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Sample records for cementless forged titanium

  1. Neck fracture of a cementless forged titanium alloy femoral stem following total hip arthroplasty: a case report and review of the literature

    PubMed Central

    Grivas, Theodoros B; Savvidou, Olga D; Psarakis, Spyridon A; Bernard, Pierre-Francois; Triantafyllopoulos, George; Kovanis, Ioannis; Alexandropoulos, Panagiotis

    2007-01-01

    Introduction Fractures of the neck of the femoral component have been reported in uncemented total hip replacements, however, to our knowledge, no fractures of the neck of a cementless forged titanium alloy femoral stem coated in the proximal third with hydroxy-apatite have been reported in the medical literature. Case presentation This case report describes a fracture of the neck of a cementless forged titanium alloy stem coated in the proximal third with hydroxy-apatite. Conclusion The neck of the femoral stem failed from fatigue probably because of a combination of factors described analytically below. PMID:18062807

  2. 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.

  3. Successful hip arthroplasty using cementless titanium implants in rheumatoid arthritis.

    PubMed

    Effenberger, Harald; Ramsauer, Thomas; Böhm, Gerhard; Hilzensauer, Gerhard; Dorn, Ulrich; Lintner, Felix

    2002-03-01

    Over a period of eight years, we implanted a total of 76 cementless hip prostheses in patients with rheumatoid arthritis. The clinical results of 47 patients (70 hips) increased from a mean Harris Hip Score of 33 to 85 after an average of 49 months (range 1-11 years). One threaded cup has had to be revised because of loosening, and one stem because of femoral fracture. At the latest follow-up, 88% of Hofer-Imhof threaded cups had complete bone ingrowth (Type 0); 10% had near-complete bone ingrowth with minimal radiolucency in one third of the bone contact area (Type 1), and 2% had radiolucency in two thirds of the bone contact area (Type 2). Hemispherical push-in cups showed significantly more radiolucency around the cup. For the stems (Uni, Zweymüller SL), 83% showed no radiolucency (Type 0); 17% had radiolucency only very proximally (Type 1). Minor remodelling (Type 1) occurred in 60% of the femoral shafts; 30% had moderate femoral density loss (Type 2), and 10% had severe bone loss and cortical thinning (Type 3). There was no correlation between marked shaft atrophy and clinical symptoms. With regard to radiolucency and remodelling, there was no significant difference between the two types of stem used. Cementless hip arthroplasty using titanium implants has an excellent outcome in the medium term. PMID:11880907

  4. 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.

  5. Survey of ultrasonic properties of aircraft Engine Titanium forgings

    NASA Astrophysics Data System (ADS)

    Yu, Linxiao; Margetan, F. J.; Thompson, R. B.; Degtyar, Andrei

    2002-05-01

    The Engine Titanium Consortium is surveying the ultrasonic properties of representative Ti-6-4 forgings used in rotating jet engine components. Velocity, attenuation and backscattered grain noise are being measured as function of position and inspection direction. The overall goal is to better understand and improve ultrasonic defect detection. This paper provides a summary of the work to date on this ongoing project. UT properties are generally found to vary systematically with position, and some properties, such as the grain noise anisotropy, appears to be well correlated to the local forging strain. We demonstrate how the UT properties from the highest noise region of a forging are being used to estimate defect detectability for improved inspection schemes.

  6. Cementless Fixation of Osteoporotic VCFs Using Titanium Mesh Implants (OsseoFix): Preliminary Results

    PubMed Central

    Ender, Stephan Albrecht; Ulmar, Benjamin; Gradl, Georg

    2014-01-01

    Introduction. Vertebral compression fractures (VCFs) affect 20% of people over the age of 70 with increasing incidence. Kypho-/vertebroplasty as standard operative procedures are associated with limitations like cement leakage, limited reduction capabilities, and risk for adjacent fractures. To address these shortcomings, we introduce a new minimal invasive cementless VCF fixation technique. Methods. Four patients (72.3 years, range 70–76) with VCFs type AO/Müller A1.3 and concomitant osteoporosis were treated by minimal invasive transpedicular placement of two intervertebral mesh cages for fracture reduction and maintenance. Follow-up included functional/radiological assessment and clinical scores and averaged 27.7 months (24–28). Results. Endplate reduction was achieved in all cases (mean surgery time: 28.5 minutes). Kyphotic (KA) and Cobb angle revealed considerable improvements postoperatively (KA 14.5° to 10.7°/Cobb 10.1° to 8.3°). Slight loss of vertebral reduction (KA: 12.6°) and segment rekyphosis (Cobb: 10.7°) were observed for final follow-up. Pain improved from 8.8 to 2.8 (visual analogue scale). All cases showed signs of bony healing. No perioperative complications and no adjacent fractures occurred. Conclusion. Preliminary results in a small, selected patient collective indicate the ability of bony healing for osteoporotic VCFs. Cementless fixation using intravertebral titanium mesh cages revealed substantial pain relief, adequate reduction, and reduction maintenance without complications. Trial registration number is DRKS00005657, German Clinical Trials Register (DKRS). PMID:25110699

  7. 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.

  8. 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

  9. 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.

  10. Survival analysis of cementless grit-blasted titanium total hip arthroplasties.

    PubMed

    Delaunay, C; Kapandji, A I

    2001-04-01

    Although about 200000 cementless Zweymüller-Alloclassic total hip arthroplasties (THAs) were carried out worldwide in the last decade, the survival analysis of these prostheses was not available in the 2000 report of the Swedish national hip arthroplasty registry. We report a prospective survivorship analysis of 200 consecutive grit-blasted cementless Alloclassic primary THAs carried out since 1988. Using surgical, clinical and radiological endpoints for the stem and the threaded cup the ten-year survivorship was 91.5% for reoperation for any cause, 96.4% for hip pain (Merle d'Aubigné score < 5 points, clinical failure), 99.4% for definite aseptic loosening (radiological failure) and 99.3% for revision for aseptic loosening. Using the Swedish registry criteria of primary osteoarthritis and revision for aseptic loosening as the endpoint, the survival rate of 99.1% at ten years for the subgroup of 157 Alloclassic THAs in osteoarthritis compares favourably with that of the best modern cemented hip replacements reported in the Swedish arthroplasty registry. PMID:11341429

  11. 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.

  12. 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.

  13. Formation and Microstructure of Ultrafine-Grained Titanium Processed by Multi-Directional Forging

    NASA Astrophysics Data System (ADS)

    Wang, Bingfeng; Wang, Xiaoyan; Li, Juan

    2016-06-01

    Ultrafine-grained titanium with uniform grain size for medical applications is obtained by multi-directional forging at 773 K in air. The microstructures and microtextures in the deformed titanium specimens are investigated by optical microscopy, electron backscattered diffraction technique, and transmission electron microscopy. Titanium specimen experience the recrystallization softening at cumulative strain about 1.2. After six passes with the cumulative strains of 2.4, the coarse grain sizes are gradually refined from about 25 μm to about 0.2 μm. New microtextures with recrystallized features generate in the specimens after multi-directional forgings. Grain boundaries in the specimens are geometrical necessary boundaries aiming to accommodate the imposed strain. It is suggested that the continuous dynamic recrystallization induced by deformation bands is responsible for the formation of ultrafine-grained titanium during multi-directional forging. Meanwhile the subdivision of grains by the mechanical twinning dramatically enhanced grain refinement to develop ultrafine-grained microstructure.

  14. Formation and Microstructure of Ultrafine-Grained Titanium Processed by Multi-Directional Forging

    NASA Astrophysics Data System (ADS)

    Wang, Bingfeng; Wang, Xiaoyan; Li, Juan

    2016-05-01

    Ultrafine-grained titanium with uniform grain size for medical applications is obtained by multi-directional forging at 773 K in air. The microstructures and microtextures in the deformed titanium specimens are investigated by optical microscopy, electron backscattered diffraction technique, and transmission electron microscopy. Titanium specimen experience the recrystallization softening at cumulative strain about 1.2. After six passes with the cumulative strains of 2.4, the coarse grain sizes are gradually refined from about 25 μm to about 0.2 μm. New microtextures with recrystallized features generate in the specimens after multi-directional forgings. Grain boundaries in the specimens are geometrical necessary boundaries aiming to accommodate the imposed strain. It is suggested that the continuous dynamic recrystallization induced by deformation bands is responsible for the formation of ultrafine-grained titanium during multi-directional forging. Meanwhile the subdivision of grains by the mechanical twinning dramatically enhanced grain refinement to develop ultrafine-grained microstructure.

  15. 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.

  16. POD of ultrasonic detection of synthetic hard alpha inclusions in titanium aircraft engine forgings

    SciTech Connect

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

    2011-06-23

    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, number 3 and number 5, with each size including seeds with nominal nitrogen concentrations of both 3 and 17 wt. %. The FBHs included sizes of number 1, number 3, and number 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 a circumflex 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.

  17. 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.

  18. Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model.

    PubMed

    Eschler, Anica; Roepenack, Paula; Roesner, Jan; Herlyn, Philipp Karl Ewald; Martin, Heiner; Reichel, Martin; Rotter, Robert; Vollmar, Brigitte; Mittlmeier, Thomas; Gradl, Georg

    2016-01-01

    Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications. PMID:27019848

  19. Cementless Titanium Mesh Fixation of Osteoporotic Burst Fractures of the Lumbar Spine Leads to Bony Healing: Results of an Experimental Sheep Model

    PubMed Central

    Roepenack, Paula; Roesner, Jan; Herlyn, Philipp Karl Ewald; Martin, Heiner; Reichel, Martin; Rotter, Robert; Vollmar, Brigitte; Mittlmeier, Thomas; Gradl, Georg

    2016-01-01

    Introduction. Current treatment strategies for osteoporotic vertebral compression fractures (VCFs) focus on cement-associated solutions. Complications associated with cement application are leakage, embolism, adjacent fractures, and compromise in bony healing. This study comprises a validated VCF model in osteoporotic sheep in order to (1) evaluate a new cementless fracture fixation technique using titanium mesh implants (TMIs) and (2) demonstrate the healing capabilities in osteoporotic VCFs. Methods. Twelve 5-year-old Merino sheep received ovariectomy, corticosteroid injections, and a calcium/phosphorus/vitamin D-deficient diet for osteoporosis induction. Standardized VCFs (type AO A3.1) were created, reduced, and fixed using intravertebral TMIs. Randomly additional autologous spongiosa grafting (G1) or no augmentation was performed (G2, n = 6 each). Two months postoperatively, macroscopic, micro-CT and biomechanical evaluation assessed bony consolidation. Results. Fracture reduction succeeded in all cases without intraoperative complications. Bony consolidation was proven for all cases with increased amounts of callus development for G2 (58.3%). Micro-CT revealed cage integration. Neither group showed improved results with biomechanical testing. Conclusions. Fracture reduction/fixation using TMIs without cement in osteoporotic sheep lumbar VCF resulted in bony fracture healing. Intravertebral application of autologous spongiosa showed no beneficial effects. The technique is now available for clinical use; thus, it offers an opportunity to abandon cement-associated complications. PMID:27019848

  20. Influence of the microstructure on the fracture toughness and fracture mechanisms of forging steels microalloyed with titanium with ferrite-perlite structures

    SciTech Connect

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

    1993-08-15

    Titanium addition to vanadium microalloyed forging steels is one of the ways proposed to improve fracture toughness. Fine TiN particles inhibit austenite grain growth after recrystallization at the high temperatures used to forge these steels. TiN particles, however, can be formed in the liquid, and as their sizes exceed one micron, they could act as cleavage nucleation sites, impairing the fracture toughness. The present work reports fracture toughness results obtained in Ti treated microalloyed forging steels, showing that in coarse microstructures cleavage is nucleated in coarse TiN particles, but that after refining the microstructure, voids originate at the same particles, resulting in ductile rupture.

  1. 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. PMID:23590780

  2. [Results of cementless hip arthroplasty].

    PubMed

    Grübl, A

    2006-09-01

    Hip arthroplasty is performed nowadays according to the needs of the patients irrespective of their age. Tapered rectangular stems for cementless fixation are chosen in most cases in central Europe. They provide primary stability by press-fit implantation into a precisely rasped osseous bed and secondary stability by bone ingrowth into the highly biocompatible titanium alloy with a microrough surface. The 10-year survival of such devices is 92%. Typical radiographic patterns include cortical atrophy and radiolucent lines in Gruen zones 1 and 7. They are due to stress shielding with these distally fixed implants. The number one reason for revision is polyethylene wear and subsequent osteolysis. Metal-on-metal and ceramic-on-ceramic bearings show less wear but osteolysis continues to be a problem. PMID:16552511

  3. Manufacturing of Precision Forgings by Radial Forging

    SciTech Connect

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

    2011-01-17

    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.

  4. Long-term results of cementless primary total hip arthroplasty with a threaded cup and a tapered, rectangular titanium stem in rheumatoid arthritis and osteoarthritis.

    PubMed

    Zwartele, Rob; Peters, Anil; Brouwers, Johannes; Olsthoorn, Paul; Brand, Ronald; Doets, Cornelis

    2008-10-01

    The aim of this study was to assess the outcome of primary cementless total hip arthroplasty in rheumatoid arthritis patients and to compare the results with osteoarthritis patients. Sixty-four patients (77 hips) with rheumatoid arthritis and 120 patients (135 hips) with osteoarthritis had a conical-shaped Zweymueller threaded cup and a tapered, rectangular Zweymueller stem implanted and were assessed after an average of 12.5 years. The endpoints for survival analysis were failure of one or both components due to radiographic loosening or revision. Revision was defined as exchange of cup, stem or both. When the PE-insert or the ceramic ball head were exchanged leaving cup and stem in place, e.g. for PE-wear or dislocation, this was not considered a revision but a re-intervention. No differences were found in survival rates; however, in the rheumatoid arthritis group there was an increased rate of malposition of the cup, avulsions of the greater trochanter, and increased bone resorption in the trochanteric region. This study shows that despite altered biomechanical properties of rheumatoid bone, mechanical stability and osseous integration of cementless prosthesis are not compromised and, although a higher complication rate did occur, long-term survival is excellent. PMID:17609955

  5. Cementless total hip arthroplasty with the rectangular titanium Zweymuller stem. A concise follow-up, at a minimum of fifteen years, of a previous report.

    PubMed

    Grübl, Alexander; Chiari, Catharina; Giurea, Alexander; Gruber, Martin; Kaider, Alexandra; Marker, Martina; Zehetgruber, Harald; Gottsauner-Wolf, Florian

    2006-10-01

    Between October 1986 and November 1987, 208 total hip arthroplasties were performed with use of the cementless Zweymüller stem and a threaded cup in 200 consecutive patients. Of 102 patients (108 hips) who were available for follow-up at a minimum of 180 months postoperatively, eighty-three (eighty-nine hips) had the primary joint replacement still intact. No stem had been revised because of aseptic loosening, but we found various degrees of osteolysis around sixteen (18%) of the implants. The probability of survival of the stem at fifteen years was 0.98 (95% confidence interval, 0.96 to 1.00). The probability of survival of the cup was 0.85 (95% confidence interval, 0.79 to 0.91). PMID:17015598

  6. Ten-year follow-up of the non-porous Allofit cementless acetabular component.

    PubMed

    Zenz, P; Stiehl, J B; Knechtel, H; Titzer-Hochmaier, G; Schwagerl, W

    2009-11-01

    Cementless acetabular fixation has demonstrated superior long-term durability in total hip replacement, but most series have studied implants with porous metal surfaces. We retrospectively evaluated the results of 100 consecutive patients undergoing total hip replacement where a non-porous Allofit component was used for primary press-fit fixation. This implant is titanium alloy, grit-blasted, with a macrostructure of forged teeth and has a biradial shape. A total of 81 patients (82 hips) were evaluated at final follow-up at a mean of 10.1 years (8.9 to 11.9). The Harris Hip Score improved from a mean 53 points (23 to 73) pre-operatively to a mean of 96 points (78 to 100) at final review. The osseointegration of all acetabular components was radiologically evaluated with no evidence of loosening. The survival rate with revision of the component as the endpoint was 97.5% (95% confidence interval 94 to 100) after 11.9 years. Radiolucency was found in one DeLee-Charnley zone in four acetabular components. None of the implants required revision for aseptic loosening. Two patients were treated for infection, one requiring a two-stage revision of the implant. One femoral stem was revised for osteolysis due to the production of metal wear debris, but the acetabular shell did not require revision. This study demonstrates that a non-porous titanium acetabular component with adjunct surface fixation offers an alternative to standard porous-coated implants. PMID:19880887

  7. 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

    2016-04-01

    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.

  8. 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.

  9. Effects of femoral component material properties on cementless fixation in total hip arthroplasty. A comparison study between carbon composite, titanium alloy, and stainless steel.

    PubMed

    Otani, T; Whiteside, L A; White, S E; McCarthy, D S

    1993-02-01

    Carbon-fiber-reinforced-carbon composite material is an attractive implant material because its modulus of elasticity can be made similar to that of cortical bone. This study investigated the effect of femoral prosthesis elastic modulus on cementless implant fixation. Distal, as well as proximal, relative micromovements between implant and bone were measured in two testing protocols (axial-load and torsional-load), comparing identically shaped carbon composite (modulus of elasticity = 18.6 GPa), Ti6Al4V (100 GPa), and 630 stainless steel (200 GPa) prostheses. In the axial-load test, proximal mediolateral micromotions were significantly larger in the flexible composite stem than in the two metals. In the torsional-load test, rotational micromotions and "slop" displacements in the flexible stem were significantly larger proximally and significantly smaller distally than in the two metals. While these results suggest that proximal stress transfer may be improved by a flexible stem, they raise the possibility of increased proximal micromotion, and suggest that improved proximal fixation may be necessary to achieve clinical success with flexible composite femoral components. PMID:8436992

  10. Cementless Oxford unicompartmental knee replacement shows reduced radiolucency at one year.

    PubMed

    Pandit, H; Jenkins, C; Beard, D J; Gallagher, J; Price, A J; Dodd, C A F; Goodfellow, J W; Murray, D W

    2009-02-01

    We randomised 62 knees to receive either cemented or cementless versions of the Oxford unicompartmental knee replacement. The implants used in both arms of the study were similar, except that the cementless components were coated with porous titanium and hydroxyapatite. The tibial interfaces were studied with fluoroscopically-aligned radiographs. At one year there was no difference in clinical outcome between the two groups. Narrow radiolucent lines were seen at the bone-implant interfaces in 75% of cemented tibial components. These were partial in 43%, and complete in 32%. In the cementless implants, partial radiolucencies were seen in 7% and complete radiolucencies in none. These differences are statistically significant (p < 0.0001) and imply satisfactory bone ingrowth into the cementless implants. PMID:19190051

  11. Cementless total hip arthroplasty.

    PubMed

    Morscher, E W

    1983-12-01

    The differences between prostheses fixed with and without cement are mainly in the design and nature of the surface implant. The shapes of the sockets to be implanted without cement show a wide variety: cylinder, square, conus, and ellipsoid with and without threads. The hemispheric shape, however, which was chosen for the acetabular component of the isoelastic hip joint, does not disturb the natural form and function of the hip joint since the outer surface is closely adapted to the original subchondral bone layer. The noncemented cup is secured by threads, pegs, screws, etc., and by ingrowth of bony tissue in the grooves of the surfaces. Most femoral stems are based on the self-locking principle. All prosthetic models incorporate attempts to increase the surface of the stem (ribs, wings, corrugations, rims, etc.). There is a tendency to use less rigid elastic implants instead of the well known rigid metallic prostheses. The aim is to overcome the problems of stress protection and stress concentration observed with rigid implants. For the biomechanical integration of an implant, the properties of the surface, especially macroporosity and microporosity, are important. Most European models of noncemented endoprostheses are based on macroporosity (porometal, madreporic, etc.). The increase in implant surface area achieved with macroscopic perforations and recesses is relatively minor compared with the possibilities offered by microporosity ("alumine fritée," Proplast, fiber-metal, etc.). The best indication for use of a cementless hip endoprosthesis is in revision arthroplasty. The lost bone stock is replaced by bone grafts, thereby creating a situation comparable with that of a primary arthroplasty. Clinical experience with noncemented hip endoprostheses is, to date, promising, although the observation time for most models is short. PMID:6357588

  12. 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.

  13. 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

  14. 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

  15. 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

  16. Cementless bulk alumina socket: preliminary results at 6 years.

    PubMed

    Hamadouche, M; Nizard, R S; Meunier, A; Bizot, P; Sedel, L

    1999-09-01

    To avoid polyethylene wear observed in total hip replacement, an alumina-alumina combination has been used since 1977. The aim of this study is to report the results of a hybrid alumina-alumina total hip arthroplasty with a cementless press-fit bulk alumina socket and a cemented titanium alloy stem in 55 patients (62 hips) operated on between 1982 and 1990. The bearing surfaces were a 32-mm alumina head articulating within the alumina socket. Four failures occurred: 3 aseptic loosenings of the socket and 1 femoral head fracture. Considering aseptic loosening as the endpoint, the survival rate was 93.2% after 6 years. At a mean of 72.1 months' follow-up, 92.4% of the surviving hips were graded as very good or good using the Merle d'Aubigné-Postel hip score. Radiolucent lines were observed on the acetabular side in 68.1 of the hips. The future of this interface, which is probably fibrous, remains questionable. With the exception of 1 femoral head fracture, all revisions were related to failure of the bony fixation of the socket, and no problem was encountered related to the alumina-alumina friction coupling. Alumina sockets with other types of cementless fixation have therefore been designed and are presently under clinical investigation. PMID:10512442

  17. 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.

  18. 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

  19. 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.

  20. Ten to twelve-year results with the Zweymüller cementless total hip prosthesis.

    PubMed

    Vervest, Ton M J S; Anderson, Patricia G; Van Hout, Freek; Wapstra, Frits-Hein; Louwerse, Robert T; Koetsier, Juriaan W A

    2005-04-01

    Between January 1987 and December 1990, 221 Zweymüller cementless total hip arthroplasties were performed in 211 patients with idiopathic osteoarthritis. A total of 136 patients (142 prostheses) were evaluated at a mean follow-up of 134 months (SD 9.5). The study group consisted of 78 Hochgezogen and 64 Stepless stem prostheses, all with a threaded titanium cup and ceramic head. No clinical and radiological differences were found between the 2 stem prostheses. Seven cups had been revised because of aseptic loosening; 17 cups showed radiolucent lines, osteolysis, or migration. Mean linear polyethylene wear of 105 (74%) cups was 0.46 mm (SD 0.27), with an annual wear of 0.04 mm (SD 0.02). Wear did not correlate with pain, cup migration, radiolucent lines, or osteolysis. Cumulative survival was 96%. Zweymüller cementless total hip arthroplasty showed good midterm results. PMID:15809956

  1. Cementless fixation in total knee arthroplasty: past, present, and future.

    PubMed

    Meneghini, R Michael; Hanssen, Arlen D

    2008-10-01

    Cementless fixation in total knee arthroplasty (TKA) has had limited use in recent decades due to past failures in the early generation of cementless designs. Screw track osteolysis, poor polyethylene, and metal-backed patellar component failures contributed to a controversial track record and created a reluctance to embrace cementless fixation in TKA; however, these failure mechanisms are correctable. In addition, there is renewed interest in cementless fixation due to the recent development of improved biomaterials, particularly highly porous metals and highly crosslinked polyethylene, as well as time-saving advantages and long-term osseointegration of cementless fixation. There are long-term reports of successful designs of cementless knee arthroplasty that are nearly equal to the results of cemented designs. This article discusses the past history, current long-term results, and future of cementless fixation in TKA. PMID:18979934

  2. A cementless, elastic press-fit socket with and without screws

    PubMed Central

    2012-01-01

    Background The acetabular component has remained the weakest link in hip arthroplasty regarding achievement of long-term survival. Primary fixation is a prerequisite for long-term performance. For this reason, we investigated the stability of a unique cementless titanium-coated elastic monoblock socket and the influence of supplementary screw fixation. Patient and methods During 2006–2008, we performed a randomized controlled trial on 37 patients (mean age 63 years (SD 7), 22 females) in whom we implanted a cementless press-fit socket. The socket was implanted with additional screw fixation (group A, n = 19) and without additional screw fixation (group B, n = 18). Using radiostereometric analysis with a 2-year follow-up, we determined the stability of the socket. Clinically relevant migration was defined as > 1 mm translation and > 2º rotation. Clinical scores were determined. Results The sockets without screw fixation showed a statistically significantly higher proximal translation compared to the socket with additional screw fixation. However, this higher migration was below the clinically relevant threshold. The numbers of migratory sockets were not significantly different between groups. After the 2-year follow-up, there were no clinically relevant differences between groups A and B regarding the clinical scores. 1 patient dropped out of the study. In the others, no sockets were revised. Interpretation We found that additional screw fixation is not necessary to achieve stability of the cementless press-fit elastic RM socket. We saw no postoperative benefit or clinical effect of additional screw fixation. PMID:23083434

  3. Good short-term outcome of primary total hip arthroplasty with cementless bioactive glass ceramic bottom-coated implants

    PubMed Central

    2012-01-01

    Background and purpose Cementless total hip arthroplasty is currently favored by many orthopedic surgeons. The design of the porous surface is critically important for long-term fixation. We examined the clinical and radiographic outcome of the cementless titanium hip implant with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. Methods We retrospectively reviewed 109 hips (92 patients) that had undergone primary cementless total hip arthroplasty with bioactive glass ceramic bottom-coated implants. The mean follow-up period was 7 (3–9) years. Hip joint function was evaluated with the Merle d’Aubigné and Postel hip score, and radiographic changes were determined from anteroposterior radiographs. Results The mean hip score improved from 9.7 preoperatively to 17 at the final follow-up. The overall survival rate was 100% at 9 years, when radiographic loosening or revision for any reason was used as the endpoint. 3 stems in 2 patients subsided more than 3 mm vertically within 1 year after implantation. Radiographs of the interface of the stem and femur were all classified as bone ingrowth fixation. Conclusions The short-term results of this study show good outcome for cementless implants with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. PMID:23043270

  4. 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. PMID:22793261

  5. Cement or cementless fixation in total knee arthroplasty?

    PubMed

    Rand, J A

    1991-12-01

    A prospectively studied group of 59 knees with cementless fixation were compared to a retrospectively studied but matched group of 59 knees with cement fixation using a Press Fit Condylar prosthesis. The only significant preoperative difference between the patient groups was mean age; the cemented group was on average nine years older than the cementless group (p less than 0.0001). At an average of 2.8 years after surgery, there were no significant differences in knee scores between the two groups. Radiolucent lines adjacent to the tibial component were similar in both groups. The complication rate of 20% in the cementless knees was higher than the 12% rate in the cemented knees; this was primarily related to polyethylene wear of metal-backed patellar components. Cement or cementless fixation of this prosthesis appears to provide equivalent early results. PMID:1959287

  6. 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.

  7. 31. FORGE, ANVIL, POWER FORGE HAMMER (FRONT TO BACK), AND ...

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

    31. FORGE, ANVIL, POWER FORGE HAMMER (FRONT TO BACK), AND DOORWAY INTO MAIN SHOP-LOOKING SOUTHWEST. - W. A. Young & Sons Foundry & Machine Shop, On Water Street along Monongahela River, Rices Landing, Greene County, PA

  8. 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.

  9. Cemented versus cementless fixation in total knee arthroplasty

    PubMed Central

    MATASSI, FABRIZIO; CARULLI, CHRISTIAN; CIVININI, ROBERTO; INNOCENTI, MASSIMO

    2013-01-01

    The question of whether to use cemented or cement-less fixation for a total knee arthroplasty (TKA) is still debated. Discouraging preliminary results of cement-less TKAs have determined the worldwide use of cemented implants. However, with the development of biotechnologies and new biomaterials with high osteoconductive properties, biological fixation is now becoming an attractive option for improving the longevity of TKAs, especially in young patients. There is no evidence in the current literature to support the use of one method of fixation. The extensive clinical experience with cemented implants gathered over the years justifies their widespread use. New randomized clinical trials are necessary to compare cementless fixation based on the new ingrowth surfaces with standard cemented implants. PMID:25606521

  10. Cemented versus cementless fixation in total knee arthroplasty.

    PubMed

    Matassi, Fabrizio; Carulli, Christian; Civinini, Roberto; Innocenti, Massimo

    2013-01-01

    The question of whether to use cemented or cement-less fixation for a total knee arthroplasty (TKA) is still debated. Discouraging preliminary results of cement-less TKAs have determined the worldwide use of cemented implants. However, with the development of biotechnologies and new biomaterials with high osteoconductive properties, biological fixation is now becoming an attractive option for improving the longevity of TKAs, especially in young patients. There is no evidence in the current literature to support the use of one method of fixation. The extensive clinical experience with cemented implants gathered over the years justifies their widespread use. New randomized clinical trials are necessary to compare cementless fixation based on the new ingrowth surfaces with standard cemented implants. PMID:25606521

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  12. Fallon FORGE Well Lithologies

    DOE Data Explorer

    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.

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

    PubMed

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

    2010-11-01

    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. PMID:21053885

  14. 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.

  15. 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.

  16. The effect of extracorporeal shock wave lithotripsy on the prosthesis interface in cementless arthroplasty. Evaluation in a rabbit model.

    PubMed

    Stranne, S K; Callaghan, J J; Fyda, T M; Fulghum, C S; Glisson, R R; Weinerth, J L; Seaber, A V

    1992-06-01

    The effect of extracorporeal shock wave lithotripsy on interfacial strength between prosthesis and bone in cementless arthroplasty was examined using a rabbit model. Paired femora, each implanted with fiber mesh porous coated titanium implants, were harvested from rabbits 15 weeks after implantation. In group I, one femur from each pair was exposed to lithotripsy treatment consisting of 2,000 shocks at 20 kV. In group II, one femur from each pair was exposed to 2,000 shocks at 26 kV. Contralateral femora from each pair served as controls in both groups. Mechanical pushout tests were conducted on the implants using a 1321 Instron testing machine at a constant rate of 1 mm/minute. Shock waves generated at 20 kV were found to have no significant decrease on either the prosthesis/bone interfacial strength or energy to failure of cementless implants. Shock waves generated at 26 kV produced a mean 17.45% decrease in the prosthesis/bone interfacial strength, which approached statistical significance (P = .062), and a 7.84% mean decrease in the energy to failure (P = .268). However, in four of the seven group II specimens, cortical fractures occurred. These findings suggest that lithotripsy will not aid in the removal of uncemented porous coated devices and lithotripsy inadvertently focused at an uncemented device will not disrupt significantly the prosthesis-bone interface. PMID:1613525

  17. Proposal to study stem forgings

    SciTech Connect

    Odegard, B.C.

    1982-06-25

    Reservoir designs consist of two primary features including the stem(s) and the body segment. The stem is either an integral part of the reservoir or is joined at some point in the fabrication sequence. The current interest is in high strength stems for advanced reservoir designs. The processing necessary to achieve these strength levels may result in heavily cold worked microstructures which may not interface well with the stem requirements. For instance, cold worked 316 plate stock has shown decreased hydrogen compatibility when contrasted to the annealed version in laboratory tests. More recently, Precision Forge produced a 100 ksi yield strength, 304L stem forging with a heavily deformed microstructure which also may show decreased compatibility in hydrogen. The proposed forging contract will evaluate the influence of forging parameters on the microstructure and mechanical properties of 304L and 316 stem forgings. A summary of the data available on 304L stem forgings is shown graphically. The yield strength values are shown for each set of forging parameters. Tensile tests and microstructural examination will be conducted to complete the information for 304L and create a similar graph for 316 stem forgings.

