Heat treatment giving a stable high temperature micro-structure in cast austenitic stainless steel

DOEpatents

Anton, Donald L.; Lemkey, Franklin D.

1988-01-01

A novel micro-structure developed in a cast austenitic stainless steel alloy and a heat treatment thereof are disclosed. The alloy is based on a multicomponent Fe-Cr-Mn-Mo-Si-Nb-C system consisting of an austenitic iron solid solution (.gamma.) matrix reinforced by finely dispersed carbide phases and a heat treatment to produce the micro-structure. The heat treatment includes a prebraze heat treatment followed by a three stage braze cycle heat treatment.

Operational Determination of Physical and Mechanical Properties of Cast Samples of High-Strength Iron by Means of a Magnetic-Mechanical Method

NASA Astrophysics Data System (ADS)

Slyusarev, Yu. K.; Braga, A. V.; Slyusarev, I. Yu.

2017-09-01

The effect of the chemical composition of high-strength cast iron VCh35 on the content, shape and diameter of graphite inclusions and on the presence of structurally-free cementite and defects is studied. A relationship is determined between the structure and metallurgical defects and characteristics of the mechanical and magnetic rigidity of cast samples. Relationships are established in a group of factors and property characteristics: chemical composition - microstructure - mechanical rigidity - magnetic stiffness. The basis of a method is established making it possible to perform operative non-destructive monitoring of the melt quality preparation for high-strength iron casting.

Age-Strengthening of Cast Iron and Its Effects on Machinability: Review of the Literature

NASA Astrophysics Data System (ADS)

Richards, Von L.

This presentation is a review of the research performed over several years to characterize the age-strengthening behavior of graphitic cast iron alloys (gray iron, ductile iron and CG iron.) Nitrogen in metastable solid solution in ferrite is necessary for the age strengthening to occur, similar to quench aging of steels. The activation energy for age strengthening is similar to that for diffusion of nitrogen. Age-strengthening can occur even if the ferrite is present as a phase in pearlite. However, machinability benefits only occur when there is free ferrite in the microstructure.

Microstructure Aspects of a Newly Developed, Low Cost, Corrosion-Resistant White Cast Iron

NASA Astrophysics Data System (ADS)

Sain, P. K.; Sharma, C. P.; Bhargava, A. K.

2013-04-01

The purpose of this work is to study the influence of heat treatment on the corrosion resistance of a newly developed white cast iron, basically suitable for corrosion- and wear-resistant applications, and to attain a microstructure that is most suitable from the corrosion resistance point of view. The composition was selected with an aim to have austenitic matrix both in as-cast and heat-treated conditions. The difference in electrochemical potential between austenite and carbide is less in comparison to that between austenite and graphite. Additionally, graphitic corrosion which is frequently encountered in gray cast irons is absent in white cast irons. These basic facts encouraged us to undertake this work. Optical metallography, hardness testing, X-ray diffractometry, and SEM-EDX techniques were employed to identify the phases present in the as-cast and heat-treated specimens of the investigated alloy and to correlate microstructure with corrosion resistance and hardness. Corrosion testing was carried out in 5 pct NaCl solution (approximate chloride content of sea water) using the weight loss method. In the investigated alloy, austenite was retained the in as-cast and heat-treated conditions. The same was confirmed by X-ray and EDX analysis. The stability and volume fraction of austenite increased with an increase of heat-treated temperature/time with a simultaneous decrease in the volume fraction of massive carbides. The decrease in volume fraction of massive carbides resulted in the availability of alloying elements. These alloying elements, on increasing the heat treatment temperature or increasing the soaking period at certain temperatures, get dissolved in austenite. As a consequence, austenite gets enriched as well as becomes more stable. On cooling from lower soaking period/temperature, enriched austenite decomposes to lesser enriched austenite and to a dispersed phase due to decreasing solid solubility of alloying elements with decreasing temperature. The dispersed second phase precipitated from the austenite adversely influenced corrosion resistance due to unfavorable morphology and enhanced galvanic action. Corrosion rate and hardness were found to decrease with an increase in heat treatment temperatures/soaking periods. It was essentially due to the increase in the volume fraction and stability of the austenitic matrix and favorable morphology of the second phase (carbides). The corrosion resistance of the investigated alloy, heat treated at 1223 K (950 °C) for 8 hours, was comparable to that of Ni-Resist iron. Thus, a microstructure comprising austenite and nearly spherical and finer carbides is the most appropriate from a corrosion point of view. Fortunately, the literature reveals that the same microstructure is also well suited from a wear point of view. It confirms that this investigated alloy will be suitable for corrosive-wear applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vazehrad, S., E-mail: vazehrad@kth.se; Elfsberg, J., E-mail: jessica.elfsberg@scania.com; Diószegi, A., E-mail: attila.dioszegi@jth.hj.se

An investigation on silicon segregation of lamellar, compacted and nodular graphite iron was carried out by applying a selective, immersion color etching and a modified electron microprobe to study the microstructure. The color etched micrographs of the investigated cast irons by revealing the austenite phase have provided data about the chronology and mechanism of microstructure formation. Moreover, electron microprobe has provided two dimensional segregation maps of silicon. A good agreement was found between the segregation profile of silicon in the color etched microstructure and the silicon maps achieved by electron microprobe analysis. However, quantitative silicon investigation was found to bemore » more accurate than color etching results to study the size of the eutectic colonies. - Highlights: • Sensitivity of a color etchant to silicon segregation is quantitatively demonstrated. • Si segregation measurement by EMPA approved the results achieved by color etching. • Color etched micrographs provided data about solidification mechanism in cast irons. • Austenite grain boundaries were identified by measuring the local Si concentration.« less

Imposed Thermal Fatigue and Post-Thermal-Cycle Wear Resistance of Biomimetic Gray Cast Iron by Laser Treatment

NASA Astrophysics Data System (ADS)

Sui, Qi; Zhou, Hong; Zhang, Deping; Chen, Zhikai; Zhang, Peng

2017-08-01

The present study aims to create coupling biomimetic units on gray cast iron substrate by laser surface treatment (LST). LSTs for single-step (LST1) and two-step (LST2) processes, were carried out on gray cast iron in different media (air and water). Their effects on microstructure, thermal fatigue, and post-thermal-cycle wear (PTW) resistance on the specimens were studied. The tests were carried out to examine the influence of crack-resistance behavior as well as the biomimetic surface on its post-thermal-cycle wear behavior and different units, with different laser treatments for comparison. Results showed that LST2 enhanced the PTW behaviors of gray cast iron, which then led to an increase in its crack resistance. Among the treated cast irons, the one treated by LST2 in air showed the lowest residual stress, due to the positive effect of the lower steepness of the thermal gradient. Moreover, the same specimen showed the best PTW performance, due to its superior crack resistance and higher hardness as a result of it.

Stable Eutectoid Transformation in Nodular Cast Iron: Modeling and Validation

NASA Astrophysics Data System (ADS)

Carazo, Fernando D.; Dardati, Patricia M.; Celentano, Diego J.; Godoy, Luis A.

2017-01-01

This paper presents a new microstructural model of the stable eutectoid transformation in a spheroidal cast iron. The model takes into account the nucleation and growth of ferrite grains and the growth of graphite spheroids. Different laws are assumed for the growth of both phases during and below the intercritical stable eutectoid. At a microstructural level, the initial conditions for the phase transformations are obtained from the microstructural simulation of solidification of the material, which considers the divorced eutectic and the subsequent growth of graphite spheroids up to the initiation of the stable eutectoid transformation. The temperature field is obtained by solving the energy equation by means of finite elements. The microstructural (phase change) and macrostructural (energy balance) models are coupled by a sequential multiscale procedure. Experimental validation of the model is achieved by comparison with measured values of fractions and radius of 2D view of ferrite grains. Agreement with such experiments indicates that the present model is capable of predicting ferrite phase fraction and grain size with reasonable accuracy.

Effects of MC-Type Carbide Forming and Graphitizing Elements on Thermal Fatigue Behavior of Indefinite Chilled Cast Iron Rolls

NASA Astrophysics Data System (ADS)

Ahiale, Godwin Kwame; Choi, Won-Doo; Suh, Yongchan; Lee, Young-Kook; Oh, Yong-Jun

2015-11-01

The thermal fatigue behavior of indefinite chilled cast iron rolls with various V+Nb contents and Si/Cr ratios was evaluated. Increasing the ratio of Si/Cr prolonged the life of the rolls by reducing brittle cementites. Higher V+Nb addition also increased the life through the formation of carbides that refined and toughened the martensite matrix and reduced the thermal expansion mismatch in the microstructure.

Effect of deep cryogenic treatment on the microstructure and wear performance of Cr-Mn-Cu white cast iron grinding media

NASA Astrophysics Data System (ADS)

Vidyarthi, M. K.; Ghose, A. K.; Chakrabarty, I.

2013-12-01

The phase transformation and grinding wear behavior of Cr-Mn-Cu white cast irons subjected to destabilization treatment followed by air cooling or deep cryogenic treatment were studied as a part of the development program of substitute alloys for existing costly wear resistant alloys. The microstructural evolution during heat treatment and the consequent improvement in grinding wear performance were evaluated with optical and scanning electron microscopy, X-ray diffraction analysis, bulk hardness, impact toughness and corrosion rate measurements, laboratory ball mill grinding wear test etc. The deep cryogenic treatment has a significant effect in minimizing the retained austenite content and converts it to martensite embedded with fine M7C3 alloy carbides. The cumulative wear losses in cryotreated alloys are lesser than those with conventionally destabilized alloys followed by air cooling both in wet and dry grinding conditions. The cryotreated Cr-Mn-Cu irons exhibit comparable wear performance to high chromium irons.

Induction hardening treatment and simulation for a grey cast iron used in engine cylinder liners

NASA Astrophysics Data System (ADS)

Castellanos-Leal, E. L.; Miranda, D. A.; Coy, A. E.; Barrero, J. G.; González, J. A.; Vesga Rueda, O. P.

2017-01-01

In this research, a technical study of induction hardening in a grey cast iron used in engine cylinder liners manufactured by LAVCO Ltda., a Colombian foundry company, was carried out. Metallurgical parameters such as austenitization temperature, cooling rate, and quenching severity were determined. These factors are exclusively dependent on chemical composition and initial microstructure of grey cast iron. Simulations of induction heating through finite elements method were performed and, the most appropriate experimental conditions to achieve the critical transformation temperature was evaluated to reach a proper surface hardening on the piece. Preliminary results revealed an excellent approximation between simulation and heating test performed with a full bridge inverter voltage adapted with local technology.

High-Cycle Fatigue Resistance of Si-Mo Ductile Cast Iron as Affected by Temperature and Strain Rate

NASA Astrophysics Data System (ADS)

Matteis, Paolo; Scavino, Giorgio; Castello, Alessandro; Firrao, Donato

2015-09-01

Silicon-molybdenum ductile cast irons are used to fabricate exhaust manifolds of internal combustion engines of large series cars, where the maximum pointwise temperature at full engine load may be higher than 973 K (700 °C). In this application, high-temperature oxidation and thermo-mechanical fatigue (the latter being caused by the engine start and stop and by the variation of its power output) have been the subject of several studies and are well known, whereas little attention has been devoted to the high-cycle fatigue, arising from the engine vibration. Therefore, the mechanical behavior of Si-Mo cast iron is studied here by means of stress-life fatigue tests up to 10 million cycles, at temperatures gradually increasing up to 973 K (700 °C). The mechanical characterization is completed by tensile and compressive tests and ensuing fractographic examinations; the mechanical test results are correlated with the cast iron microstructure and heat treatment.

Effect of medium on friction and wear properties of compacted graphite cast iron processed by biomimetic coupling laser remelting process

NASA Astrophysics Data System (ADS)

Guo, Qing-chun; Zhou, Hong; Wang, Cheng-tao; Zhang, Wei; Lin, Peng-yu; Sun, Na; Ren, Luquan

2009-04-01

Stimulated by the cuticles of soil animals, an attempt to improve the wear resistance of compact graphite cast iron (CGI) with biomimetic units on the surface was made by using a biomimetic coupled laser remelting process in air and various thicknesses water film, respectively. The microstructures of biomimetic units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases in the melted zone. Microhardness was measured and the wear behaviors of biomimetic specimens as functions of different mediums as well as various water film thicknesses were investigated under dry sliding condition, respectively. The results indicated that the microstructure zones in the biomimetic specimens processed with water film are refined compared with that processed in air and had better wear resistance increased by 60%, the microhardness of biomimetic units has been improved significantly. The application of water film provided finer microstructures and much more regular grain shape in biomimetic units, which played a key role in improving the friction properties and wear resistance of CGI.

