and High Pressure Vessels

    NASA Astrophysics Data System (ADS)

    Radtke, W.

    2004-10-01

    A modular titanium tank and liner manufacturing approach is presented. Special forgings with long lead time and important recurrent and non-recurrent cost are avoided. Starting with standard forms of supply, special forming methods allow for quick and cost efficient accommodation to the spacecraft requirements. Even propellant tanks for pressure-fed engines are proposed to be CFRP over-wrapped for mass savings reasons. Skirt mounting is realized by integral CFRP wrapping on the vessel's own over-wrap. Compatibility problems are hence avoided. The approach to apply standard forms of supply has been qualified for the first time with the ATV propellant tanks. It is currently expanded to the whole field of spacecraft tanks in terms of hardware demonstration and with respect to the related engineering effort.

  20. A "clickable" titanium surface platform.

    PubMed

    Watson, Matthew A; Lyskawa, Joël; Zobrist, Cédric; Fournier, David; Jimenez, Maude; Traisnel, Michel; Gengembre, Léon; Woisel, Patrice

    2010-10-19

    A straightforward functionalization of a titanium surface using "click" chemistry is reported. A "clickable" titanium surface platform was prepared by the immobilization of an azide-functionalized electroactive catechol anchor and was subsequently derivatized with an electroactive or fluorinated probe via the CuAAC (copper-catalyzed azide-alkyne cycloaddition) reaction. The course of the reaction was investigated by contact angle, XPS, and electrochemical measurements.