  18. Bone ingrowth through porous titanium granulate around a femoral stem: histological assessment in a six-month canine hemiarthroplasty model.

    PubMed

    Turner, Thomas M; Urban, Robert M; Hall, Deborah J; Andersson, Gunnar B J

    2007-01-01

    The procedure of using of porous titanium granules for cementless fixation of a hip replacement femoral stem was studied in a hemiarthroplasty model in 10 canines for 6 months. A vibrating instrument was used to facilitate both the delivery and distribution of the irregularly shaped porous titanium granules into the femoral canal as well as the subsequent insertion of a titanium alloy stem into the intramedullary bed of granules. Histological examination revealed lamellar bone formation through the mantle of porous titanium granules in continuity with the surrounding cortex resulting in the formation of an integrated mantle of bone and titanium granulate around the prosthesis. PMID:17578819

  19. Method of making multilayered titanium ceramic composites

    DOEpatents

    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.

  20. 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.

  1. Method of making multilayered titanium ceramic composites

    DOEpatents

    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.

  2. 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.

  3. Cementless total hip arthroplasty using a threaded cup and a rectangular tapered stem. Follow-up for ten to 17 years.

    PubMed

    Pospischill, M; Knahr, K

    2005-09-01

    We carried out a clinical and radiological review of 103 cementless primary hip arthroplasties with a tapered rectangular grit-blasted titanium press-fit femoral component and a threaded conical titanium acetabular component at a mean follow-up of 14.4 years (10.2 to 17.1). The mean Harris hip score at the last follow-up was 89.2 (32 to 100). No early loosening and no fracture of the implant were found. One patient needed revision surgery because of a late deep infection. In 11 hips (10.7%), the reason for revision was progressive wear of the polyethylene liner. Exchange of the acetabular component because of aseptic loosening without detectable liner wear was carried out in three hips (2.9%). After 15 years the survivorship with aseptic loosening as the definition for failure was 95.6% for the acetabular component and 100% for the femoral component. PMID:16129743

  4. 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.

  5. The pathogenesis of osteolysis in two different cementless hip replacements.

    PubMed

    Learmonth, I D; Smith, E J; Cunningham, J L

    1997-01-01

    Wear of ultra-high molecular weight polyethylene has been incriminated in the osteolysis associated with aseptic loosening of hip implants. A variety of different factors can contribute to accelerated patterns of polyethylene wear and subsequent osteolysis. This paper examines the incidence of osteolysis observed in two different well-matched cohorts of cementless total hip arthroplasties. The patterns of osteolysis observed, which are ascribed to the generation of polyethylene debris, are interpreted with reference to the design of the individual prostheses. PMID:9141891

  6. Early results with the cementless Variall hip system.

    PubMed

    Suda, Arnold J; Knahr, Karl

    2009-01-01

    This study presents the early results of the Variall cementless hip system, a further development of the reliable Alloclassic Zweymüller system. In a prospective randomized study, 319 patients (333 hips) underwent the Variall cementless hip system with four different bearings and were scored using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) Score and the Short Form-36 health survey form, with a follow-up period of 3 years. The patients were grouped according to age, with those in the age range 23-75 years as group one (n = 285) and those over 75 years of age as group two (n = 48). For both the Short Form-36 and WOMAC scoring, worse function was found in group two (i.e., patients >75 years). In this group, the function scores were worse in patients who received a conventional polyethylene bearing. The clinical and radiological results after 5 or more years will lead to a clearer prediction. PMID:19105776

  7. Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.

    PubMed

    Decking, R; Reuter, P; Hüttner, M; Puhl, W; Claes, L E; Scharf, H P

    2003-02-15

    The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants. PMID:12516084

  8. 48 CFR 225.7102 - Forgings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Forgings. 225.7102 Section 225.7102 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF... Forgings....

  9. 48 CFR 225.7102 - Forgings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 3 2012-10-01 2012-10-01 false Forgings. 225.7102 Section 225.7102 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF... Forgings....

  10. 48 CFR 225.7102 - Forgings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 3 2013-10-01 2013-10-01 false Forgings. 225.7102 Section 225.7102 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF... Forgings....

  11. 48 CFR 225.7102 - Forgings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Forgings. 225.7102 Section 225.7102 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF... Forgings....

  12. 48 CFR 225.7102 - Forgings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 3 2014-10-01 2014-10-01 false Forgings. 225.7102 Section 225.7102 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM, DEPARTMENT OF... Forgings....

  13. Twenty-year survivorship of cementless anatomic graduated component total knee arthroplasty.

    PubMed

    Ritter, Merrill A; Meneghini, R Michael

    2010-06-01

    There is a renewed interest in cementless total knee arthroplasty (TKA) due to improved biomaterials, desire for decreased surgical times and the potential increased longevity. Seventy-three cementless TKAs (AGC, Biomet, Warsaw, Ind) were performed from 1984 to 1986. All components were implanted without cement and without screws and obtained minimum 10 years of follow-up. No patient was lost to follow-up. Fifteen failures occurred, including 12 failed metal-backed patellae, and survivorship for aseptic loosening of any component was 76.4% at 20 years. Two tibial components failed of aseptic loosening at 1.1 and 2.2 years. Excluding patella failures, the survivorship for the cementless tibial component was 96.8% at 20 years. There were no femoral component failures. After eliminating patella failures, this cementless monoblock tibial component without screws demonstrated excellent 20-year survivorship. PMID:19427163

  14. 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.

  15. Fallon FORGE Well Temp data

    DOE Data Explorer

    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.

  16. High-energy rate forgings of wedges :

    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.

  17. 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.

  18. 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.

  19. Outcomes of a Newer-Generation Cementless Total Knee Arthroplasty Design.

    PubMed

    Harwin, Steven F; Elmallah, Randa K; Jauregui, Julio J; Cherian, Jeffrey J; Mont, Michael A

    2015-10-01

    Newer-generation cementless total knee arthroplasties (TKAs) aim to improve durability, function, and longevity. In a large series of cementless TKAs at a mean 4-year follow-up, the authors evaluated (1) survivorship, (2) range of motion, (3) patient-reported outcomes, and (4) complications. Mean age was 66 years (range, 34-88 years) and mean body mass index was 32.5 kg/m(2) (range, 20-54 kg/m(2)). Aseptic and septic implant survivorships were 99.6% and 99.5%, respectively. Mean extension, flexion, and Knee Society scores improved significantly. There were 3 septic failures. Aseptic failures included 3 aseptic loosenings, 1 polyethylene revision, and 1 revision to a cemented patella. This study showed excellent clinical and patient-reported outcomes of cementless TKA. PMID:26488775

  20. 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

  1. Osteolytic lesion of the tibial diaphysis after cementless TKA.

    PubMed

    Vernon, Brian A; Bollinger, Alexander J; Garvin, Kevin L; McGarry, Sean V

    2011-03-01

    Biomaterial wear debris is a known contributing factor in aseptic loosening of total joint prostheses, particularly when cementless tibial trays are used in total knee arthroplasty (TKA). Local inflammatory response can lead to osteolysis and aseptic loosening of implants. The resulting lesions require careful clinical evaluation. This article presents a case of a 76-year old man with a remote history of prostate cancer and cigarette smoking who presented with acute onset left knee and tibia pain 15 years after TKA. Radiographs showed an osteolytic lesion in the distal tibial diaphysis and magnetic resonance imaging revealed a cystic lesion with evidence concerning for pathologic mid-shaft fracture. Biopsy of the lesion confirmed a foreign body reaction and revision TKA was performed. The patient was seen at 3-year follow-up without complication. The existing literature presents cases reporting osteolytic lesions of the distal femur and proximal tibial metaphysis due to polyethylene wear debris and foreign body reaction following TKA. We are unaware of case reports involving osteolysis of this etiology extending into the distal tibial diaphysis. We conclude that polyethylene wear debris with foreign body reaction should be considered in the differential diagnosis of an osteolytic lesion extending into the tibial diaphysis following TKA. PMID:21410114

  2. Morphological Study of the Newly Designed Cementless Femoral Stem

    PubMed Central

    Baharuddin, Mohd Yusof; Salleh, Sh-Hussain; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Mohd Noor, Alias

    2014-01-01

    A morphology study was essential to the development of the cementless femoral stem because accurate dimensions for both the periosteal and endosteal canal ensure primary fixation stability for the stem, bone interface, and prevent stress shielding at the calcar region. This paper focused on a three-dimensional femoral model for Asian patients that applied preoperative planning and femoral stem design. We measured various femoral parameters such as the femoral head offset, collodiaphyseal angle, bowing angle, anteversion, and medullary canal diameters from the osteotomy level to 150 mm below the osteotomy level to determine the position of the isthmus. Other indices and ratios for the endosteal canal, metaphyseal, and flares were computed and examined. The results showed that Asian femurs are smaller than Western femurs, except in the metaphyseal region. The canal flare index (CFI) was poorly correlated (r < 0.50) to the metaphyseal canal flare index (MCFI), but correlated well (r = 0.66) with the corticomedullary index (CMI). The diversity of the femoral size, particularly in the metaphyseal region, allows for proper femoral stem design for Asian patients, improves osseointegration, and prolongs the life of the implant. PMID:25025068

  3. Preparation of the proximal femur in cementless total hip revision.

    PubMed

    Mallory, T H

    1988-10-01

    With an increased incidence of revision for the failed cemented total hip arthroplasty, techniques of revision surgery need meticulous attention to detail. Although the causes of the failed cemented total hip arthroplasty are many, they tend to follow characteristic patterns. The proximal femur can be exposed through an extensive muscle split incision, which offers a complete circumferential view of the femur. The cement removal is enhanced by controlled perforation using high-speed drills. Classification of bony deficits of the proximal femur can be divided into Type I, including intact cortex and medullary content; Type II, in which there is intact cortex but deficient medullary content; and Type III, in which deficits of both the cortex and medullary canal are present. Prosthetic selection is based on residual bone stock. In general, cementless fixation is advocated, with distal fixation using long-stem devices. Augmentation of bone deficits requires the use of segmental prosthetic replacement or fresh-frozen allografts. One hundred sixty patients were followed for two to six years. Satisfactory results have occurred in over 90% of the patients; better results are anticipated in patients with minimal bone deficits. Aseptic loosening requiring rerevision has occurred in 5% of the patient population. Understanding the dynamics of failure and the residual bone deficits allows one to manage the failed cemented total hip arthroplasty with greater efficiency and predictability. PMID:3416541

  4. 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.

  5. 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 Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.218 Forging machines. (a) General requirements—(1) Use of lead....

  6. Impedance analysis of forging process and strategy study on compliance for forging manipulator

    NASA Astrophysics Data System (ADS)

    Zhang, Pu; Yao, Zhenqiang; Du, Zhengchun

    2013-07-01

    In the field of heavy forging, there are numerous researches on deformation rule in forging process by FEM simulation, however, not many scholars take the equipment constraint and the mutual reaction load between the forging manipulator clamp and the forging blank into account, which will impact on safety of manipulator body and quality of forging blank. This paper presents an impedance model to describe the load and formulates compliance strategies correspondingly to reduce the mutual reaction load for forging manipulator. Firstly, an FEM model of forging process is built. Meanwhile, the clamp of forging manipulator is added to the model as movement constraint and interaction part between the manipulator and the forming process. Secondly, a typical forging process is simulated by changing the movement constraint, and then an impedance model is established to describe the relationship between the load and movement constraint. Finally, two kinds of compliance strategies are formulated according to the impedance model, one is called free compliance, and the other is initiative/passive compliance. The simulation results show that compliance strategies reduce the load amounting to 5 000 kN in z direction between the manipulator clamp and the forging blank obviously, which may lead to serious accidents, such as the capsizing of forging manipulator, the fracture of manipulator clamp, and so on. The proposed research simulates the more real forging process, gets the initiative/passive compliance strategy which is more simple and suitable to the real producing and better for forming a forging process planning and control system in the modern production, and improves the quality and efficiency of heavy forging.

  7. 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.

  8. 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. PMID:26210779

  9. 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.

  10. 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.

  11. 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.

  12. Selecting forged aluminum for automotive applications

    SciTech Connect

    Holtz, M.A.; Davis, J.; Crawford, D.

    1984-01-01

    With the current and future efforts to downsize automobiles and reduce their weight, strong lightweight materials, in various product forms, are being substituted for many traditionally ferrous components. One of the substitute materials is aluminum, which although itself is not new to automobiles is finding novel applications as forgings in critical chassis and suspension areas. The 1984 Corvette provides an excellent example of how the use of forged aluminum can reduce unsprung and overall weight as well as improve performance without compromising the integrity of the vehicle. Using aluminum as forgings permits taking maximum advantage of its high strength-to-weight ratio, excellent ductility and toughness, and good corrosion resistance. This paper discusses the various considerations to be entertained when looking at aluminum forgings for automotive applications and the benefits of planning for these lightweight parts early in the design phase.

  13. 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.

  14. 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.

  15. Cementless porous-coated anatomic medullary locking total hip prostheses.

    PubMed

    Kim, Y H; Kim, V E

    1994-06-01

    the cementless Anatomic Medullary Locking prosthesis. PMID:8077972

  16. 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.

  17. 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.

  18. An investigation on the effect of groove geometry on cementless femoral stem component in hip arthroplasty.

    PubMed

    Rawal, B R; Bhatnagar, Naresh

    2013-12-15

    The optimal surface for a cementless femoral stem has been a subject of debate for the past several years. Several researchers have stressed the need for research on how an implant surface shape contributes to long-term stability after implantation, in the field of orthopaedics. The introduction of optimized grooves on an implant proximal surface may enhance long-term stability of an implant. This study thus analyzes the effect of different groove dimensions and angles in a transverse plane on stress transmission by a constant load at the femur by using Finite Element Analysis (FEA). Results suggest that the tendency of stress transmission differs depending on the size, position and angle of the grooves. An optimized groove size and inclination plays a vital role for long-term stability of cementless femoral stems. PMID:24517034

  19. Removal of a well-fixed cementless femoral component with an extended proximal femoral osteotomy.

    PubMed

    Younger, T I; Bradford, M S; Paprosky, W G

    1995-05-01

    Removal of a stable, well-fixed cementless femoral arthroplasty component occasionally is necessary because of infection, component malposition, persistent pain, or incompatibility with a femoral revision component. Restricted access to ingrowth surfaces may make implant removal exceedingly difficult and increases the risk of iatrogenic damage to the proximal femur. A new extended proximal femoral osteotomy technique is described for use in removing well-fixed cementless femoral components. Previous techniques have been modified to allow access to the bone-implant interface and to provide straight-shot access to the femoral canal for proper sizing and positioning of the revision implant. The osteotomy can be extended to accommodate the entire length of the porous coating on the revision component. If a shorter osteotomy is desired, access to the prosthesis for transection with a metal-cutting burr is possible. The osteotomy is easily repositioned with cerclage wires or cables and reliable healing has been demonstrated. PMID:10150358

  20. Total knee arthroplasty using cementless keels and cemented tibial trays: 10-year results

    PubMed Central

    Kolisek, Frank R.; Mont, Michael A.; Seyler, Thorsten M.; Marker, David R.; Jessup, Nenette M.; Siddiqui, Junaed A.; Monesmith, Eric

    2008-01-01

    The problem of early mechanical stability of cemented and cementless keels of the tibial component in total knee arthroplasty (TKA) is controversial. The purpose of this study was to assess clinical and radiographic outcomes of a cohort of 51 TKAs using a cemented platform with cementless keel fixation. At a mean follow-up of 10.4 years (range, 7 to 14 years), the mean Knee Society Score (KSS) was 93 points (range, 59 to 100 points), and the mean functional score was 73 points (range, 0 to 100 points). Only one patient demonstrated progressive tibial radiolucencies at 13.1 years follow-up, which resolved with a revision with an exchange of components. The results of this study suggest that a proximally cemented tibial tray with a press-fit keel TKA provides excellent mean 10-year outcomes. PMID:18185931

  1. Cementless Hip Arthroplasty in Southern Iran, Midterm Outcome and Comparison of Two Designs

    PubMed Central

    Shahcheraghi, Gholam Hossein; Hashemi, Seyed Ali

    2015-01-01

    Background: Cementless hip prosthesis was designed to provide biologic fixation, without the use of cement. The second generation components have shown more reliable bone ingrowths and survival rates. We are reporting a midterm result of two designs of cementless prosthesis in a unique culture with different social habits and expectations. Methods: 52 primary cementless total hip arthroplasty in 42 patients with the mean age of 48.8 years were retrospectively studied. Two groups of prosthesis had been implanted: Harris-Galante II (HGII) in 15 and Versys-Trilogy (V-T) in 37 hips, both from Zimmer company. The patients were assessed clinically, radiographically and with Harris hip score, SF36, WOMAC, and MACTAR questionnaires, with 65 months (26-136) mean follow-up. Results: All the V-T prostheses had survived well. Eight of HG II were revised by the last follow-up in 19-102 months. All had undergone acetabular revision and 2 combined with femoral revision. Broken tines of HGII cups were seen in 4 radiographs. The 65 months overall survival was 96.2% for femoral and 84.6% for acetabular components. 90% had good or excellent Harris hip scores. The functional scores were poorer in the HG II group. Pain relief and improved walking were the two main patients’ expectations fulfilled in 97.6% and 92.8%, respectively. Conclusions: The outcome of cementless total hip arthroplasty (THA) is satisfactory and comparable with the literature based on the results of function and survival of this small comparative group. The use of HGII acetabular component should be abandoned. PMID:26379348

  2. [An unusual early complication in cementless replacement of the hip joint. Case report].

    PubMed

    Kauschke, T; Zilch, H

    1994-12-01

    This is the first description of a dislocation of the polyethyleninlay from the cup of a cementless hip prosthesis. Due to a fall of the patient 8 months after the implantation an unspecific complaint arised. In spite of detailed diagnostic no reason could have been found. During the renewed operation we saw the dislocated inlay by mechanical anchorage of the cup and the shaft. Retrospective there were made suggestions how the described complication could be recognized earlier. PMID:7871611

  3. The Early Result of Cementless Arthroplasty for Femur Neck Fracture in Elderly Patients with Severe Osteoporosis

    PubMed Central

    Seo, Jae-Seong; Shin, Seong-Kee; Jun, Sung-Han; Cho, Chang-Ho

    2014-01-01

    Purpose The purposes of the current study were to assess the early results of cementless hip arthroplasty (HA) for femoral neck fractures in elderly patients with severe osteoporosis and to compare the clinical outcomes between those who underwent total HA (THA) or bipolar hemiarthroplasty (BHA). Materials and Methods From April 2011 to May 2012, we performed 87 cementless HAs for displaced femoral neck fractures in elderly patients (≥65 years) with severe osteoporosis. Among them, we studied 70 hips that were able to be followed-up for >24 months. Of these, 34 underwent THA and 36 underwent BHA. Clinical results were evaluated using the Harris hip score (HHS), Koval classification, and radiographs. Results Only one instance of femoral stem loosening was observed. Additionally, no dislocations were observed and no revision surgeries were required. The mean changes in the functional items of the HHS scores were 2.8 and 5.2 for those who underwent THA and BHA, respectively (P<0.05). According to the Koval classification used for the ambulatory status analysis, the mean perioperative change in the grade was 0.8 (0-4), with no significant differences noted between the THA and BHA groups. Conclusion The early results of cementless HA for femur neck fractures in elderly patients with osteoporosis were satisfactory, and THA was found to have a functional advantage over BHA.

  4. 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.

  5. 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

  6. 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

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

    PubMed Central

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

    2016-01-01

    AIM: To investigate the short-term clinical results of the Oxford phase III cementless medial unicondylar knee prosthesis (UKP) compared to the cemented medial UKP. METHODS: 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. RESULTS: 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. CONCLUSION: The cementless Oxford phase III medial UKP shows good short-term clinical results, when used in a specialist clinic by an experienced surgeon. PMID:27114932

  8. 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.

  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. 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... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings, and machined bodies. The U.S. Munitions List controls as defense articles those forgings, castings, and other unfinished products, such...

  11. 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…

  12. 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…

  13. 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.

  14. Analysis of forging limit for sintered porous metals

    SciTech Connect

    Han, H.N.; Oh, K.H.; Lee, D.N.

    1995-06-15

    Forging of sintered porous metals has been developed as a method for producing machine parts with good mechanical properties. To extend this manufacturing method to a wide range of applications, it will be helpful to have an understanding of the deformation, density change and fracture of sintered porous metals during forging. Especially, in order to avoid the possibility of surface fracture in forging of porous metals, it is necessary to know the forging limits of sintered porous metals. The purpose of this work is to calculate the forging limit curves of sintered porous metals using the various yield functions for porous metals.

  15. The importance of trochanteric lag screws to achieve primary stability in cementless fixation of the RM hip prosthesis.

    PubMed

    Heitemeyer, U; Hierholzer, G; Haines, J

    1987-01-01

    To allow the bony incorporation of a cementless prosthesis it is important to achieve stability at the time of operation. To neutralize tension and torsional stresses the RM-shaft prosthesis is fixed with two lag screws in the trochanteric part of the femur. By measuring the applied torque intraoperatively we could demonstrate that the threads of the screws found a better grip when inserted from the bone to the prosthesis. Thus, the stronger fixation of the screws enhanced the primary stability of the cementless prosthesis. PMID:3566504

  16. Risk factors for intraoperative calcar fracture in cementless total hip arthroplasty

    PubMed Central

    Miettinen, Simo S A; Mäkinen, Tatu J; Kostensalo, Inari; Mäkelä, Keijo; Huhtala, Heini; Kettunen, Jukka S; Remes, Ville

    2016-01-01

    Background and purpose — Intraoperative periprosthetic femoral fracture is a known complication of cementless total hip arthroplasty (THA). We determined the incidence of—and risk factors for—intraoperative calcar fracture, and assessed its influence on the risk of revision. Patients and methods — This retrospective analysis included 3,207 cementless THAs (in 2,913 patients). 118 intraoperative calcar fractures were observed in these hips (3.7%). A control group of 118 patients/hips without calcar fractures was randomly selected. The mean follow-up was 4.2 (1.8–8.0) years. Demographic data, surgical data, type of implant, and proximal femur morphology were evaluated to determine risk factors for intraoperative calcar fracture. Results — The revision rates in the calcar fracture group and the control group were 10% (95% CI: 5.9–17) and 3.4% (CI: 1.3–8.4), respectively. The revision rate directly related to intraoperative calcar fracture was 7.6%. The Hardinge approach and lower age were risk factors for calcar fracture. In the fracture group, 55 of 118 patients (47%) had at least one risk factor, while only 23 of118 patients in the control group (20%) had a risk factor (p = 0.001). Radiological analysis showed that in the calcar fracture group, there were more deviated femoral anatomies and proximal femur bone cortices were thinner. Interpretation — Intraoperative calcar fracture increased the risk of revision. The Hardinge approach and lower age were risk factors for intraoperative calcar fracture. To avoid intraoperative fractures, special attention should be paid when cementless stems are used with deviant-shaped proximal femurs and with thin cortices. PMID:26541230

  17. Endo medullary extractability of cementless full HA coated femoral stem: Results from 19 cases.

    PubMed

    Lecuire, François; Melere, Gilles; Martres, Sébastien

    2015-03-01

    The Aura cementless full HA coated stem is an anatomical femoral component with a different surface treatment in the metaphyseal and diaphyseal areas. We have studied the feasibility of isolated endo-medullar extraction of the stem. 19 patients (6 infections, 6 neck fractures, 3 stems with risk of fracture, 3 head fractures, and 1 recurrent dislocation) were subjected to the removal of a stable and bone integrated implant at a mean of 4.5 years after surgery. The 19 cases represent the entire population of Aura cementless integrated stem requiring revision during the period of 2003 through 2011, excluding periprosthetic bone fracture cases. The technique consisted of a careful release of the metaphyseal part of the implant with thin osteotomes, followed by the use of a highly efficient extractor. The re-implanted procedure always utilised standard stems: 17 cementless stems full HA coated (13 had the same size as the removed implant, 4 cases had larger sizes) and two received cemented stems. The 19 stems were extracted by simple endo-medullary approach, without the need for additional action. Several complications were encountered, 1 intraoperative diaphyseal fracture, requiring a wiring, 1 fracture of the lesser trochanter at 15 days post-surgery, requiring a revision and 2 postoperative dislocations. Except for the early revision due to fracture, no other stem was revised. There was no recurrence of infection and the functional results were satisfactory (PMA 15-18). 3 patients showed metaphyseal lucent lines on X-Ray leading us to advise the use of a standard stem with larger size after distal reaming, combined with preventive circulate of the calcar. The use of dedicated instrumentation allows successful extraction of full HA coated short stem by endomedullary approach. PMID:26280859

  18. No medium-term advantage of electrochemical deposition of hydroxyapatite in cementless femoral stems

    PubMed Central

    Flatøy, Bernhard; Röhrl, Stephan M; Bøe, Berte; Nordsletten, Lars

    2016-01-01

    Background and purpose Hydroxyapatite has been used for a long time as an adjunct to enhance cementless fixation. The benefit of this is still debated, but new methods of hydroxyapatite deposition have emerged, offering possible gains. In order to investigate this further, we compared the migration pattern and periprosthetic bone remodeling in a cementless femoral stem with either electrochemically deposited hydroxyapatite—called Bonemaster (BM)—or a conventional plasma-sprayed hydroxyapatite (HA) coating. Patients and methods 55 hips were randomized to either BM or HA cementless femoral stems. Patients were followed with radiostereometry (RSA), dual-energy X-ray absorptiometry (DXA), radiographic measurements, and hip questionnaires for 5 years. Results For both stems, migration occurred mainly as subsidence and retroversion during the first 3 months. The BM group had a higher retroversion rate of 0.17° per month during this period, as compared to 0.06° per month for the HA group (p = 0.006). Thereafter, there was almost no movement in any direction for both stem types. Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing. The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years. There was a slightly higher resorption rate in Gruen zone 7 from 2 to 5 years in the BM group (1.3% per year; p = 0.04), but in a magnitude that would scarcely affect stem stability or survival. Interpretation There were no clinically relevant differences between the 2 stems regarding stability or periprosthetic bone loss at 5 years. Electrochemically deposited HA does not appear to affect fixation or bone remodeling when compared to conventional plasma spraying at 5 years. Thus, at this point, Bonemaster appears to be safe. PMID:26364953

  19. 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.

  20. 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.

  1. 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

  2. Computer-based gait analysis of dogs: evaluation of kinetic and kinematic parameters after cemented and cementless total hip replacement.

    PubMed

    Drüen, S; Böddeker, J; Meyer-Lindenberg, A; Fehr, M; Nolte, I; Wefstaedt, P

    2012-01-01

    To date it is unclear whether cementless total hip replacement (THR) in dogs is of clinical advantage in comparison to cemented THR with regard to lameness improvement. Thus the aim of this study was to compare objectively the development of the gait pattern after cemented and cementless THR in dogs. For this purpose, 18 adult dogs with hip dysplasia underwent computer-based gait analysis on an instrumented treadmill prior to unilateral THR and then again ten days, four weeks and four months after surgery. Analysed kinetic parameters were symmetry indices (SI) of vertical ground reaction forces (GRF), which included peak vertical forces (PFz), mean vertical forces (MFz), vertical impulse (IFz), and vertical ground reaction forces of the arthroplasty limbs only. Analysed kinematic parameters were range-of-motion and the flexion and extension angles of hip, stifle and hock joints. The symmetry indice for PVF, MFz and IFz decreased to a value less than six in both THR groups four months after surgery, which is defined as not lame. Improvement in lameness of the arthroplasty limbs during the examination period of four months was not significantly different between the cemented and cementless groups. The results suggest that within a short-term observation period of four months after surgery, neither cementless nor cemented THR have a greater advantage with regard to lameness improvement. Additional studies with larger pools of subjects and longer time periods for follow-up examinations are necessary to verify these findings. PMID:22828804

  3. 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.

  4. Custom Cementless Stem Improves Hip Function in Young Patients at 15-year Followup

    PubMed Central

    Flecher, Xavier; Pearce, Oliver; Parratte, Sebastien; Aubaniac, Jean-Manuel

    2009-01-01

    THA in young patients is challenging regarding restoration and survival because patients are young, active, and tend to have disturbed anatomy. We asked whether a three-dimensional custom cementless stem could restore hip function, decrease osteolysis and wear, and enhance stem survival in young patients. We retrospectively reviewed 212 patients (233 hips) younger than 50 years (mean, 40 years) at a followup of 5 to 16 years (mean, 10 years). The Merle D’Aubigné-Postel and Harris hip scores improved at last followup. No thigh pain was recorded for any of the patients; 187 of the 212 patients (88%) had full activity recovery, 206 had full range of motion, and 151 had a score greater than 80 points for all five categories of the Hip disability and Osteoarthritis Outcome score. Five patients had femoral osteolysis not associated with pain. With revision for any reason as an end point, the survivorship was 87% (range, 77%–97%) at 15 years, and considering stem revision only, the survivorship was 93% (confidence interval, 90%–97%) at 15 years. Our data compare favorably with those from series using standard cementless stems at the same followup with a high percentage of patients achieving functional restoration and a low rate of complications. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:19690930

  5. 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. PMID:25392855

  6. 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.

  7. 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,...

  8. 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,...

  9. Fallon FORGE 3D Geologic Model

    DOE Data Explorer

    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

    DOE Data Explorer

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

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 22 Foreign Relations 1 2013-04-01 2013-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as...

  13. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 22 Foreign Relations 1 2012-04-01 2012-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles on the U.S. Munitions List include articles in a partially completed state (such as...

  14. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2012-04-01 2010-04-01 true Forgings, castings, and... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as...

  15. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2013-04-01 2013-04-01 false Forgings, castings, and... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as...

  16. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 3 2014-04-01 2014-04-01 false Forgings, castings, and... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles on the U.S. Munitions Import List include articles in a partially completed state (such as...

  17. 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

  18. 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

  19. 22 CFR 121.10 - Forgings, castings and machined bodies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 22 Foreign Relations 1 2011-04-01 2011-04-01 false Forgings, castings and machined bodies. 121.10... STATES MUNITIONS LIST Enumeration of Articles § 121.10 Forgings, castings and machined bodies. Articles..., castings, extrusions and machined bodies) which have reached a stage in manufacture where they are...