Nucleation and Growth of Graphite in Eutectic Spheroidal Cast Iron: Modeling and Testing

NASA Astrophysics Data System (ADS)

Carazo, Fernando D.; Dardati, Patricia M.; Celentano, Diego J.; Godoy, Luis A.

2016-06-01

A new model of graphite growth during the continuous cooling of eutectic spheroidal cast iron is presented in this paper. The model considers the nucleation and growth of graphite from pouring to room temperature. The microstructural model of solidification accounts for the eutectic as divorced and graphite growth rate as a function of carbon gradient at the liquid in contact with the graphite. In the solid state, the microstructural model takes into account three stages for graphite growth, namely (1) from the end of solidification to the upper bound of intercritical stable eutectoid, (2) during the intercritical stable eutectoid, and (3) from the lower bound of intercritical stable eutectoid to room temperature. The micro- and macrostructural models are coupled using a sequential multiscale approach. Numerical results for graphite fraction and size distribution are compared with experimental results obtained from a cylindrical cup, in which the graphite volumetric fraction and size distribution were obtained using the Schwartz-Saltykov approach. The agreements between the experimental and numerical results for the fraction of graphite and the size distribution of spheroids reveal the importance of numerical models in the prediction of the main aspects of graphite in spheroidal cast iron.

Characterization of a 12-pdr wrought-iron cannonball from the Akko 1 shipwreck

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cvikel, D.; Ashkenazi, D., E-mail: dana@eng.tau.ac.il; Stern, A.

2013-09-15

The Akko 1 shipwreck, discovered in Akko harbor, Israel, is the remains of an eastern Mediterranean brig built at the beginning of the 19th century. Among other finds, eleven cannonballs were found in the shipwreck and three of them were retrieved. Two of the cannonballs, the 9- and 24-pdrs, have been studied previously. The present study of the 12-pdr cannonball included γ-rays radiographic testing, XRF analysis, density measurements, optical microscopy and SEM-EDS observation, OES analysis and microhardness tests. The investigation included characterization of the composition, microstructure and slag analysis. The results revealed a quite homogenous microstructure of α-ferrite phase, withmore » glassy, wüstite and fayalite slags, as typical for a wrought-iron—annealed product, a more complicated and an earlier technology, compared to the 9- and 24-pdr that were made of cast-iron. Ferritic cannonballs are extremely rare, especially in the 19th century, when cannonballs were manufactured of cast iron by the sand casting process. The different manufacturing methods may indicate a different place of fabrication, and an apparently earlier production date for the 12-pdr, which might have even been used as ballast. - Highlights: • Three cannonballs were retrieved from the 19th century Akko 1 shipwreck. • The 12-pdr differs from the 9- and 24-pdr cannonballs previously studied. • The 12-pdr was made of high quality annealed wrought-iron, not of cast-iron. • The technology used indicates a date earlier than the middle of the 19th century. • Perhaps the 12-pdr belonged to another navy than the other two or used as ballast.« less

Effect of Iron and Magnesium on Alloy AL9M Structure and Properties

NASA Astrophysics Data System (ADS)

Bazhenov, V. E.; Koltygin, A. V.; Belov, V. D.

2017-09-01

The effect of iron impurity on the structure and properties of aluminum alloy AL9M, especially its action on magnesium distribution within the structure, is studied. The microstructure of a cast component of this alloy broken during operation is analyzed. It is shown that iron impurity has an unfavorable effect on structure and mechanical properties of a casting due to appearance of Al9Fe2Si and Al18Fe2Mg7Si10 intermetallics. Formation of these intermetallics consumes a considerable amount of magnesium and lowers the content of the Q(Al5Cu2Mg8Si6) strengthening phase in the alloy structure.

On the Solidification and Structure Formation during Casting of Large Inserts in Ferritic Nodular Cast Iron

NASA Astrophysics Data System (ADS)

Tadesse, Abel; Fredriksson, Hasse

2018-06-01

The graphite nodule count and size distributions for boiling water reactor (BWR) and pressurized water reactor (PWR) inserts were investigated by taking samples at heights of 2160 and 1150 mm, respectively. In each cross section, two locations were taken into consideration for both the microstructural and solidification modeling. The numerical solidification modeling was performed in a two-dimensional model by considering the nucleation and growth in eutectic ductile cast iron. The microstructural results reveal that the nodule size and count distribution along the cross sections are different in each location for both inserts. Finer graphite nodules appear in the thinner sections and close to the mold walls. The coarser nodules are distributed mostly in the last solidified location. The simulation result indicates that the finer nodules are related to a higher cooling rate and a lower degree of microsegregation, whereas the coarser nodules are related to a lower cooling rate and a higher degree of microsegregation. The solidification time interval and the last solidifying locations in the BWR and PWR are also different.

Effect of Thermal and Chemical Treatment on the Microstructural, Mechanical and Machining Performance of W319 Al-Si-Cu Cast Alloy Engine Blocks and Directionally Solidified Machinability Test Blocks

NASA Astrophysics Data System (ADS)

Szablewski, Daniel

The research presented in this work is focused on making a link between casting microstructural, mechanical and machining properties for 319 Al-Si sand cast components. In order to achieve this, a unique Machinability Test Block (MTB) is designed to simulate the Nemak V6 Al-Si engine block solidification behavior. This MTB is then utilized to cast structures with in-situ nano-alumina particle master alloy additions that are Mg based, as well as independent in-situ Mg additions, and Sr additions to the MTB. The Universal Metallurgical Simulator and Analyzer (UMSA) Technology Platform is utilized for characterization of each cast structure at different Secondary Dendrite Arm Spacing (SDAS) levels. The rapid quench method and Jominy testing is used to assess the capability of the nano-alumina master alloy to modify the microstructure at different SDAS levels. Mechanical property assessment of the MTB is done at different SDAS levels on cast structures with master alloy additions described above. Weibull and Quality Index statistical analysis tools are then utilized to assess the mechanical properties. The MTB is also used to study single pass high speed face milling and bi-metallic cutting operations where the Al-Si hypoeutectic structure is combined with hypereutectoid Al-Si liners and cast iron cylinder liners. These studies are utilized to aid the implementation of Al-Si liners into the Nemak V6 engine block and bi-metallic cutting of the head decks. Machining behavior is also quantified for the investigated microstructures, and the Silicon Modification Level (SiML) is utilized for microstructural analysis as it relates to the machining behavior.

Fatigue limit prediction of ferritic-pearlitic ductile cast iron considering stress ratio and notch size

NASA Astrophysics Data System (ADS)

Deguchi, T.; Kim, H. J.; Ikeda, T.

2017-05-01

The mechanical behavior of ductile cast iron is governed by graphite particles and casting defects in the microstructures, which can significantly decrease the fatigue strength. In our previous study, the fatigue limit of ferritic-pearlitic ductile cast iron specimens with small defects ((\\sqrt{{area}}=80˜ 1500{{μ }}{{m}})) could successfully be predicted based on the \\sqrt{{area}} parameter model by using \\sqrt{{area}} as a geometrical parameter of defect as well as the tensile strength as a material parameter. In addition, the fatigue limit for larger defects could be predicted based on the conventional fracture mechanics approach. In this study, rotating bending and tension-compression fatigue tests with ferritic-pearlitic ductile cast iron containing circumferential sharp notches as well as smooth specimens were performed to investigate quantitatively the effects of defect. The notch depths ranged 10 ˜ 2500 μm and the notch root radii were 5 and 50 μm. The stress ratios were R = -1 and 0.1. The microscopic observation of crack propagation near fatigue limit revealed that the fatigue limit was determined by the threshold condition for propagation of a small crack emanating from graphite particles. The fatigue limit could be successfully predicted as a function of R using a method proposed in this study.

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding

PubMed Central

Liu, Yanhui; Qu, Weicheng; Su, Yu

2016-01-01

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α-Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage. PMID:28773934

TiC Reinforcement Composite Coating Produced Using Graphite of the Cast Iron by Laser Cladding.

PubMed

Liu, Yanhui; Qu, Weicheng; Su, Yu

2016-09-30

In this study, a TiC-reinforced composite coating was produced to improve the wear resistance of a pearlite matrix grey iron using a pre-placed Ti powder by laser cladding. Results of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and energy dispersive X-ray spectroscopy (EDS) confirmed that the coating was composed of TiC particles and two kinds of α -Fe phase. The fine TiC particles were only a few microns in size and uniformly distributed on the matrix phase in the composite coating. The microstructure characteristic of the composite coating resulted in the microhardness rising to about 1000 HV0.3 (China GB/T 4342-1991) and the wear resistance significantly increased relative to the substrate. In addition, the fine and homogeneous solidification microstructure without graphite phase in the transition zone led to a good metallurgical bonding and transition between the coating and the substrate. It was of great significance for the cast iron to modify the surface and repair surface defects or surface damage.

Effects of W on microstructure of as-cast 28 wt.%Cr–2.6 wt.%C–(0–10)wt.%W irons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Imurai, S.; Thanachayanont, C.; Pearce, J.T.H.

2015-01-15

Microstructures of as-cast 28 wt.%Cr–2.6 wt.%C irons containing (0–10)wt.%W with the Cr/C ratio about 10 were studied and related to their hardness. The experimental irons were cast into dry sand molds. Microstructural investigation was performed by light microscopy, X-ray diffractometry, scanning electron microscopy, transmission electron microscopy and energy-dispersive X-ray spectrometry. It was found that the irons with 1 to 10 wt.%W addition was hypereutectic containing large primary M{sub 7}C{sub 3}, whereas the reference iron without W addition was hypoeutectic. The matrix in all irons was austenite, partly transformed to martensite during cooling. The volume fractions of primary M{sub 7}C{sub 3}more » and the total carbides increased, but that of eutectic carbides decreased with increasing the W content of the irons. W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M{sub 23}C{sub 6}. At about 4 wt.%W, two eutectic carbides including M{sub 7}C{sub 3} and M{sub 6}C were observed together with primary M{sub 7}C{sub 3}. At 10 wt.%W, multiple carbides including primary M{sub 7}C{sub 3}, fish-bone M{sub 23}C{sub 6}, and M{sub 6}C were observed. M{sub x}C where x = 3 or less has not been found due possibly to the high M/C ratio in the studied irons. W distribution to all carbides has been determined increasing from ca. 0.3 to 0.8 in mass fraction as the W content in the irons was increased. W addition led to an increase in Vickers macro-hardness of the irons up to 671 kgf/(mm){sup 2} (HV30/15) obtained from the iron with 10 wt.%W. The formation of primary M{sub 7}C{sub 3} and aggregates of M{sub 6}C and M{sub 23}C{sub 6} were the main reasons for hardness increase, indicating potentially improved wear performance of the as-cast irons with W addition. - Highlights: • W addition at 1 up to 10 wt.%W to Fe–28Cr–2.6C produced “hypereutectic” structure. • W addition promoted the formation of W-rich M{sub 7}C{sub 3}, M{sub 6}C and M{sub 23}C{sub 6}. • M{sub 23}C{sub 6} has higher Fe/Cr and W/Cr atm% ratios than those in M{sub 7}C{sub 3}. • Si content and high W content over about 11 atm% are characteristics of M{sub 6}C. • Primary M{sub 7}C{sub 3} and aggregates of M{sub 6}C and M{sub 23}C{sub 6} increased the alloy macro-hardness.« less

Production of Selected Key Ductile Iron Castings Used in Large-Scale Windmills

NASA Astrophysics Data System (ADS)

Pan, Yung-Ning; Lin, Hsuan-Te; Lin, Chi-Chia; Chang, Re-Mo

Both the optimal alloy design and microstructures that conform to the mechanical properties requirements of selected key components used in large-scale windmills have been established in this study. The target specifications in this study are EN-GJS-350-22U-LT, EN-GJS-350-22U-LT and EN-GJS-700-2U. In order to meet the impact requirement of spec. EN-GJS-350-22U-LT, the Si content should be kept below 1.97%, and also the maximum pearlite content shouldn't exceed 7.8%. On the other hand, Si content below 2.15% and pearlite content below 12.5% were registered for specification EN-GJS-400-18U-LT. On the other hand, the optimal alloy designs that can comply with specification EN-GJS-700-2U include 0.25%Mn+0.6%Cu+0.05%Sn, 0.25%Mn+0.8%Cu+0.01%Sn and 0.45%Mn+0.6%Cu+0.01%Sn. Furthermore, based upon the experimental results, multiple regression analyses have been performed to correlate the mechanical properties with chemical compositions and microstructures. The derived regression equations can be used to attain the optimal alloy design for castings with target specifications. Furthermore, by employing these regression equations, the mechanical properties can be predicted based upon the chemical compositions and microstructures of cast irons.