  20. 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

  1. Biomechanical Study on Distal Filling Effects in Cementless Total Hip Replacement

    NASA Astrophysics Data System (ADS)

    Chae, Soo-Won; Lee, Jun-Hyoung; Choi, Hyung-Yun

    In cementless total hip replacement, initial stability of the femoral component is important in the long term fixation of the femoral stem. Initial stability is closely related to the relative displacement between the prosthesis and the cancellous bone of the proximal femur. After implantation of the prosthesis, the surrounding bone is partially shielded from load carrying and starts to resorb. Stress shielding causes the loss of the proximal bone. The stress distribution of femur must be assessed to predict stress shielding. The initial stability and the stress shielding were investigated for two loading conditions approximating a single leg stance and stair climbing. Two types of stems involving a distal filling and a distal short stem were studied by the finite element method to investigate the biomechanical distal filling effects. The distal short stem produced less stress shielding at the proximal bone than the distal filling stem, while both types of stems seemed to satisfy the initial stability requirement.

  2. Second-Generation Versus First-Generation Cementless Tapered Wedge Femoral Stems.

    PubMed

    Pierce, Todd P; Jauregui, Julio J; Kapadia, Bhaveen H; Elmallah, Randa K; Cherian, Jeffrey J; Harwin, Steven F; Mont, Michael A

    2015-09-01

    Clinical outcomes of a new second-generation proximally coated, tapered wedge cementless stem were compared with those of its predecessor regarding (1) all-cause implant survivorship; (2) objective and subjective outcomes; (3) complications; and (4) radiographic features. Patients who underwent a primary total hip arthroplasty with the second-generation stem (68 hips) were compared with those who received the first-generation stem (136 hips) at a mean follow-up of 3.5 years. Although the first-generation stem was designed in the traditional manner, the second-generation stem was shortened to accommodate all surgical approaches and designed using a computed tomography scan-based database to enhance fit. The second-generation stem had survivorship, functional, and subjective outcomes similar to those of the first-generation stem. PMID:26375526

  3. Valgus subsidence of the tibial component in cementless Oxford unicompartmental knee replacement

    PubMed Central

    Liddle, A. D.; Pandit, H. G.; Jenkins, C.; Lobenhoffer, P.; Jackson, W. F. M.; Dodd, C. A. F.; Murray, D. W.

    2014-01-01

    The cementless Oxford unicompartmental knee replacement has been demonstrated to have superior fixation on radiographs and a similar early complication rate compared with the cemented version. However, a small number of cases have come to our attention where, after an apparently successful procedure, the tibial component subsides into a valgus position with an increased posterior slope, before becoming well-fixed. We present the clinical and radiological findings of these six patients and describe their natural history and the likely causes. Two underwent revision in the early post-operative period, and in four the implant stabilised and became well-fixed radiologically with a good functional outcome. This situation appears to be avoidable by minor modifications to the operative technique, and it appears that it can be treated conservatively in most patients. Cite this article: Bone Joint J 2014;96-B:345–9. PMID:24589789

  4. An analysis of screw fixation of the femoral component in cementless hip arthroplasty.

    PubMed

    Martin, J W; Sugiyama, H; Kaiser, A D; Van Hoech, J; Whiteside, L A

    1990-01-01

    A cementless hip stem that allows screw fixation of the collar to cortical bone in the calcar region was found to achieve enhanced rotational stability when implanted in preserved cadaveric human femora. Although the implants with screws showed less tendency for subsidence than the implants without screws, rotational micromotion was not found to be statistically different under light loading conditions. When implanted in composite bone, the addition of screws in the configuration tested was associated with significant metal-on-metal wear during combined compression and rotational cyclic loading. This finding is of concern due to potential wear particle toxicity and possible lowered fatigue life of the prosthesis. Therefore, specific design changes are recommended. PMID:2243211

  5. Does the ingrowth surface make a difference? A retrieval study of 423 cementless acetabular components.

    PubMed

    Swarts, Eric; Bucher, Thomas A; Phillips, Michael; Yap, Francis H X

    2015-04-01

    The effect of factors such as design, alloy and coating type on bony or fibrous tissue ingrowth was evaluated in a study of 423 retrieved cementless acetabular shells representing 16 shell designs. Small-beaded (250μm) porous coatings, either with or without hydroxyapatite (HA) coatings, proved to be the superior porous surface for bone ingrowth. Small-beaded shells that were Duofix coated had predominantly fibrous tissue ingrowth. In addition to bead size, alloy type and surface type have significant effect on bone ingrowth. In contrast, there is no significant association between bone ingrowth and time in situ, with most bone ingrowth occurring early. Although roughened, press-fit shells have acceptable clinical and Registry data, they showed some of the lowest ingrowth/ongrowth scores of all the shells tested. PMID:25515944

  6. Outcomes of Surgical Treatment of Periprosthetic Femoral Fractures in Cementless Hip Arthroplasty

    PubMed Central

    Kim, Min-Wook; Lee, Jung-Ho; Park, Ji-Hoon

    2015-01-01

    Purpose We aimed to evaluate the results of surgical treatment of periprosthetic femoral fractures in cementless total hip arthroplasty (THA). Materials and Methods From June 2002 to May 2012, 40 patients who could be followed-up for more than 1 year after surgery were enrolled in this study. The mean duration of follow-up was 28.5 months (range, 15-97 months) and the average age at the time of surgery was 71.5 years (range, 38-89 years). The fracture types were determined by using the Vancouver classification. Among intraoperative fractures, there were type A in 3 hips, type B2 in 2 hips and type B3 in one. Among postoperative fractures, type AG was present in 5 hips, type AL in 2 hips, type B1 in 15 hips, type B2 in 6 hips, type B3 in 3 hips, and type C in 3 hips. Evaluation of the results was based on bony union, stability of the prosthesis, postoperative complications, and Harris hip score at the final follow-up. Results Bony union was achieved in all but one case and the average time for bony union was 21 weeks. The mean Harris hip score was 86 at the final follow-up. Clinical results were above good in 34 of 40 hips (85.0%). Stem loosening occurred in one patient with a type B1 fracture treated with open reduction and plate fixation. Nonunion was observed in 1 patient with an AG type fracture. Conclusion Open reduction and fixation using a plate with a screw and cerclage wiring provided good results for periprosthetic fractures in patients who had a stable femoral stem without bone defects. Revision surgery with a cementless long stem should be considered in patients with an unstable stem or suspected stability in B1 type of THA using a proximal fixation type. PMID:27536618

  7. [Cementless total hip arthroplasty--results of 8-year follow-up study].

    PubMed

    Wall, Andrzej; Dragan, Szymon

    2006-01-01

    The subjects of the clinical examinations were 382 patients who from 1994 to 1999 were treated with the method of total cementless arthroplasty. The observation time ranged from 3 to 8 years. In the examined group the secondary cause of degenerative changes was identified in 210 (55%) patients. In the remaining 172 cases (45%) the primary cause of degenerative changes in the hip was diagnosed. Four types of cementless endoprostheses, varied in their construction, structure of their surfaces and material they were made of, were used to carry out the postoperative treatment of the degenerative changes in the hip: Antega, Zweymüller SL PLUS (Endoprosthetic) or Alloclasic type of stem, GSS-CL and PM-Plasmapore. The findings of the clinical investigation made it possible to determine the probability of surviving of an endoprosthesis up to the 8th year after an operation depending on a type of implanted stem, which according to Kaplan-Meier's method, amounted to 0.9603. The results of Harris scale evaluation of the function of the operated joints demonstrated the existence of the relationship between the function and the course of bone osteointegration and growth process. The detailed analysis of the X-ray examinations, and especially of the roentgenometric ones, taking into account stability of the endoprosthesis stem enabled to distinguish two stages of the clinical and roentgenological changes: the early stage (up to 6 months after an operation) characterised by settling and micromotions of the stem and the late stage (starting 6-9 months after an operation) with slowly gradual increasing of the function and holding back of stem settling. PMID:17017478

  8. Primary Cementless Hip Arthroplasty in Unstable Intertrochanteric Femur Fracture in Elderlys: Short-term Results

    PubMed Central

    Cho, Hyung Lae; Cho, Hong

    2014-01-01

    Purpose This study was aimed to explore and report the short term results of primary cementless hip arthroplasty in treatment of unstable intertrochanteric femur fracture in elderlys. Materials and Methods Between March 2009 and Feburary 2012, 35 arthroplasty cases performed by single surgeon and followed up for more than one year were evaluated. They were 21 females and 14 males with mean age of 78 years (range, 71-92 years). Preoperative evaluation was performed by American Society of Anesthesia score. Retrospective evaluation was performed by operative time, transfusion amount, time to operation days, hospital stay and time to full weight bearing. Clinically, ambulatory ability was checked by Parker and Palmer (P&P) score and function of hip was appraised by Harris hip score (HSS). Radiologically, bone healing of fractured trochanteric fragment and presence of subsidence, stress shielding or osteolysis were checked. Results Fracture type was 11 cases of A2.2, 18 cases of A2.3 and 6 cases of A3.3. Femoral stems used were 8 cases of rectangular tapered wedge type and 27 cases of fluted modular distal fixation type. P&P score improved from mean preinjury score of 7.1 to mean postoperative last follow-up score of 6.5. Median HHS at last follow-up was 75. Mean time to full weight bearing was 47 days (24-79 days). Postoperative complications were one case of linear periprosthetic femoral fracture and one case of postoperative dislocation. Conclusion Cementless hip replacement arthroplasty could be a good option for unstable intertrochanteric femoral fracture in elderlys.

  9. Analysis of cementless implants using interface nonlinear friction--experimental and finite element studies.

    PubMed

    Dammak, M; Shirazi-Adl, A; Zukor, D J

    1997-02-01

    Measured interface nonlinear friction properties are used to develop models to study the short-term fixation response of smooth- and porous-surfaced posts, bone screws, and plates fixed with and without posts/screws. Experimental studies are carried out to validate the model predictions and identify the relative role of posts and screws in fixation of a plate on a polyurethane block under symmetric/eccentric axial compression loads. The idealized Coulomb's friction is also used for the sake of comparison. The incorporation of measured nonlinear, rather than the idealized Coulomb, friction is essential to compute realistic results. For plate fixation, the experimental and finite element results show that the screw fixation yields the stiffest response followed by the smooth- and then porous-coated post fixation. For example, under 1000 N eccentric axial compression, the edge of the plate opposite the loaded edge is measured to lift by 1147 +/- 72, 244 +/- 38, or 112 +/- 28 microns, respectively, for the cases with no fixation, with smooth-surfaced posts, or with screws. The corresponding models predict, respectively, values of 1538, 347, or 259 microns and also 556 microns for the plate fixed with porous coated posts. The satisfactory agreement between numerical and experimental results confirms the importance of proper interface modelling for the analysis of posts, screws, and complex fixation systems. This becomes further evident when considering cementless implants in which the bone-implant interface exhibits relatively large displacements as the maximum resistance force is reached. The developed models can be used to investigate the post-operative short-term stability of various cementless implant designs. PMID:9001932

  10. Clinical results of cementless total hip arthroplasty with shortening osteotomy for high dislocation with developmental dysplasia.

    PubMed

    Desteli, Engin Eren; Imren, Yunus; Tan, Erkan; Erdoğan, Murat; Özcan, Hüseyin

    2015-03-01

    Total hip arthroplasty for severe developmental dysplasia of the hip is a technically challenging procedure. Subtrochanteric femoral osteotomy enables reducing the femoral head and restoring abductor muscle strength without compromising proximal femoral bone stock in advanced dysplasia.We aimed to retrospectively evaluate Crowe type III or IV developmental dysplasia of the hip who underwent reconstruction with cementless total hip arthroplasty combined with a transverse subtrochanteric femoral osteotomy. Sixty hips of 52 patients (11 male, 49 female) with Crowe type III (n: 37) or IV (n: 23) developmental dysplasia of the hip were included. The average age was 51.4 years. Surgery was performed in lateral decubitis position with posterolateral approach. Subtrochanteric transverse femoral osteotomy were used with cementless components. 40 of the femoral components were Secur-Fit type, and 20 of them were secur-fit plus max type. Ceramic-ceramic coupling was used in 24 cases and metal-polyethylene coupling was used in 36 cases. Merle D'Aubigne and Harris Hip score were used to rate the clinical outcome at the final follow up. All femoral shortening osteotomies were united at a mean of 5.7 months. Mean Merle D'Aubigne pain score was increased from 3.1 to 5.4, and mean Harris Hip score improved from 39 to 92.8, postoperatively (p<0.01). There was no significant difference in time to union between different types of stems. 4 femoral stems had asymptomatic radiolucent lines. There was no significant difference in time to union between different types of stems. PMID:26280851

  11. Cementless porous-coated total knee arthroplasty: 10-year results in a consecutive series.

    PubMed

    Schrøder, H M; Berthelsen, A; Hassani, G; Hansen, E B; Solgaard, S

    2001-08-01

    We report the results of 114 AGC 2000 porous-coated, cementless total knee arthroplasties (TKA) performed consecutively in 102 patients during the period 1984-1986. After 10 years, 58 TKAs in 52 patients were evaluated with patient assessment, Hospital for Special Surgery knee score, weight-bearing radiographs done under fluoroscopic control, and survivorship analysis. All dropouts within the first 9 years were patients dying with a functioning TKA except 1 revision secondary to a supracondylar fracture after 8.5 years. Of the patients, 53 (92%) were satisfied or very satisfied with their TKA, and 55 (95%) of the knees were rated good or excellent. There was no pain in 53 knees, and the median knee flexion was 110 degrees. Six radiolucencies >1 mm were found beneath parts of the tibial component, and 5 radiolucencies were seen beneath the femoral component. None had progressed compared with the 5-year follow-up, and in all cases trabeculae could be seen reaching the prosthetic component. No migrations had occurred since the 5-year follow-up. No obvious joint space reduction was seen. Osteolysis presenting as an isolated cyst was found in 1 knee in the lateral tibial condyle and was not progressive. Two tibial components had been revised because of aseptic loosening and 1 because of septic loosening, all within the first 3 years. No femoral or patellar components were revised. The cumulative prosthesis survival rate after 10 to 11 years was 97%. When pain and radiographic loosening also were considered, the success rate was 87%. Cementless insertion of a nonmodular, porous-coated TKA resulted in a long-term durable bone-prosthesis interface. The flat-on-flat articulation did not result in catastrophic polyethylene wear or osteolysis within the first 10 years. PMID:11503114

  12. Prospective study of the cementless "New Wave" total knee mobile-bearing arthroplasty: 8-year follow-up.

    PubMed

    Normand, Xavier; Pinçon, Jean-Louis; Ragot, Jean-Marie; Verdier, Régis; Aslanian, Thierry

    2015-02-01

    One of the main factors affecting the survival of a total knee arthroplasty (TKA) is the fixation method. The constraints placed on the bone-implant interface of a mobile-bearing TKA must be taken in account during the design and evaluation phases. For more than two decades, calcium phosphate ceramics, particularly hydroxyapatitis, have been used in Europe to accelerate the bone integration of cementless implants. A prospective study of patients continuously recruited by three senior surgeons at three French private hospitals has been carried out. There were no exclusion criteria. Eighty-four (84) cementless mobile-bearing total knee prosthesis of the brand "New Wave" were implanted in 74 patients over a 2-year period (2004-2005). Implant survival at 8 years was 95% [with a confidence interval of 95%: 80.2-96.4%] when revision for any cause was defined as the endpoint. Five implants required surgical revision to exchange all or part of the implant: two for aseptic loosening of tibial component, one for osteolysis, one for persistent flessum (30°) and one for tibial periprosthetic fracture. Completely integrated implants and event-free outcomes were recorded in 91.4% of the cases at eight-year follow-up. The Hospital for Special Surgery score significantly improved from 56.8/100 points before the surgery to 83.9/100 points at the last follow-up (p < 0.05). Radiologically, only one patient had radiolucent lines around the tibial and femoral components. This cementless total knee prosthesis yielded good medium-term survival. Cementless arthroplasty can generate solid and durable bone fixation in this total weight-bearing implant, and it seems that the hidroxyapathitis surface in this series stimulate the bone integration at the bone-implant interface. PMID:24858380

  13. Bipolar Hemarthroplasty Using Cementless Conical Stem for Treatment of Dorr Type B and C Femoral Neck Fracture

    PubMed Central

    Kang, Jeong Hoon; Jung, Sung

    2015-01-01

    Purpose The current study aims to evaluate the clinical and the radiological outcome of bipolar hemiarthroplasty using cementless cone stem to treat osteoporotic femoral neck fracture and compare the results according to the proximal femur geometry. Materials and Methods Seventy-five hips (75 patients) that underwent bipolar hemiarthroplasty with cementless cone stem between September 2006 and December 2011 were analyzed. The minimum follow-up period was 3 years. Thirty-three hips were classified as type B and 41 as type C. The clinical outcome was assessed using Harris hip score and the walking ability score. Radiographic evaluation was performed to evaluate the stability of the prosthesis. Results At the most recent follow up, the mean Harris hip score was 86 (range, 70-92) and 65% recovered to preoperative ambulatory status. In the radiographic exam, stable stem fixation was achieved in all cases. For the complications, eight hips developed deep vein thrombosis while three hips showed heterotopic ossification. Dislocation and delayed deep infection occurred in one hip resepectively. There were no significance differences in Harris hip score and walking ability score when the type B group was compare with the type C. Conclusion Bipolar hemiarthroplasty with cementless cone stem showed an excellent early outcome both clinically and radiographically regardless of the shape of the proximal femur. We believe this prosthesis can provide early stability to the Dorr type B and C femur and is an effective treatment for treating osteoporotic femoral neck fracture. PMID:27536631

  14. Total hip arthroplasty in patients with avascular necrosis of the hip. Follow-up observations on cementless and cemented operations.

    PubMed

    Katz, R L; Bourne, R B; Rorabeck, C H; McGee, H

    1992-08-01

    Thirty-one patients with avascular necrosis of the hip were treated by 34 total hip arthroplasties (THAs). All patients were observed prospectively with a minimum two-year follow-up evaluation (average, 46 months; range, 24-84 months). Twenty had cemented arthroplasties using contemporary cementing techniques. This included insertion of a medullary plug, cleansing of the canal with a medullary brush, pulsatile lavage irrigation, and insertion of the cement with a cement gun. In 14 hips, a cementless prosthesis was used. Patients were rated using a modified Harris hip score. Sequential postoperative roentgenograms were analyzed in each patient. The overall Harris hip score ratings were 88 in the cemented and 84 in the noncemented groups. Mechanical failure with loosening of the femoral component occurred in one patient who developed deep sepsis. Significant thigh pain occurred in four patients in the noncemented group. Previous studies in the literature have generally reported unfavorable results in patients with avascular necrosis of the hip treated with THA. Using cementless and cemented fixation with contemporary cementing techniques, improved results can be expected. A high incidence of thigh pain (29%) in the cementless group remains a problem. PMID:1499201

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

    PubMed

    Zilkens, C; Djalali, S; Bittersohl, B; Kälicke, T; Kraft, C N; Krauspe, R; Jäger, Marcus

    2011-03-28

    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

  16. A technique to remove a well-fixed titanium-coated rm acetabular cup in revision hip arthroplasty

    PubMed Central

    2011-01-01

    A major concern during revision hip arthroplasty is acetabular bone loss and bleeding during the extraction of well-fixed cementless acetabular cup, because no interface exists between the host bone and the cup. Forceful removal of such component using curved gouges and osteotomes often leads to extended bone loss and compromises reimplantation of a new socket. In the following case report, we removed a well-fixed polyethylene titanium-coated RM acetabular cup with 20 years of follow-up, by significant wear of the polyethylene layer. The isoelastic femoral stem was also removed by mechanical failure. We report a technique for removal of the cementless acetabular cup using powered acetabular reamers. The RM cup was sequentially reamed and when the polyethylene layer was thin enough, the remaining cup was removed easily by hand tools. The acetabular bone stock is preserved and the risks of bone fractures and bleeding are minimized. To our knowledge, these principles were applied only in cemented cups. We have used this technique in 10 cases with excellent results and no complications were noted. This is a simple, reproducible, non-costly, non-timing consuming, safe and successful technique to remove well-fixed titanium-coated RM acetabular cups. PMID:21689456

  17. Factors Affecting Scale Adhesion on Steel Forgings

    NASA Astrophysics Data System (ADS)

    Zitterman, J. A.; Bacco, R. P.; Boggs, W. E.

    1982-04-01

    Occasionally, undesirable "sticky" adherent scale forms on low-carbon steel during reheating for hot forging. The mechanical abrading or chemical pickling required to remove this scale adds appreciably to the fabrication cost. Characterization of the steel-scale system by metallographic examination, x-ray diffraction, and electron-probe microanalysis revealed that nickel, silicon, and/or sulfur might be involved in the mechanism of sticky-scale formation. Laboratory reheating tests were conducted on steels with varied concentrations of nickel and silicon in atmospheres simulating those resulting from burning natural gas or sulfur-bearing fuels. Subsequent characterization of the scale formed during the tests tends to confirm that the composition of the steel, especially increased nickel and silicon contents, and the presence of the sulfur in the furnace atmosphere cause the formation of this undesirable scale.

  18. 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.

  19. Grain size modeling and optimization of rotary forged Alloy 718

    SciTech Connect

    Domblesky, J.P.; Shivpuri, R.

    1997-04-01

    The study presented describes the simulation procedure and methodology used to develop two models for predicting recrystallized grain size in Alloy 718 billet. To simulate multiple pass forging of billet, controlled, high temperature compression testing was used to apply alternate deformation and dwell cycles to Alloy 718 specimens. Grain size obtained by simulation was found to be in excellent agreement with grain size from forged billet when cooling rate was included. The study also revealed that strain per pass and forging temperature were the predominant factors in controlling the recrystallized grain size. Both models were found to accurately predict the recrystallized grain size obtained by compression tests performed at super-solvus temperatures.

  20. To Cement or Not? Two-Year Results of a Prospective, Randomized Study Comparing Cemented Vs. Cementless Total Knee Arthroplasty (TKA).

    PubMed

    Fricka, Kevin B; Sritulanondha, Supatra; McAsey, Craig J

    2015-09-01

    The optimal mode of fixation in total knee arthroplasty (TKA) is a subject of debate. We enrolled 100 TKA patients randomized to cemented or cementless fixation. Knee Society Scores (KSS), Oxford scores and pain visual analog scales (VAS) were collected pre-operatively and post-operatively. Two-year follow-up was obtained for 93 patients. The mean VAS trended higher for the cementless group at 4 months (P=0.06). At 2 years, the KSS functional scores, Oxford scores, and self-reported questions for satisfaction, less pain and better function were similar but the cemented group had higher KSS clinical scores (96.4 vs. 92.3, P=0.03). More radiolucencies were seen in cementless knees (P<0.001). The cementless group had one revision for instability and one cemented knee was revised for infection. Cementless TKA showed equivalent survivorship (revision for any reason as the endpoint) compared to cemented TKA at this early follow-up. Close monitoring of radiolucencies is important with continued follow-up. PMID:26118567

  1. 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.

  2. 3D finite element simulation of microstructure evolution in blade forging of Ti-6Al-4V alloy based on the internal state variable models

    NASA Astrophysics Data System (ADS)

    Luo, Jiao; Wu, Bin; Li, Miao-Quan

    2012-02-01

    The physically-based internal state variable (ISV) models were used to describe the changes of dislocation density, grain size, and flow stress in the high temperature deformation of titanium alloys in this study. The constants of the present models could be identified based on experimental results, which were conducted at deformation temperatures ranging from 1093 K to 1303 K, height reductions ranging from 20% to 60%, and the strain rates of 0.001, 0.01, 0.1, 1.0, and 10.0 s-1. The physically-based internal state variable models were implemented into the commercial finite element (FE) code. Then, a three-dimensional (3D) FE simulation system coupling of deformation, heat transfer, and microstructure evolution was developed for the blade forging of Ti-6Al-4V alloy. FE analysis was carried out to simulate the microstructure evolution in the blade forging of Ti-6Al-4V alloy. Finally, the blade forging tests of Ti-6Al-4V alloy were performed to validate the results of FE simulation. According to the tensile tests, it is seen that the mechanical properties, such as tensile strength and elongation, satisfy the application requirements well. The maximum and minimum differences between the calculated and experimental grain size of primary α phase are 11.71% and 4.23%, respectively. Thus, the industrial trials show a good agreement with FE simulation of blade forging.

  3. Modeling microstructural development during the forging of Waspaloy

    NASA Astrophysics Data System (ADS)

    Shen, Gangshu; Semiatin, S. L.; Shivpuri, Rajiv

    1995-07-01

    A model for predicting the evolution of microstructure in Waspaloy during thermomechanical proc-essing 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. FOUNDRY SHOP, FORGE SHOP, NORTH ARMORY, EAST ARMORY. Colt ...

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

    FOUNDRY SHOP, FORGE SHOP, NORTH ARMORY, EAST ARMORY. - Colt Fire Arms Company, East Armory Building, 36-150 Huyshope Avenue, 17-170 Van Dyke Avenue, 49 Vredendale Avenue, Hartford, Hartford County, CT

  9. 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

  10. Etiology of osteolysis around porous-coated cementless total hip arthroplasties.

    PubMed

    Jasty, M; Bragdon, C; Jiranek, W; Chandler, H; Maloney, W; Harris, W H

    1994-11-01

    The prosthetic components and tissues retrieved from 12 hips with osteolysis in association with well-fixed cementless porous-coated total hip prostheses (5 Porous Coated Anatomic, 6 Harris-Galante Porous, and 1 Omniflex) were examined using a variety specific techniques including electron microscopy, standard histology, immunohistochemistry, and particle identification. The patients were young and active. Extensive osteolysis developed in all 12 femurs and 3 acetabula between 36 and 84 months after arthroplasty (mean, 63 months). All of the polyethylene liners were noted to be worn substantially (mean volumetric wear, 1140 +/- 810 mm3). The wear was unrelated to the head diameter in this small number of cases. In all 12 cases, the articulating surfaces were wear polished and contained numerous fine multidirectional scratches, suggesting 3-body abrasive wear mechanisms in addition to adhesive wear liberating very small (micron to submicron) wear particles. In 4 cases, surface delamination and flaking of polyethylene were also found, suggesting fatigue wear liberating larger wear particles. Nine of 10 cobalt alloy heads showed numerous fine scratches with sharp edges presumably from 3-body abrasive wear. Corrosion and fretting at the femoral head-neck junction in 5 cases, burnishing of the femoral stem against bone in 4 cases, and metal staining of tissues opposite the porous coatings in 7 cases provided evidence for the liberation of fine metal particles from outside the articulation. Histologic and immunohistochemical studies of tissue in the regions of osteolysis in all cases showed numerous focal aggregates of KP1 antibody positive activated macrophages containing large amounts of submicron intracellular particles of polyethylene (presumably related to the 3-body abrasive wear polishing) and giant cells within a fibrous stroma. In 5 cases, some of the macrophages also contained submicron metal particles but smaller in numbers. T lymphocytes, plasma cells, and

  11. 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. PMID:27387718

  12. [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. PMID:1859861

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. Forging the future: the public health imperative.

    PubMed Central

    Allukian, M

    1993-01-01

    During the 1980s, national policy promoted military expenditures and downsized domestic programs. These priorities, along with tax reform and deregulation, created a "domestic gulf crisis" with a new wave of vulnerable populations--poor children, the homeless, the elderly, and the uninsured. Our lack of a national health program compounds the problem. The 1990s will be a decade of change and challenge. To forge a healthier and stronger future for our nation, we must implement five public health imperatives: (1) We must have a national health program that is universal, comprehensive, and prevention-oriented, with built-in assurances for quality, efficiency, and a strong public health infrastructure. (2) We must have a comprehensive national health education and promotion program for all schoolchildren. (3) Women must have freedom of choice. (4) Prevention and public health must become one of our country's highest health priorities. (5) The federal government must increase its leadership, commitments, and resources to reach the goals set forth in Healthy Communities 2000 and Healthy People 2000. PMID:8484444

  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. PMID:22300407

  19. Mid-term Results of Revision Total Hip Arthroplasty Using Modular Cementless Femoral Stems

    PubMed Central

    Jang, Hyung-Gyu; Min, Byung-Woo; Ye, Hee-Uk; Lim, Kyung-Hwan

    2015-01-01

    Purpose The purpose of this study was to evaluate the clinical and radiological results of revision total hip arthroplasty using modular distal fixation stems for proximal femoral deficiency. Materials and Methods Forty-five patients (47 hips) were analyzed more than 24 months after revision total hip arthroplasty that used modular distal fixation stems and was performed between 2006 and 2012. There were proximal femoral defects in all cases. Preoperative femoral defect classification revealed Paprosky type II in 31 cases, type IIIA in 7, and type IIIB in 9. The mean duration of follow-up was 53.4 (25-100) months. We evaluated the Harris hip score (HHS), walking ability according to Koval as clinical parameters, stem stability, and stem position change as radiographic parameters. Kaplan-Meier survival analysis was performed. Results The average HHS improved form 39.5 points to 91.3 points and walking ability also improved in most cases; all patients had stable fixation of the femoral stem. Postoperative complications included 5 cases of infection and 2 cases of dislocation. The survival rate with the end point of re-revision surgery due to infection or dislocation was 86% after 8-year follow-up. Conclusion Cementless revision total hip arthroplasty using modular femoral stems is useful because the stems can be stably fixed on the diaphyseal portion of the femur, which has relatively good bone quality at mid-term follow-up. PMID:27536616

  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. PMID:24404766

  1. Mid-term results of Copeland shoulder cementless surface replacement arthroplasty from an independent centre

    PubMed Central

    Modi, Chetan S; Drew, Stephen J; Turner, Stephen M

    2014-01-01

    Background The present study reports our experience of Copeland shoulder cementless surface replacement arthroplasty (CSRA) and whether glenoid microfracture influences the progression of glenoid erosion. Methods One-hundred-and-twelve CSRAs were performed in 101 patients between 2002 and 2007. Eighty-three patients were alive at the median follow-up time of 72 months (range 9 to 121 months; interquartile range 46 to 93 months). Assessment included an Oxford shoulder score (OSS), patient satisfaction score and plain radiographs. Results The mean (range) OSS was 27 (7 to 48) and 64 of 73 (87.7%) patients were ‘very satisfied’ or ‘satisfied’ with their shoulder. Twenty-three (20.5%) shoulders had over 2 mm of glenoid erosion. Microfracture was performed in 43 of 112 shoulders (38.4%) and did not influence the progression of glenoid erosion. Further surgery was performed in 27 (24.1%) shoulders, including 15 revisions, eight arthrolyses and four subacromial decompressions. Revision to total shoulder arthroplasty was performed in 14 : 10 for glenoid erosion; one each for loosening, periprosthetic fracture, deep infection, and chronic pain. One was revised to reverse arthroplasty for chronic pain. Conclusions CSRA performed in an independent centre reproduces the functional outcomes reported by the designer. Glenoid erosion, however, was a common occurrence and the main cause of revision – microfracture did not influence its progression.

  2. Primary stability recognition of the newly designed cementless femoral stem using digital signal processing.

    PubMed

    Baharuddin, Mohd Yusof; Salleh, Sh-Hussain; Hamedi, Mahyar; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Mohd Noor, Alias; Harris, Arief Ruhullah A; Abdul Majid, Norazman

    2014-01-01

    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing. PMID:24800230

  3. Cementless total knee arthroplasty with Profix: a 8- to 10-year follow-up study.

    PubMed

    Hardeman, François; Vandenneucker, Hilde; Van Lauwe, Johan; Bellemans, Johan

    2006-12-01

    A consecutive series of 115 cementless Profix (Smith and Nephew, Memphis, USA) Total Knee Arthroplasties performed in 113 patients were followed in order to determine the functional results and survivorship at 8 to 10 years. All patients were included in a prospective database and were reviewed annually until final follow-up. Patients overall satisfaction was excellent or good in 91.3% of cases. The mean Knee Society's knee and function scores increased respectively from 49.3 and 36.7 preoperatively to 93.1 and 82.2 postoperatively. The Kaplan-Meier estimate of implant survival at 10 years was 97.1%. Two patients underwent revision and were considered as failures. One patient had a fracture of the medial condyle at 4 days post-surgery, and the other was revised for aseptic loosening of the tibial component at 6 years post-surgery. On the basis of this long-term follow-up study, we can conclude that the Profix Total Knee System is effective and safe. PMID:17064905

  4. Primary Stability Recognition of the Newly Designed Cementless Femoral Stem Using Digital Signal Processing

    PubMed Central

    Salleh, Sh-Hussain; Hamedi, Mahyar; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Mohd Noor, Alias; Harris, Arief Ruhullah A.; Abdul Majid, Norazman

    2014-01-01

    Stress shielding and micromotion are two major issues which determine the success of newly designed cementless femoral stems. The correlation of experimental validation with finite element analysis (FEA) is commonly used to evaluate the stress distribution and fixation stability of the stem within the femoral canal. This paper focused on the applications of feature extraction and pattern recognition using support vector machine (SVM) to determine the primary stability of the implant. We measured strain with triaxial rosette at the metaphyseal region and micromotion with linear variable direct transducer proximally and distally using composite femora. The root mean squares technique is used to feed the classifier which provides maximum likelihood estimation of amplitude, and radial basis function is used as the kernel parameter which mapped the datasets into separable hyperplanes. The results showed 100% pattern recognition accuracy using SVM for both strain and micromotion. This indicates that DSP could be applied in determining the femoral stem primary stability with high pattern recognition accuracy in biomechanical testing. PMID:24800230

  5. 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

  6. Ex vivo estimation of cementless acetabular cup stability using an impact hammer.

    PubMed

    Michel, Adrien; Bosc, Romain; Sailhan, Frédéric; Vayron, Romain; Haiat, Guillaume

    2016-02-01

    Obtaining primary stability of acetabular cup (AC) implants is one of the main objectives of press-fit procedures used for cementless hip arthroplasty. The aim of this study is to investigate whether the AC implant primary stability can be evaluated using the signals obtained with an impact hammer. A hammer equipped with a force sensor was used to impact the AC implant in 20 bovine bone samples. For each sample, different stability conditions were obtained by changing the cavity diameter. For each configuration, the inserted AC implant was impacted four times with a maximum force comprised between 2500 and 4500 N. An indicator I was determined based on the partial impulse estimation and the pull-out force was measured. The implant stability and the value of the indicator I reached a maximum value for an interference fit equal to 1 mm for 18 out of 20 samples. When pooling all samples and all configurations, the implant stability and I were significantly correlated (R(2) = 0.83). The AC implant primary stability can be assessed through the analysis of the impact force signals obtained using an impact hammer. Based on these ex vivo results, a medical device could be developed to provide a decision support system to the orthopedic surgeons. PMID:26671784

  7. The effect of stem fit on bone hypertrophy and pain relief in cementless total hip arthroplasty.

    PubMed

    Whiteside, L A

    1989-10-01

    This study was designed to clinically evaluate the effects of a tight distal fit and collar seating in hips with a cylindrical distal stem, collar, and proximal porous coating. A clinical assessment of pain and a roentgenographic assessment of patterns of proximal femoral hypertrophy were made in 105 patients. Intraoperative evaluations of the distal stem fit were performed so that a tight distal fit was ensured in 67 patients. Thirty-eight patients who did not have intraoperative sizing were determined roentgenographically to have a loose distal fit. Pain was significantly more likely to occur in those patients with a loose distal fit (20 of 38) than in those with a tight distal fit (two of 67). Collar seating was associated with hypertrophy under the seated portion of the collar in all cases, and failure to seat the collar was associated with recession and rounding of the upper femoral cortical edge. Distal hypertrophy occurred in 24 of the 67 hips with a tight distal fit, and a tight distal fit did not prevent proximal hypertrophy. It was concluded that a tight distal fit is associated with more complete pain relief in cementless total hip arthroplasty and that a tight distal fit of a cylindrical stem does not prevent proximal load bearing. PMID:2791383

  8. Advanced rotor forgings for high-temperature steam turbines. Volume 1. Ingot and forging production. Final report

    SciTech Connect

    Swaminathan, V.P.; Steiner, J.E.; Mitchell, A.

    1986-05-01

    Three advanced steel-melting processes - low-sulfur vacuum silicon deoxidation, electroslag remelting, and vacuum carbon deoxidation (VCD) - were applied to produce three CrMoV (ASTM A470, Class 8) steel forgings for steam turbine application. Ingots weighing about 100 t each were produced using these three processes, and rotors were forged with final weights of about 30 t each. Compared to the conventionally produced forgings, the advanced technology forgings show better tensile ductility and better uniformity along the radial and longitudinal directions. Charpy upper-shelf energy shows about 40% improvement, and no temper embrittlement was found using step-cooled and isothermal-aging treatments. Significant improvement in fracture toughness (K/sub IC/ and J/sub IC/) is realized for these forgings. Low-cycle fatigue life is better at high temperatures because of the absence of nonmetallic inclusions. Creep strength shows slight improvement. However, creep ductility is improved, probably because of low residual elements. The VCD forgings show excellent creep ductility, even with long lives. Both the toughness and creep properties are equal to or better than those of oil-quenched rotors produced by European practices. These improvements are attributed to cleaner steel, better control of ingot solidification, low residual elements (especially very low sulfur content), and the associated reduction of nonmetallic inclusions. These three rotors have been placed in service in three operating power plants in units rated at 520 MW each. Volume 1 of this report covers ingot and forging production, and volume 2 covers mechanical property evaluation.

  9. Opportunities in the electrowinning of molten titanium from titanium dioxide

    NASA Astrophysics Data System (ADS)

    van Vuuren, D. S.; Engelbrecht, A. D.; Hadley, T. D.

    2005-10-01

    The value chain of titanium products shows that the difference between the cost of titanium ingot and titanium dioxide is about 9/kg titanium. In contrast, the price of aluminum, which is produced in a similar way, is only about 1.7/kg. Electrowinning of molten titanium from titanium dioxide is therefore believed to have significant potential to reduce the cost of titanium products. The process is hampered by the high operating temperatures and sophisticated materials of construction required; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium.

  10. 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.

  11. Inter-subject variability effects on the primary stability of a short cementless femoral stem.

    PubMed

    Bah, Mamadou T; Shi, Junfen; Heller, Markus O; Suchier, Yanneck; Lefebvre, Fabien; Young, Philippe; King, Leonard; Dunlop, Doug G; Boettcher, Mick; Draper, Edward; Browne, Martin

    2015-04-13

    This paper is concerned with the primary stability of the Furlong Evolution(®) cementless short stem across a spectrum of patient morphology. A computational tool is developed that automatically selects and positions the most suitable stem from an implant system made of a total of 48 collarless stems to best match a 3D model based on a library of CT femur scans (75 males and 34 females). Finite Element contact models of reconstructed hips, subjected to physiologically-based boundary constraints and peak loads of walking mode, were simulated using a coefficient of friction of 0.4 and an interference-fit of 50 μm. Maximum and average implant micromotions across the subpopulation were predicted to be 100±7 μm and 7±5 μm with ranges [15 μm, 350 μm] and [1 μm, 25 μm], respectively. The computed percentage of implant area with micromotions greater than reported critical values of 50 μm, 100 μm and 150 μm never exceeded 14%, 8% and 7%, respectively. To explore the possible correlations between anatomy and implant performance, response surface models for micromotion metrics were constructed. Detailed morphological analyses were conducted and a clear nonlinear decreasing trend was observed between implant average micromotion and both the metaphyseal canal flare indices and average densities in Gruen zones. The present study demonstrates that the primary stability and tolerance of the short stem to variability in patient anatomy were high, reducing the need for patient stratification. In addition, the developed tool could be utilised to support implant design and planning of femoral reconstructive surgery. PMID:25724937

  12. 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

  13. Outcome of the cementless Taperloc stem: a comprehensive literature review including arthroplasty register data

    PubMed Central

    2011-01-01

    Background and purpose The validity of various data sources for the assessment of the outcome quality of medical devices was investigated by comparative analysis of the published data sources available for a sample of implants. It was the aim of the study to determine the performance of this implant and to identify potential bias factors inherent to the various datasets. Methods A comprehensive literature search was carried out from English-language, peer-reviewed journals and worldwide reports from national arthroplasty registers. Publications from Medline-listed journals were included. The main parameter was revision rate, calculated as “revisions per 100 observed component years” to allow adjusted direct comparison of different datasets. Results Of 16 clinical studies that met the inclusion criteria, 9 originated from the implant developer's hospital. In the clinical studies category, publications from the developer's hospital suggested considerably lower revision rates than the other datasets. In fact, the values quoted were 5.5 times below the average of all other studies, and 9.51 times lower than in the Australian arthroplasty register. These differences are statistically significant. Interpretation The cementless Taperloc stem is an implant that shows good performance regarding revision rates in registry data and in clinical studies. However, the excellent results published by the developer's clinic are generally not reproducible by other surgeons. In terms of reference data, registry data are able to make an important contribution to the assessment of clinical sample-based studies, particularly regarding evaluation of the extent to which published results are reproducible in daily routine. PMID:21463220

  14. The effect of deformation rate on JBK-75 stainless steel forgings

    SciTech Connect

    Odegard, B.C.

    1987-10-01

    A parametric study was conducted to evaluate the effect of forging rate and forging temperature on the strength and microstructure of a precipitation-hardened, austenitic stainless steel forging. High and low forging rates were achieved using a high energy rate forging (HERF) process and a low velocity mechanical press (MP) respectively. The forging geometry required a two-stage forging sequence. The first stage or preform was identical for both forging processes. The final stage used similar die geometries with minor modifications to accommodate the attachment to the respective hammers. The resulting microstructure and mechanical properties were significantly different. These differences are attributed to the effects of strain rate and temperature. 10 figs., 1 tab.

  15. Looking west inside of the machine/forge shop at chargin door ...

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

    Looking west inside of the machine/forge shop at chargin door of the forging furnace. - U.S. Steel Edgar Thomson Works, Auxiliary Buildings & Shops, Along Monongahela River, Braddock, Allegheny County, PA

  16. Loosening pattern in a cementless custom-made hip stem: X-ray analysis, finite-elements and photoelasticity measurements.

    PubMed

    Plath, J; Schuhr, T; Fethke, K; Zacharias, T; Johnson, M; Mach, J

    2000-01-01

    Thirty-three X-press cementless stems (Depuy) manufactured according to standardized X-rays were inserted from 1992 to 1994. The patients' mean age was 49 (range 15-79) years with a mean follow-up of 32 (+/-6) months. A characteristic radiographic pattern of aseptic loosening with erosion of the medial cortex by the tip of the stem occurred in 28 patients and a valgus shift of the implant in 14 cases. A radiolucent line with increased sclerosis below the tip (zone Gruen 4) was observed in 17 cases. Four stems were revised due to histologically confirmed aseptic loosening. Biomechanical investigation of one of the revised stems with the typical pattern of valgus angulation and medial cortex erosion included photoelasticity and finite-element analysis. The intertrochanteric fit and fill obviously resulted in an unfavorable distribution of contact areas, including peaks of high stress on the medial tip of the stem. These experimental findings are even evident for a postulated rotational stability. The clinical and radiographic results of the cementless X-press stems do not seem to support the fixation concept of intertrochanteric fit and fill of femoral components. PMID:10653115

  17. 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.

  18. 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

  19. 48 CFR 252.225-7025 - Restriction on acquisition of forgings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of forgings. 252.225-7025 Section 252.225-7025 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7025 Restriction on acquisition of forgings. As prescribed in 225.7102-4, use the following clause: Restriction on Acquisition of Forgings (DEC 2009)...

  20. 48 CFR 252.225-7025 - Restriction on acquisition of forgings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... of forgings. 252.225-7025 Section 252.225-7025 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7025 Restriction on acquisition of forgings. As prescribed in 225.7102-4, use the following clause: Restriction on Acquisition of Forgings (DEC 2009)...

  1. 40 CFR 467.40 - Applicability; description of the forging subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... forging subcategory. 467.40 Section 467.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ALUMINUM FORMING POINT SOURCE CATEGORY Forging Subcategory § 467.40 Applicability; description of the forging subcategory. This subpart applies to...

  2. 48 CFR 252.225-7025 - Restriction on acquisition of forgings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of forgings. 252.225-7025 Section 252.225-7025 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7025 Restriction on acquisition of forgings. As prescribed in 225.7102-4, use the following clause: Restriction on Acquisition of Forgings (DEC 2009)...

  3. 40 CFR 467.40 - Applicability; description of the forging subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... forging subcategory. 467.40 Section 467.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ALUMINUM FORMING POINT SOURCE CATEGORY Forging Subcategory § 467.40 Applicability; description of the forging subcategory. This subpart applies to discharges...

  4. 48 CFR 252.225-7025 - Restriction on acquisition of forgings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of forgings. 252.225-7025 Section 252.225-7025 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7025 Restriction on acquisition of forgings. As prescribed in 225.7102-4, use the following clause: Restriction on Acquisition of Forgings (DEC 2009)...

  5. 40 CFR 467.40 - Applicability; description of the forging subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... forging subcategory. 467.40 Section 467.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ALUMINUM FORMING POINT SOURCE CATEGORY Forging Subcategory § 467.40 Applicability; description of the forging subcategory. This subpart applies to...

  6. 40 CFR 467.40 - Applicability; description of the forging subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... forging subcategory. 467.40 Section 467.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ALUMINUM FORMING POINT SOURCE CATEGORY Forging Subcategory § 467.40 Applicability; description of the forging subcategory. This subpart applies to discharges...

  7. 48 CFR 252.225-7025 - Restriction on acquisition of forgings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of forgings. 252.225-7025 Section 252.225-7025 Federal Acquisition Regulations System DEFENSE... CLAUSES Text of Provisions And Clauses 252.225-7025 Restriction on acquisition of forgings. As prescribed in 225.7102-4, use the following clause: Restriction on Acquisition of Forgings (DEC 2009)...

  8. 40 CFR 467.40 - Applicability; description of the forging subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... forging subcategory. 467.40 Section 467.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ALUMINUM FORMING POINT SOURCE CATEGORY Forging Subcategory § 467.40 Applicability; description of the forging subcategory. This subpart applies to...

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... FR 49139 (Aug. 28, 2007). Information about filing electronically is available on the NRC's public... 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. 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.

  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. 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.

  14. 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.

  15. 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

  16. 76 FR 168 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-03

    ... part 207), as most recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request..., (3) hammers and sledges, and (4) picks and mattocks (56 FR 6622). Following the first five-year... antidumping duty order on imports of heavy forged hand tools from China (65 FR 48962). Following second...

  17. 76 FR 50755 - Heavy Forged Hand Tools From China

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-16

    ... determined on April 8, 2011 that it would conduct expedited reviews (76 FR 31631, June 1, 2011). The... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Heavy Forged Hand Tools From China Determinations On the basis of the record \\1\\ developed in...

  18. 27 CFR 447.22 - Forgings, castings, and machined bodies.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... machined bodies. 447.22 Section 447.22 Alcohol, Tobacco Products, and Firearms BUREAU OF ALCOHOL, TOBACCO... IMPLEMENTS OF WAR The U.S. Munitions Import List § 447.22 Forgings, castings, and machined bodies. Articles..., castings, extrusions, and machined bodies) which have reached a stage in manufacture where they are...

  19. 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…

  20. 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…

  1. 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,…

  2. 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…

  3. 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.

  4. 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,…

  5. Nonadherence to the isochrony principle in forged signatures.

    PubMed

    Caligiuri, Michael P; Mohammed, Linton A; Found, Bryan; Rogers, Doug

    2012-11-30

    Highly programmed skilled movements are executed in such a way that their kinematic features adhere to certain rules referred to as minimization principles. One such principle is the isochrony principle, which states that the duration of voluntary movement remains approximately constant across a range of movement distances; that is, movement duration is independent of movement extent. The concept of isochrony suggests that some information stored in the motor program is constant, thus reducing the storage demands of the program. The aim of the present study was to examine whether forged signatures can be distinguished from genuine signatures on the basis of isochrony kinematics. Sixty writers were asked to write their own signatures and to forge model signatures representing three different writing styles: text-based, stylized, and mixed. All signatures were digitized to enable high precision dynamic analyses of stroke kinematics. Vertical stroke duration and absolute amplitude were measured for each pen stroke of the signatures using MovAlyzeR(®) software. Slope coefficients derived from simple regression models of the relationship between stroke duration and amplitude served as our measure of isochrony. The slope coefficient reflects the degree to which stroke duration increases in relation to stroke amplitude. Higher coefficients indicate greater increases in stroke duration for a given stroke amplitude and thus violate the isochrony principle. We hypothesized that the duration-amplitude coefficients for forged signatures would be significantly greater than for genuine signatures suggesting non-adherence to the isochrony principle. Results indicated that regardless of the style of the writer, genuine signatures were associated with low slope coefficients Pen strokes forming forged signatures had significantly greater duration-amplitude slope coefficients than genuine signatures. These findings suggest that when forging signatures, writers execute pen movements

  6. 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.

  7. Cementless total hip arthroplasty in developmental dysplasia of the hip with end stage osteoarthritis: 2-7 years' clinical results.

    PubMed

    Yildirim, Tugrul; Guclu, Berk; Karaguven, Dogac; Kaya, Alper; Akan, Burak; Cetin, Ilker

    2015-01-01

    Between 2006 and 2011, 102 hips of 78 patients with end-stage osteoarthritis secondary to developmental dysplasia of the hip (DDH) underwent cementless total hip arthroplasty (THA). According to the Crowe's classification, 22 hips (21%) were type 1, 19 hips (18%) were type 2, 22 hips (21%) were type 3 and 39 hips (38%) were type 4 respectively. Functional and clinical analyses were performed by Harris Hip Scores (HHS). There were 73 (71%) excellent or good results according to HHS. The postoperative HHS was significantly lower in patients who underwent femoral shortening (p<0.01). We observed 25 (24.5%) complications in total, 15 (14.7%) of which required revision surgery. The authors concluded that THA for DDH is a safe and a reliable procedure with good clinical outcomes. PMID:25907395

  8. Transverse Subtrochanteric Shortening Osteotomy During Cementless Total Hip Arthroplasty in Crowe Type-III or IV Developmental Dysplasia.

    PubMed

    Sofu, Hakan; Kockara, Nizamettin; Gursu, Sarper; Issin, Ahmet; Oner, Ali; Sahin, Vedat

    2015-06-01

    The purpose of this study was to review the outcomes of transverse subtrochanteric shortening osteotomy during cementless total hip arthroplasty in Crowe Type-III or IV developmental dysplasia. Seventy-three osteotomies were included in our study. Mean follow-up was 61 months. Harris hip score, leg length discrepancy, neurological status, union status of the osteotomy, and femoral component stability were the criteria for evaluation. All complications were noted. The mean Harris hip score improved from 38.6 points to 83.7 points. The mean leg length discrepancy decreased from 56.5 mm to 10.7 at the latest follow-up. The mean union time was 5.2 months. We observed 4 non-unions. Transverse subtrochanteric shortening osteotomy is an effective and reliable method in restoration of a more normal limb. PMID:25707993

  9. 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.

  10. Metallography of gamma titanium aluminides

    SciTech Connect

    Baeslack, W.A. III . Dept. of Welding Engineering); McQuay, P.A.; Lee, D.S. ); Fletcher, E.D. )

    1993-12-01

    The microstructures of forged and heat treated Ti-48A1-2Nb-2Mn (at.%) and Ti-48A1-2Nb-2Cr (at.%) gamma titanium aluminides have been revealed by the application of selected metallographic preparation techniques and characterized using light microscopy. Examination of the as-polished specimen surface under polarized light was highly effective in revealing the equiaxed gamma grain structure and twins within the gamma grains, but it did not delineate alpha-two phase present at gamma grain boundaries or within a lamellar gamma/alpha-two constituent. Bright-field and differential-interference contrast light microscopy analyses of specimens chemically etched with Kroll's reagent (100mL H[sub 2]O + 4mL HNO[sub 3] + 2mL HF) were marginally effective in characterizing the equiaxed gamma grain structure and likewise did not reveal the alpha-two phase. Furthermore, the application of Kroll's reagent resulted in localized dissolution in the form of fine grooves or microcracks oriented in preferred directions within the equiaxed gamma grains. Under light microscopy, gamma grains that experienced this attack resembled the lamellar gamma/alpha-two constituent. The alpha-two phase was most clearly revealed using an etching solution comprised of 30mL lactic acid + 30mL HNO[sub 3] + 3mL HF, while the gamma grain and twin boundaries were most effectively revealed using an etching solution comprised of 30mL HCL + 10mL HNO[sub 3] + 5mL H[sub 2]O[sub 2] + 3mL HF. An etching solution of 25 mL H[sub 2]O + 50mL glycerol + 25mL HNO[sub 3] + 2mL HF was very effective in simultaneously revealing both the gamma and alpha-two phase morphologies.

  11. Cementless press-fit cup. Principles, experimental data, and three-year follow-up study.

    PubMed

    Morscher, E; Bereiter, H; Lampert, C

    1989-12-01

    The concept of the press-fit cup includes an operative defect as small as possible, achievement of intrinsic stability by press-fit, and surface coating by an orderly, oriented wire mesh coating. The design is a modified hemisphere with flattening in the pole area and oversized cup diameter. A first series of press-fit cups were fitted with titanium nitride-coated stainless steel mesh. The manufacturing of such chemically pure titanium has only recently become feasible. Animal experiments using mountain sheep have shown an increase in the stability of the press-fit cup within the acetabulum with time and progressive bony ingrowth; this was verified in cups retrieved at autopsy. Three hundred eighty-seven first-generation titanium nitride-coated stainless steel mesh implants have been reviewed with a follow-up time of 12 to 39 months (average, 16.6 months). There were no intraoperative complications related to the cup. The roentgenographic follow-up study of 330 (85.1%) hips showed only a single case with a radiolucent line in all zones (1-3) as a roentgenographic sign of loosening, i.e., fibrous ingrowth. Two cups had to be revised due to insufficient primary stability and tilting. PMID:2582662

  12. 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.

  13. Eleven- to 14-year follow-up results of cementless total hip arthroplasty using a third-generation alumina ceramic-on-ceramic bearing.

    PubMed

    Sugano, Nobuhiko; Takao, Masaki; Sakai, Takashi; Nishii, Takashi; Miki, Hidenobu; Ohzono, Kenji

    2012-05-01

    To analyze long-term survivorship of cementless total hip arthroplasties (THAs) with the third-generation alumina ceramic-on-ceramic bearing, 100 consecutive THAs between 1996 and 1998 were reviewed. One cup and 2 stems were revised due to aseptic loosening. Another cup showed chipping of the acetabular liner at 8 years and required cup revision. The remaining hips showed stable bone ingrowth fixation with no osteolysis at the final follow-up. The 14-year survivorship as the end point of revision was 97.9% for the cup, 97.8% for the stem, and 95.7% for the overall implants, respectively. We conclude that cementless THA with the third-generation ceramic-on-ceramic hip bearing provided an excellent survivorship and eliminated periprosthetic osteolysis for 11 to 14 years. PMID:21978563

  14. X-Ray Analysis of the Ultrafine-Grained VT6 Titanium Alloy Subjected to Flat Rolling

    NASA Astrophysics Data System (ADS)

    Sitdikov, V. D.; Alexandrov, I. V.; Danilenko, V. N.; Popov, V. A.

    2015-10-01

    Results are presented of experimental x-ray diffraction analysis of the microstructure of VT6 titanium alloy billets in ultrafine-grained (UFG) state subjected to flat rolling. The UFG state was formed by six cycles of isothermal multiaxial forging at 650°C. The regularities of changes of the structural parameters (the lattice parameter, coherently scattering domain size, and microdistortions of the crystal lattice) are revealed depending on the degree of flat rolling reduction.

  15. 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.

  16. 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.

  17. West Flank Coso, CA FORGE ArcGIS data 2

    DOE Data Explorer

    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

  18. 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.

  19. 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.

  20. Superior fixation of pegged trabecular metal over screw-fixed pegged porous titanium fiber mesh

    PubMed Central

    2011-01-01

    Background and purpose Lasting stability of cementless implants depends on osseointegration into the implant surface, and long-term implant fixation can be predicted using radiostereometric analysis (RSA) with short-term follow-up. We hypothesized that there would be improved fixation of high-porosity trabecular metal (TM) tibial components compared to low-porosity titanium pegged porous fiber-metal (Ti) polyethylene metal backings. Methods In a prospective, parallel-group, randomized unblinded clinical trial, we compared cementless tibial components in patients aged 70 years and younger with osteoarthritis. The pre-study sample size calculation was 22 patients per group. 25 TM tibial components were fixed press-fit by 2 hexagonal pegs (TM group) and 25 Ti tibial components were fixed press-fit and by 4 supplemental screws (Ti group). Stereo radiographs for evaluation of absolute component migration (primary effect size) and single-direction absolute component migration (secondary effect size) were obtained within the first postoperative week and at 6 weeks, 6 months, 1 year, and 2 years. American Knee Society score was used for clinical assessment preoperatively, and at 1 and 2 years. Results There were no intraoperative complications, and no postoperative infections or revisions. All patients had improved function and regained full extension. All tibial components migrated initially. Most migration of the TM components (n = 24) occurred within the first 3 months after surgery whereas migration of the Ti components (n = 22) appeared to stabilize first after 1 year. The TM components migrated less than the Ti components at 1 year (p = 0.01) and 2 years (p = 0.004). Interpretation We conclude that the mechanical fixation of TM tibial components is superior to that of screw-fixed Ti tibial components. We expect long-term implant survival to be better with the TM tibial component. PMID:21434781

  1. 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.

  2. Sinter-forging of nanocrystalline zirconia. 1: Experimental

    SciTech Connect

    Hague, D.C.; Mayo, M.J.

    1997-01-01

    Nanocrystalline (15 nm) yttria (3 mol%)-stabilized zirconia (3Y-TZP) was sinter-forged under conditions of varying temperature (1,050--1,200 C), plastic strain rate (5 {times} 10{sup {minus}5} to 2 {times} 10{sup {minus}3} s{sup {minus}1}), and green density (33--48%), using constant-crosshead-speed tests, constant-load (i.e., load-and-hold) tests, and constant-loading-rate tests. The densification and pore size evolution results indicate that plastic strain is largely responsible for elimination of large pores, while diffusional mechanisms control the elimination of small pores. Grain growth during sinter-forging is observed to be dependent solely on porosity during intermediate-stage sintering. Once the powder compact enters final-stage sintering, however, both static (time- and temperature-dependent) and dynamic (plastic-strain-dependent) grain growth take place, greatly accelerating the overall rate of grain growth. The use of fast strain rates to impose plastic strain before the onset of dynamic grain growth is proposed as a method of preserving small grain sizes during sinter-forging.

  3. Laser Gas Nitriding of Titanium and Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Dai, J. J.; Hou, S. Q.

    Titanium and titanium alloys are widely used in many fields due to some of their characteristics such as light density, high strength, and excellent corrosion resistance. However, poor mechanical performances limit their practical applications. Laser gas nitriding is a promising method used to improve the surface properties of components. Recent developments on laser gas nitriding of titanium and titanium alloys are reviewed. The processing parameters have important effects on the resulting characteristics of titanium and titanium alloys. The resulting microstructure and properties of laser gas nitrided specimens are presented. The problems to be solved and the prospects in the field of laser gas nitriding of titanium and titanium alloys are discussed.

  4. Dichloromethane photodegradation using titanium catalysts

    SciTech Connect

    Tanguay, J.F.; Suib, S.L.; Coughlin, R.W. )

    1989-06-01

    The use of titanium dioxide and titanium aluminosilicates in the photocatalytic destruction of chlorinated hydrocarbons is investigated. Titanium-exchanged clays, titanium-pillared clays, and titanium dioxide in the amorphous, anatase, and rutile forms are used to photocatalytically degrade dichloromethane to hydrochloric acid and carbon dioxide. Bentonite clays pillared by titanium dioxide are observed to be more catalytically active than titanium-exchanged clays. Clays pillared by titanium aluminum polymeric cations display about the same catalytic activity as that of titanium-exchanged clays. The rutile form of titanium dioxide is the most active catalyst studied for the dichloromethane degradation reaction. The anatase form of titanium dioxide supported on carbon felt was also used as a catalyst. This material is about five times more active than titanium dioxide-pillared clays. Degradation of dichloromethane using any of these catalysts can be enhanced by oxygen enrichment of the reaction solution or by preirradiating the catalyst with light.

  5. 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.

  6. 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.

  7. Net-Shape Forging of Aerofoil Blade based on Flash Trimming and Compensation methods

    SciTech Connect

    Lu, B.; Ou, H.; Armstrong, C. G.

    2011-05-04

    In this research, an automatic blade forging die shape optimisation system was developed by using direct compensation and flash trimming algorithms and integrating with the DEFORM 3D software package. To validate the developed system, a 3D blade forging case problem was simulated and optimised with and without the consideration of trimming simulation. The results were compared with actual measurement data of the forged aerofoil blade with excellent results obtained with the fast trimming simulation procedure used.

  8. Direct visualization and quantification of bone growth into porous titanium implants using micro computed tomography.

    PubMed

    Baril, E; Lefebvre, L P; Hacking, S A

    2011-05-01

    The utility of porous metals for the integration of orthopaedic implants with host bone has been well established. Quantification of the tissue response to cementless implants is laborious and time consuming process requiring tissue processing, embedding, sectioning, polishing, imaging and image analysis. Micro-computed tomography (μCT) is a promising three dimensional (3D) imaging technique to quantify the tissue response to porous metals. However, the suitability and effectiveness of μCT for the quantification of bone ingrowth remains unknown. The purpose of this study was to evaluate and compare bone growth within porous titanium implants using both μCT and traditional hard-tissue histology techniques. Cylindrical implants were implanted in the distal femora and proximal tibiae of a rabbit. After 6 weeks, bone ingrowth was quantified and compared by μCT, light microscopy and backscattered electron microscopy. Quantification of bone volume and implant porosity as determined by μCT compared well with data obtained by traditional histology techniques. Analysis of the 3D dataset showed that bone was present in the pores connected with openings larger 9.4 μm. For pore openings greater than 28.2 μm, the size of the interconnection had little impact on the bone density within the porosity for the titanium foams. PMID:21512898

  9. 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.

  10. 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).

  11. 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.

  12. 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.

  13. Successful Long-Term Fixation and Progression of Osteolysis Associated with First-Generation Cementless Acetabular Components Retrieved Post Mortem

    PubMed Central

    Urban, Robert M.; Hall, Deborah J.; Della Valle, Craig; Wimmer, Markus A.; Jacobs, Joshua J.; Galante, Jorge O.