Iron rich low cost superalloys. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Wayne, S. F.

1985-01-01

An iron-rich low-cost superalloy was developed. The alloy, when processed by conventional chill casting, has physical and mechanical properties that compare favorably with existing nickel and cobalt based superalloys while containing significantly lower amounts of strategic elements. Studies were also made on the properties of Cr(20)-Mn(10)-C(3.4)-Fe(bal.), a eutectic alloy processed by chill casting and directional solidification which produced an aligned microstructure consisting of M7C3 fibers in a gamma-Fe matrix. Thermal expansion of the M7C3 (M = Fe, Cr, Mn) carbide lattice was measured up to 800 C and found to be highly anisotropic, with the a-axis being the predominant mode of expansion. Repetitive impact sliding wear experiments performed with the Fe rich eutectic alloy showed that the directionally solidified microstructure greatly improved the alloy's wear resistance as compared to the chill cast microstructure and conventional nickel base superalloys. Studies on the molybdenum cementite phase prove that the crystal structure of the xi phase is not orthorhombic. The crystal structure of the xi phase is made up of octahedra building elements consisting of four Mo and two Fe atoms and trigonal prisms consisting of four Fe and two Mo atoms. The voids are occupied by carbon atoms. The previous chemical formula for the molybdenum cementite MoFe2C is now clearly seen to be Mo12Fe22C10.

Preliminary science report on the directional solidification of hypereutectic cast iron during KC-135 low-G maneuvers

NASA Technical Reports Server (NTRS)

Curreri, P. A.; Stefanescu, D. M.; Hendrix, J. C.

1983-01-01

An ADSS-P directional solidification furnace was reconfigured for operation on the KC-135 low-g aircraft. The system offers many advantages over quench ingot methods for study of the effects of sedimentation and convection on alloy formation. The directional sodification furnace system was first flown during the September 1982 series of flights. The microstructure of the hypereutectic cast iron sample solidified on one of these flights suggests a low-g effect on graphite morphology. Further experiments are needed to ascertain that this effect is due to low-gravity and to deduce which of the possible mechanisms is responsible for it.

Microstructure, texture evolution and magnetic properties of strip-casting non-oriented 6.5 wt.% Si electrical steel doped with cerium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hao-Ze, E-mail: lhzqq83@163.com; Liu, Hai-Tao; Liu, Zhen-Yu, E-mail: zyliu@mail.neu.edu.cn

A 0.3 mm thick non-oriented 6.5 wt.% Si electrical steel sheet doped with cerium is produced by twin-roll strip casting, hot rolling, warm rolling and annealing. A detailed study of the cerium precipitates in the as-cast strip, microstructure and texture evolution at different processing stages is carried out by electron probe micro-analysis, optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. Grain interior distributing precipitates identified as Ce-oxides, Ce-oxysulfides and Ce-phosphides, and boundary distributing Ce-oxides and Ce-phosphides are observed in the as-cast strip. The initial as-cast strip is characterized by a much finer solidification microstructure and dominated by obvious //ND texture through the strip thickness. After hot and warm rolling, inhomogeneous microstructure containing large amounts of in-grain shear bands is characterized by mixed < 110 >//RD and < 111 >//ND textures. The texture of the annealed sheet with a relatively large average grain size is far more optimized by the domination of the beneficial cube, rotated cube, (001)< 120 > to (001)< 130 > and Goss texture components, and the elimination of the detrimental γ-fiber texture, leading to a superior magnetic induction and improved iron loss. - Highlights: • An Fe–6.5 wt.% Si as-cast strip doped with cerium was produced. • A thin warm rolled sheet with limited edge cracks was obtained. • Microstructure and texture evolution at each stage were investigated. • Strong λ-fiber and Goss recrystallization textures were formed. • The magnetic properties of the annealed sheet were significantly improved.« less

Research on the transformation mechanism of graphite phase and microstructure in the heated region of gray cast iron by laser cladding

NASA Astrophysics Data System (ADS)

Liu, Yancong; Zhan, Xianghua; Yi, Peng; Liu, Tuo; Liu, Benliang; Wu, Qiong

2018-03-01

A double-track lap cladding experiment involving gray cast iron was established to investigate the transformation mechanism of graphite phase and microstructure in a laser cladding heated region. The graphite phase and microstructure in different heated regions were observed under a microscope, and the distribution of elements in various heated regions was analyzed using an electron probe. Results show that no graphite existed in the cladding layer and in the middle and upper parts of the binding region. Only some of the undissolved small graphite were observed at the bottom of the binding region. Except the refined graphite size, the morphological characteristics of substrate graphite and graphite in the heat-affected zone were similar. Some eutectic clusters, which grew along the direction of heat flux, were observed in the heat-affected zone whose microstructure was transformed into a mixture of austenite, needle-like martensite, and flake graphite. Needle-like martensite around graphite was fine, but this martensite became sparse and coarse when it was away from graphite. Some martensite clusters appeared in the local area near the binding region, and the carbon atoms in the substrate did not diffuse into the cladding layer through laser cladding, which only affected the bonding area and the bottom of the cladding layer.

The influence of flushing time on the bonding quality of liquid white cast iron on the solid surface of similar material

NASA Astrophysics Data System (ADS)

Bandanadjaja, Beny; Purwadi, Wiwik; Idamayanti, Dewi; Lilansa, Noval; Hanaldi, Kus; Nurzaenal, Friya Kurnia

2018-05-01

Hard metal castings are widely used in the coal mill pulverizer as construction material for coal crushers. During its operation crushers and mills experience degradation caused by abrasion load. This research dealed with the surface overlaying of similiar material on the surface of white cast iron by mean of gravity casting. The die blank casting was preheated prior to the casting process of outer layer made of Ni-Hard white cast iron to guarantee bonding processes and avoid any crack. The preheating temperature of die blankin ther range of 500C up to 850C was set up to reach the interface temperature in the range of 887°C -1198°C and the flushing time was varied between 10-20 seconds. Studies carried on the microstructure of sample material revealed a formation of metallurgical bonding at the preheating temperature above 625 °C by pouring temperature ranging from 1438 °C to 1468 °C. Metallographical and chemical composition by mean of EDS examination were performed to observed the resut. This research concludes that the casting of Ni-Hard 1 overlay by applying gravity casting method can be done by preheating the surface of casting to 625 °C, interface temperature of 1150 °C, flushing time of 7 seconds and pouring temperature of 1430 °C. Excellent metallurgical bonding at the contact area between dieblank and overlay material has been achieved in which there is no parting line at the interface area to be observed.

Rolling Contact Fatigue Failure Mechanisms of Plasma-Nitrided Ductile Cast Iron

NASA Astrophysics Data System (ADS)

Wollmann, D.; Soares, G. P. P. P.; Grabarski, M. I.; Weigert, N. B.; Escobar, J. A.; Pintaude, G.; Neves, J. C. K.

2017-05-01

Rolling contact fatigue (RCF) of a nitrided ductile cast iron was investigated. Flat washers machined from a pearlitic ductile cast iron bar were quenched and tempered to maximum hardness, ground, polished and divided into four groups: (1) specimens tested as quenched and tempered; (2) specimens plasma-nitrided for 8 h at 400 °C; (3) specimens plasma-nitrided and submitted to a diffusion process for 16 h at 400 °C; and (4) specimens submitted to a second tempering for 24 h at 400 °C. Hardness profiles, phase analyses and residual stress measurements by x-ray diffraction, surface roughness and scanning electron microscopy were applied to characterize the surfaces at each step of this work. Ball-on-flat washer tests were conducted with a maximum contact pressure of 3.6 GPa, under flood lubrication with a SAE 90 API GL-5 oil at 50 °C. Test ending criterion was the occurrence of a spalling. Weibull analysis was used to characterize RCF's lifetime data. Plasma-nitrided specimens exhibited a shorter RCF lifetime than those just quenched and tempered. The effects of nitriding on the mechanical properties and microstructure of the ductile cast iron are discussed in order to explain the shorter endurance of nitrided samples.

TEM investigation of ductile iron alloyed with vanadium.

PubMed

Dymek, S; Blicharski, M; Morgiel, J; Fraś, E

2010-03-01

This article presents results of the processing and microstructure evolution of ductile cast iron, modified by an addition of vanadium. The ductile iron was austenitized closed to the solidus (1095 degrees C) for 100 h, cooled down to 640 degrees C and held on at this temperature for 16 h. The heat treatment led to the dissolution of primary vanadium-rich carbides and their subsequent re-precipitation in a more dispersed form. The result of mechanical tests indicated that addition of vanadium and an appropriate heat treatment makes age hardening of ductile iron feasible. The precipitation processes as well as the effect of Si content on the alloy microstructure were examined by scanning and transmission electron microscopy. It was shown that adjacent to uniformly spread out vanadium-rich carbides with an average size of 50 nm, a dispersoid composed of extremely small approximately 1 nm precipitates was also revealed.

Creep-rupture and fractographic analysis of candidate Stirling engine superalloys tested in air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattachryya, S.

The creep-rupture behavior of six candidate Stirling engine iron-base superalloys was determined in air. The alloys tested included four wrought alloys (A-286, INCOLOY Alloy 800H, N-155, and 19-9DL) and two cast alloys (CRM-6D and XF-818). The wrought alloys were evaluated in the form of sheet; the cast alloy specimens were investment cast to shape. The creep-rupture specimens were tested in air for up to 3000 hours over the temperature range 650/sup 0/ to 925/sup 0/C. Microstructural and fractographic aspects of the ruptured specimens are discussed with a few correlational graphical analyses included for XF-818 and 19-9DL. Tests are continuing inmore » 15 MPa hydrogen, and later these data will be correlated with air data and microstructural analysis of the specimens conducted.« less

Method of making metal matrix composites reinforced with ceramic particulates

DOEpatents

Cornie, James A.; Kattamis, Theodoulos; Chambers, Brent V.; Bond, Bruce E.; Varela, Raul H.

1989-01-01

Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys.

Method of making metal matrix composites reinforced with ceramic particulates

DOEpatents

Cornie, J.A.; Kattamis, T.; Chambers, B.V.; Bond, B.E.; Varela, R.H.

1989-08-01

Composite materials and methods for making such materials are disclosed in which dispersed ceramic particles are at chemical equilibrium with a base metal matrix, thereby permitting such materials to be remelted and subsequently cast or otherwise processed to form net weight parts and other finished (or semi-finished) articles while maintaining the microstructure and mechanical properties (e.g. wear resistance or hardness) of the original composite. The composite materials of the present invention are composed of ceramic particles in a base metal matrix. The ceramics are preferably carbides of titanium, zirconium, tungsten, molybdenum or other refractory metals. The base metal can be iron, nickel, cobalt, chromium or other high temperature metal and alloys thereof. For ferrous matrices, alloys suitable for use as the base metal include cast iron, carbon steels, stainless steels and iron-based superalloys. 2 figs.

Investigation the effect of modification with nanopowders on crystallization process and microstructure of some alloys

NASA Astrophysics Data System (ADS)

Kuzmanov, P. M.; Popov, S. I.; Yovkov, L. V.; Dimitrova, R. N.; Cherepanov, A. N.; Manolov, V. K.

2017-10-01

Modified with nano-powders (NP), AlSi7Mg aluminum alloy, P265GH steel and GG25 gray cast iron, have been investigated. Thermal and metallographic analyses have been made. For modified AlSi7Mg alloy, reduction of overcooling and duration of crystallization at the initial crystallization and their increase at eutectic crystallization have been found. For cast iron GG25, reduction of overcooling at crystallization was established and for P265GH steel, overcooling was not recorded, only a change in the slope of the temperature dependence. The thermal effects obtained in the crystallization correspond to the refinement of micro- and macrostructures. A mathematical model for crystallization of samples for thermal analysis has been developed and solved.

Three-dimensional local residual stress and orientation gradients near graphite nodules in ductile cast iron [3D local residual stress and orientation gradients near graphite nodules in ductile cast iron

DOE PAGES

Zhang, Y. B.; Andriollo, T.; Faester, S.; ...