    2012-01-01

    Background: Primary cementless acetabular reconstruction has shown durable long-term fixation. Late failures secondary to aseptic loosening are rare but may occur in patients with previously well-fixed components. In the present study, the histopathological characteristics of postmortem specimens were correlated with wear damage and radiographic data in an attempt to better understand the long-term events in the periacetabular tissue around well-functioning devices. Methods: Seventeen primary cementless Harris-Galante I acetabular components with adjacent tissues were harvested after a mean of eleven years (range, four to twenty-five years) from patients whose implants were well functioning at the time of death. Undecalcified and paraffin sections were used to quantify the extent of bone and soft tissues within the porous coating and at the interface between the coating and the surrounding bone. Wear particles were identified with use of polarized light microscopy and energy-dispersive x-ray analysis. Bearing-surface volumetric wear and backside wear damage of the polyethylene liner were assessed. Results: All of the components were fixed by bone ingrowth (mean extent, 33% ± 21%). Particle-induced granulomas were present in the porous coating and along the interface and progressed through screw holes, ballooning into the retroacetabular bone in the longer-term specimens. Particles of femoral and acetabular origin were identified in the granulomas. Bearing-surface volumetric wear (mean, 41.6 mm3/year) increased with duration and correlated with increasing extent of granuloma in the porous coating and the increasing size of pelvic granulomas. Radiolucencies on radiographs correlated with the extent of bone and fibrous tissue ingrowth. Of the six pelvic granulomas that were identified histologically, only one was apparent on routine radiographs. Conclusions: Acetabular fixation by bone ingrowth can be successful into the third decade after implantation. Osteolysis

  14. 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.

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

    DOE Data Explorer

    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.

  16. Sinter-forging characteristics of fine-grained zirconia

    SciTech Connect

    Panda, P.C.; Wang, J.; Raj, R.

    1988-12-01

    Powder preforms of zirconia, containing 2.85 mol% yttria, were sinter-forged in simple uniaxial compression at 1400/sup 0/C by applying constant displacement rates to the specimens. Shear and densification strains and the uniaxial stress were measured as a function of time. In contrast with alumina and silicon nitride, zirconia appears to densify by a dislocation mechanism. As a consequence, the densification rate is linked to the applied strain rather than to the applied hydrostatic pressure: the powder compact requires a critical amount of compressive strain to consolidate to full density, irrespective of the strain rate or the stress at which that strain is applied.

  17. 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).

  18. 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.

  19. 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.

  20. 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…

  1. 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

    ... Order No. 5-2010 (72 FR 55355). Signed at Washington, DC, on May 19, 2011. David Michaels, Assistant... 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...

  2. Winter Weather at Valley Forge 1777-1778: A Lesson in Climatic Reconstruction.

    ERIC Educational Resources Information Center

    Ansley, Mary Jane; Pritchard, Sandra F.

    1987-01-01

    Notes that the story of George Washington's encampment at Valley Forge is seldom told without reference to the bitter cold winter Washington and his troops endured. Shows how to use historical reports of weather information to allow students to judge for themselves whether the winter at Valley Forge then was harsher than winters in the same area…

  3. 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.

  4. 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.

  5. Correlative analysis of MRI-evident abductor hip muscle degeneration and power after minimally invasive versus conventional unilateral cementless THA.

    PubMed

    Vasilakis, Ioannis; Solomou, Ekaterini; Vitsas, Vasilis; Fennema, Peter; Korovessis, Panagiotis; Siamblis, Dimitrios K

    2012-12-01

    The 2 main null hypotheses of this study were: (1) the 4-year surgical trauma-related degeneration within the hip abductor muscles after a minimally invasive approach to total hip arthroplasty would be similar to that following a conventional approach; and (2) no differences in perioperative blood loss or postoperative hip pain would be observed between the minimally invasive and conventional approaches.In 40 consecutive randomly selected adult patients with unilateral primary hip osteoarthritis, a cementless Zweymüller-Plus THA (Smith & Nephew Orthopaedics, Baar, Switzerland) was implanted by a single surgeon in 1 institution during the same period. Twenty patients underwent a minimally invasive approach (group A), and 20 patients underwent a conventional anterolateral approach (group B). Four years postoperatively, the operated and contralateral nonoperated hips of 37 available patients from both groups were examined with magnetic resonance imaging to show any changes in the gluteus medius and tensor fascia latae. Simultaneously, hip abductor power was measured bilaterally in both groups. Anthropometric data, blood loss, Short Form 36 self-assessment questionnaire, visual analog pain score, and walking distance were also analyzed.The reliability of magnetic resonance imaging and hip abductor power measurements was high. No difference was found in hip abductor power on the operated side between the 2 groups, whereas hip abductor power on the nonoperated side was significantly higher in both groups. This study revealed no mechanical and functional benefits in favor of patients undergoing minimally invasive vs conventional total hip arthroplasty. PMID:23218622

  6. Trade-off between stress shielding and initial stability on an anatomical cementless stem shortening: in-vitro biomechanical study.

    PubMed

    Yamako, Go; Chosa, Etsuo; Totoribe, Koji; Watanabe, Shinji; Sakamoto, Takero

    2015-08-01

    Shortened cementless femoral stems have become popular with the advent of minimally invasive total hip arthroplasty (THA). Successful THA requires initial stem stability and prevention of stress shielding-mediated bone loss, although the effect of stem shortening is controversial. Here we experimentally examined whether stem shortening affects stress shielding and initial stability. Anatomical stems (length, 120 mm) were cut to an 80 mm or 50 mm length. Ten tri-axial strain gauges measured the cortical strain on each stem-implanted femur to evaluate stress shielding. Two transducers measured axial relative displacement and rotation under single-leg stance loading. The 50 mm stem increased the equivalent strains with respect to the original stem in the proximal calcar region (31.0% relative to intact strain), proximal medial region (63.1%), and proximal lateral region (53.9%). In contrast, axial displacement and rotation increased with a decreasing stem length. However, the axial displacement of the 50 mm stem was below a critical value of 150 µm for bone ingrowth. Our findings indicate that, with regard to a reduction in stem length, there is a tradeoff between stress shielding and initial stability. Shortening the stem up to 50 mm can promote proximal load transfer, but bone loss would be inevitable, even with sufficient initial stability for long-term fixation. PMID:26117334

  7. Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

    PubMed Central

    Mishima, Hajime; Sugaya, Hisashi; Nishino, Tomofumi; Yamazaki, Masashi

    2016-01-01

    The cementless stem Excia (B. Braun, Melsungen, Germany) implant has a rectangular cross-sectional shape with back-and-forth flanges and a plasma-sprayed, dicalcium phosphate dihydrate coating from the middle to proximal portion to increase initial fixation and early bone formation. Here, the conformity of the Excia stem to the femoral canal morphology was three-dimensionally assessed using computed tomography. Forty-three patients (45 hips) were examined after primary total hip arthroplasty with a mean follow-up of 27 ± 3 months (range: 24–36 months). Spot welds occurred at zone 2 in 16 hips and at zone 6 in 24 hips, with 83% (20/24 hips) of those occurring within 3 months after surgery. First- (n = 12 hips), second- (n = 32), and third- (n = 1) degree stress shielding were observed. The stem was typically in contact with the cortical bone in the anterolateral mid-portion (100%) and posteromedial distal portions (85%). Stress shielding did not progress, even in cases where the stems were in contact with the distal portions. The anterior flange was in contact with the bone in all cases. The stability of the mid-lateral portion with the dicalcium phosphate dihydrate coating and the anterior flange may have inhibited the progression of stress shielding beyond the second degree. PMID:26881087

  8. The effect of patient age, gender, and tibial component fixation on pain relief after cementless total knee arthroplasty.

    PubMed

    Whiteside, L A

    1991-10-01

    Cementless total knee arthroplasties (TKAs) were prospectively evaluated for pain relief in 1110 knees. The effect of screws in the tibial component, the age of the patients, and the gender of the patients were studied to determine the effect of these parameters on pain relief one and two years postsurgery. The group with screws in the tibial component (Ortholoc II) had a significantly higher percentage of pain-free knees at one year than at two years postsurgery, and the older patients had a significantly higher rate of pain-free knees at one- and two years postsurgery than the younger patients. Older female patients with Ortholoc I TKAs had a significantly higher percentage of pain-free knees than did older male patients at one-year postsurgery, but not at two years. The group with screws in the tibial components (Ortholoc II) had a higher percentage of pain-free knees at one-year postsurgery than did the Ortholoc I knees, but there was no difference between Ortholoc I and II at two-years postsurgery. In the Ortholoc II group, there was also no difference in results among sexes or between patients older and younger than 65 years old. The correlation coefficient was calculated to evaluate the relationship between body weight and the degree of pain after TKA. No significant correlation could be found at one and two years after surgery. PMID:1914298

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Morphometric examination of straight, tapered titanium stems: a retrieval study.

    PubMed

    Böhm, G; Lintner, F; Auterith, A; Lester, D K; Zweymüller, K A

    2001-12-01

    Cementless straight, tapered rectangular cross section titanium stems have been used by the senior author since 1979. Thirty-four stems retrieved postmortem, after between 10 days and 15.2 years in situ, were studied morphometrically and histologically. Nineteen stems were first generation (1979-1986), with an incomplete sagittal taper and a mean surface roughness of 1 microm (Ra 1.23 +/- 0.3 microm); 15 stems were second generation after 1986, with a full biplane taper and a mean surface roughness of 4 microm (Ra 4.14 +/- 0.36 microm). Implant surface bony coverage was determined morphometrically in 10 segments of the stems, and expressed as a bone implant contact index. Histologically, there were no differences between implants with different levels of roughness. Morphometrically, the first-generation stems showed significant differences in coverage (distal > proximal); second-generation stems had a more uniform pattern. Stems retrieved early after arthroplasty had a mean bone implant contact index of 10%. The mean bone implant contact index showed attainment of maximum coverage by 5 years after arthroplasty, without additional apposition or loss thereafter. Patients younger than 65 years at arthroplasty had similar bone implant contact indices to patients 65 years or older; coverage in the six patients 80 years of age at retrieval did not differ from the rates in the other patients. Morphometry was able to provide objective evidence of design change effects. No differences in coverage were found in terms of times in situ, patient age at arthroplasty and at retrieval, and degree of stem surface roughness. PMID:11764342

  16. Titanium Allergy: A Literature Review

    PubMed Central

    Goutam, Manish; Giriyapura, Chandu; Mishra, Sunil Kumar; Gupta, Siddharth

    2014-01-01

    Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium. PMID:25484409

  17. 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

  18. 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

  19. 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

  20. FRACTURE MECHANICAL MEASUREMENTS WITH COMMERCIAL STAINLESS STEELS AT 4 K AND WITH CP-TITANIUM AT 173 K

    SciTech Connect

    Nyilas, A.; Mitterbacher, H.

    2010-04-08

    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 MPasq root(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.

  1. 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.

  2. Cementless total hip arthroplasty with the rectangular titanium Zweymüller stem: a concise follow-up, at a minimum of twenty years, of previous reports.

    PubMed

    Kolb, Alexander; Grübl, Alexander; Schneckener, Charlotte-Dorothé; Chiari, Catharina; Kaider, Alexandra; Lass, Richard; Windhager, Reinhard

    2012-09-19

    In 2002 and 2006, we reported the long-term results of 208 total hip replacements performed with the Zweymüller stem and a threaded cup in 200 patients. The present study gives an update on this patient cohort. At a minimum of twenty years postoperatively, seventy-three patients (seventy-five hips) were available for follow-up; twelve patients were lost to follow-up. The key findings of our previous reports were the absence of aseptic femoral stem loosening and a poor rate of survival of the threaded cup. Since then, two revisions have been performed because of aseptic stem loosening. We observed osteolytic lesions around the proximal part of the femoral component on twenty-four (47%) of fifty-one radiographs, but no stem was deemed at risk for loosening. The probability of survival of the stem at twenty years was 0.96 (95% confidence interval, 0.91 to 0.99), and the probability of survival of the cup at twenty years was 0.67 (95% confidence interval, 0.57 to 0.75). The Zweymüller femoral stem, a tapered, rectangular implant, continues to give excellent long-term results. PMID:22992879

  3. 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

    2016-05-01

    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.

  4. 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.

  5. Process Modelling of IN718 for Free Forging

    SciTech Connect

    Yoshida, Hiroaki; Hatta, Takeshi; Hironaka, Tomohisa; Isogawa, Sachihiro; Sekiguchi, Hideaki

    2007-05-17

    Ni based alloy IN718 is important material used for engine shafts, turbine disks of gas turbine engines. The grain refining of the IN718 becomes important because of the improvement of reliability. We have developed newly advanced {delta} process to obtain the grain of less than 22.5 {mu} m (ASTM No.8.0) even after solution treatment. Furthermore we have developed the microstructural prediction system of IN718 for the process modelling. In this paper, the advanced {delta} process and it's process modelling in the turbine disk forging were reported. As the result, we could obtain successful fine microstructure less than 22.5 {mu} m after solution treatment in turbine disk.

  6. Automatic feature extraction from micrographs of forged superalloys

    NASA Astrophysics Data System (ADS)

    Berhuber, E.; Rinnhofer, A.; Stockinger, M.; Benesova, W.; Jakob, G.

    2008-07-01

    The manual determination of metallurgical parameters of forged superalloys can be dramatically improved by automatic, image-processing-based feature extraction. With the proposed methods, the typical errors during grain size estimation for Inconel 718 and Allvac 718Plus ™ , caused by twins and other artifacts like scratches, can be eliminated. Different processing strategies for grain size estimation allow the application of a wide range of ASTM grain size numbers from G3 to G12 with the typical variations in the manifestation of metallurgical details and the magnification-related limitations of image quality. Intercept counting strategies show advantages for samples with pronounced anisotropy and can produce detailed statistics on grain orientation. In addition to a single grain size number, grain size histograms offer a more precise description of the material properties.

  7. 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. PMID:24934422

  8. 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.

  9. 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.

  10. 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).

  11. 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).

  12. 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.

  13. 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.

  14. [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. PMID:23586224

  15. Engine Performance of Precision-forged, Electropolished and Machined Blades of Nimonic 80 and 80A Alloys

    NASA Technical Reports Server (NTRS)

    Sikora, Paul F; Johnston, James R

    1955-01-01

    An investigation was conducted to determine the effect of electropolishing precision-forged blades and of machining blades from oversize forgings on the engine performance of Nimonic 80 and Nimonic 80A turbine blades. These blades, along with precision-forged blades, were run in a J33-9 turbojet engine. The tests resulted in the following conclusions: (1) Electropolishing of precision-forged blades did not improve engine life relative to the life of nonelectropolished blades. (2) Machining blades from oversize forgings did not improve the engine life of precision-forged blades. (3) The precision-forging and heat-treating practice used in fabricating the blades investigated was such that the surface roughness and oxide penetration was so slight, approximately 0.0005 inch in depth, as to preclude any benefits derived from surface removal by electropolishing or machining.

  16. 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. PMID:26462678

  17. 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.

  18. Survival of the Cementless Spotorno® Stem in the Second Decade

    PubMed Central

    Jung, Alexander W.; Breusch, Steffen J.; Ewerbeck, Volker; Parsch, Dominik

    2009-01-01

    High survival rates have been reported for the uncemented CLS® Spotorno® stem up to 10 years. To confirm survival at longer followup we report the minimum 15-year (mean, 17 years; range, 15–20 years) for 257 hips using this stem. We retrospectively evaluated the clinical and radiographic results of all 326 patients (354 THAs) operated between 1985 and 1989. The patients had a mean age of 57 years using an uncemented grit-blasted, tapered titanium femoral stem. Eighty-six patients (89 hips) died and eight patients (eight hips) were lost to followup, leaving 240 patients (257 hips) for evaluation. The femoral component was revised in 35 hips: eight for infection, nine for periprosthetic fracture, one for traumatic loosening, and 17 for aseptic loosening. Survival of the stem was 88% at 17 years (95% confidence interval, 84%–92%), and survival with femoral revision for aseptic loosening as an end point was 94% (95% confidence interval, 91%–97%). The median Harris hip score at followup was 80 points. No thigh pain was reported. Small osteolytic lesions (< 1 cm2) were found in the proximal Gruen zones (1 or/and 7) in 28 hips (15%). No distal femoral osteolysis was found. The long-term survival with this type of femoral component remains high in the second decade. Level of Evidence: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. PMID:19504161

  19. High-temperature oxidation of titanium silicide coatings on titanium

    SciTech Connect

    Abba, A.; Caillet, M.; Galerie, A.

    1982-02-01

    Coatings of Ti/sub 5/Si/sub 3/ on titanium have been prepared by means of decomposition of silane SiH/sub 4/ on heated titanium ribbons. Oxidation of the coated titanium specimens was much slower than that of the noncoated ones. Gravimetric and morphological experiments allowed to propose a mechanism describing the oxidation process.

  20. Structure and Mechanical Properties of Nitrogen Austenitic Steel after Ultrasonic Forging

    NASA Astrophysics Data System (ADS)

    Narkevich, N. A.; Tolmachev, A. I.; Vlasov, I. V.; Surikova, N. S.

    2016-03-01

    Electron microscopy and X-ray diffraction have been used to investigate a nitrogen 07Kh17AG18 steel with an austenitic structure after the surface deformation treatment—ultrasonic forging. During ultrasonic forging, an austenitic structure transforms into a new structure with an elevated concentration of deformation-induced stacking faults, a lot of deformation microtwins, ɛ-martensite crystals. The austenite lattice parameter is found to be decreased in the surface layer. After ultrasonic forging, nitrided steel exhibits enhanced strength properties with retained high plasticity.

  1. Deformation Mechanisms in Tube Billets from Zr-1%Nb Alloy under Radial Forging

    SciTech Connect

    Perlovich, Yuriy; Isaenkova, Margarita; Fesenko, Vladimir; Krymskaya, Olga; Zavodchikov, Alexander

    2011-05-04

    Features of the deformation process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray data concerning their structure and texture. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially active slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual deformation and recrystallization textures arise. These textures differ from usual textures of {alpha}-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.

  2. 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.

  3. 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.

  4. 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.

  5. Titanium Cold Spray Coatings

    NASA Astrophysics Data System (ADS)

    Ajaja, Jihane; Goldbaum, Dina; Chromik, Richard; Yue, Stephen; Rezaeian, Ahmad; Wong, Wilson; Irissou, Eric; Legoux, Jean-Gabriel

    Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical properties similar to a traditional bulk material. Vickers hardness testing and nanoindentation were used as micro-and nano-scale measurement techniques to characterize the mechanical properties of titanium coatings, deposited at different deposition conditions, and bulk Ti. The mechanical properties of bulk titanium and titanium coatings were measured over a range of length scales, with the indentation size effect examined with Meyer's law. Hardness measurements are shown to be affected by material porosity, microstructure and coating particle bonding mechanism. Hard-ness measurements showed that Ti coatings deposited at higher gas pressures and temperatures demonstrate an indentation load response similar to bulk Ti. Key words: titanium, cold spray, Vickers hardness, nanoindentation, indentation size effect, microstructure, mechanical properties

  6. Loss in mechanical contact of cementless acetabular prostheses due to post-operative weight bearing: a biomechanical model.

    PubMed

    Bellini, Chiara Maria; Galbusera, Fabio; Ceroni, Roberto Giacometti; Raimondi, Manuela Teresa

    2007-03-01

    The primary stability of cementless acetabular components is a prerequisite for their clinical success. The target of the present study was to analyse possible effects of post-operative joint loading on the initial mechanical stability of a press-fitted acetabular prosthesis. For this purpose, a three-dimensional finite element model of the pelvic bone with acetabular reconstruction was set-up. The analysis included two steps: (1) simulation of the prosthesis press-fit implantation and (2) simulation of the instant of peak resultant hip loading during the one-legged stance. The difference between the contact pressures at the bone/implant interface, at the end of the second step and those at the end of the first step was calculated and assumed as an index of variation in mechanical contact due to post-operative weight bearing. The results show that, due to hip loading, contact pressures given by press-fit increase in the postero-superior acetabular region but decrease in the antero-inferior acetabular region. The calculated area in which the contact pressures decrease extend to about 30% of the total contact surface. These results imply that post-operative joint loading significantly reduces the mechanical stability given by press-fit. The decrease in contact pressures at the bone/implant interface may result in a lack of osteointegration, possibly hindering the implant secondary stability. It may also create a route for wear debris, possibly favouring periprosthetic osteolysis, which may lead to further loss in contact and clinical failure of the implant due to loosening. PMID:16569508

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Five-year results of a cementless short-hip-stem prosthesis

    PubMed Central

    Wittenberg, Ralf H.; Steffen, Reinhard; Windhagen, Henning; Bücking, Petra; Wilcke, Andreas

    2013-01-01

    Hip prosthesis stems with a short stem length and proximal fixation geometry support a bone-preserving and muscle-sparing implantation and should also allow for revision surgery with a standard hip stem. We present 250 prospectively documented clinical and radiological results from the Metha Short Hip Stem prosthesis (B. Braun-Aesculap, Tuttlingen, Germany) after an average follow-up of 4.9 years. The average patient age at surgery was 60 years. Indication for total hip replacement was primary osteoarthrosis (OA) (78% of patients), OA based on developmental dysplasia of the hip (16%), and other indications (6%). At the last follow-up, the average Harris Hip Score was 97 points. 85% of patients were very satisfied and 14% were satisfied after surgery, whereas 1% were dissatisfied. Pain according to the Visual Analogue Scale improved from 7.4 (min 1.6, max 9.5) pre-operatively to 0.23 (min 0, max 6.6). No joint dislocations occurred when predominantly using 28 mm and 32 mm prosthesis heads. Nine short-stems were revised: three after bacterial infections, two after primary via valsa with penetration of the femoral cortex two and three months after surgery, and three after early aseptic cases of loosening within the first year. A further nine osseously consolidated short-stems had to be replaced due to breakage of the modular titanium cone adapter after an average of 3.1 years (min 1.9, max 4.4). All surgical revisions were performed using primary standard stems. Without taking the material-related adapter failures into account, a five year Kaplan-Meier survival rate of 96.7% (95% confidence interval 93.4–98.3) was determined for the short-stem prostheses. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination. Fine sclerotic lines were detected in Gruen's AP zones 1 (19%) and 2 (10.5%), individual hypertrophies in zone 3 (3.5%), fine seams in zones 4 (5.5%) and 5 (4%), without pedestal formations in zone 4, clear

  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. 75 FR 20859 - Notice of Realty Action, Independence National Historical Park, Pennsylvania and Valley Forge...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-21

    ... National Park Service Notice of Realty Action, Independence National Historical Park, Pennsylvania and Valley Forge National Historical Park, Pennsylvania AGENCY: National Park Service, Department of the... is located within the boundary of Independence National Historical Park (INDE). The privately...

  15. 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

  16. VIEW OF SMITH FORGING METAL SPECIMEN USING 3,000POUND DROP HAMMER ...

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

    VIEW OF SMITH FORGING METAL SPECIMEN USING 3,000-POUND DROP HAMMER NO. 1, MAN TO RIGHT IS OPERATING HAMMER WHILE OTHER SHAPES SPECIMEN. - Cambria Iron Company, Blacksmith Shop, Lower Works, Johnstown, Cambria County, PA

  17. 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.

  18. 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.

  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. Computer simulation of the forging of fine grain IN-718 alloy

    NASA Astrophysics Data System (ADS)

    Srinivasan, R.; Ramnarayan, V.; Deshpande, U.; Jain, V.; Weiss, I.

    1993-09-01

    In recent years, there has been great emphasis on the use of computer-aided tools in process design. The key to the success of any computer modeling is the accurate knowledge of the mechanical and thermal properties of the various components of a manufacturing system. In order to develop a data base of forging properties of the nickel-base alloy IN-718, isothermal constant strain-rate compression tests were conducted on the annealed fine-grain material over the temperature range 871 °C to 1149 °C (1600 °F to 2100 °F) and strain-rate range 0. 001 to 10 s-1. Empirical relationships among flow stress, strain rate, and temperature developed based on these tests, along with experimentally measured heat-transfer and friction coefficients, were used in the program ALPID to simulate nonisothermal forging of “double-cone” specimens. The simulation results were compared with actual forging in an industrial forge press. The good agreement between simulation and forging results indicates that when a complete data base of materials properties is available, computer modeling can be used effectively to study the forging process.

  1. Computer simulation of the forging of fine grain IN-718 alloy

    SciTech Connect

    Srinivasan, R.; Deshpande, U.; Weiss, I. . Mechanical and Materials Engineering Dept.); Ramnarayan, V. ); Jain, V. . Mechanical and Aerospace Engineering Dept.)

    1993-09-01

    In recent years, there has been great emphasis on the use of computer-aided tools in process design. The key to the success of any computer modeling is the accurate knowledge of the mechanical and thermal properties of the various components of a manufacturing system. In order to develop a data base of forging properties of the nickel-base alloy IN-718, isothermal constant strain-rate compression tests were conducted on the annealed fine-grain material over the temperature range 871 C to 1,149 C (1,600 F to 2,100 F) and strain-rate range 0.001 to 10 s[sup [minus]1]. Empirical relationships among flow stress, strain rate, and temperature developed based on these tests, along with experimentally measured heat-transfer and friction coefficients, were used in the program ALPID to simulate nonisothermal forging of double-cone specimens. The simulation results were compared with actual forging in an industrial forge press. The good agreement between simulation and forging results indicates that when a complete data base of materials properties is available, computer modeling can be used effectively to study the forging process.

  2. 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

    2016-08-01

    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.

  3. 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.

  4. 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

  5. Superplastic forging of aluminum 6061-silicon carbide(P) composites

    NASA Astrophysics Data System (ADS)

    Memongkol, Napisporn

    This work describes the processing and characterization of mechanically alloyed Al6061-SiCP composites. The SiC dispersion strengthened Al6061 was synthesized by mechanical alloying of SiC powder and Al6061 powder in an argon atmosphere followed by hot pressing or cold compaction and sinter forging in air. The microstructure of the Al-SiC composites showed a fine grain size of Al matrix with SiC particles and dispersoids distributed homogeneously in the Al matrix. The microstructure of unreinforced MA6061 showed a fine grain size with small dispersoids. The preferred orientation in these composites was measured using the neutron diffraction technique. The hot pressed material had a random texture while a <111> preferred texture was developed in the sinter forged samples. The amount of texture developed depends on the applied load but not on the sintering temperature. The compressive strengths of these composites (4%SiC and 8%SiC) were characterized in the temperatures range from 723 to 833K and at strain rates of 10-4 to 10-1 s-1 . The true compressive stress strain curves exhibit strain softening behavior. The results showed significantly higher strength than the base material. The strain rate sensitivity, m, from the compression test is much lower than required for superplastic behavior. Tensile tests on the MA Al-8%SiC composite and MA6061 monolithic material were performed at temperatures of 673, 723, and 773K and strain rates from 10-2 to 10 s-1 . The true tensile stress strain curves show the strain hardening behavior. The relationship between microstructure, texture, densification and mechanical properties was studied and the strengthening mechanisms were identified. Uniaxial consolidation experiments have been conducted at room temperature and elevated temperature for three different powders, Al6061, MA6061 and MA6061-8%SiC. The experiments illustrated that the densification mechanisms of the three different powders at room temperature are similar but they

  6. 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

  7. Refurbishment of fatigue-cracked generator rotor forgings

    SciTech Connect

    Roberts, B.W.; Zielke, W.; Puri, A.

    1996-12-31

    In a paper presented at the 1994 IJPGC in Phoenix, AZ, TVA discussed the management of a fleet of fourteen generator rotors which had developed cracks in the axial cooling holes under the retaining rings and in the radial cooling holes in the rotor body. The management consisted of establishing the root cause of the crack initiation and propagation, initially establishing the flaw size distribution by eddy-current testing (ECT), performing reinspection at appropriate intervals, preheating the rotor prior to startup, lowering overspeed trip settings to 105%, confirming overspeed trip response by simulation rather than actual overspeed, and maintaining a spare generator rotor. Since the 1994 paper, one of the rotors developed an electrical liability, forcing its removal from service. While a replacement rotor which was on hand resolved the immediate crisis, the long term options were: (1) operate without a spare, (b) procure a new rotor with substantially improved mechanical properties and slightly improved electrical performance, or (c) refurbish the existing forging. After an exhaustive economic analysis, option C was identified as the most cost effective solution. This paper addresses the 43-inch rotor rehabilitation and rewind that has been successfully executed for less than half the cost of a new replacement rotor, without loss in operating flexibility.

  8. 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.

  9. 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.

  10. 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. PMID:26952418

  11. Optimization and mechanical accuracy reliability of a new type of forging manipulator

    NASA Astrophysics Data System (ADS)

    Chen, Kang; Ma, Chunxiang; Zheng, Maoqi; Gao, Feng

    2015-03-01

    Researches on forging manipulator have enormous influence on the development of the forging industry and national economy. Clamp device and lifting mechanism are the core parts of forging manipulator, and have been studied for longer time. However, the optimization and mechanical accuracy reliability of them are less analyzed. Based on General Function( G F) set and parallel mechanism theory, proper configuration of 10t forging manipulator is selected firstly. A new type of forging manipulator driven by cylinders is proposed. After solved mechanical analysis of manipulator's core mechanisms, expressions of force of cylinders are carried out. In order to achieve smaller force afforded by cylinders and better mechanical characteristics, some particular sizes of core mechanisms are optimized intuitively through the combined use of the genetic algorithms(GA) and GUI interface in MATLAB. Comparing with the original mechanisms, optimized clamp saves at least 8 percent efforts and optimized lifting mechanism 20 percent under maximum working condition. Finally, considering the existed manufacture error of components, mechanical accuracy reliability of optimized clamp, lifting mechanism and whole manipulator are demonstrated respectively based on fuzzy reliability theory. Obtained results show that the accuracy reliability of optimized clamp is bigger than 0.991 and that of optimized lifting mechanism is 0.995. To the whole manipulator under maximum working condition, that value exceeds 0.986 4, which means that optimized manipulator has high motion accuracy and is reliable. A new intuitive method is created to optimize forging manipulator sizes efficiently and more practical theory is utilized to analyze mechanical accuracy reliability of forging manipulator precisely.

  12. 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

    2015-01-01

    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. PMID:26044814

  13. 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.

  14. 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.

  15. Corrosion of stainless steel, nickel-titanium, coated nickel-titanium, and titanium orthodontic wires.

    PubMed

    Kim, H; Johnson, J W

    1999-02-01

    Orthodontic wires containing nickel have been implicated in allergic reactions. The potential for orthodontic wires to cause allergic reactions is related to the pattern and mode of corrosion with subsequent release of metal ions, such as nickel, into the oral cavity. The purpose of this study was to determine if there is a significant difference in the corrosive potential of stainless steel, nickel titanium, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium orthodontic wires. At least two specimens of each wire were subjected to potentiostatic anodic dissolution in 0.9% NaCl solution with neutral pH at room temperature. Using a Wenking MP 95 potentiostat and an electrochemical corrosion cell, the breakdown potential of each wire was determined. Photographs were taken of the wire speci mens using a scanning electron microscope, and surface changes were qualitatively evaluated. The breakdown potentials of stainless steel, two nickel titanium wires, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium were 400 mV, 300 mV, 750 mV, 300 mV, 1800 mV, and >2000 mV, respectively. SEM photographs revealed that some nickel titanium and stainless steel wires were susceptible to pitting and localized corrosion. The results indicate that corrosion occurred readily in stainless steel. Variability in breakdown potential of nickel titanium alloy wires differed across vendors' wires. The nitride coating did not affect the corrosion of the alloy, but epoxy coating decreased corrosion. Titanium wires and epoxy-coated nickel titanium wires exhibited the least corrosive potential. For patients allergic to nickel, the use of titanium or epoxy-coated wires during orthodontic treatment is recommended. PMID:10022183

  16. Hydride precipitation in titanium

    SciTech Connect

    Numakura, H.; Kowia, M.

    1984-10-01

    The crystal structure and morphology of hydride (deuteride) precipitates are investigated on ..cap alpha..-titanium specimens containing 1-3 at.% H or D by transmission electron microscopy. The hydride is found to have a face-centered tetragonal structure (c/a = 1.09) with an ordered arrangement of hydrogen, being isomorphous to ..gamma..-zirconium hydride. Two types of precipitation mode are observed with the habit planes (0110) and near (0225).

  17. 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.

  18. A Case Series of Total Hip Arthroplasty Using Cementless Hip Stem Customized for Patients of a Specific Race: 10- to 15-Year Results.

    PubMed

    Tsukada, Sachiyuki; Wakui, Motohiro

    2016-01-01

    We report a minimum of 10-year results of patients undergoing total hip arthroplasty (THA) using the cementless BiCONTACT N stem, which was developed to fit the femur in a specific race in which the predominant etiology of hip diseases was developmental dysplasia. A total of 108 hips were evaluated with a mean follow-up of 11.9 ± 1.4 years. The etiology for THA was secondary osteoarthritis due to developmental dysplasia in 90.3% of patients. No evidence of aseptic loosening of the BiCONTACT N stem was observed. The survivorship with the end point as revision surgery for any reason was 94.4% (95% confidence interval 88.7%-97.3%) at 15.0 years postoperatively. BiCONTACT N stem may be an effective alternative for patients with developmental dysplasia of the hip. PMID:26321076

  19. Cementless Total Hip Arthroplasty in Hip Dysplasia with an Extensively Porous-Coated Cylindrical Stem Modified for Asians: A 12-Year Follow-Up Study.

    PubMed

    Kato, Tsutomu; Otani, Takuya; Sugiyama, Hajime; Hayama, Tetsuo; Katsumata, Souichi; Marumo, Keishi

    2015-06-01

    Long-term outcomes of primary cementless total hip arthroplasty were examined for 198 hips of Asian patients with developmental dysplasia of the hip. AML stems were modified for patients' relatively small physique. Stable fixation was achieved despite various proximal femoral deformities. At follow up (mean 12.1 years), radiographs demonstrated fixation in all hips, with 100% stem survivorship. Radiographic changes revealed that the severity of stress-shielding was mild in 55% of hips, moderate in 26%, and severe in 19%. Longer follow up is needed to determine whether these changes will develop into clinical manifestations. A distal fixation stem can be a useful reconstruction option when application of a proximal fixation stem in primary total hip arthroplasty is difficult for various reasons. PMID:25677937

  20. 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

  1. 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

    2016-05-01

    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. PMID:26920509

  2. 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.

  3. 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.

  4. INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 26. TITANIUM INDUSTRY

    EPA Science Inventory

    The titanium industry produces two principal products, titanium metal and titanium dioxide. For purposes of analyses, therefore, the industry is considered in two segments: titanium metal production and titanium dioxide production. Two industrial process flow diagrams and eleven ...

  5. 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.

  6. 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. PMID:24176248

  7. 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.

  8. Identification of forged Bank of England £20 banknotes using IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Sonnex, Emily; Almond, Matthew J.; Baum, John V.; Bond, John W.

    2014-01-01

    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 (CO32-) 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(Csbnd H) (ca. 2900 cm-1) and ν(Cdbnd 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.

  9. 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.

  10. [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. PMID:22827063

  11. 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.

  12. 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.

  13. Reactive sputtering of titanium diboride and titanium disilicide

    SciTech Connect

    Maya, L.; Vallet, C.E.; Fiedor, J.N.

    1997-07-01

    Nanocomposite films of titanium nitride in either boron nitride or silicon nitride matrices were prepared by reactive sputtering of titanium diboride or titanium disilicide targets in a nitrogen plasma. These films were expected to have high dielectric constants and in the case of the silicon nitride matrix high hardness. The films were characterized by a variety of physicochemical techniques including photoelectron spectroscopy, Rutherford backscattering spectroscopy, RBS, and transmission electron microscopy. The films derived from titanium diboride incorporated oxygen as an inadvertent impurity in the form of titanium monoxide and dioxide. A silicon oxynitride underlayer is suggested by the RBS analysis of the silicon nitride based film, apparently arising from exposure of the native oxide on silicon to the nitrogen plasma. Capacitance measurements of the films showed moderately high dielectric constants of about 30{endash}60 and a hardness of 11 GPa for the silicon nitride nanocomposite. {copyright} {ital 1997 American Vacuum Society.}

  14. Evaluation of Die Chilling Effects during Forging of Nimonic-80A Superalloy

    NASA Astrophysics Data System (ADS)

    Shahriari, D.; Sadeghi, M. H.; Amiri, A.; Cheraghzadeh, M.

    2010-06-01

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Titanium minerals for new materials

    NASA Astrophysics Data System (ADS)

    Kotova, O.; Ozhogina, E.; Ponaryadov, A.; Golubeva, I.

    2016-04-01

    The mineral composition of titanium minerals of modern coastal-marine placer in Stradbroke Island (Australia) and Pizhma paleoplacer in Middle Timan (Russia) has been presented. The physical features of titanium minerals and their modification methods were shown. Photocatalysts on the basis of the Pizhma leucoxene were developed for water purification.

  2. Examination on the use of acoustic emission for monitoring metal forging process: A study using simulation technique

    SciTech Connect

    Mullins, W.M.; Malas, J.C. III; Venugopal, S.

    1997-05-01

    The aim of this study is to determine the feasibility of using acoustic emission as a monitoring technique for metal forging operations. From the sensor development paradigm proposed by McClean et al. the most likely approach to determining feasibility for application is through signal recognition. For this reason, signature prediction and analysis was chosen to determine the suitability for forging applications.

  3. 76 FR 5331 - Forged Stainless Steel Flanges From India and Taiwan: Final Results of Sunset Reviews and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-31

    .... See Initiation of Five-Year (``Sunset'') Review, 75 FR 67082 (November 1, 2010). We did not receive a... Forged Stainless Steel Flanges From India, 59 FR 5994 (February 9, 1994) and Antidumping Duty Order: Certain Forged Stainless Steel Flanges From Taiwan, 59 FR 5995 (February 9, 1994). On January 23,...

  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. Estimation of friction under forging conditions by means of the ring-on-disc test

    SciTech Connect

    Buchner, Bernhard; Umgeher, Andreas; Buchmayr, Bruno

    2007-04-07

    In order to understand the tribological processes and interactions in the tool-workpiece-interface systematically, basic experiments that allow an independent variation of influencing parameters are necessary. The ring-on-disc test is a popular model experiment that is often used in tribological analyses at low normal contact pressures.The scope of the paper is an analysis of the applicability of the ring-on-disc test for high normal pressures as used in forging processes, using aluminium AA6082 as workpiece material. It turned out, that this test is a convenient method to measure friction under forging conditions.

  6. 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.

  7. Citation Corporation: Compressed Air System Optimization Project Saves Energy and Improves Production at Forging Plant

    SciTech Connect

    Not Available

    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.

  8. A material based approach to creating wear resistant surfaces for hot forging

    NASA Astrophysics Data System (ADS)

    Babu, Sailesh

    Tools and dies used in metal forming are characterized by extremely high temperatures at the interface, high local pressures and large metal to metal sliding. These harsh conditions result in accelerated wear of tooling. Lubrication of tools, done to improve metal flow drastically quenches the surface layers of the tools and compounds the tool failure problem. This phenomenon becomes a serious issue when parts forged at complex and are expected to meet tight tolerances. Unpredictable and hence uncontrolled wear and degradation of tooling result in poor part quality and premature tool failure that result in high scrap, shop downtime, poor efficiency and high cost. The objective of this dissertation is to develop a computer-based methodology for analyzing the requirements hot forging tooling to resist wear and plastic deformation and wear and predicting life cycle of forge tooling. Development of such is a system is complicated by the fact that wear and degradation of tooling is influenced by not only the die material used but also numerous process controls like lubricant, dilution ratio, forging temperature, equipment used, tool geometries among others. Phenomenological models available u1 the literature give us a good thumb rule to selecting materials but do not provide a way to evaluate pits performance in field. Once a material is chosen, there are no proven approaches to create surfaces out of these materials. Coating approaches like PVD and CVD cannot generate thick coatings necessary to withstand the conditions under hot forging. Welding cannot generate complex surfaces without several secondary operations like heat treating and machining. If careful procedures are not followed, welds crack and seldom survive forging loads. There is a strong need for an approach to selectively, reliably and precisely deposit material of choice reliably on an existing surface which exhibit not only good tribological properties but also good adhesion to the substrate

  9. 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.

  10. 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. PMID:23348799

  11. Biocompatibility of Titanium

    NASA Astrophysics Data System (ADS)

    Namavar, Fereydoon; Sabirianov, Renat; Marton, Denes; Rubinstein, Alexander; Garvin, Kevin

    2012-02-01

    Titanium is the material of choice for orthopaedic applications because of its known biocompatibility. In order to enhance osteogenic properties of the Ti implants, it is necessary to understand the origin of its biocompatibility. We addresses the origin of Ti biocompatibility through (1) theoretical modeling, (2) the precise determination of Ti surface chemistry by X-ray photoelectron spectroscopy (XPS), (3) and the study of fibronectin adsorption as a function of Ti (near) surface chemistry by Enzyme-linked immunosorbent assay (ELISA). We compare the protein adsorption on Ti with the native oxide layer and the one coated by TiO2 in anatase phase using ion beam assisted deposition (IBAD). We show that the thin native sub-stoichiometric titanium oxide layer is crucial for biocompatibility of Ti surface. This is due to the enhancement of the non-specific adsorption of proteins which mediate cell adhesion. Improving the surface oxide quality, i.e. fabricating stoichiometric TiO2 (using IBAD) as well as nanoengineering the surface topology that matches its dimensions to that of adhesive proteins, is crucial for increased protein adsorption and, as a result, further increases biocompatibility of Ti implant materials.

  12. 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.

  13. Cementless total knee arthroplasty

    PubMed Central

    Risitano, Salvatore; Sabatini, Luigi; Giachino, Matteo; Agati, Gabriele; Massè, Alessandro

    2016-01-01

    Interest for uncemented total knee arthroplasty (TKA) has greatly increased in recent years. This technique, less used than cemented knee replacement in the last decades, sees a revival thanks an advance in prosthetic design, instrumentation and operative technique. The related literature in some cases shows conflicting data on survival and on the revision’s rate, but in most cases a success rate comparable to cemented TKA is reported. The optimal fixation in TKA is a subject of debate with the majority of surgeons favouring cemented fixation. PMID:27162779

  14. 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.

  15. A Life Study of Ausforged, Standard Forged and Standard Machined AISI M-50 Spur Gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

    1975-01-01

    Tests were conducted at 350 K (170 F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum induction melted (VIM) consumable-electrode vacuum-arc melted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears, but the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

  16. A life study of ausforged, standard forged, and standard machined AISI M-50 spur gears

    NASA Technical Reports Server (NTRS)

    Townsend, D. P.; Zaretsky, E. V.; Bamberger, E. N.

    1975-01-01

    Tests were conducted at 350 K with three groups of 8.9 cm pitch diameter spur gears made of vacuum-induction melted (VIM), vacuum-arc remelted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears. However, the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

  17. 76 FR 8773 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... reviews, * * *'' (76 FR 5331). Accordingly, pursuant to section 751(c) of the Tariff Act of 1930 (19 U.S.C... COMMISSION Forged Stainless Steel Flanges From India and Taiwan AGENCY: United States International Trade... steel flanges from India and Taiwan would be likely to lead to continuation or recurrence of...

  18. 75 FR 67110 - Forged Stainless Steel Flanges From India and Taiwan

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-01

    ... stainless steel flanges from India and Taiwan (65 FR 49964). Following second five-year reviews by Commerce... duty orders on imports of forged stainless steel flanges from India and Taiwan (71 FR 3457, January 23... part 201), and part 207, subparts A, D, E, and F (19 CFR part 207), as most recently amended at 74...

  19. From Pastoralism to Industrial Antipathy in William Attaway's Blood on the Forge

    ERIC Educational Resources Information Center

    Vaughan, Philip

    1975-01-01

    Asserts that Blood on the Forge, published in 1941 by black novelist, William Attaway, represented a literary achievement in its own right, and at the same time realistically portrayed the transition of a people from a structured, authoritarian, rural existence to an industrialized urban frontier. Attaway rejected traditional forms of agrarianism…

  20. The Ties That Bind: How Social Capital Is Forged and Forfeited in Teacher Communities

    ERIC Educational Resources Information Center

    Bridwell-Mitchell, E. N.; Cooc, North

    2016-01-01

    The effects of social capital on school improvement make it important to understand how teachers forge, maintain, or forfeit collegial relationships. Two common explanations focused on formal organizational features and individual characteristics do not address how social capital accrues from informal dynamics of teachers' interactions in…

  1. TRITIUM AGING EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEEL

    SciTech Connect

    Morgan, M

    2008-04-14

    The fracture toughness properties of Type 21-6-9 stainless steel were measured for forgings in the unexposed, hydrogen-exposed, and tritium-exposed-and-aged conditions. Fracture toughness samples were cut from conventionally-forged and high-energy-rate-forged forward-extruded cylinders and mechanically tested at room temperature using ASTM fracture-toughness testing procedures. Some of the samples were exposed to either hydrogen or tritium gas (340 MPa, 623 K) prior to testing. Tritium-exposed samples were aged for up to seven years and tested periodically in order to measure the effect on fracture toughness of {sup 3}He from radioactive tritium decay. The results show that hydrogen-exposed and tritium-exposed samples had lower fracture- toughness values than unexposed samples and that fracture toughness decreased with increasing decay {sup 3}He content. Forged steels were more resistant to the embrittling effects of tritium and decay {sup 3}He than annealed steels, although their fracture-toughness properties depended on the degree of sensitization that occurred during processing. The fracture process was dominated by microvoid nucleation, growth and coalescence; however, the size and spacing of microvoids on the fracture surfaces were affected by hydrogen and tritium with the lowest-toughness samples having the smallest microvoids and finest spacing.

  2. Forging limits for an aluminum matrix composite; Part 1: Experimental results

    SciTech Connect

    Syu, D.G.C.; Ghosh, A.K. )

    1994-09-01

    Forging limits in a discontinuously reinforced aluminum (DRA) matrix composite, 2014 Al/15 vol pct Al[sub 2]O[sub 3], were determined by compressing samples of various cylindrical geometries under different conditions of temperature, strain rate, and lubrication and measuring the limit strains attained prior to incipient crack formation. In some cases, circumferential grids were machined on the sample surface to obtain the local fracture strain states. Crack formation was caused by the secondary tensile stresses; however, crack propagation was relatively slow and somewhat more severe at 300 C than at 400 C. The forging limit of the composite was found to be higher at 400 C than at 300 C and also higher at slower strain rates. The plane-strain forging limit of the composite at 300 C and a strain rate of 0.5 s[sup [minus]1] was less than 0.05, while that of the matrix was higher than 0.5. It was found that the forging limits can be influenced by the depth of the circumferential grids and can be lower than those for the smooth surface samples.

  3. Interior of shop, detail of 8,000 pound forging hammer, looking ...

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

    Interior of shop, detail of 8,000 pound forging hammer, looking west - Bethlehem Steel Corporation, South Bethlehem Works, Tool Steel-Electric Furnace Shop, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

  4. Standard specification for forged carbon and alloy steel flanges for low-temperature service. ASTM standard

    SciTech Connect

    1998-10-01

    This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel, and Related Alloys and is the direct responsibility of Subcommittee A01.22 on Steel Forgings and Wrought Fittings for Piping Applications and Bolting Materials for Piping and Special Purpose Applications. Current edition approved Mar. 10, 1998 and published October 1998.

  5. Standard specification for alloy steel forgings for nonmagnetic retaining rings for generators. ASTM standard

    SciTech Connect

    1998-08-01

    This specification is under the jurisdiction of ASTM Committee A-1 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.06 on Steel Forgings and Billets. Current edition approved Nov. 10, 1997 and published August 1998. Originally published as A 289-46. Last previous edition was A 289-94.

  6. 76 FR 66996 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Forging...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-28

    ..., see the related notice published in the Federal Register on May 24, 2011 (76 FR 30200). Interested...; 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...

  7. Jernberg Industries, Inc: Forging Facility Uses Plant-Wide Assessment to Aid Conversion to Lean Manufacturing

    SciTech Connect

    2004-10-01

    Jernberg Industries conducted a plant-wide assessment while converting to lean manufacturing at a forging plant. Seven projects were identified that could yield annual savings of $791,000, 64,000 MMBtu in fuel and 6 million kWh.

  8. 75 FR 70689 - Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum-Greenwood Forge Division; Currently...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-18

    ... in the Federal Register on November 17, 2009 (74 FR 59254). At the request of the State agency and a... Employment and Training Administration Kaiser Aluminum Fabricated Products, LLC; Kaiser Aluminum- Greenwood... Aluminum Fabricated Products, LLC, Kaiser Aluminum-Greenwood Forge Division, including on- site...

  9. 76 FR 31585 - Forged Stainless Steel Flanges From India: Notice of Rescission of Antidumping Duty...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-01

    ... International Trade Administration Forged Stainless Steel Flanges From India: Notice of Rescission of... stainless steel flanges from India. The period of review is February 1, 2010, through January 22, 2011... stainless steel flanges from India. See Antidumping or Countervailing Duty Order, Finding, or...

  10. Social Work and Engineering Collaboration: Forging Innovative Global Community Development Education

    ERIC Educational Resources Information Center

    Gilbert, Dorie J.

    2014-01-01

    Interdisciplinary programs in schools of social work are growing in scope and number. This article reports on collaboration between a school of social work and a school of engineering, which is forging a new area of interdisciplinary education. The program engages social work students working alongside engineering students in a team approach to…

  11. HotEye (tm) Based Coordinate Measuring Machine for Forging Industry

    SciTech Connect

    OG Technologies

    2003-06-09

    The objective of this project is to develop a 3 dimensional measurement system for the domestic forging industry based on HotEye{trademark}. This technology will allow high definition camera to accurately image a red hot object. The project marries conventional Coordinate Measurement Machine ''CMM'' technology to HotEye{trademark} technology to permit the accurate measurement of forged parts while they are at high temperature. Being able to take such measurements will dramatically reduce the amount of scrap produced by the domestic forging industry. This industry wastes a significant amount of energy because of the high rate of scrap it produces. OGT will: (1) Develop a 3D measurement sensor head that will work on a part at a temperature up to 1,450 C with an accuracy of 0.1mm or better and with a scanning speed of less than 10 seconds for an area of 100mm x 100mm. (2) Develop a Virtual-Fixturing software package to alleviate the need of precise hard fixturing. (3) Integrate the 3D measurement sensor head and the Virtual-Fixturing software into a standard CMM, both hardware (replacing the probes) and software (data format and user interface match) so that the system can automatically perform a complete preprogrammed measurement of a hot product. (4) Test and evaluate the system in a forging facility.

  12. iPads as Placed Resources: Forging Community in Online and Off line Spaces

    ERIC Educational Resources Information Center

    Rowsell, Jennifer; Saudelli, Mary Gene; Scott, Ruth Mcquirter; Bishop, Andrea

    2013-01-01

    The article focuses on the notion of tablet technologies as placed resources (Prinsloo, 2005; Prinsloo & Rowsell, 2012) by exploring how an international research project in Australia, Canada, and the United States forged community through online spaces. There is a tendency in media and in literature to romanticize technologies like iPads as a…

  13. Hot Cutting of Real-Time Cast-Forged GS Ductile Iron for Automotive Rods

    NASA Astrophysics Data System (ADS)

    Fouilland, Laurence; Mansori, Mohamed El

    2011-01-01

    In the global economy context, automotive industry suppliers have to keep a constant advance on products design and manufacturing process. Concerning automotive rods, the substitution of forged steel by spherical graphite iron (SG iron) with high mechanical properties constitutes a valid economic alternative. Such rods are produced using a complex coupled process: casting and forging followed by an austempered heat treatment. The forging operation is capable to shape the cast rod which introduces hot deformation to increase mechanical properties of net-shape SG iron rod. However, the intermediate re-heating between casting and forging must be avoided to keep competitive manufacturing costs. A major concern of this new process development is the cracks produced in rod's surface which are consecutive to hot spruing involved after casting operations. This issue is addressed in this paper which discusses the physical mechanisms involved in the hot ductile damage of SG iron. Hot cutting tests were performed to simulate the spruing operation which shows the close interactions between microstructure, machining parameters and resulting damages. The damage mechanisms in terms of crack initiation and its growth have been studied with respect to the constituent phases (austenite+graphite nodules), the cut surface morphology and the hot cutting performance.

  14. Interior of shop, detail of 8,000 pound forging hammer (this ...

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

    Interior of shop, detail of 8,000 pound forging hammer (this hammer was probably manufactured the Chambersburg Engineering Company of Chambersburg, Pennsylvania), looking east - Bethlehem Steel Corporation, South Bethlehem Works, Tool Steel-Electric Furnace Shop, Along Lehigh River, North of Fourth Street, West of Minsi Trail Bridge, Bethlehem, Northampton County, PA

  15. T & I--Metalworking, Forging. Kit No. 55. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Lake, Robert J.

    An instructor's manual and student activity guide on forging are provided in this set of prevocational education materials which focuses on the vocational area of trade and industry (metalworking). (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture, home…

  16. 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.

  17. Descaling and cleaning titanium and titanium alloy surfaces

    SciTech Connect

    Not Available

    1981-01-01

    The recommended practice covers a cleaning and descaling procedure useful to producers, users, and fabricators of titanium and titanium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants. The procedures are not mandatory for removal of the indicated soils but rather serve as a guide when titanium and titanium alloys are being processed in the wrought, cast, or fabricated form. The soils should be removed prior to chemical milling, joining, plating, fabrication, and in any situation where foreign substances interfere with the corrosion resistance, stability, and quality of the finished product. The recommended practice discusses processing soil removal, blast cleaning, pickling, descaling, and inspection. (JMT)

  18. 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''?

  19. 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.

  20. Bony Healing of Unstable Thoracolumbar Burst Fractures in the Elderly Using Percutaneously Applied Titanium Mesh Cages and a Transpedicular Fixation System with Expandable Screws

    PubMed Central

    Eschler, Anica; Ender, Stephan Albrecht; Schiml, Katharina; Mittlmeier, Thomas; Gradl, Georg

    2015-01-01

    Introduction There is a high incidence of vertebral burst fractures following low velocity trauma in the elderly. Treatment of unstable vertebral burst fractures using the same principles like in stable vertebral burst fractures may show less favourable results in terms of fracture reduction, maintenance of reduction and cement leakage. In order to address these shortcomings this study introduces cementless fixation of unstable vertebral burst fractures using internal fixators and expandable intravertebral titanium mesh cages in a one-stage procedure via minimum-invasive techniques. Material and Methods A total of 16 consecutive patients (median age 76 years, range 58–94) with unstable thoracolumbar burst fractures and concomitant osteoporosis were treated by an internal fixator inserted via minimum invasive technique one level above and below the fractured vertebra. Fracture reduction was achieved and maintained by transpedicular placement of two titanium mesh cages into the fractured vertebral body during the same procedure. Intra- and postoperative safety of the procedure as well as analysis of reduction quality was analysed by 3D C-arm imaging or CT, respectively. Clinical and radiographic follow-up averaged 10.4 months (range 4.5–24.5). Results Stabilization of the collapsed vertebral body was achieved in all 16 cases without any intraoperative complication. Surgical time averaged 102±6.6 minutes (71–194). The postoperative kyphotic angle (KA) and Cobb angle revealed significant improvements (KA 13.7° to 7.4°, p<0.001; Cobb 9.6° to 6.0°, p<0.002) with partial loss of reduction at final follow-up (KA 8.3°, Cobb 8.7°). VAS (Visual Analogue Scale) improved from 7.6 to 2.6 (p<0.001). Adjacent fractures were not observed. One minor (malposition of pedicle screw) complication was encountered. Conclusion Cementless fixation of osteoporotic burst fractures revealed substantial pain relief, adequate maintenance of reduction and a low complication rate

  1. The use of β titanium alloys in the aerospace industry

    NASA Astrophysics Data System (ADS)

    Boyer, R. R.; Briggs, R. D.

    2005-12-01

    Beta titanium alloys have been available since the 1950s (Ti-13V-11Cr-3Mo or B120VCA), but significant applications of these alloys, beyond the SR-71 Blackbird, have been slow in coming. The next significant usage of a β alloy did not occur until the mid-1980s on the B-1B bomber. This aircraft used Ti-15V-3Cr-3Al-3Sn sheet due to its capability for strip rolling, improved formability, and higher strength than Ti-6Al-4V. The next major usage was on a commercial aircraft, the Boeing 777, which made extensive use of Ti-10V-2Fe-3Al high-strength forgings. Ti-15V-3Cr-3Al-3Sn environmental control system ducting, castings, and springs were also used, along with Ti-3Al-8V-6Cr-4Mo-4Zr (β-C) springs. Beta-21S was also introduced for high-temperature usage. More recent work at Boeing has focused on the development of Ti-5Al-5Mo-5V-3Cr, a high-strength alloy that can be used at higher strength than Ti-10V-2Fe-3Al and is much more robust; it has a much wider, or friendlier, processing window. This, along with additional studies at Boeing, and from within the aerospace industry in general will be discussed in detail, summarizing applications and the rationale for the selection of this alloy system for aerospace applications.

  2. 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.

  3. Titanium/gold process characterization

    SciTech Connect

    Fajardo, L.S.

    1991-11-01

    Characterization of the titanium/gold (Ti/Au) deposition process used at the Allied-Signal Inc., Albuquerque Microelectronics Operation (AMO) was performed. Tests were conducted to set up evaporation parameters, correlate titanium and gold thicknesses to sheet resistance, improve thickness uniformity, and reduce frontside contamination of deposit material on product wafers. The Ti/Au process is the final step in the production of integrated circuits (ICs) at the AMO wafer fabrication facility. 3 figs.

  4. Continuous production of titanium powder

    SciTech Connect

    Gerdemann, Stephen J.; Oden, Laurence L.; White, Jack C.

    1997-01-01

    Although incremental improvements have been made to the Kroll process since its inception in 1948, the process in use today remains essentially the same batch process developed by Dr. Kroll and perfected by the U.S. Bureau of Mines. In this process, titanium tetrachloride (TiCl4) is reduced by magnesium to produce titanium metal. There are two major limitations to the Kroll process: (1) it is a batch process; and (2) the reduction of TiCl4 proceeds so rapidly that the sponge formed is an interlocking dendritic mass with inclusions of magnesium, magnesium salts and titanium subchloride that must undergo several purification steps before the metal is suitable for use. The Albany Research Center (ARC), formerly the U.S. Bureau of Mines, has investigated a new, continuous titanium metal production process in which a titanium powder is produced in a bath of molten salt. In this process, the rate of the reduction reaction was slowed and controlled by diluting the reactants with molten chloride salts. The diluted reactant streams were combined in a continuous stirred tank reactor, operated much like a crystallizer. New titanium metal forms on the already present small Ti particles. When the Ti particles become too large to remain suspended in solution, they fall to the bottom of the reactor and are removed. Initial experiments show promise but problems remain in obtaining the required purity and uniform particle size.

  5. Low cost titanium--myth or reality

    SciTech Connect

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    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, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  6. TC17 titanium alloy laser melting deposition repair process and properties

    NASA Astrophysics Data System (ADS)

    Liu, Qi; Wang, Yudai; Zheng, Hang; Tang, Kang; Li, Huaixue; Gong, Shuili

    2016-08-01

    Due to the high manufacturing cost of titanium compressor blisks, aero engine repairing process research has important engineering significance and economic value. TC17 titanium alloy is a rich β stable element dual α+β phase alloy whose nominal composition is Ti-5Al-2Sn-2Zr-4Mo-4Cr. It has high mechanical strength, good fracture toughness, high hardenability and a wide forging-temperature range. Through a surface response experiment with different laser powers, scanning speeds and powder feeding speeds, the coaxial powder feeding laser melting deposition repair process is studied for the surface circular groove defects. In this paper, the tensile properties, relative density, microhardness, elemental composition, internal defects and microstructure of the laser-repaired TC17 forging plate are analyzed. The results show that the laser melting deposition process could realize the form restoration of groove defect; tensile strength and elongation could reach 1100 MPa and 10%, which could reach 91-98% that of original TC17 wrought material; with the optimal parameters (1000 W-25 V-8 mm/s), the microhardness of the additive zone, the heat-affected zone and base material is evenly distributed at 370-390 HV500. The element content difference between the additive zone and base material is less than ±0.15%. Due to the existence of the pores 10 μm in diameter, the relative density could reach 99%, which is mainly inversely proportional to the powder feeding speed. The repaired zone is typically columnar and dendrite crystal, and the 0.5-1.5 mm-deep heat-affected zone in the groove interface is coarse equiaxial crystal.

  7. Omega phase formation in titanium and titanium alloys

    SciTech Connect

    Gray, G.T. III; Morris, C.E.; Lawson, A.C.

    1992-05-01

    Although the response of titanium alloys to dynamic loading is receiving increased attention in the literature (particularly in the area of shear-band formation), a more limited experimental database exists concerning the detailed structure/property relationships of titanium alloys subjected to shock loading. In this study, preliminary results concerning the influence of alloy chemistry on the property of omega-phase formation and its structure in three titanium alloys are presented. The influence of shock-wave deformation on the phase stability and substructure evolution of high-purity (low-interstitial) titanium, A-70 (3700 ppm oxygen) titanium, and Ti-6Al-4V were probed utilizing real-time velocity interferometry (VISAR) and ``soft`` shock-recovery techniques. VISAR wave profiles of shock-loaded high-purity titanium revealed the omega-phase pressure-induced transition to occur at approximately 10.4 GPa. Wave profile measurements on A-70 Ti shocked to pressures up to 35 GPa and Ti-6Al-4V shocked to pressures up to 25 GPa exhibited no evidence of a three-wave structure indicative of a pressure-induced phase transition. Neutron and X-ray diffractometry and TEM analysis confirmed the presence of retained {omega}-phase in the electrolytic-Ti and the absence of {omega}-phase in the shock-recovered A-70 Ti and Ti-6Al-4V. Suppression of the {alpha}-{omega} phase transition in A-70 Ti, containing a high interstitial oxygen content, is seen to simultaneously correlate with suppression of deformation twinning. Neutron diffraction was used to measure the in-situ bulk lattice constants and volume fraction of the {alpha} and {omega} phases in the recovered high-purity titanium samples that were shock loaded. The influence of alloy content on the kinetics of formation/retention of {omega}-phase and substructure evolution is discussed and contrasted in light of previous literature studies.