2016-09-14

A synchrotron technique, differential aperture X-ray microscopy (DAXM), has been applied to characterize the microstructure and analyze the local mesoscale residual elastic strain fields around graphite nodules embedded in ferrite matrix grains in ductile cast iron. Compressive residual elastic strains are measured with a maximum strain of ~6.5–8 × 10 –4 near the graphite nodules extending into the matrix about 20 μm, where the elastic strain is near zero. The experimental data are compared with a strain gradient calculated by a finite element model, and good accord has been found but with a significant overprediction of the maximum strain. Thismore » is discussed in terms of stress relaxation during cooling or during storage by plastic deformation of the nodule, the matrix or both. Furthermore, relaxation by plastic deformation of the ferrite is demonstrated by the formation of low energy dislocation cell structure also quantified by the DAXM technique.« less

Effect of Reclamation on the Skin Layer of Ductile Iron Cast in Furan Molds

NASA Astrophysics Data System (ADS)

Dańko, R.; Holtzer, M.; Górny, M.; Żymankowska-Kumon, S.

2013-11-01

The paper presents the results of investigations of the influence of the quality of molding sand with furan resin hardened by paratoluenesulfonic acid, on the formation of microstructure and surface quality of ductile iron castings. Within the studies different molding sands were used: molding sand prepared with fresh sand and molding sands prepared with reclaimed sands of a different purification degree, determined by the ignition loss value. Various concentrations of sulfur and nitrogen in the sand molds as a function of the ignition loss were shown in the paper. A series of experimental melts of ductile iron in molds made of molding sand characterized by different levels of surface-active elements (e.g., sulfur) and different gas evolution rates were performed. It was shown that there exists a significant effect of the quality of the sand on the formation of the graphite degeneration layer.

Comprehensive study of the abrasive wear and slurry erosion behavior of an expanded system of high chromium cast iron and microstructural modification for enhanced wear resistance

NASA Astrophysics Data System (ADS)

Chung, Reinaldo Javier

High chromium cast irons (HCCIs) have been demonstrated to be an effective material for a wide range of applications in aggressive environments, where resistances to abrasion, erosion and erosion-corrosion are required. For instance, machinery and facilities used in mining and extraction in Alberta's oil sands suffer from erosion and erosion-corrosion caused by silica-containing slurries, which create challenges for the reliability and maintenance of slurry pumping systems as well as other processing and handling equipment. Considerable efforts have been made to determine and understand the relationship between microstructural features of the HCCIs and their wear performance, in order to guide the material selection and development for specific service conditions with optimal performance. The focus was previously put on a narrow group of compositions dictated by ASTM A532. However, with recent advances in casting technology, the HCCI compositional range can be significantly expanded, which potentially brings new alloys that can be superior to those which are currently employed. This work consists of three main aspects of study. The first one is the investigation of an expanded system of white irons with their composition ranging from 1 to 6 wt.% C and 5 to 45 wt.% Cr, covering 53 alloys. This work has generated wear and corrosion maps and established correlation between the performance and microstructural features for the alloys. The work was conducted in collaboration with the Materials Development Center of Weir Minerals in Australia, and the results have been collected in a database that is used by the company to guide materials selection for slurry pump components in Alberta oil sands and in other mining operations throughout the world. The second part consists of three case studies on effects of high chromium and high carbon, respectively, on the performance of the HCCIs. The third aspect is the development of an approach to enhance the wear resistance of HCCIs by microstructural modification through addition of strong carbide-forming elements to produce eutectic microstructures reinforced with in-situ formed foreign carbides. Very promising results have been obtained in lab, which demonstrates that the approach is feasible and effective in tailoring HCCIs for improved performance.

Strain rate effects on fracture behavior of Austempered Ductile Irons

NASA Astrophysics Data System (ADS)

Ruggiero, Andrew; Bonora, Nicola; Gentile, Domenico; Iannitti, Gianluca; Testa, Gabriel; Hörnqvist Colliander, Magnus; Masaggia, Stefano; Vettore, Federico

2017-06-01

Austempered Ductile Irons (ADIs), combining high strength, good ductility and low density, are candidates to be a suitable alternative to high-strength steels. Nevertheless, the concern about a low ductility under dynamic loads often leads designers to exclude cast irons for structural applications. However, results from dynamic tensile tests contradict this perception showing larger failure strain with respect to quasistatic data. The fracture behaviour of ADIs depends on damage mechanisms occurring in the spheroids of graphite, in the matrix and at their interface, with the matrix (ausferrite) consisting of acicular ferrite in carbon-enriched austenite. Here, a detailed microstructural analysis was performed on the ADI 1050-6 deformed under different conditions of strain rates, temperatures, and states of stress. Beside the smooth specimens used for uniaxial tensile tests, round notched bars to evaluate the ductility reduction with increasing stress triaxiality and tophat geometries to evaluate the propensity to shear localization and the associated microstructural alterations were tested. The aim of the work is to link the mechanical and fracture behavior of ADIs to the load condition through the microstructural modifications that occur for the corresponding deformation path.

Integrated modeling and heat treatment simulation of austempered ductile iron

NASA Astrophysics Data System (ADS)

Hepp, E.; Hurevich, V.; Schäfer, W.

2012-07-01

The integrated modeling and simulation of the casting and heat treatment processes for producing austempered ductile iron (ADI) castings is presented. The focus is on describing different models to simulate the austenitization, quenching and austempering steps during ADI heat treatment. The starting point for the heat treatment simulation is the simulated microstructure after solidification and cooling. The austenitization model considers the transformation of the initial ferrite-pearlite matrix into austenite as well as the dissolution of graphite in austenite to attain a uniform carbon distribution. The quenching model is based on measured CCT diagrams. Measurements have been carried out to obtain these diagrams for different alloys with varying Cu, Ni and Mo contents. The austempering model includes nucleation and growth kinetics of the ADI matrix. The model of ADI nucleation is based on experimental measurements made for varied Cu, Ni, Mo contents and austempering temperatures. The ADI kinetic model uses a diffusion controlled approach to model the growth. The models have been integrated in a tool for casting process simulation. Results are shown for the optimization of the heat treatment process of a planetary carrier casting.

Numerical Simulation of Austempering Heat Treatment of a Ductile Cast Iron

NASA Astrophysics Data System (ADS)

Boccardo, Adrián D.; Dardati, Patricia M.; Celentano, Diego J.; Godoy, Luis A.; Górny, Marcin; Tyrała, Edward

2016-02-01

This paper presents a coupled thermo-mechanical-metallurgical formulation to predict the dimensional changes and microstructure of a ductile cast iron part as a consequence of an austempering heat process. To take into account the different complex phenomena which are present in the process, the stress-strain law and plastic evolution equations are defined within the context of the associate rate-independent thermo-plasticity theory. The metallurgical model considers the reverse eutectoid, ausferritic, and martensitic transformations using macro- and micro-models. The resulting model is solved using the finite element method. The performance of this model is evaluated by comparison with experimental results of a dilatometric test. The results indicate that both the experimental evolution of deformation and temperature are well represented by the numerical model.

Characterization of the interfacial heat transfer coefficient for hot stamping processes

NASA Astrophysics Data System (ADS)

Luan, Xi; Liu, Xiaochuan; Fang, Haomiao; Ji, Kang; El Fakir, Omer; Wang, LiLiang

2016-08-01

In hot stamping processes, the interfacial heat transfer coefficient (IHTC) between the forming tools and hot blank is an essential parameter which determines the quenching rate of the process and hence the resulting material microstructure. The present work focuses on the characterization of the IHTC between an aluminium alloy 7075-T6 blank and two different die materials, cast iron (G3500) and H13 die steel, at various contact pressures. It was found that the IHTC between AA7075 and cast iron had values 78.6% higher than that obtained between AA7075 and H13 die steel. Die materials and contact pressures had pronounced effects on the IHTC, suggesting that the IHTC can be used to guide the selection of stamping tool materials and the precise control of processing parameters.

Study on the Microstructure and Liquid Phase Formation in a Semisolid Gray Cast Iron

NASA Astrophysics Data System (ADS)

Benati, Davi Munhoz; Ito, Kazuhiro; Kohama, Kazuyuki; Yamamoto, Hajime; Zoqui, Eugenio José

2017-10-01

The development of high-quality semisolid raw materials requires an understanding of the phase transformations that occur as the material is heated up to the semisolid state, i.e., its melting behavior. The microstructure of the material plays a very important role during semisolid processing as it determines the flow behavior of the material when it is formed, making a thorough understanding of the microstructural evolution essential. In this study, the phase transformations and microstructural evolution in Fe2.5C1.5Si gray cast iron specially designed for thixoforming processes as it was heated to the semisolid state were observed using in situ high-temperature confocal laser scanning microscopy. At room temperature, the alloy has a matrix of pearlite and ferrite with fine interdendritic type D flake graphite. During heating, the main transformations observed were graphite precipitation inside the grains and at the austenite grain boundaries; graphite flakes and graphite precipitates growing and becoming coarser with the increasing temperature; and the beginning of melting at around 1413 K to 1423 K (1140 °C to 1150 °C). Melting begins with the eutectic phase ( i.e., the carbon-rich phase) and continues with the primary phase (primary austenite), which is consumed as the temperature increases. Melting of the eutectic phase composed by coarsened interdendritic graphite flakes produced a semi-continuous liquid network homogeneously surrounding and wetting the dendrites of the solid phase, causing grains to detach from each other and producing the intended solid globules immersed in liquid.

46 CFR 56.60-10 - Cast iron and malleable iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Cast iron and malleable iron. 56.60-10 Section 56.60-10... APPURTENANCES Materials § 56.60-10 Cast iron and malleable iron. (a) The low ductility of cast iron and... avoided. Cast iron and malleable iron components shall not be used at temperatures above 450 °F. Cast iron...

Transition temperature and fracture mode of as-castand austempered ductile iron.

PubMed

Rajnovic, D; Eric, O; Sidjanin, L

2008-12-01

The ductile to brittle transition temperature is a very important criterion that is used for selection of materials in some applications, especially in low-temperature conditions. For that reason, in this paper transition temperature of as-cast and austempered copper and copper-nickel alloyed ductile iron (DI) in the temperature interval from -196 to +150 degrees C have been investigated. The microstructures of DIs and ADIs were examined by light microscope, whereas the fractured surfaces were observed by scanning electron microscope. The ADI materials have higher impact energies compared with DIs in an as-cast condition. In addition, the transition curves for ADIs are shifted towards lower temperatures. The fracture mode of Dls is influenced by a dominantly pearlitic matrix, exhibiting mostly brittle fracture through all temperatures of testing. By contrast, with decrease of temperature, the fracture mode for ADI materials changes gradually from fully ductile to fully brittle.

49 CFR 192.373 - Service lines: Cast iron and ductile iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Cast iron and ductile iron. 192.373... Regulators, and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron... cast iron pipe or ductile iron pipe is installed for use as a service line, the part of the service...

3D analysis of macrosegregation in twin-roll cast AA3003 alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Šlapáková, Michaela, E-mail: slapakova@karlov.mff.

Twin-roll cast aluminium alloys have a high potential for industrial applications. However, one of the drawbacks of such materials is an inhomogeneous structure generated by macrosegregation, which appears under certain conditions in the center of sheets during solidification. Segregations in AA3003 alloy form as manganese, iron and silicon rich channels spread in the rolling direction. Their spatial distribution was successfully detected by X-ray computed tomography. Scanning electron microscopy was used for a detailed observation of microstructure, morphology and chemical analysis of the segregation. - Highlights: •Macrosegregations in twin-roll cast sheets stretch along the rolling direction. •X-ray computed tomography is anmore » effective tool for visualization of the segregation. •The segregations copy the shape of grain boundaries.« less

Characteristics microstructure and microhardness of cast Ti-6Al-4V ELI for biomedical application submitted to solution treatment

NASA Astrophysics Data System (ADS)

Damisih, Jujur, I. Nyoman; Sah, Joni; Agustanhakri, Prajitno, Djoko Hadi

2018-05-01

Ti 6Al-4V ELI (Extra Low Interstitial)alloy containing 6wt% of aluminum, 4wt% of vanadium with controlled level of iron and oxygen is one of most popular alloy employed in biomedical applications as implant material. Heat treatment process for titanium alloys becomes important and could be performed by some of different ways in order to develop microstructure as well as its properties. The objective of this paper is to study the effects of solution treatment temperature on microstructure and mechanical properties of as-cast Ti-6Al-4V ELI especially microhardness value. The alloy was melted by single arc melting furnace with a water-cooled copper crucible hearth under argon atmosphere and then casted. It was heat treated through solution treatment at 3 (three) different temperaturesi.e. 850°C, 950°C and 1050°C in an argon gas atmosphere for around 30 minutes. After solution treatment, samples were water quenched and then aged at temperature of 500°C for 4 hours. To investigate its microstructure, the alloy was investigated under optical microscope and scanning electron microscope (SEM). It was observed Widmanstätten microstructure consisting of mixture α and β phase with basket-weave pattern. The Vickers microhardness test was performed and the results exhibited the optimum value was obtained at temperature of 950°C of solution treatment. From the observation, it revealed that the heat treatment has substantial effect on microstructural properties where microhardness increased due to formation of α' martensite structure. It was showed also that solution treatment followed by aging could improve mechanical properties especially microhardness value of Ti-6Al-4V ELI alloy. These results were suggesting the optimized conditions of heat treatment to obtain the best microstructure properties and microhardness value.

Uncovering the local inelastic interactions during manufacture of ductile cast iron: How the substructure of the graphite particles can induce residual stress concentrations in the matrix

NASA Astrophysics Data System (ADS)

Andriollo, Tito; Hellström, Kristina; Sonne, Mads Rostgaard; Thorborg, Jesper; Tiedje, Niels; Hattel, Jesper

2018-02-01

Recent X-ray diffraction (XRD) measurements have revealed that plastic deformation and a residual elastic strain field can be present around the graphite particles in ductile cast iron after manufacturing, probably due to some local mismatch in thermal contraction. However, as only one component of the elastic strain tensor could be obtained from the XRD data, the shape and magnitude of the associated residual stress field have remained unknown. To compensate for this and to provide theoretical insight into this unexplored topic, a combined experimental-numerical approach is presented in this paper. First, a material equivalent to the ductile cast iron matrix is manufactured and subjected to dilatometric and high-temperature tensile tests. Subsequently, a two-scale hierarchical top-down model is devised, calibrated on the basis of the collected data and used to simulate the interaction between the graphite particles and the matrix during manufacturing of the industrial part considered in the XRD study. The model indicates that, besides the viscoplastic deformation of the matrix, the effect of the inelastic deformation of the graphite has to be considered to explain the magnitude of the XRD strain. Moreover, the model shows that the large elastic strain perturbations recorded with XRD close to the graphite-matrix interface are not artifacts due to e.g. sharp gradients in chemical composition, but correspond to residual stress concentrations induced by the conical sectors forming the internal structure of the graphite particles. In contrast to common belief, these results thus suggest that ductile cast iron parts cannot be considered, in general, as stress-free at the microstructural scale.

Influence of Casting Section Thickness on Fatigue Strength of Austempered Ductile Iron

NASA Astrophysics Data System (ADS)

Olawale, J. O.; Ibitoye, S. A.

2017-10-01

The influence of casting section thickness on fatigue strength of austempered ductile iron was investigated in this study. ASTM A536 65-45-12 grade of ductile iron was produced, machined into round samples of 10, 15, 20 and 25 mm diameter, austenitized at a temperature of 820 °C, quenched into an austempering temperature (TA) of 300 and 375 °C and allowed to be isothermally transformed at these temperatures for a fixed period of 2 h. From the samples, fatigue test specimens were machined to conform to ASTM E-466. Scanning electron microscopy (SEM) and x-ray diffraction (XRD) methods were used to characterize microstructural morphology and phase distribution of heat-treated samples. The fatigue strength decreases as the section thickness increases. The SEM image and XRD patterns show a matrix of acicular ferrite and carbon-stabilized austenite with ferrite coarsening and volume fraction of austenite reducing as the section thickness increases. The study concluded that the higher the value of carbon-stabilized austenite the higher the fatigue strength while it decreases as the ausferrite structure becomes coarse.

Inhomogeneity of Microstructure and Damping Capacity of a FC25 Disc-Brake Rotor and Their Interrelationship

NASA Astrophysics Data System (ADS)

Park, Jongbin; Han, Jeongho; Lee, Seung-Joon; Yi, Kyoungdon; Kwon, Chelwoong; Lee, Young-Kook

2016-08-01

The objective of the present study was to investigate the inhomogeneity of microstructure and damping capacity of a FC25 disc-brake rotor made of gray cast iron (GCI) and their interrelationship. The rotor had inhomogeneous microstructure due to different cooling rates caused by the position of inlets in a mold during casting. The volume fraction and size of graphite decreased with increasing cooling rate. A maximum deviation of the volume fraction of graphite within the rotor was approximately 2 pct, whereas that of the total perimeter of graphite per unit area was approximately 33 pct. Damping capacities measured at the first vibrational mode of both the real rotor and cantilever specimens, which were taken from four different regions within the rotor, depended on the location within the rotor. This result indicates that the damping capacity of the rotor is influenced by the inhomogeneous microstructure; particularly, the damping capacity was proportional to the total perimeter of graphite per unit area. Therefore, it was concluded that the damping of the GCI rotor used in the present study occurs primarily by the viscous or plastic flow at the interphase boundaries between the pearlite matrix and graphite particles at least at the frequencies of below 1140 Hz.

49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to a... 49 Transportation 3 2011-10-01 2011-10-01 false Remedial measures: Cast iron and ductile iron...

49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to a... 49 Transportation 3 2010-10-01 2010-10-01 false Remedial measures: Cast iron and ductile iron...

Materials processing threshold report: 2. Use of low gravity for cast iron process development

NASA Technical Reports Server (NTRS)

Frankhouser, W. L.

1980-01-01

Potential applications of a low gravity environment of interest to the commercial producers of cast iron were assessed to determine whether low gravity conditions offer potential opportunities to producers for improving cast iron properties and expanding the use of cast irons. The assessment is limited to the gray and nodular types of iron, however, the findings are applicable to all cast irons. The potential advantages accrued through low gravity experiments with cast irons are described.

Numerical simulation of the solidification microstructure of a 17-4PH stainless steel investment casting and its experimental verification

NASA Astrophysics Data System (ADS)

Li, You Yun; Tsai, DeChang; Hwang, Weng Sing

2008-06-01

The purpose of this study is to develop a technique of numerically simulating the microstructure of 17-4PH (precipitation hardening) stainless steel during investment casting. A cellular automation (CA) algorithm was adopted to simulate the nucleation and grain growth. First a calibration casting was made, and then by comparing the microstructures of the calibration casting with those simulated using different kinetic growth coefficients (a2, a3) in CA, the most appropriate set of values for a2 and a3 would be obtained. Then, this set of values was applied to the microstructure simulation of a separate casting, where the casting was actually made. Through this approach, this study has arrived at a set of growth kinetic coefficients from the calibration casting: a2 is 2.9 × 10-5, a3 is 1.49 × 10-7, which is then used to predict the microstructure of the other test casting. Consequently, a good correlation has been found between the microstructure of actual 17-4PH casting and the simulation result.

75 FR 23295 - Iron Construction Castings From Brazil, Canada, and China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-03

... ``heavy'' iron construction castings from Brazil, the antidumping duty order on ``heavy'' iron... the countervailing duty order on ``heavy'' iron construction castings from Brazil, the antidumping duty order on ``heavy'' iron construction castings from Canada, and the antidumping duty orders on iron...

Effect of iron-intermetallics and porosity on tensile and impact properties of aluminum-silicon-copper and aluminum-silicon-magnesium cast alloys

NASA Astrophysics Data System (ADS)

Ma, Zheyuan

Aluminum-silicon (Al-Si) alloys are an important class of materials that constitute the majority of aluminum cast parts produced, due to their superior properties and excellent casting characteristics. Within this family of alloys, Al-Si-Cu and Al-Si-Mg cast alloys are frequently employed in automotive applications. The commercially popular 319 and 356 alloys, representing these two alloy systems, were selected for study in the present work, with the aim of investigating the effect of iron intermetallics and porosity on the alloy performance. This was carried out through a study of the tensile and impact properties, these being two of the important mechanical properties used in design calculations. Iron, through the precipitation of second phase intermetallic constituents, in particular the platelike beta-Al5FeSi phase, is harmful to the alloy properties. Likewise, gas- or shrinkage porosity in castings is also detrimental to the mechanical properties. By determining the optimum alloying, melt processing and solidification parameters (viz., Fe content, Sr modification and cooling rate) required to minimize the harmful effects of porosity and iron intermetallics, and studying their role on the fracture behavior, the fracture mechanism in the alloys could be determined. Castings were prepared from both industrial and experimental 319.2, B319.2 and A356.2 alloy melts, containing Fe levels of 0.2--1.0 wt%. Sr-modified (˜200 ppm) melts were also prepared for each alloy Fe level. The end-chilled refractory mold used provided directional solidification and a range of cooling rates (or dendrite arm spacings, DAS) within the same casting. Tensile and impact test samples machined from specimen blanks sectioned from the castings at various heights above the chill end provided DASs of 23--85mum. All samples were T6-heat-treated before testing. Tests were carried out employing Instron Universal and Instrumented Charpy testing machines. Optical microscopy, image analysis, SEM and EPMA techniques were used for microstructural and fracture analysis. The results show that the highest cooling rate (23 mum DAS) is the most significant parameter controlling the size and distribution of the beta-Al 5FeSi phase and porosity in the unmodified 319.2 and A356.2 alloys. (Abstract shortened by UMI.)

Secondary Al-Si-Mg High-pressure Die Casting Alloys with Enhanced Ductility

NASA Astrophysics Data System (ADS)

Bösch, Dominik; Pogatscher, Stefan; Hummel, Marc; Fragner, Werner; Uggowitzer, Peter J.; Göken, Mathias; Höppel, Heinz Werner

2015-03-01

Al-Si-Mg-based secondary cast alloys are attractive candidates for thin-walled high-pressure die castings for applications in the transport industry. The present study investigates the effect of manganese additions at high cooling rates on microstructure, mechanical properties, and on the dominating fracture mechanisms of alloy AlSi10Mg with an elevated iron concentration. Systematic variations of the Mn content from 0.20 to 0.85 wt pct at a constant Fe content of 0.55 wt pct illustrate the key changes in type, phase fraction, and shape of the Fe-containing intermetallic phases, and the corresponding influence on the alloy's ductility. For high-pressure die casting (HPDC), an optimal range of the Mn content between 0.40 and 0.60 wt pct, equivalent to a Mn/Fe ratio of approximately 1, has been identified. At these Mn and Fe contents, the high cooling rates obtained in HPDC result in the formation of fine and homogeneously distributed α-Al15(Fe,Mn)3Si2 phase, and crack initiation is transferred from AlFeSi intermetallics to eutectic silicon. The study interprets the microstructure-property relationship in the light of thermodynamic calculations which reveal a significant increase in undercooling of the α-Al15(Fe,Mn)3Si2 phase with increased Mn content. It concludes that the interdependence of the well-defined Mn/Fe ratio and the high cooling rate in HPDC can generate superior ductility in secondary AlSi10Mg cast alloys.

Microstructural Evolution in Intensively Melt Sheared Direct Chill Cast Al-Alloys

NASA Astrophysics Data System (ADS)

Jones, S.; Rao, A. K. Prasada; Patel, J. B.; Scamans, G. M.; Fan, Z.

The work presented here introduces the novel melt conditioned direct chill casting (MC-DC) technology, where intensive melt shearing is applied to the conventional direct-chill casting process. MC-DC casting can successfully produce high quality Al-alloy billets. The results obtained from 80 mm diameter billets cast at speed of 200 mm/min show that MC-DC casting of Al-alloys, substantially refines the microstructure and reduces macro-segregation. In this paper, we present the preliminary results and discuss microstructural evolution during MC-DC casting of Al-alloys.

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the cast... Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis... of pollutants into publicly owned treatment works from porcelain enameling of cast iron basis...

The effect of Si-contents on the impact properties and dynamic graphite growth for cast iron QT400-18L

NASA Astrophysics Data System (ADS)

Lipeng, Jiang; Yingdong, Qu; Rongde, Li

2018-03-01

Low temperature impact test of QT400-18L ductile iron was investigated. The microstructure and fracture morphology were analyzed by the optical microscope and scanning electron microscope. The effect of different Si content on the graphite growth by liquid quenching method was discussed. There are the highest impact energies for the cast iron with 2.1% of Si over the whole investigated temperature range (‑60 to 20 °C). With the Si element addition increased from 1.9% to 2.1%, the graphite nodulizing grade of QT400 18L is increased from 5 to 7. However the graphite nodulizing grade is reduced from 7 to 6 with Si content increasing from 2.1% to 2.3%. When the Si element addition is exceed 2.1%, the excess of Si content also leads to abnormal graphite. The large size of the abnormal graphite is equivalent to a larger microcrack in the ferrite matrix, and it is helpful for the crack propagation. Large size of abnormal graphite not only destroyed the continuity of ferritic matrix, but also it creates the stress concentration in the surrounding.

75 FR 49945 - Iron Construction Castings From Brazil, Canada, and China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-16

... Review)] Iron Construction Castings From Brazil, Canada, and China AGENCY: United States International... and antidumping duty orders on iron construction castings from Brazil, Canada, and China. SUMMARY: The... duty and or antidumping duty orders on iron construction castings from Brazil, Canada, and China would...