  8. Cementless surface replacement hemiarthroplasty for primary glenohumeral osteoarthritis: results of over 5-year follow-up in patients with or without rotator cuff deficiency

    PubMed Central

    Al-Hadithy, Nawfal; Furness, Nicholas; Patel, Ronak; Jonas, Sam; Jobbagy, Attila; Lowdon, Ian

    2015-01-01

    Background Cementless surface replacement hemiarthroplasty (CSRHA) is an established treatment for glenohumeral osteoarthritis; however, studies evaluating its role in arthritis with rotator cuff deficiency are limited. This study reviews the outcomes of CSRHA for glenohumeral osteoarthritis with and without rotator cuff tears. Methods 41 CSRHA (Mark III Copeland prosthesis) were performed for glenohumeral osteoarthritis with intact rotator cuffs (n = 21) and cuff-deficient shoulders (n = 20). Patients were assessed using Oxford and Constant questionnaires, patient satisfaction, range of motion measurements and by radiography. Results Mean age and follow-up were 75 years and 5.1 years, respectively. Functional gains were significantly higher in patients with intact rotator cuffs compared to cuff-deficient shoulders, with Oxford Shoulder Score improving from 18 to 37.5 and 15 to 27 and forward flexion improved from 60° to 126° and 44° to 77° in each group, respectively. Two patients with deficient cuffs had deficient subscapularis tendons; one of which was dislocated anteriorly. Conclusions CSRHA provides significant improvements in pain and function in patients with glenohumeral osteoarthritis. In patients with deficient cuffs, functional gains are limited, and should be considered in low-demand patients where pain is the primary problem. Caution should be taken in patients with a deficient subscapularis as a result of the risk of dislocation.

  9. REVISION TOTAL HIP ARTHROPLASTY USING A MODULAR CEMENTLESS DISTAL FIXATION PROSTHESIS: THE ZMR® HIP SYSTEM. CLINICAL AND RADIOGRAPHIC ANALYSIS OF 30 CASES

    PubMed Central

    Canella, Richard Prazeres; de Alencar, Paulo Gilberto Cimbalista; Ganev, Gerson Gandhi; de Vincenzi, Luiz Fernando

    2015-01-01

    Objective: To evaluate the clinical and radiographic results from 30 cases of revision of total hip arthroplasty using a modular cementless distal fixation prosthesis: the ZMR® Hip System. Method: Between July 2005 and December 2008, 30 operations were performed, on 14 men and 14 women. Two male patients had bilateral surgery. The mean age was 59.2 years (29-81 years), with a mean follow-up of 24 months. The Paprosky classification was used for periprosthetic bone loss, and the Harris Hip Score (HHS) was used to evaluate clinical results. On radiographs, distal migration of the femoral stem was defined in accordance with Sporer. Proximal bone remodeling was classified using the Callaghan criteria. Results: The mean preoperative HHS was 39, and there was a significant increase to 93 points in the final evaluation, which indicated excellent clinical results. No femoral stem migration greater than 5 mm (Sporer) was observed on radiographs, thus suggesting that all the femoral prostheses presented osseointegration and remained stable from the time of the surgery until the final evaluation. The proximal femoral remodeling was either type B or type C in 29 hips, according to Callaghan. Seven patients had complications, but without interfering with osseointegration of the femoral components. Conclusion: Our results from revision of total hip arthroplasty using the ZMR® Hip System were extremely encouraging, and all the components became osseointegrated and remained fixed at the time of the final evaluation. PMID:27022553

  10. Cell response of anodized nanotubes on titanium and titanium alloys.

    PubMed

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells. PMID:23436766

  11. Titanium nanostructures for biomedical applications.

    PubMed

    Kulkarni, M; Mazare, A; Gongadze, E; Perutkova, Š; Kralj-Iglič, V; Milošev, I; Schmuki, P; A Iglič; Mozetič, M

    2015-02-13

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties. PMID:25611515

  12. Titanium nanostructures for biomedical applications

    NASA Astrophysics Data System (ADS)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  13. 76 FR 52313 - Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges, and Picks...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Heavy Forged Hand Tools (i.e., Axes & Adzes, Bars & Wedges, Hammers & Sledges... AGENCY: Import Administration, International Trade Administration, Department of Commerce. SUMMARY: As...

  14. Effects of Cryogenic Forging and Anodization on the Mechanical Properties of AA 7075-T73 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Shih, Teng-Shih; Liao, Tien-Wei; Hsu, Wen-Nong

    2016-03-01

    In this study, high-strength AA7075 alloy samples were cryogenically forged after annealing and then subjected to solution and aging treatments. The cryogenically forged 7075-T73 alloy samples displayed equiaxed fine grains associated with abundant fine precipitates in their matrix. Compared with conventional 7075-T73 alloy samples, the cryogenically forged samples exhibited an 8-12% reduction in tensile strength and an increased fatigue strength and higher corrosion resistance. The fatigue strength measured at 107 cycles was 225 MPa in the bare samples; the strength was increased to 250 MPa in the cryogenically forged samples. The effect of anodization on the corrosion resistance of the bare samples was improved from (E corr) -0.80 to -0.61 V.

  15. Forging processes: Lubrication. January 1970-January 1990 (A Bibliography from the COMPENDEX data base). Report for January 1970-January 1990

    SciTech Connect

    Not Available

    1990-05-01

    This bibliography contains citations concerning lubricants used in the forging industries to reduce tool wear and help prevent buildup formation on tools. Methods developed to select and evaluate forging lubricants for both safety and effectiveness are described. Low-pollution level, water-based synthetic lubricants, and non-corrosive, graphite-free lubricants are described. Mathematical modelling and finite element analyses used to determine lubricant dosage and distribution are included. (Contains 189 citations fully indexed and including a title list.)

  16. Plasma quench production of titanium from titanium tetrachloride

    SciTech Connect

    Sears, J.W.

    1994-10-01

    This project, Plasma Quench Production of Titanium from Titanium Tetrachloride, centers on developing a technique for rapidly quenching the high temperature metal species and preventing back reactions with the halide. The quenching technique chosen uses the temperature drop produced in a converging/diverging supersonic nozzle. The rapid quench provided by this nozzle prevents the back reaction of the halide and metal. The nature of the process produces nanosized particles (10 to 100 nm). The powders are collected by cyclone separators, the hydrogen flared, and the acid scrubbed. Aluminum and titanium powders have been produced in the laboratory-scale device at 1 gram per hour. Efforts to date to scale up this process have not been successful.

  17. Meta-Model Based Optimisation Algorithms for Robust Optimization of 3D Forging Sequences

    SciTech Connect

    Fourment, Lionel

    2007-04-07

    In order to handle costly and complex 3D metal forming optimization problems, we develop a new optimization algorithm that allows finding satisfactory solutions within less than 50 iterations (/function evaluation) in the presence of local extrema. It is based on the sequential approximation of the problem objective function by the Meshless Finite Difference Method (MFDM). This changing meta-model allows taking into account the gradient information, if available, or not. It can be easily extended to take into account uncertainties on the optimization parameters. This new algorithm is first evaluated on analytic functions, before being applied to a 3D forging benchmark, the preform tool shape optimization that allows minimizing the potential of fold formation during the two-stepped forging sequence.

  18. HYDROGEN EFFECTS ON THE FRACTURE TOUGHNESS PROPERTIES OF FORGED STAINLESS STEELS

    SciTech Connect

    Morgan, M

    2008-03-28

    The effect of hydrogen on the fracture toughness properties of Types 304L, 316L and 21-6-9 forged stainless steels was investigated. Fracture toughness samples were fabricated from forward-extruded forgings. Samples were uniformly saturated with hydrogen after exposure to hydrogen gas at 34 MPa or 69 and 623 K prior to testing. The fracture toughness properties were characterized by measuring the J-R behavior at ambient temperature in air. The results show that the hydrogen-charged steels have fracture toughness values that were about 50-60% of the values measured for the unexposed steels. The reduction in fracture toughness was accompanied by a change in fracture appearance. Both uncharged and hydrogen-charged samples failed by microvoid nucleation and coalescence, but the fracture surfaces of the hydrogen-charged steels had smaller microvoids. Type 316L stainless steel had the highest fracture toughness properties and the greatest resistance to hydrogen degradation.

  19. Structure of magnesium alloy MA14 after multistep isothermal forging and subsequent isothermal rolling

    NASA Astrophysics Data System (ADS)

    Nugmanov, D. R.; Sitdikov, O. Sh.; Markushev, M. V.

    2015-10-01

    Optical metallography and electron microscopy have been used to analyze the structural changes in magnesium MA14 alloy subjected to processing that combines multistep isothermal forging and isothermal rolling. It has been found that forging of a bulk workpiece leads to the formation of a structure, 85-90% of which consists of recrystallized grains with an average size of less than 5 µm. Subsequent rolling results in a completely recrystallized structure with a grain size of 1-2 µm. It is shown that the resultant structural states are characterized by grain size nonuniformity inherited from the initial hot-pressed semi-finished product. The nature and features of crystallization processes that take place in the alloy during processing are discussed.

  20. A marvel of medieval Indian metallurgy: Thanjavur's forge-welded iron cannon

    NASA Astrophysics Data System (ADS)

    Balasubramaniam, R.; Saxena, A.; Anantharaman, Tanjore R.; Reguer, S.; Dillmann, P.

    2004-01-01

    In this article, metallurgical aspects of a 17th century forge-welded iron cannon at Thanjavur are addressed, including an analysis of manufacturing methodology based on careful observation of its constructional details. Microstructural examination of iron from the cannon reveals that the iron was extracted from ore by the direct process. Thus, the cannon was fabricated by forge welding and not by casting. Electrochemical polarization studies indicate that the corrosion rate of the cannon iron can be compared to that of 0.05% carbon mild steel under complete immersion conditions. However, the atmospheric corrosion resistance of the cannon is far superior to that of modern steel and can be attributed to the formation of an adherent protective passive film. It is concluded that this cannon constitutes a marvel of medieval Indian metallurgical skill.

  1. Effect of isothermal forging on microstructure and fatigue behavior of blended elemental Ti-6Al-4V powder compacts

    NASA Astrophysics Data System (ADS)

    Weiss, I.; Eylon, D.; Toaz, M. W.; Froes, F. H.

    1986-03-01

    The effect of isothermal hot forging (IHF) on microstructure, pore closure, and tensile and fatigue properties of Ti-6A1-4V blended elemental cold pressed and sintered powder compacts was investigated. Two types of sponge fines were used: (a) high chloride produced by the Hunter sodium reduction process (HP) and (b) low chloride produced by the electrolytic process (EP). The as-sintered HP compacts were 99 pct dense while the EP compacts were only 92 pct dense. All sintered preforms were isothermally hot forged below the beta transus temperature and reached almost full density. The microstructure of the HP forged compacts consisted of fine equiaxed alpha, while the EP forged compacts exhibited a coarse lenticular alpha structure after 30 pct reduction and a partially recrystallized structure after 68 pct reduction. It was found that EP compacts forged to a 30 pct reduction exhibited a low fatigue limit of 172 MPa (25 ksi), since the lenticular alpha morphology and the residual porosity resulted in premature fatigue crack initiation. On the other hand, a higher fatigue strength of 485 MPa (70 ksi) was obtained for EP compacts forged to a 78 pct reduction due to the mixed equiaxed/lenticular alpha morphology as well as removal of stress concentration features such as interparticle pore interfaces.

  2. Titanium pigmentation. An electron probe microanalysis study

    SciTech Connect

    Dupre, A.; Touron, P.; Daste, J.; Lassere, J.; Bonafe, J.L.; Viraben, R.

    1985-05-01

    A patient had an unusual pigmentary disease induced by titanium dioxide. The use of a topical cream containing titanium dioxide caused a xanthomalike appearance on the patient's penis. Electron probe microanalysis was valuable in establishing the cause of this balanitis.

  3. Method for Surface Texturing Titanium Products

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    1998-01-01

    The present invention teaches a method of producing a textured surface upon an arbitrarily configured titanium or titanium alloy object for the purpose of improving bonding between the object and other materials such as polymer matrix composites and/or human bone for the direct in-growth of orthopaedic implants. The titanium or titanium alloy object is placed in an electrolytic cell having an ultrasonically agitated solution of sodium chloride therein whereby a pattern of uniform "pock mark" like pores or cavities are produced upon the object's surface. The process is very cost effective compared to other methods of producing rough surfaces on titanium and titanium alloy components. The surface textures produced by the present invention are etched directly into the parent metal at discrete sites separated by areas unaffected by the etching process. Bonding materials to such surface textures on titanium or titanium alloy can thus support a shear load even if adhesion of the bonding material is poor.

  4. Parallel investigation of double forged pure tungsten samples irradiated in three DPF devices

    NASA Astrophysics Data System (ADS)

    Gribkov, V. A.; Paduch, M.; Zielinska, E.; Laas, T.; Shirokova, V.; Väli, B.; Paju, J.; Pimenov, V. N.; Demina, E. V.; Latyshev, S. V.; Niemela, J.; Crespo, M.-L.; Cicuttin, A.; Talab, A. A.; Pokatilov, A.; Parker, M.

    2015-08-01

    The double forged pure tungsten (W) samples (supplied by IAEA CRP from the FZJ team in Juelich, Germany) were irradiated in DPF (dense plasma focus) devices PF-12, "Bora" and PF-1000 by hot plasma and fast ion streams. We have used the following analytical methods: microscopy (optical and scanning electron), X-ray photoelectron spectroscopy, electrical conductivity and microroughness measurements. The damage dependence of the tungsten grades on irradiation conditions and power flux densities of irradiation processes is discussed.

  5. Innovative Die Material and Lubrication Strategies for Clean and Energy Conserving Forging Technologies

    SciTech Connect

    Rajiv Shivpuri; Sailesh Babu; Lin Yang; Yijun Zhu

    2007-01-08

    The objective of this project was to develop and implement innovative die material and surface coating strategies such as composite dies and lubricated coatings to increase die lives and to reduce environmental pollution. In this project approaches and software were developed for die life optimization and optimal design of lubrication systems for hot forging. In addition, LENS applied nickel-aluminide coatings were developed and validated in the industrial environment for significant improvements in die life.

  6. Evolution of the Ultrasonic Inspection of Heavy Rotor Forgings Over the Last Decades

    NASA Astrophysics Data System (ADS)

    Zimmer, A.; Vrana, J.; Meiser, J.; Maximini, W.; Blaes, N.

    2010-02-01

    All types of heavy forgings that are used in energy machine industry, rotor shafts as well as discs, retaining rings or tie bolts are subject to extensive nondestructive inspections before they are delivered to the customer. Due to the availability of the parts in simple shapes, these forgings are very well suited for full volmetric inspections using ultrasound. In the beginning, these inspections were carried out manually, using straight beam probes and analogue equipment. Higher requirements in reliability, efficiency, safety and power output in the machines have lead to higher requirements for the ultrasonic inspection in the form of more scanning directions, higher sensitivity demands and improved documentation means. This and the increasing use of high alloy materials for ever growing parts, increase the need for more and more sophisticated methods for testing the forgings. Angle scans and sizing technologies like DGS have been implemented, and for more than 15 years now, mechanized and automated inspections have gained importance since they allow better documentation as well as easier evaluation of the recorded data using different views (B- C- or D-Scans), projections or tomography views. The latest major development has been the availability of phased array probes to increase the flexibility of the inspection systems. Many results of the ongoing research in ultrasonic's have not been implemented yet. Today's availability of fast computers, large and fast data storages allows saving RF inspection data and applying sophisticated signal processing methods. For example linear diffraction tomography methods like SAFT offer tools for 3D reconstruction of inspection data, simplifying sizing and locating of defects as well as for improving signal to noise ratios. While such methods are already applied in medical ultrasonic's, they are still to be implemented in the steel industry. This paper describes the development of the ultrasonic inspection of heavy forgings

  7. Lightweight Protective Coatings For Titanium Alloys

    NASA Technical Reports Server (NTRS)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  8. Process for reproducibly preparing titanium subhydride

    SciTech Connect

    Carlson, R.S.

    1982-01-05

    Titanium subhydride is produced in a reactor by heating a selected amount of finely divided titanium compound at a selected temperature for a selected period of time under dynamic vacuum conditions. Hydrogen is removed substantially uniformly from each powder grain and there is produced a subhydride of substantially uniform titanium-hydrogen composition. Selection of the amount, temperature and time produces a subhydride of selected titanium hydrogen composition.

  9. Process for reproducibly preparing titanium subhydride

    DOEpatents

    Carlson, Richard S.

    1982-01-01

    Titanium subhydride is produced in a reactor by heating a selected amount of finely divided titanium compound at a selected temperature for a selected period of time under dynamic vacuum conditions. Hydrogen is removed substantially uniformly from each powder grain and there is produced a subhydride of substantially uniform titanium-hydrogen composition. Selection of the amount, temperature and time produces a subhydride of selected titanium-hydrogen composition.

  10. Grain Size Estimation of Superalloy Inconel 718 After Upset Forging by a Fuzzy Inference System

    NASA Astrophysics Data System (ADS)

    Toro, Luis; Cavazos, Alberto; Colás, Rafael

    2009-12-01

    A fuzzy logic inference system was designed to predict the grain size of Inconel 718 alloy after upset forging. The system takes as input the original grain size, temperature, and reduction rate at forging and predicts the final grain size at room temperature. It is assumed that the system takes into account the effects that the heterogeneity of deformation and grain growth exerts in this particular material. Experimental trials were conducted in a factory that relies on upset forging to produce preforms for ring rolling. The grain size was reported as ASTM number, as this value is used on site. A first attempt was carried out using a series of 15 empirically based set of rules; the estimation error with these was above two ASTM numbers; which is considered to be very high. The system was modified and expanded to take into account 28 rules; the estimation error of this new system resulted to be close to one ASTM number, which is considered to be adequate for the prediction.

  11. Cavitation and failure during hot forging of Ti-6Al-4V

    SciTech Connect

    Semiatin, S.L.; Goetz, R.L.; Seetharaman, V.; Shell, E.B.; Ghosh, A.K.

    1999-05-01

    The occurrence of cavity initiation and gross, free-surface fracture during subtransus hot pancake forging of Ti-6Al-4V with a transformed beta (colony) microstructure was established. Cavity initiation mechanisms were one of two distinct types. At temperatures approximately 75 C or more below the beta transus temperature (T{sub {beta}}), cavity initiation occurred at relatively low strains in the beta phase lying between the grain-boundary alpha phase and the lamellar colonies. By contrast, at temperatures near the transus (i.e., T {approx} T{sub {beta}} {minus} 25 C), cavity initiation occurred at much larger strains as a result of microfracture of partially-to-fully globularized alpha phase. Finite element method (FEM) modeling of the pancake forging process revealed that secondary tensile stresses were used to correlate both the cavity initiation and the gross free-surface fracture results to previous observations from uniaxial hot tension tests in which identical damage mechanisms had been observed. The tensile work criterion of Cockcroft and Latham (C + L) gave moderately good (quantitative) correlation between the forging and uniaxial tension behaviors. An alternate comparison based on the Rice and Tracey cavity growth model gave reasonable predictions of free-surface fracture but tended to overestimate the incidence of subsurface cavity initiation.

  12. Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape

    SciTech Connect

    Filice, Luigino; Gagliardi, Francesco; Umbrello, Domenico; Shivpuri, Rajiv

    2007-05-17

    Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load.

  13. Experimental and Numerical Investigation of Forging Process to Reproduce a 3D Aluminium Foam Complex Shape

    NASA Astrophysics Data System (ADS)

    Filice, Luigino; Gagliardi, Francesco; Shivpuri, Rajiv; Umbrello, Domenico

    2007-05-01

    Metallic foams represent one of the most exciting materials introduced in the manufacturing scenario in the last years. In the study here addressed, the experimental and numerical investigations on the forging process of a simple foam billet shaped into complex sculptured parts were carried out. In particular, the deformation behavior of metallic foams and the development of density gradients were investigated through a series of experimental forging tests in order to produce a selected portion of a hip prosthesis. The human bone replacement was chosen as case study due to its industrial demand and for its particular 3D complex shape. A finite element code (Deform 3D®) was utilized for modeling the foam behavior during the forging process and an accurate material rheology description was used based on a porous material model which includes the measured local density. Once the effectiveness of the utilized Finite Element model was verified through the comparison with the experimental evidences, a numerical study of the influence of the foam density was investigated. The obtained numerical results shown as the initial billet density plays an important role on the prediction of the final shape, the optimization of the flash as well as the estimation of the punch load.

  14. Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Kim, H. H.; Kang, C. G.

    2010-06-01

    Die casting process has been used widely for complex automotive products such as the knuckle, arm and etc. Generally, a part fabricated by casting has limited strength due to manufacturing defects by origin such as the dendrite structure and segregation. As an attempt to offer a solution to these problems, forging has been used as an alternative process. However, the forging process provides limited formability for complex shape products. Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of A356 aluminum molten state. This paper presents the results of an A356 aluminum alloy sample, which were obtained by experiment and by simulation using DEFORM 3D V6.1. Samples of metal parts were subsequently fabricated by using hydraulic press machinery. In order to compare the influence of loading method, two types of samples were fabricated: (1) samples fabricated under direct loading die sets (2) those fabricated under indirect loading die sets. The formability and defects, which were predicted by FEM simulation, were similar to those of samples used in practice.

  15. Non-destructive Testing of Forged Metallic Materials by Active Infrared Thermography

    NASA Astrophysics Data System (ADS)

    Maillard, S.; Cadith, J.; Bouteille, P.; Legros, G.; Bodnar, J. L.; Detalle, V.

    2012-11-01

    Nowadays, infrared thermography is considered as the reference method in many applications such as safety, the inspection of electric installations, or the inspection of buildings' heat insulation. In recent years, the evolution of both material and data-processing tools also allows the development of thermography as a real non-destructive testing method. Thus, by subjecting the element to be inspected to an external excitation and by analyzing the propagation of heat in the examined zone, it is possible to highlight surface or subsurface defects such as cracks, delaminations, or corrosion. One speaks then about active infrared thermography. In this study, some results obtained during the collective studies carried out by CETIM and the University of Reims for the forging industry are presented. Various experimental possibilities offered by active thermography are presented and the interest in this method in comparison with the traditional non-destructive testing methods (penetrant testing and magnetic particle inspection) is discussed. For example, comparative results on a forged cracked hub, a steering joint, and a threaded rod are presented. They highlight the interest of infrared thermography stimulated by induction for forged parts.

  16. Effects of Forging Process Parameters on Microstructure Evolution of Aluminum Alloy 7050

    SciTech Connect

    Yi Youping; Shi Yan; Yang Jihui; Lin Yongcheng

    2007-04-07

    The objective of this work is to investigate the behavior of microstructure evolution of aluminum alloy 7050 under the condition of different forging process parameters by means of combining materials physical model with finite element code. For the purpose of establishing constitutive equation and physical model of microstructure evolution, the isothermal compression test were performed by machine Gleeble 1500 on the condition of temperatures ranging from 250 deg. C to 450 deg. C and constant strain rates of 0.01s-1, 0.1s-1, 1s-1 and 10s-1. The behaviors of microstructure evolutions of aluminum alloy 7050 under difference process parameters were studied by metallographic observations. The experiment results showed that recrystallization during forming process occurred at the critical strain and the volume fraction of recrystallization changed with the temperature and strain rate. According to the results of isothermal compression test, a constitutive equation and an empirical model of DRX were obtained. A finite element code DEFORM 3D was used to analyze the influence of different forging process parameters on the behavior of microstructure evolution in details. The present model and simulation method can be served as a useful tool to predict and control the properties and shape of aluminum alloy 7050 components during forging.

  17. Material Behavior Based Hybrid Process for Sheet Draw-Forging Thin Walled Magnesium Alloys

    SciTech Connect

    Sheng, Z.Q.; Shivpuri, R.

    2005-08-05

    Magnesium alloys are conventionally formed at the elevated temperatures. The thermally improved formability is sensitive to the temperature and strain rate. Due to limitations in forming speeds, tooling strength and narrow processing windows, complex thin walled parts cannot be made by traditional warm drawing or hot forging processes. A hybrid process, which is based on the deformation mechanism of magnesium alloys at the elevated temperature, is proposed that combines warm drawing and hot forging modes to produce an aggressive geometry at acceptable forming speed. The process parameters, such as temperatures, forming speeds etc. are determined by the FEM modeling and simulation. Sensitivity analysis under the constraint of forming limits of Mg alloy sheet material and strength of tooling material is carried out. The proposed approach is demonstrated on a conical geometry with thin walls and with bottom features. Results show that designed geometry can be formed in about 8 seconds, this cannot be formed by conventional forging while around 1000s is required for warm drawing. This process is being further investigated through controlled experiments.

  18. Computer-assisted Rheo-forging Processing of A356 Aluminum Alloys

    SciTech Connect

    Kim, H. H.; Kang, C. G.

    2010-06-15

    Die casting process has been used widely for complex automotive products such as the knuckle, arm and etc. Generally, a part fabricated by casting has limited strength due to manufacturing defects by origin such as the dendrite structure and segregation. As an attempt to offer a solution to these problems, forging has been used as an alternative process. However, the forging process provides limited formability for complex shape products. Rheo-forging of metal offers not only superior mechanical strength but also requires significantly lower machine loads than solid forming processes. In order to produce semi-solid materials of the desired microstructure, a stirring process is applied during solidification of A356 aluminum molten state. This paper presents the results of an A356 aluminum alloy sample, which were obtained by experiment and by simulation using DEFORM 3D V6.1. Samples of metal parts were subsequently fabricated by using hydraulic press machinery. In order to compare the influence of loading method, two types of samples were fabricated: (1) samples fabricated under direct loading die sets (2) those fabricated under indirect loading die sets. The formability and defects, which were predicted by FEM simulation, were similar to those of samples used in practice.

  19. FEA Based Tool Life Quantity Estimation of Hot Forging Dies Under Cyclic Thermo-Mechanical Loads

    NASA Astrophysics Data System (ADS)

    Behrens, B.-A.; Bouguecha, A.; Schäfer, F.; Hadifi, T.

    2011-01-01

    Hot forging dies are exposed during service to a combination of cyclic thermo-mechanical, tribological and chemical loads. Besides abrasive and adhesive wear on the die surface, fatigue crack initiation with subsequent fracture is one of the most frequent causes of failure. In order to extend the tool life, the finite element analysis (FEA) may serve as a means for process design and process optimisation. So far the FEA based estimation of the production cycles until initial cracking is limited as tool material behaviour due to repeated loading is not captured with the required accuracy. Material models which are able to account for cyclic effects are not verified for the fatigue life predictions of forging dies. Furthermore fatigue properties from strain controlled fatigue tests of relevant hot work steels are to date not available to allow for a close-to-reality fatigue life prediction. Two industrial forging processes, where clear fatigue crack initiation has been observed are considered for a fatigue analysis. For this purpose the relevant tool components are modelled with elasto-plastic material behaviour. The predicted sites, where crack initiation occurs, agree with the ones observed on the real die component.

  20. Simulations and Experiments of the Nonisothermal Forging Process of a Ti-6Al-4V Impeller

    NASA Astrophysics Data System (ADS)

    Prabhu, T. Ram

    2016-06-01

    In the present study, a nonisothermal precision forging process of a Ti-6Al-4V first-stage impeller for the gas turbine engine was simulated using the finite element software. The simulation results such as load requirements, damage, velocity field, stress, strain, and temperature distributions are discussed in detail. Simulations predicted the maximum load requirement of about 80 MN. The maximum temperature loss was observed at the contour surface regions. The center and contour regions are the high-strained regions in the part. To validate the model, forging experiments mimicking simulations were performed in the α + β phases region (930 °C). The selected locations of the part were characterized for tensile properties at 27 and 200 °C, hardness, microstructure, grain size, and the amount of primary α phase based on the strain distribution results. The soundness of the forged part was verified using fluorescent penetrant test (Mil Std 2175 Grade A) and ultrasonic test (AMS 2630 class A1). From the experimental results, it was found that the variations in the hardness, tensile properties at room, and elevated temperature are not significant. The microstructure, grain size, and primary α phase content are nearly same.

  1. An Approach to Optimize Size Parameters of Forging by Combining Hot-Processing Map and FEM

    NASA Astrophysics Data System (ADS)

    Hu, H. E.; Wang, X. Y.; Deng, L.

    2014-11-01

    The size parameters of 6061 aluminum alloy rib-web forging were optimized by using hot-processing map and finite element method (FEM) based on high-temperature compression data. The results show that the stress level of the alloy can be represented by a Zener-Holloman parameter in a hyperbolic sine-type equation with the hot deformation activation energy of 343.7 kJ/mol. Dynamic recovery and dynamic recrystallization concurrently preceded during high-temperature deformation of the alloy. Optimal hot-processing parameters for the alloy corresponding to the peak value of 0.42 are 753 K and 0.001 s-1. The instability domain occurs at deformation temperature lower than 653 K. FEM is an available method to validate hot-processing map in actual manufacture by analyzing the effect of corner radius, rib width, and web thickness on workability of rib-web forging of the alloy. Size parameters of die forgings can be optimized conveniently by combining hot-processing map and FEM.

  2. Mechanical properties of titanium connectors.

    PubMed

    Neo, T K; Chai, J; Gilbert, J L; Wozniak, W T; Engelman, M J

    1996-01-01

    The tensile mechanical properties of welded titanium joints were studied, and intact titanium was used as controls. Welded joints were fabricated with either a stereographic laser-welding technique or a gas tungsten arc welding technique. The effect of heat treatment following a simulated porcelain application was also investigated. Heat-treated laser welds had significantly lower ultimate tensile strengths. Heat treatment had no effect on the modulus of elasticity or elongation, but generally significantly decreased the yield strength of the titanium specimens. The gas tungsten are welding specimens had significantly higher yield strengths and elastic moduli than the other two groups. The elongation of the control specimens was significantly greater than the elongation of the gas tungsten arc welding specimens, which was in turn significantly higher than that of the laser-welded specimens. PMID:8957877

  3. Photonuclear reactions on titanium isotopes

    SciTech Connect

    Belyshev, S. S.; Dzhilavyan, L. Z.; Ishkhanov, B. S.; Kapitonov, I. M.; Kuznetsov, A. A. Orlin, V. N.; Stopani, K. A.

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  4. Adaptive mesh refinement in titanium

    SciTech Connect

    Colella, Phillip; Wen, Tong

    2005-01-21

    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  5. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  6. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  7. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  8. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  9. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  10. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  11. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  12. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  13. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  14. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  15. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  16. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  17. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  18. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  19. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  20. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  1. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  2. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  3. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  4. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  5. Thermal Stir Welds in Titanium

    NASA Astrophysics Data System (ADS)

    Fonda, Richard W.; Knipling, Keith E.; Pilchak, Adam L.