Microstructures and properties of aluminum die casting alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. M. Makhlouf; D. Apelian; L. Wang

1998-10-01

This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

Wear and Friction Behavior of Metal Impregnated Microporous Carbon Composites

NASA Technical Reports Server (NTRS)

Goller, Gultekin; Koty, D. P.; Tewari, S. N.; Singh, M.; Tekin, A.

1996-01-01

Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

75 FR 67395 - Iron Construction Castings From Brazil, Canada, and China; Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-02

... Review)] Iron Construction Castings From Brazil, Canada, and China; Determinations On the basis of the...), that revocation of the countervailing duty order on heavy iron construction castings from Brazil, the... iron construction castings (both heavy and light) from Brazil and China would be likely to lead to...

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast-iron pipelines. When an operator has knowledge that the support for a segment of a buried cast-iron...

Peak Stir Zone Temperature During Friction Stir Processing

DTIC Science & Technology

2010-03-01

jii reprecipitation. The nonequilibrium trans- formation products of b may include fine Widmanstät- ten a as well as bainite and martensite, depending... bainite , reflecting cooling at 2 to 3 9 101 C/s (Table II), i.e., rates ~104 times that of the as-cast condition. In region 2, the microstructure...Shepard, and O.D. Sherby: J. Iron Steel Inst., 1964, vol. 202, pp. 804–07. 26. O.D. Sherby, B. Walser, C.M. Young, and E.M. Cady: Scripta Metall

Effect of carbon content on friction and wear of cast irons

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1977-01-01

Friction and wear experiments were conducted with cast irons and wrought steels containing various amounts of carbon in the alloy structure in contact with 52100 steel. Gray cast irons were found to exhibit lower friction and wear characteristics than white cast irons. Further, gray cast iron wear was more sensitive to carbon content than was white. Wear with gray cast iron was linearly related to load, and friction was found to be sensitive to relative humidity and carbon content. The form, in which the carbon is present in the alloy, is more important, as the carbon content and no strong relationship seems to exist between hardness of these ferrous alloys and wear.

Three-dimensional microstructure simulation of Ni-based superalloy investment castings

NASA Astrophysics Data System (ADS)

Pan, Dong; Xu, Qingyan; Liu, Baicheng

2011-05-01

An integrated macro and micro multi-scale model for the three-dimensional microstructure simulation of Ni-based superalloy investment castings was developed, and applied to industrial castings to investigate grain evolution during solidification. A ray tracing method was used to deal with the complex heat radiation transfer. The microstructure evolution was simulated based on the Modified Cellular Automaton method, which was coupled with three-dimensional nested macro and micro grids. Experiments for Ni-based superalloy turbine wheel investment casting were carried out, which showed a good correspondence with the simulated results. It is indicated that the proposed model is able to predict the microstructure of the casting precisely, which provides a tool for the optimizing process.

75 FR 10216 - Malleable Cast Iron Pipe Fittings from the People's Republic of China: Notice of Rescission of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-05

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-881] Malleable Cast Iron Pipe... antidumping duty order on malleable cast iron pipe fittings from the People's Republic of China (``PRC''). See... malleable cast iron pipe fittings from the PRC. See Initiation of Antidumping and Countervailing Duty...

46 CFR 153.239 - Use of cast iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Use of cast iron. 153.239 Section 153.239 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Systems § 153.239 Use of cast iron. (a) Cast iron used in a cargo containment system must meet the...

An innovative method for nondestructive analysis of cast iron artifacts at Hopewell Furnace National Historic Site, Pennsylvania

USGS Publications Warehouse

Sloto, R.A.; Helmke, M.F.

2011-01-01

Iron ore containing elevated concentrations of trace metals was smelted at Hopewell Furnace during its 113 years of operation (1771-1883). For this study, we sampled iron ore, cast iron furnace products, slag, soil, groundwater, streamflow, and streambed sediment to determine the fate of trace metals released into the environment during the iron-smelting process. Standard techniques were used to sample and analyze all media except cast iron. We analyzed the trace-metal content of the cast iron using a portable X-ray fluorescence spectrometer, which provided rapid, on-site, nondestructive analyses for 23 elements. The artifacts analyzed included eight cast iron stoves, a footed pot, and a kettle in the Hopewell Furnace museum. We measured elevated concentrations of arsenic, copper, lead, and zinc in the cast iron. Lead concentrations as great as 3,150 parts per million were measured in the stoves. Cobalt was detectable but not quantifiable because of interference with iron. Our study found that arsenic, cobalt, and lead were not released to soil or slag, which could pose a significant health risk to visitors and employees. Instead, our study demonstrates these heavy metals remained with the cast iron and were removed from the site.

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

Code of Federal Regulations, 2013 CFR

2013-10-01

... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

Code of Federal Regulations, 2012 CFR

2012-10-01

... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

49 CFR 192.487 - Remedial measures: Distribution lines other than cast iron or ductile iron lines.

Code of Federal Regulations, 2014 CFR

2014-10-01

... STANDARDS Requirements for Corrosion Control § 192.487 Remedial measures: Distribution lines other than cast iron or ductile iron lines. (a) General corrosion. Except for cast iron or ductile iron pipe, each... engineering tests and analyses show can permanently restore the serviceability of the pipe. Corrosion pitting...

Application of the Billet Casting Method to Determine the Onset of Incipient Melting of 319 Al Alloy Engine Blocks

NASA Astrophysics Data System (ADS)

Lombardi, A.; Ravindran, C.; MacKay, R.

2015-06-01

The increased use of Al for automotive applications has resulted from the need to improve vehicle fuel efficiency. Aluminum alloy engine blocks fulfil the need of lightweighting. However, there are many challenges associated with thermo-mechanical mismatch between Al and the gray cast iron cylinder liners, which result in large tensile residual stress along the cylinder bores. This requires improced mechanical properties in this region to prevent premature engine failure. In this study, replicating billet castings were used to simulate the engine block solution heat treatment process and determine the onset of incipient melting. Microstructural changes during heat treatment were assessed with SEM and EDX, while thermal analysis was carried out using differential scanning calorimetry. The results suggest that solution heat treatment at 500 °C was effective in dissolving secondary phase particles, while solutionizing at 515 or 530 °C caused incipient melting of Al2Cu and Al5Mg8Cu2Si6. Incipient melting caused the formation ultra-fine eutectic clusters consisting of Al, Al2Cu, and Al5Mg8Cu2Si6 on quenching. In addition, DSC analysis found that incipient melting initiated at 507 °C for all billets, although the quantity of local melting reduced with microstructural refinement as evidenced by smaller endothermic peaks and energy absorption. The results from this study will assist in improving engine block casting integrity and process efficiency.

The Effect of Nb Addition on the Microstructure and the High-Temperature Strength of Fe3Al Aluminide

NASA Astrophysics Data System (ADS)

Kratochvíl, Petr; Švec, Martin; Král, Robert; Veselý, Jozef; Lukáč, Pavel; Vlasák, Tomáš

2018-02-01

The microstructural and high-temperature mechanical properties of Fe-26Al-xNb (x = 3 and 5 at. pct) are compared. The alloys were investigated "as cast" and after hot rolling at 1473 K (1200 °C). Scanning electron microscopes equipped with EDS and EBSD were used for the microstructure and phase identification. The addition of 3 at. pct of Nb into the Fe3Al matrix leads to the formation of C14 λ—Laves phase (Fe,Al)2Nb (LP) particles spread in the Fe3Al matrix, while an eutectic with thin lamellae of LP C14 λ—Laves phase (Fe,Al)2Nb and matrix is also formed in the iron aluminide with 5 at. pct of Nb. The presence of incoherent precipitates is connected with the enhancement of the high-temperature strength and creep resistance.

75 FR 75964 - Non-Malleable Cast Iron Pipe Fittings From the People's Republic of China: Extension of Time...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-875] Non-Malleable Cast Iron Pipe...-malleable cast iron pipe fittings from the People's Republic of China (``PRC''). See Initiation of...-malleable cast iron pipe fittings from the PRC within the time limits mandated by section 751(a)(3)(A) of...

Effect of Heating Time on Hardness Properties of Laser Clad Gray Cast Iron Surface

NASA Astrophysics Data System (ADS)

Norhafzan, B.; Aqida, S. N.; Mifthal, F.; Zulhishamuddin, A. R.; Ismail, I.

2018-03-01

This paper presents effect of heating time on cladded gray cast iron. In this study, the effect of heating time on cladded gray cast iron and melted gray cast iron were analysed. The gray cast iron sample were added with mixed Mo-Cr powder using laser cladding technique. The mixed Mo and Cr powder was pre-placed on gray cast iron surface. Modified layer were sectioned using diamond blade cutter and polish using SiC abrasive paper before heated. Sample was heated in furnace for 15, 30 and 45 minutes at 650 °C and cool down in room temperature. Metallographic study was conduct using inverted microscope while surface hardness properties were tested using Wilson hardness test with Vickers scale. Results for metallographic study showed graphite flakes within matrix of pearlite. The surface hardness for modified layer decreased when increased heating time process. These findings are significant to structure stability of laser cladded gray cast iron with different heating times.

Coating Bores of Light Metal Engine Blocks with a Nanocomposite Material using the Plasma Transferred Wire Arc Thermal Spray Process

NASA Astrophysics Data System (ADS)

Bobzin, K.; Ernst, F.; Zwick, J.; Schlaefer, T.; Cook, D.; Nassenstein, K.; Schwenk, A.; Schreiber, F.; Wenz, T.; Flores, G.; Hahn, M.

2008-09-01

Engine blocks of modern passenger car engines are generally made of light metal alloys, mostly hypoeutectic AlSi-alloys. Due to their low hardness, these alloys do not meet the tribological requirements of the system cylinder running surface—piston rings—lubricating oil. In order to provide a suitable cylinder running surface, nowadays cylinder liners made of gray cast iron are pressed in or cast into the engine block. A newer approach is to apply thermal spray coatings onto the cylinder bore walls. Due to the geometric conditions, the coatings are applied with specifically designed internal diameter thermal spray systems. With these processes a broad variety of feedstock can be applied, whereas mostly low-alloyed carbon steel feedstock is being used for this application. In the context of this work, an iron-based wire feedstock has been developed, which leads to a nanocrystalline coating. The application of this material was carried out with the Plasma Transferred Wire Arc system. AlMgSi0.5 liners were used as substrates. The coating microstructure and the properties of the coatings were analyzed.

40 CFR 721.10667 - Slimes and sludges, aluminum and iron casting, wastewater treatment, solid waste.

Code of Federal Regulations, 2014 CFR

2014-07-01

... casting, wastewater treatment, solid waste. 721.10667 Section 721.10667 Protection of Environment... iron casting, wastewater treatment, solid waste. (a) Chemical substance and significant new uses... and iron casting, wastewater treatment, solid waste (PMN P-12-560; CAS No. 1391739-82-4; chemical...

40 CFR 721.10667 - Slimes and sludges, aluminum and iron casting, wastewater treatment, solid waste.

Code of Federal Regulations, 2013 CFR

2013-07-01

... casting, wastewater treatment, solid waste. 721.10667 Section 721.10667 Protection of Environment... iron casting, wastewater treatment, solid waste. (a) Chemical substance and significant new uses... and iron casting, wastewater treatment, solid waste (PMN P-12-560; CAS No. 1391739-82-4; chemical...

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; B. Anamerie; T.C. Eisele

The pig iron nugget process was developed as an alternative to the traditional blast furnace process by Kobe Steel. The process aimed to produce pig iron nuggets, which have similar chemical and physical properties to blast furnace pig iron, in a single step. The pig iron nugget process utilizes coal instead of coke and self reducing and fluxing dried green balls instead of pellets and sinters. In this process the environmental emissions caused by coke and sinter production, and energy lost between pellet induration (heat hardening) and transportation to the blast furnace can be eliminated. The objectives of this researchmore » were to (1) produce pig iron nuggets in the laboratory, (2) characterize the pig iron nugget produced and compare them with blast furnace pig iron, (3) investigate the furnace temperature and residence time effects on the pig iron nugget production, and (4) optimize the operational furnace temperatures and residence times. The experiments involved heat treatment of self reducing and fluxing dried green balls at various furnace temperatures and residence times. Three chemically and physically different products were produced after the compete reduction of iron oxides to iron depending on the operational furnace temperatures and/or residence times. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets. The increase in the carbon content of the system as a function of furnace temperature and/or residence time dictated the formation of these products. The direct reduced iron, transition direct reduced iron, and pig iron nuggets produced were analyzed for their chemical composition, degree of metallization, apparent density, microstructure and microhardness. In addition, the change in the carbon content of the system with the changing furnace temperature and/or residence time was detected by optical microscopy and Microhardness measurements. The sufficient carbon dissolution required for the production of pig iron nuggets was determined. It was determined that pig iron nuggets produced had a high apparent density (6.7-7.2 gr/cm3), highly metallized, slag free structure, high iron content (95-97%), high microhardness values (> 325 HVN) and microstructure similar to white cast iron. These properties made them a competitive alternative to blast furnace pig iron.« less

Additive Manufacturing and Casting Technology Comparison: Mechanical Properties, Productivity and Cost Benchmark

NASA Astrophysics Data System (ADS)

Vevers, A.; Kromanis, A.; Gerins, E.; Ozolins, J.

2018-04-01

The casting technology is one of the oldest production technologies in the world but in the recent years metal additive manufacturing also known as metal 3D printing has been evolving with huge steps. Both technologies have capabilities to produce parts with internal holes and at first glance surface roughness is similar for both technologies, which means that for precise dimensions parts have to be machined in places where precise fit is necessary. Benchmark tests have been made to find out if parts which are produced with metal additive manufacturing can be used to replace parts which are produced with casting technology. Most of the comparative tests have been made with GJS-400-15 grade which is one of the most popular cast iron grades. To compare mechanical properties samples have been produced using additive manufacturing and tested for tensile strength, hardness, surface roughness and microstructure and then the results have been compared with the samples produced with casting technology. In addition, both technologies have been compared in terms of the production time and production costs to see if additive manufacturing is competitive with the casting technology. The original paper has been written in the Latvian language as part of the Master Thesis within the framework of the production technology study programme at Riga Technical University.

78 FR 68474 - Non-Malleable Cast Iron Pipe Fittings From China; Scheduling of an Expedited Five-Year Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-990 (Second Review)] Non-Malleable Cast... Duty Order on Non-Malleable Cast Iron Pipe Fittings From China AGENCY: United States International... determine whether revocation of the antidumping duty order on non-malleable cast iron pipe fittings from...

Wear resistance of metals and alloys; Proceedings of the Conference, Chicago, IL, Sept. 24-30, 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kingsbury, G.R.

1988-01-01

Techniques for characterizing and improving the wear properties of metals and composites are discussed in reviews and reports. Topics addressed include the use of interatomic potentials to study the relationship between abrasive wear and other mechanical properties, gas-detonation powder spraying of diamond coatings, a fluidized-bed test method for erosion resistance, the wear behavior of Al and Al-Si-Cu alloys, and abrasive wear of bronze and ZA alloys with and without lubrication. Consideration is given to continuously cast vs sand-cast Zn-Al alloys for bearings, sintered 6061 Al-alloy-based particulate composites with dry lubricants, Cu-based particulate composites, high-temperature friction and wear of X-750 andmore » X-188 superalloys for low-heat-rejection engines, a new metallurgical conception of wear-resistant steels, and the effect of matrix microstructure on the abrasion resistance of high-Cr white cast irons. Extensive graphs and micrographs are provided.« less

Fractographic and three body abrasion behaviour of Al-Garnet-C hybrid chill cast composites

NASA Astrophysics Data System (ADS)

Bandekar, Nityanand; Prasad, M. G. Anantha

2017-08-01

Fractographic and tribological behaviour of hybrid composite of aluminum alloy LM13 matrix with garnet and carbon was investigated. Conventional stir casting technique was used to fabricate the composites with chill cast technique. Various chill materials like Copper, Steel, Iron and Silicon carbide were used to improve the directional solidification. The garnet being added ranges from 3 to 12 wt-% in steps of 3wt-% and constant 3wt-% of carbon. The experiment evaluates the mechanical, fractographic and three body abrasion behaviour of the hybrid composites for various parameters of load, garnet and chills. Microstructural characterization of the composite samples revealed a uniform distribution of reinforcements with minimum clustering. SEM was used for examine worn surfaces. The addition of garnet and carbon reinforcement decreases the wear rate of hybrid composites. Fracture behaviour showed the changes from ductile mode to brittle mode of failure. Further, directional chilling with copper chill improves the wear resistance of the composites.

Effect of bionic coupling units' forms on wear resistance of gray cast iron under dry linear reciprocating sliding condition

NASA Astrophysics Data System (ADS)

Pang, Zuobo; Zhou, Hong; Xie, Guofeng; Cong, Dalong; Meng, Chao; Ren, Luquan

2015-07-01

In order to get close to the wear form of guide rails, the homemade linear reciprocating wear testing machine was used for the wear test. In order to improve the wear-resistance of gray cast iron guide rail, bionic coupling units of different forms were manufactured by a laser. Wear behavior of gray-cast-iron with bionic-coupling units has been studied under dry sliding condition at room temperature using the wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that bionic coupling unit could improve the wear resistance of gray cast iron. The wear resistance of gray cast iron with reticulation bionic coupling unit is the best. When the load and speed changed, reticulation bionic coupling unit still has excellent performance in improving the wear resistance of gray cast iron.

75 FR 54595 - Certain Iron Construction Castings From Brazil, Canada, and the People's Republic of China: Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-08

...] Certain Iron Construction Castings From Brazil, Canada, and the People's Republic of China: Final Results... construction castings from Brazil, Canada, and the People's Republic of China (PRC), pursuant to section 751(c... antidumping duty orders\\1\\ on certain iron construction castings from Brazil, Canada, and the PRC pursuant to...

Microstructures and Surface Stabilities of {Ni-0.4C-6Ta- xCr, 0 ≤ x ≤ 50 Wt Pct} Cast Alloys at High Temperature

NASA Astrophysics Data System (ADS)

Berthod, Patrice

2018-06-01

Nickel-based cast alloys rich in chromium and reinforced by TaC carbides are potentially very interesting alloys for applications at elevated temperatures. Unfortunately, unlike cobalt-chromium and iron-chromium alloys, it is difficult to obtain exclusively TaC as primary carbides in Ni-Cr alloys. In alloys containing 30 wt pct Cr tantalum, carbides coexist with chromium carbides. The latter tend to weaken the alloy at elevated temperatures because they become rapidly spherical and then quickly lose their reinforcing effect. In this work, we attempted to stabilize TaC as a single carbide phase by testing different chromium contents in the [0, 50 wt pct] range. Six alloys containing 0.4C and 6Ta, weight contents corresponding to equivalent molar contents, were elaborated by foundry, and their as-cast microstructures were characterized. Samples of all alloys were exposed to 1127 °C and 1237 °C for 24 hours to characterize their stabilized microstructures. The surface fractions of chromium carbides and tantalum carbides were measured by image analysis, and their evolutions vs the chromium content were studied. For the chosen C and Ta contents, it appears that obtaining TaC only is possible by decreasing the chromium content to 10 wt pct. At the same time, TaC fractions are unfortunately too low because a large portion of tantalum integrates into the solid solution in the matrix. A second consequence is a critical decrease in oxidation resistance. Other possible methods to stabilize TaC as a single carbide are evocated, such as the simultaneous increase in Ta and decrease in chromium from 30 wt pct Cr.

Modern Cast Irons in Chemical Engineering

DTIC Science & Technology

1934-11-09

fl’ceew. T I SOCIETY OF CHEMICAL INDUSTRY CHEMICAL ENGINEERING GROUP MODERN CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P...CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P., M.I.E.E.* INTRODUCTION to chemical or thermal resistance. Small blow-holes Any...consideration of modern cast irons in chemical seldom appear to reduce the mechanical strength of engineering should strictly be prefaced by a definition

Integrated System of Thermal/Dimensional Analysis for Quality Control of Metallic Melt and Ductile Iron Casting Solidification

NASA Astrophysics Data System (ADS)

Stan, Stelian; Chisamera, Mihai; Riposan, Iulian; Neacsu, Loredana; Cojocaru, Ana Maria; Stan, Iuliana

2018-03-01

The main objective of the present work is to introduce a specific experimental instrument and technique for simultaneously evaluating cooling curves and expansion or contraction of cast metals during solidification. Contraction/expansion analysis illustrates the solidification parameters progression, according to the molten cast iron characteristics, which are dependent on the melting procedure and applied metallurgical treatments, mold media rigidity and thermal behavior [heat transfer parameters]. The first part of the paper summarizes the performance of this two-mold device. Its function is illustrated by representative shrinkage tendency results in ductile cast iron as affected by mold rigidity (green sand and furan resin sand molds) and inoculant type (FeSi-based alloys), published in part previously. The second part of the paper illustrates an application of this equipment adapted for commercial foundry use. It conducts thermal analysis and volume change measurements in a single ceramic cup so that mold media as well as solidification conditions are constants, with cast iron quality as the variable. Experiments compared gray and ductile cast iron solidification patterns. Gray iron castings are characterized by higher undercooling at the beginning and at the end of solidification and lower graphitic expansion. Typically, ductile cast iron exhibits higher graphitic, initial expansion, conducive for shrinkage formation in soft molds.

Phase-field simulation of microstructure formation in technical castings - A self-consistent homoenthalpic approach to the micro-macro problem

NASA Astrophysics Data System (ADS)

Böttger, B.; Eiken, J.; Apel, M.

2009-10-01

Performing microstructure simulation of technical casting processes suffers from the strong interdependency between latent heat release due to local microstructure formation and heat diffusion on the macroscopic scale: local microstructure formation depends on the macroscopic heat fluxes and, in turn, the macroscopic temperature solution depends on the latent heat release, and therefore on the microstructure formation, in all parts of the casting. A self-consistent homoenthalpic approximation to this micro-macro problem is proposed, based on the assumption of a common enthalpy-temperature relation for the whole casting which is used for the description of latent heat production on the macroscale. This enthalpy-temperature relation is iteratively obtained by phase-field simulations on the microscale, thus taking into account the specific morphological impact on the latent heat production. This new approach is discussed and compared to other approximations for the coupling of the macroscopic heat flux to complex microstructure models. Simulations are performed for the binary alloy Al-3at%Cu, using a multiphase-field solidification model which is coupled to a thermodynamic database. Microstructure formation is simulated for several positions in a simple model plate casting, using a one-dimensional macroscopic temperature solver which can be directly coupled to the microscopic phase-field simulation tool.

Micro-structural study and Rietveld analysis of fast reactor fuels: U-Mo fuels

NASA Astrophysics Data System (ADS)

Chakraborty, S.; Choudhuri, G.; Banerjee, J.; Agarwal, Renu; Khan, K. B.; Kumar, Arun

2015-12-01

U-Mo alloys are the candidate fuels for both research reactors and fast breeder reactors. In-reactor performance of the fuel depends on the microstructural stability and thermal properties of the fuel. To improve the fuel performance, alloying elements viz. Zr, Mo, Nb, Ti and fissium are added in the fuel. The first reactor fuels are normally prepared by injection casting. The objective of this work is to compare microstructure, phase-fields and hardness of as-cast four different U-Mo alloy (2, 5, 10 and 33 at.% Mo) fuels with the equilibrium microstructure of the alloys. Scanning electron microscope with energy dispersive spectrometer and optical microscope have been used to characterize the morphology of the as-cast and annealed alloys. The monoclinic α'' phase in as-cast U-10 at.% Mo alloy has been characterized through Rietveld analysis. A comparison of metallographic and Rietveld analysis of as-cast (dendritic microstructure) and annealed U-33 at.% Mo alloy, corresponding to intermetallic compound, has been reported here for the first time. This study will provide in depth understanding of microstructural and phase evolution of U-Mo alloys as fast reactor fuel.

Chemical Degradation of the Cathodic Electrical Contact Between Carbon and Cast Iron in Aluminum Production Cells

NASA Astrophysics Data System (ADS)

Brassard, Martin; Désilets, Martin; Soucy, Gervais; Bilodeau, Jean-François; Forté, Martin

2017-06-01

The cathodic carbon to cast iron electrical contact degradation is one of the factors to consider in the cathode voltage drop (CVD) increase over the lifetime of aluminum production cells. Lab-scale experiments were carried out to study the cast iron to carbon interface chemical degradation and the impact of important cell parameters like temperature and bath chemistry. Laboratory degradation results were compared with industrial samples. A thermoelectric Ansys numerical model was then used to predict the effect of cast iron surface degradation over CVD. Results show that the aluminum formation on the cast iron surface and its subsequent diffusion creates an immiscible mixture of Fe-Al metal alloy and electrolytic bath. Disparities were also observed between industrial samples taken from two different technologies, suggesting that the degradation can be slowed down. Thermoelectric calculations finally revealed that the impact of the contact resistance augmentation is by far greater than the cast iron degradation.