    2016-01-01

    Although conventional friction stir welding (FSW) has proven unsuccessful in joining thick sections of alpha and near-alpha titanium alloys, thermal stir welding, a variant of the FSW process in which an external heat source is used to preheat the workpiece, is demonstrated to be able to reliably join 12.3-mm-thick plates of CP titanium. This paper describes the microstructures and textures that develop in these thermal stir welds. The observed microstructure was used to reconstruct the high-temperature microstructure and texture present during the welding process and therefore reveal the genesis of the welding structures.

  6. Rifampicin-fosfomycin coating for cementless endoprostheses: antimicrobial effects against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Alt, Volker; Kirchhof, Kristin; Seim, Florian; Hrubesch, Isabelle; Lips, Katrin S; Mannel, Henrich; Domann, Eugen; Schnettler, Reinhard

    2014-10-01

    New strategies to decrease infection rates in cementless arthroplasty are needed, especially in the context of the growing incidence of methicillin-resistant Staphylococcus aureus (MRSA) infections. The purpose of this study was to investigate the antimicrobial activity of a rifampicin-fosfomycin coating against methicillin-sensitive Staphylococcus aureus (MSSA) and MRSA in a rabbit infection prophylaxis model. Uncoated or rifampicin-fosfomycin-coated K-wires were inserted into the intramedullary canal of the tibia in rabbits and contaminated with an inoculation dose of 10(5) or 10(6) colony-forming units of MSSA EDCC 5055 in study 1 and MRSA T6625930 in study 2, respectively. After 28days the animals were killed and clinical, histological and microbiological assessment, including pulse-field gel electrophoresis, was conducted. Positive culture growth in agar plate testing and/or clinical signs and/or histological signs were defined positive for infection. Statistical evaluation was performed using Fisher's exact test. Both studies showed a statistically significant reduction of infection rates for rifampicin-fosfomycin-coated implants compared to uncoated K-wires (P=0.015). In both studies none of the 12 animals that were treated with a rifampicin-fosfomycin-coated implant showed clinical signs of infection or a positive agar plate testing result. In both studies, one animal of the coating group showed the presence of sporadic bacteria with concomitant inflammatory signs in histology. The control groups in both studies exhibited an infection rate of 100% with clear clinical signs of infection and positive culture growth in all animals. In summary, the rifampicin-fosfomycin-coating showed excellent antimicrobial activity against both MSSA and MRSA, and therefore warrants further clinical testing. PMID:24948548

  7. Cementless anatomical prosthesis for the treatment of 3-part and 4-part proximal humerus fractures: cadaver study and prospective clinical study with minimum 2 years followup

    PubMed Central

    Obert, Laurent; Saadnia, Rachid; Loisel, François; Uhring, Julien; Adam, Antoine; Rochet, Séverin; Clappaz, Pascal; Lascar, Tristan

    2016-01-01

    Introduction: The purpose of this study was to evaluate the functional and radiological outcomes of a cementless, trauma-specific locked stem for 3- and 4-part proximal humeral fractures. Materials and methods: This study consisted of two parts: a cadaver study with 22 shoulders and a multicenter prospective clinical study of 23 fracture patients evaluated at least 2 years after treatment. In the cadaver study, the locked stem (HumelockTM, FX Solutions) and its instrumentation were evaluated. In the clinical study, five senior surgeons at four different hospitals performed the surgical procedures. An independent surgeon evaluated the patients using clinical (Constant score, QuickDASH) and radiological (X-rays, CT scans) outcome measures. Results: The cadaver study allowed us to validate the height landmarks relative to the pectoralis major tendon. In the clinical study, at the review, abduction was 95° (60–160), forward flexion was 108° (70–160), external rotation (elbow at body) was 34° (0–55), the QuickDASH was 31 (4.5–59), the overall Constant score was 54 (27–75), and the weighted Constant score was 76 (31.5–109). Discussion: This preliminary study of hemiarthroplasty (HA) with a locked stem found results that were at least equivalent to published series. As all patients had at least a 2-year follow-up, integration of the locked stem did not cause any specific complications. These results suggest that it is possible to avoid using cement when hemiarthroplasty is performed for the humeral stem. This implant makes height adjustment and transosseous suturing of the tuberosities more reproducible. PMID:27194107

  8. Synthesis and properties of nanoscale titanium boride

    NASA Astrophysics Data System (ADS)

    Efimova, K. A.; Galevskiy, G. V.; Rudneva, V. V.

    2015-09-01

    This work reports the scientific and technological grounds for plasma synthesis of titanium diboride, including thermodynamic and kinetic conditions of boride formation when titanium and titanium dioxide are interacting with products resulting from boron gasification in the nitrogen - hydrogen plasma flow, and two variations of its behavior using the powder mixtures: titanium - boron and titanium dioxide - boron. To study these technology variations, the mathematical models were derived, describing the relation between element contents in the synthesized products of titanium and free boron and basic parameters. The probable mechanism proposed for forming titanium diboride according to a "vapour - melt - crystal" pattern was examined, covering condensation of titanium vapour in the form of aerosol, boriding of nanoscale melt droplets by boron hydrides and crystallization of titanium - boron melt. The comprehensive physical - chemical certification of titanium diboride was carried out, including the study of its crystal structure, phase and chemical composition, dispersion, morphology and particle oxidation. Technological application prospects for use of titanium diboride nanoscale powder as constituent element in the wettable coating for carbon cathodes having excellent physical and mechanical performance and protective properties.

  9. Fatigue behavior of titanium alloys

    SciTech Connect

    Boyer, R.R.; Eylon, D.; Luetjering, G.

    1999-07-01

    This symposium was international in nature, with leaders in the fields of fatigue technology and the metallurgy of titanium from the US, Europe and Asia. It covered basic research, development, applications and modeling--life predictions and design of both fatigue crack initiation and propagation of titanium alloys. There were presentations on the full range of titanium alloy systems, from commercially pure and {alpha}-alloys, {alpha}/{beta}- and {beta}-alloys to the gamma titanium aluminides. The effects of processing/heat treatment/microstructure on the fatigue properties were discussed, and models proposed to correlate the microstructures to the observed fatigue performance. Test environments reported on included hard vacuum (and the effect of vacuum level), vacuums with partial pressures of miscellaneous gases, lab air and aqueous media. A session was devoted to the effects of environment and fatigue enhancement via surface treatments using techniques such as shot peening and roller burnishing. The effects of dwell on both S-N and crack growth rate behavior were covered. It was a very comprehensive symposium with presentations from academia, government laboratories and industry, with industrial participants ranging from the petroleum industry to medical and aerospace interests. This book has been separated into four sections, representing the technology areas covered in various sessions, namely Mechanisms of Fatigue crack Initiation and Propagation of Conventional Alloys, Fatigue in Intermetallics, Environmental and Surface Aspects of Fatigue, and Application, Life Prediction and Design. Separate abstracts were prepared for most papers in this volume.

  10. Lactobacillusassisted synthesis of titanium nanoparticles

    PubMed Central

    2007-01-01

    An eco-friendlylactobacillussp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  11. PLUTONIUM-URANIUM-TITANIUM ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-07-28

    A plutonium-uranium alloy suitable for use as the fuel element in a fast breeder reactor is described. The alloy contains from 15 to 60 at.% titanium with the remainder uranium and plutonium in a specific ratio, thereby limiting the undesirable zeta phase and rendering the alloy relatively resistant to corrosion and giving it the essential characteristic of good mechanical workability.

  12. Tensile and Fracture Properties of Cast and Forged Composite Synthesized by Addition of Al-Si Alloy to Magnesium

    NASA Astrophysics Data System (ADS)

    Nanjunda Swamy, H. M.; Nath, S. K.; Ray, S.

    2009-12-01

    Cast Mg-Al-Si composites synthesized by addition of Al-Si alloy containing 10, 15, and 20 wt pct of Si, in molten magnesium, to generate particles of Mg2Si by reaction between silicon and magnesium during stir casting has opened up the possibility to control the size of these particles. The microstructure of the cast composite consists of relatively dark polyhedral phase of Mg2Si and bright phase of β-Al12Mg17 along the boundary between dendrites of α-Mg solid solution. After hot forging at 350 °C, the microstructure has changed to relatively smaller sizes of β-Al12Mg17 and Mg2Si particles apart from larger grains surrounded by smaller grains due to dynamic recovery and recrystallization. Some of the Mg2Si particles crack during forging. In both the cast and forged composite, the Brinell hardness increases rapidly with increasing volume fraction of Mg2Si, but the hardness is higher in forged composites by about 100 BHN. Yield strength in cast composites improves over that of the cast alloy, but there is a marginal increase in yield strength with increasing Mg2Si content. In forged composites, there is significant improvement in yield strength with increasing Mg2Si particles and also over those observed in their cast counterpart. In cast composites, ultimate tensile strength (UTS) decreases with increasing Mg2Si content possibly due to increased casting defects such as porosity and segregation, which increases with increasing Mg2Si content and may counteract the strengthening effect of Mg2Si content. However, in forged composite, UTS increases with increasing Mg2Si content until 5.25 vol pct due to elimination of segregation and lowering of porosity, but at higher Mg2Si content of 7 vol pct, UTS decreases, possibly due to extensive cracking of Mg2Si particles. On forging, the ductility decreases in forged alloy and composites possibly due to the remaining strain and the forged microstructure. The initiation fracture toughness, J IC , decreases drastically in

  13. Small Titanium Oxo Clusters: Primary Structures of Titanium(IV) in Water.

    PubMed

    Zhang, Guanyun; Hou, Jie; Tung, Chen-Ho; Wang, Yifeng

    2016-04-01

    For sol-gel synthesis of titanium oxide, the titanium(IV) precursors are dissolved in water to form clear solutions. However, the solution status of titanium(IV) remains unclear. Herein three new and rare types of titanium oxo clusters are isolated from aqueous solutions of TiOSO4 and TiCl4 without using organic ligands. Our results indicate that titanium(IV) is readily hydrolyzed into oxo oligomers even in highly acidic solutions. The present clusters provide precise structural information for future characterization of the solution species and structural evolution of titanium(IV) in water and, meanwhile, are new molecular materials for photocatalysis. PMID:26990885

  14. Investigation of the Workability and Response of Ti-6Al-4V Titanium alloys at Lower Elevated Temperature and Higher Strain Rate

    SciTech Connect

    Huang, Cindy Xiaohui; Lim, Chao Voon; Castagne, Sylvie

    2011-05-04

    Titanium and its alloys have a wide range of applications in various industries such as aerospace, medical, automotive and even commercial products. However, formability of titanium alloys has always been an issue. This study presents the results of an investigation on the workability and response of Ti-6Al-4V deformed at different strain rates and lower elevated temperatures with different initial microstructures. Compression tests of cylindrical specimens were performed at various temperatures (300 deg. C, 400 deg. C, 450 deg. C, 500 deg. C) and at different strain rates (0.001 s{sup -1}, 0.02 s{sup -1} and 0.1 s{sup -1}). The effects of strain rate, temperature and initial microstructure on the workability of the Ti alloy were investigated. Based on these experimental results, workability maps for the respective initial microstructures were developed. Results showed that temperature played an important role in the formability of Ti-6Al-4V titanium alloys unlike strain rate. In addition, feasibility study on Multi-Directional Forging (MDF) was performed and positive results were obtained. It was demonstrated that Ti-6Al-4V titanium alloys can undergo severe plastic deformation at lower elevated temperature (400-500 deg. C) and at a higher strain rate of 0.1 s{sup -1}.

  15. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-08-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  16. Computer-Aided Design of Manufacturing Chain Based on Closed Die Forging for Hardly Deformable Cu-Based Alloys

    NASA Astrophysics Data System (ADS)

    Pietrzyk, Maciej; Kuziak, Roman; Pidvysots'kyy, Valeriy; Nowak, Jarosław; Węglarczyk, Stanisław; Drozdowski, Krzysztof

    2013-07-01

    Two copper-based alloys were considered, Cu-1 pct Cr and Cu-0.7 pct Cr-1 pct Si-2 pct Ni. The thermal, electrical, and mechanical properties of these alloys are given in the paper and compared to pure copper and steel. The role of aging and precipitation kinetics in hardening of the alloys is discussed based upon the developed model. Results of plastometric tests performed at various temperatures and various strain rates are presented. The effect of the initial microstructure on the flow stress was investigated. Rheologic models for the alloys were developed. A finite element (FE) model based on the Norton-Hoff visco-plastic flow rule was applied to the simulation of forging of the alloys. Analysis of the die wear for various processes of hot and cold forging is presented as well. A microstructure evolution model was implemented into the FE code, and the microstructure and mechanical properties of final products were predicted. Various variants of the manufacturing cycles were considered. These include different preheating schedules, hot forging, cold forging, and aging. All variants were simulated using the FE method and loads, die filling, tool wear, and mechanical properties of products were predicted. Three variants giving the best combination of forging parameters were selected and industrial trials were performed. The best manufacturing technology for the copper-based alloys is proposed.

  17. Effect of Forging Parameters on Low Cycle Fatigue Behaviour of Al/Basalt Short Fiber Metal Matrix Composites

    PubMed Central

    Karthigeyan, R.; Ranganath, G.

    2013-01-01

    This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface. PMID:24298207

  18. Effects of Low Temperature on Hydrogen-Assisted Crack Growth in Forged 304L Austenitic Stainless Steel

    NASA Astrophysics Data System (ADS)

    Jackson, Heather; San Marchi, Chris; Balch, Dorian; Somerday, Brian; Michael, Joseph

    2016-06-01

    The objective of this study was to evaluate effects of low temperature on hydrogen-assisted crack propagation in forged 304L austenitic stainless steel. Fracture initiation toughness and crack-growth resistance curves were measured using fracture mechanics specimens that were thermally precharged with 140 wppm hydrogen and tested at 293 K or 223 K (20 °C or -50 °C). Fracture initiation toughness for hydrogen-precharged forgings decreased by at least 50 to 80 pct relative to non-charged forgings. With hydrogen, low-temperature fracture initiation toughness decreased by 35 to 50 pct relative to room-temperature toughness. Crack growth without hydrogen at both temperatures was microstructure-independent and indistinguishable from blunting, while with hydrogen microcracks formed by growth and coalescence of microvoids. Initiation of microvoids in the presence of hydrogen occurred where localized deformation bands intersected grain boundaries and other deformation bands. Low temperature additionally promoted fracture initiation at annealing twin boundaries in the presence of hydrogen, which competed with deformation band intersections and grain boundaries as sites of microvoid formation and fracture initiation. A common ingredient for fracture initiation was stress concentration that arose from the intersection of deformation bands with these microstructural obstacles. The localized deformation responsible for producing stress concentrations at obstacles was intensified by low temperature and hydrogen. Crack orientation and forging strength were found to have a minor effect on fracture initiation toughness of hydrogen-supersaturated 304L forgings.

  19. Effect of forging parameters on low cycle fatigue behaviour of Al/basalt short fiber metal matrix composites.

    PubMed

    Karthigeyan, R; Ranganath, G

    2013-01-01

    This paper deals with metal matrix composites (MMCs) of Al 7075 alloy containing different weight percentage (2.5, 5, 7.5, and 10) basalt short fiber reinforcement and unreinforced matrix alloy. The samples were produced by the permanent stir casting technique. The casting ingots were cut into blanks to be forged in single stage and double stage, using MN press and graphite-based lubricant. The microstructures and fatigue properties of the matrix alloy and MMC samples were investigated in the as cast state and in the single and double stage forging operations. The microstructure results showed that the forged sample had a uniform distribution of the basalt short fiber throughout the specimens. Evaluation of the fatigue properties showed that the forged samples had higher values than those of the as cast counterparts. After forging, the enhancement of the fatigue strength of the matrix alloy was so significant and high in the case of 2.5 and 5.0 wt. percentage basalt short fiber reinforced MMC, and there was no enhancement in 7.5 and 10 weight percentages short fiber reinforced MMCs. The fracture damage was mainly due to decohesion at the matrix-fiber interface. PMID:24298207

  20. Tensile properties of titanium electrolytically charged with hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1971-01-01

    Yield strength, ultimate tensile strength, and elongation were studied for annealed titanium electrolytically charged with hydrogen. The hydrogen was present as a surface hydride layer. These tensile properties were generally lower for uncharged titanium than for titanium with a continuous surface hydride; they were greater for uncharged titanium than for titanium with an assumed discontinuous surface hydride. We suggest that the interface between titanium and titanium hydride is weak. And the hydride does not necessarily impair strength and ductility of annealed titanium. The possibility that oxygen and/or nitrogen can embrittle titanium hydride is discussed.

  1. Thermo-mechanical modeling of the electrically-assisted manufacturing (EAM) technique during open die forging

    NASA Astrophysics Data System (ADS)

    Salandro, Wesley A.

    This thesis contains all of the steps which allow the Electrically-Assisted Manufacturing (EAM) technique to be experimentally explored and analytically modeled for an electrically-assisted forging operation. Chapter 1 includes the problem statement, proposed solution, and literature reviews on EAM. Chapter 2 describes a thorough background on the EAM technique, highlights prior EAM research, and explains the research approach taken for this thesis. The coupled thermo-mechanical modeling strategy, along with the introduction of the Electroplastic Effect Coefficient (EEC) is provided in Chapter 3. Chapter 4 explains the two different approaches to determine the EEC profiles when modeling a particular metal. The simplified EAF mechanical model for electrically-assisted forging is presented in Chapter 5. Also in this chapter, the same modeling methodology (i.e. thermo-mechanical, EEC, etc.) is used to predict loads for an electrically-assisted bending (EAB) process. The following chapters explore how different material- and process-based parameters affect the EAF technique. Chapter 6 examines how different workpiece contact areas affect EAF effectiveness, along with an exploration of how well different metal forming lubricants perform with EAF. Chapter 7 explores if there is a difference in the thermal or mechanical profiles of specimens undergoing EAF forging tests with different average grain sizes. Chapter 8 examines the same effects as the previous chapter on specimens with varying levels of prior cold work. The materials- and process-based simplifications and sensitivities of the proposed modeling strategy are outlined in Chapter 9. Chapters 10-14 include the science behind the electroplastic effect, conclusions, future work, broader impacts, and intellectual merit, respectively. The overall intention of this thesis is to show the candidate's ability to take an idea for a new manufacturing process, prove that it works, and then understand and model the process

  2. Forging of eccentric co-extruded Al-Mg compounds and analysis of the interface strength

    NASA Astrophysics Data System (ADS)

    Förster, W.; Binotsch, C.; Awiszus, B.; Lehmann, T.; Müller, J.; Kirbach, C.; Stockmann, M.; Ihlemann, J.

    2016-03-01

    Within the subproject B3 of the Collaborative Research Center 692 it has been shown that Al-Mg compounds with a good bonding quality can be produced by hydrostatic coextrusion. During processing by forging, the aluminum sleeve is thinned in areas of high strains depending on the component geometry. To solve this problem an eccentric core arrangement during co-extrusion was investigated. Based on the results of FE-simulations, the experimental validation is presented in this work. Rods with an offset of 0.25, 0.5 and 0.75 mm were produced by eccentric hydrostatic co-extrusion. Ultrasonic testing was used to evaluate the bonding quality across the entire rods. For the forging investigations the basic process Rising was chosen. The still good bonding quality after forging was examined by dye penetrant testing and optical microscopy. For an optimal stress transfer between the materials across the entire component, a sufficient bonding between the materials is essential. To evaluate the interface strength, a special bending test was developed. For the conception of the bending specimens it was required to analyze the Rising specimens geometry. These analyses were performed using a reconstruction of the geometrical data based on computer tomography (CT) investigations. The comparison with the numerically deter-mined Rising specimen geometry shows good correlation. Parametric Finite Element Analyses of the bending test were used to develop the load case and the specimen geometry. By means of iterative adaption of load application, bearing and specimen geometry parameters, an advantageous stress state and experimentally applicable configuration were found. Based on this conception, the experimental setup was configured and bending tests were performed. The interface strength was deter-mined by the calculation of the maximum interlaminar interfacial tension stress using the experimental interface failure force and the bending FE model.

  3. High Temperature, Slow Strain Rate Forging of Advanced Disk Alloy ME3

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; OConnor, Kenneth

    2001-01-01

    The advanced disk alloy ME3 was designed in the HSR/EPM disk program to have extended durability at 1150 to 1250 F in large disks. This was achieved by designing a disk alloy and process producing balanced monotonic, cyclic, and time-dependent mechanical properties. combined with robust processing and manufacturing characteristics. The resulting baseline alloy, processing, and supersolvus heat treatment produces a uniform, relatively fine mean grain size of about ASTM 7, with as-large-as (ALA) grain size of about ASTM 3. There is a long term need for disks with higher rim temperature capabilities than 1250 F. This would allow higher compressor exit (T3) temperatures and allow the full utilization of advanced combustor and airfoil concepts under development. Several approaches are being studied that modify the processing and chemistry of ME3, to possibly improve high temperature properties. Promising approaches would be applied to subscale material, for screening the resulting mechanical properties at these high temperatures. n obvious path traditionally employed to improve the high temperature and time-dependent capabilities of disk alloys is to coarsen the grain size. A coarser grain size than ASTM 7 could potentially be achieved by varying the forging conditions and supersolvus heat treatment. The objective of this study was to perform forging and heat treatment experiments ("thermomechanical processing experiments") on small compression test specimens of the baseline ME3 composition, to identify a viable forging process allowing significantly coarser grain size targeted at ASTM 3-5, than that of the baseline, ASTM 7.

  4. Titanium-Oxygen Reactivity Study

    NASA Technical Reports Server (NTRS)

    Chafey, J. E.; Scheck, W. G.; Witzell, W. E.

    1962-01-01

    A program has been conducted at Astronautics to investigate the likelihood of occurrence of the catastrophic oxidation of titanium alloy sheet under conditions which simulate certain cases of accidental failure of the metal while it is in contact with liquid or gaseous oxygen. Three methods of fracturing the metal were used; they consisted of mechanical puncture, tensile fracture of welded joints, and perforation by very high velocity particles. The results of the tests which have been conducted provide further evidence of the reactivity of titanium with liquid and gaseous oxygen. The evidence indicates that the rapid fracturing of titanium sheet while it is in contact with oxygen initiates the catastrophic oxidation reaction. Initiation occurred when the speed of the fracture was some few feet per second, as in both the drop-weight puncture tests and the static tensile fracture tests of welded joints, as well as when the speed was several thousand feet per second, as in the simulated micrometeoroid penetration tests. The slow propagation of a crack, however, did not initiate the reaction. It may logically be concluded that the localized frictional heat of rapid fracture and/or spontaneous oxidation (exothermic) of minute particles emanating from the fracture cause initiation of the reaction. Under conditions of slow fracture, however, the small heat generated may be adequately dissipated and the reaction is not initiated. A portion of the study conducted consisted of investigating various means by which the reaction might be retarded or prevented. Providing a "barrier" at the titanium-oxygen interface consisting of either aluminum metal or a coating of a petroleum base corrosion inhibitor appeared to be only partially effective in retarding the reaction. The accidental puncturing or similar rupturing of thin-walled pressurized oxygen tanks on missiles and space vehicle will usually constitute loss of function, and may sometimes cause their catastrophic destruction

  5. A Metallurgical Investigation of Large Forged Discs of Low-carbon N-155 Alloy

    NASA Technical Reports Server (NTRS)

    Cross, Howard C; Freeman, J W

    1947-01-01

    Research was undertaken to ascertain the properties of better wrought heat resisting alloys in the form of large discs required for gas turbine rotors. The properties of large discs of low carbon N-155 alloy in both the as-forged and water-quenched and aged conditions were determined by means of stress-rupture and creep tests for time periods up to about 2000 hours at 1200, 1350, and 1500 F. Short-time tensile test, impact test, and time-total deformation characteristics are included. The principle results are given.

  6. Simulated comparison on kinematics properties of two typical mechanisms of forging manipulator

    NASA Astrophysics Data System (ADS)

    Ren, Yunpeng; Lu, Chongshao; Han, Qingkai; Zhang, Tianxia; Wen, Bangchun

    2007-12-01

    The kinematics of two typical mechanisms is analyzed following the concept design of a 4MNm forging manipulator for a huge hydraulic press, i.e. a parallel links mechanism and a swing links mechanism. For the first kind of mechanism, when the jaw swings up and down, the swing angle is in proportion to the extending length of its driving hydraulic cylinder. For the second kind of mechanism, it is mostly difficult for the fluid driving control system to make sure three hydraulic pressure cylinders to keep moving synchronously. Based on these simulations and considering practical technological demands, the first kind of mechanism with parallel links is chosen as a better one.

  7. Conventionally cast and forged copper alloy for high-heat-flux thrust chambers

    NASA Technical Reports Server (NTRS)

    Kazaroff, John M.; Repas, George A.

    1987-01-01

    The combustion chamber liner of the space shuttle main engine is made of NARloy-Z, a copper-silver-zirconium alloy. This alloy was produced by vacuum melting and vacuum centrifugal casting; a production method that is currently now available. Using conventional melting, casting, and forging methods, NASA has produced an alloy of the same composition called NASA-Z. This report compares the composition, microstructure, tensile properties, low-cycle fatigue life, and hot-firing life of these two materials. The results show that the materials have similar characteristics.

  8. Modelling of Viscoplastic Behaviour of IN718 Under Hot Forging Conditions

    SciTech Connect

    Lin, Y. P.; Lin, J.; Dean, T. A.; Brown, P. D.

    2007-04-07

    The mechanical properties of IN718 are directly related to microstructure such as grain size and the hardening mechanisms, which are effective during thermomechanical processing and subsequent heat treatment. In this study a set of unified viscoplastic constitutive equations were determined for IN718 from experimental data of hot forging conditions. Techniques were developed to analyse the reliability and consistency of the experimental data derived from different previous publications. In addition to viscoplastic flow of the material, the determined material model can be used to predict the evolution of dislocations, recrystallisation and grain size occurring during thermomechanical processing.

  9. Texture evolution in Al-Li 2195 alloy during net shape roll forging

    SciTech Connect

    Kalu, P.N.; Zhang, Lan

    1998-06-12

    The quest to manufacture low-cost, large complex structures with minimum material wastage has instigated research into near-net shape (NNS) technologies. In this paper, the microstructural and texture evolution in Al-Li 2195 alloy resulting from a specific NNS processing called roll forging was evaluated. The processing consists of five stages and combines conventional ingot conversion (stages I and II), back extrusion (stage III) and ring rolling to produce hollow cylinder (stage IV). Considerable potential exists for the property enhancement of the components produced by this processing method if a better understanding of the evolution of microstructure and texture is developed.

  10. Mode III cleavage of a coin-shaped titanium implant in bone: effect of friction and crack propagation.

    PubMed

    Mathieu, Vincent; Vayron, Romain; Barthel, Etienne; Dalmas, Davy; Soffer, Emmanuel; Anagnostou, Fani; Haiat, Guillaume

    2012-04-01

    Endosseous cementless implants are widely used in orthopaedic, maxillofacial and oral surgery. However, failures are still observed and remain difficult to anticipate as remodelling phenomena at the bone-implant interface are poorly understood. The assessment of the biomechanical strength of the bone-implant interface may improve the understanding of the osseointegration process. An experimental approach based on a mode III cleavage mechanical device aims at understanding the behaviour of a planar bone-implant interface submitted to torsional loading. To do so, coin-shaped titanium implants were inserted on the tibiae of a New Zealand white rabbit for seven weeks. After the sacrifice, mode III cleavage experiments were performed on bone samples. An analytical model was developed to understand the debonding process of the bone-implant interface. The model allowed to assess the values of different parameters related to bone tissue at the vicinity of the implant with the additional assumption that bone adhesion occurs over around 70% of the implant surface, which is confirmed by microscopy images. The approach allows to estimate different quantities related to the bone-implant interface such as: torsional stiffness (around 20.5 N m rad(-1)), shear modulus (around 240 MPa), maximal torsional loading (around 0.056 N.m), mode III fracture energy (around 77.5 N m(-1)) and stress intensity factor (0.27 MPa m(1/2)). This study paves the way for the use of mode III cleavage testing for the investigation of torsional loading strength of the bone-implant interface, which might help for the development and optimization of implant biomaterial, surface treatment and medical treatment investigations. PMID:22402166

  11. Submicrometer transparent alumina by sinter forging seeded {gamma}-Al{sub 2}O{sub 3} powders

    SciTech Connect

    Kwon, O.H.; Nordahl, C.S.; Messing, G.L.

    1995-02-01

    Seeding boehmite with {alpha}-Al{sub 2}O{sub 3}, followed by calcination at 600 C, results in an agglomerated alumina powder (<53 {mu}m) that can be sinter forged to full density at 1,250 C. Compressive strains as high as {var_epsilon}{sub z} = {minus}0.9, and radial flow ({var_epsilon}{sub r} = 1.0) during sinter forging remove large, interagglomerate pores. The fully dense alumina has a grain size of 0.4 {mu}m and is visually transparent. It is proposed that deformation of dense agglomerates is the primary mechanism responsible for large pore elimination and compact densification. The sinter forging of sol-gel-derived alumina powders offers a new technology to prepare highly transparent, optical ceramics at lower temperatures than conventional routes.

  12. Metallographic preparation of titanium diboride coatings

    SciTech Connect

    McAllaster, M.E.

    1980-03-01

    A method is described for preparing metallographic cross sections of thin, hard, chemically vapor deposited titanium diboride coatings on various softer substrates. Standard metallographic preparation techniques were found to result in fracturing and edge rounding of the coatings. It is shown that these problems can be avoided by unidirectional grinding on worn 600 grit silicon carbide abrasive paper. Typical photomicrographs of chemically vapor deposited titanium diboride coatings are shown along with photomicrographs of intermediate phases that form at the titanium diboride - substrate interfaces.

  13. Production of titanium from ilmenite: a review

    SciTech Connect

    Kohli, R.

    1981-12-01

    The general principles for beneficiation of titanium ores are reviewed and the specific processes used in individual units in various countries are discussed. This is followed by a critical evaluation of various current and potential reduction methods for the production of titanium metal from the processed concentrates. Finally, the report outlines a research program for the development of a commercially viable alternative method for the production of titanium metal.

  14. Ultrafine-grained titanium for medical implants

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

    2002-01-01

    We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

  15. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, S.J.; White, J.C.

    1998-08-04

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag. 1 fig.

  16. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1999-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  17. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1998-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  18. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    SciTech Connect

    Gerdemann, S.J.; White, J.C.

    1999-10-19

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  19. The effects of hydrogen embrittlement of titanium

    NASA Technical Reports Server (NTRS)

    Taylor, Delbert J.

    1989-01-01

    Titanium alloys, by virtue of their attractive strength to density ratio, fatigue, fracture toughness and corrosion resistance are now commonly used in various aerospace and marine applications. The cost, once very expensive, has been reduced, making titanium even more of a competitive material today. Titanium and titanium alloys have a great affinity to several elements. Hydrogen, even in small amounts, can cause embrittlement, which in turn causes a reduction in strength and ductility. The reduction of strength and ductility is the subject of this investigation.

  20. Method for producing titanium aluminide weld rod

    DOEpatents

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

    1995-01-01

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.