COST AND PERFORMANCE REPORT: INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

DTIC Science & Technology

2016-12-30

Operational Variable LeakFinderRT Equipment Logistics Portable Case Pipe Material Pit Cast Iron, Spun Cast Iron, Steel , Ductile Iron, Asbestos Cement ...AND ACRONYMS AC asbestos cement AMI advanced metering infrastructure AWWA American Water Works Association CI cast iron DI ductile iron DoD...assessing their ability to detect and accurately locate leaks in challenging pipe types such as polyvinyl chloride (PVC), asbestos cement (AC), and

Melt Conditioning of Light Metals by Application of High Shear for Improved Microstructure and Defect Control

NASA Astrophysics Data System (ADS)

Patel, Jayesh B.; Yang, Xinliang; Mendis, Chamini L.; Fan, Zhongyun

2017-04-01

Casting is the first step toward the production of majority of metal products whether the final processing step is casting or other thermomechanical processes such as extrusion or forging. The high shear melt conditioning provides an easily adopted pathway to producing castings with a more uniform fine-grained microstructure along with a more uniform distribution of the chemical composition leading to fewer defects as a result of reduced shrinkage porosities and the presence of large oxide films through the microstructure. The effectiveness of high shear melt conditioning in improving the microstructure of processes used in industry illustrates the versatility of the high shear melt conditioning technology. The application of high shear process to direct chill and twin roll casting process is demonstrated with examples from magnesium melts.

Synthesis, Characterization and Cold Workability of Cast Copper-Magnesium-Tin Alloys

NASA Astrophysics Data System (ADS)

Bravo Bénard, Agustín Eduardo; Martínez Hernández, David; González Reyes, José Gonzalo; Ortiz Prado, Armando; Schouwenaars Franssens, Rafael

2014-02-01

The use of Mg as an alloying element in copper alloys has largely been overlooked in scientific literature and technological applications. Its supposed tribological compatibility with iron makes it an interesting option to replace Pb in tribological alloys. This work describes the casting process of high-quality thin slabs of Cu-Mg-Sn alloys with different compositions by means of conventional methods. The resulting phases were analyzed using X-ray diffraction, scanning electron microscopy, optical microscopy, and energy dispersive X-ray spectroscopy techniques. Typical dendritic α-Cu, eutectic Cu2Mg(Sn) and eutectoid non-equilibrium microstructures were found. Tensile tests and Vickers microhardness show the excellent hardening capability of Mg as compared to other copper alloys in the as-cast condition. For some of the slabs and compositions, cold rolling reductions of over 95 pct have been easily achieved. Other compositions and slabs have failed during the deformation process. Failure analysis after cold rolling reveals that one cause for brittleness is the presence of casting defects such as microshrinkage and inclusions, which can be eliminated. However, for high Mg contents, a high volume fraction of the intermetallic phase provides a contiguous path for crack propagation through the connected interdendritic regions.

Microstructure and mechanical properties of zirconium doped NiAl/Cr(Mo) hypoeutectic alloy prepared by injection casting

NASA Astrophysics Data System (ADS)

Sheng, L. Y.; Du, B. N.; Guo, J. T.

2017-01-01

NiAl based materials has been considered as most potential candidate of turbine blade, due to its excellent high-temperature properties. However the bad room-temperature properties handicap its application. In the present paper, the zirconium doped NiAl/Cr(Mo) hypoeutectic alloy is fabricated by conventional casting and injection casting technology to improve its room-temperature properties. The microstructure and compressive properties at different temperatures of the conventionally-cast and injection-cast were investigated. The results exhibit that the conventionally-cast alloy comprises coarse primary NiAl phase and eutectic cell, which is dotted with irregular Ni2AlZr Heusler phase. Compared with the conventionally-cast alloy, the injection-cast alloy possesses refined the primary NiAl, eutectic cell and eutectic lamella. In addition, the Ni2AlZr Heusler phase become smaller and distribute uniformly. Moreover, the injection casting decrease the area fraction of primary NiAl phase at the cell interior or cell boundaries. The compressive ductility and yield strength of the injection-cast alloy at room temperature increase by about 100% and 35% over those of conventionally-cast alloy, which should be ascribed to the microstructure optimization.

Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charlot, L.A.; Westerman, R.E.

A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allowsmore » its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.« less

Modeling the Homogenization Kinetics of As-Cast U-10wt% Mo alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Zhijie; Joshi, Vineet; Hu, Shenyang Y.

2016-01-15

Low-enriched U-22at% Mo (U-10Mo) alloy has been considered as an alternative material to replace the highly enriched fuels in research reactors. For the U-10Mo to work effectively and replace the existing fuel material, a thorough understanding of the microstructure development from as-cast to the final formed structure is required. The as-cast microstructure typically resembles an inhomogeneous microstructure with regions containing molybdenum-rich and -lean regions, which may affect the processing and possibly the in-reactor performance. This as-cast structure must be homogenized by thermal treatment to produce a uniform Mo distribution. The development of a modeling capability will improve the understanding ofmore » the effect of initial microstructures on the Mo homogenization kinetics. In the current work, we investigated the effect of as-cast microstructure on the homogenization kinetics. The kinetics of the homogenization was modeled based on a rigorous algorithm that relates the line scan data of Mo concentration to the gray scale in energy dispersive spectroscopy images, which was used to generate a reconstructed Mo concentration map. The map was then used as realistic microstructure input for physics-based homogenization models, where the entire homogenization kinetics can be simulated and validated against the available experiment data at different homogenization times and temperatures.« less

High Chromium Cast Irons: Destabilized-Subcritical Secondary Carbide Precipitation and Its Effect on Hardness and Wear Properties

NASA Astrophysics Data System (ADS)

Guitar, María Agustina; Suárez, Sebastián; Prat, Orlando; Duarte Guigou, Martín; Gari, Valentina; Pereira, Gastón; Mücklich, Frank

2018-05-01

This work evaluates the effect of a destabilization treatment combined with a subcritical diffusion (SCD) and a subsequent quenching (Q) steps on precipitation of secondary carbides and their influence on the wear properties of HCCI (16%Cr). The destabilization of the austenite at high temperature leads to a final microstructure composed of eutectic and secondary carbides, with an M7C3 nature, embedded in a martensitic matrix. An improved wear resistance was observed in the SCD + Q samples in comparison with the Q one, which was attributed to the size of secondary carbides.

Mechanical properties of aluminium fused SiO2 particulate composites cast using metallic and non-metallic chills

NASA Astrophysics Data System (ADS)

Harshith, H. S.; Hemanth, Joel

2018-04-01

This research work aims at developing and mechanical characterization of aluminium (LM13) based metal matrix composite reinforced with varying percentage of fused SiO2 (3%,6%,9%,12%). The mechanical properties are completely dependent on the microstructural parameters of the system. Also the microstructure further depends on the cooling rates during solidification process. Various Chills like Silicon carbide, Mild steel, Copper were used during the casting process to increase the rate of solidification, which enhances the mechanical properties of the composite. The chill casted specimens were subjected to tensile and hardness tests followed by microstructure studies. A casting produced using mild steel chill exhibited higher young's modulus and was found to be maximum at 9% reinforcement. Finer microstructure and better UTS were seen for specimen's casted using copper chills, whereas silicon carbide and mild steel chills gave rise to very coarse structure with reduced UTS values compared to copper chills.

Modeling of Casting Defects in an Integrated Computational Materials Engineering Approach

NASA Astrophysics Data System (ADS)

Sabau, Adrian S.

To accelerate the introduction of new cast alloys the modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. The required models related to casting defects, such as microporosity and hot tears are reviewed. Three aluminum alloys are considered A356, 356 and 319. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Examples are given for predicting microporosity defects and microstructure distribution for a plate casting. Models to predict fatigue life and yield stress are briefly highlighted here for the sake of completion and to illustrate how the length scales of the microstructure features as well as porosity defects are taken into account for modeling the mechanical properties. The data on casting defects including microstructure features, is crucial for evaluating the final performance-related properties of the component.

Electroslag Treatment of Liquid Cast Iron

NASA Astrophysics Data System (ADS)

Grachev, V. A.

2018-01-01

The processes that occur in the liquid metal-slag system during electroslag treatment of cast iron are studied from an electrochemical standpoint. The role of electrolysis in the electroslag process is shown, and a method for producing high-strength cast iron with globular graphite using electrolysis of a slag containing magnesium oxides and fluorides is proposed and tested.

UNDERSTANDING CHLORINE AND CHLORAMINE DECAY KINETICS IN OLD CAST IRON PIPES, 2. CONVERSION FROM CONVENTIONAL TREATMENT TO MICROFILTRATION IN A SMALL WATER SYSTEM

EPA Science Inventory

This insitu pipe loop study was designed to determine the disinfectant kinetics associated with very old unlined cast iron pipelines with both chlorine and chloramination residuals. An abandoned 90-year-old unlined cast iron pipeline about 2000 ft long was acclimated to conduct a...

Microstructure of Dense Thin Sheets of gamma-TiAl Fabricated by Hot Isostatic Pressing of Tape-Cast Monotapes (Preprint)

DTIC Science & Technology

2007-02-01

fabrication of dense thin sheets of gamma titanium aluminide . Polarized light microscopy revealed a fine-grained microstructure but a few isolated...HIPed (near-gamma) microstructure occurred. 15. SUBJECT TERMS gamma titanium aluminide , thin sheet, tape casting, hot isostatic pressing 16...sheets (250–300 μm thick) of gamma titanium aluminide (γ-TiAl). Polarized light microscopy revealed a fine-grained microstructure (average grain

A comparative study of the microstructures observed in statically cast and continuously cast Bi-In-Sn ternary eutectic alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sengupta, S.; Soda, H.; McLean, A.

2000-01-01

A ternary eutectic alloy with a composition of 57.2 pct Bi, 24.8 pct In, and 18 pct Sn was continuously cast into wire of 2 mm diameter with casting speeds of 14 and 79 mm/min using the Ohno Continuous Casting (OCC) process. The microstructures obtained were compared with those of statically cast specimens. Extensive segregation of massive Bi blocks, Bi complex structures, and tin-rich dendrites was found in specimens that were statically cast. Decomposition of {radical}Sn by a eutectoid reaction was confirmed based on microstructural evidence. Ternary eutectic alloy with a cooling rate of approximately 1 C/min formed a doublemore » binary eutectic. The double binary eutectic consisted of regions of BiIn and decomposed {radical}Sn in the form of a dendrite cell structure and regions of Bi and decomposed {radical}Sn in the form of a complex-regular cell. The Bi complex-regular cells, which are a ternary eutectic constituent, existed either along the boundaries of the BiIn-decomposed {radical}Sn dendrite cells or at the front of elongated dendrite cell structures. In the continuously cast wires, primary Sn dendrites coupled with a small Bi phase were uniformly distributed within the Bi-In alloy matrix. Neither massive Bi phase, Bi complex-regular cells, no BiIn eutectic dendrite cells were observed, resulting in a more uniform microstructure in contrast to the heavily segregated structures of the statically cast specimens.« less

An innovative method for nondestructive analysis of cast iron artifacts at Hopewell Furnace National Historic Site, Pennsylvania

USGS Publications Warehouse

Sloto, Ronald A.; Martin f. Helmke,

2014-01-01

Sampling cast iron produced by the furnace posed two problems. First, verification that the iron was actually cast at Hopewell Furnace was necessary, as some iron objects found at Hopewell may not have originated there. This was accomplished by using artifacts on display at the Hopewell visitor center (fig. 2). All artifacts on display have been positively attributed to the furnace, and stoves produced by the furnace are easily recognized by the name “Hopewell” cast into them. The second problem was the analysis of the trace metal content of the cast iron, because it was not possible to break off part of a historically important artifact and send it to a laboratory for analysis. This problem was solved when the USGS collaborated with West Chester University, which owns a portable X-ray fluorescence (XRF) spectrometer.

Upgrade Recycling of Cast Iron Scrap Chips towards β-FeSi₂ Thermoelectric Materials.

PubMed

Laila, Assayidatul; Nanko, Makoto; Takeda, Masatoshi

2014-09-04

The upgrade recycling of cast-iron scrap chips towards β-FeSi₂ thermoelectric materials is proposed as an eco-friendly and cost-effective production process. By using scrap waste from the machining process of cast-iron components, the material cost to fabricate β-FeSi₂ is reduced and the industrial waste is recycled. In this study, β-FeSi₂ specimens obtained from cast iron scrap chips were prepared both in the undoped form and doped with Al and Co elements. The maximum figure of merit ( ZT ) indicated a thermoelectric performance of approximately 70% in p-type samples and nearly 90% in n-type samples compared to β-FeSi₂ prepared from pure Fe and other published studies. The use of cast iron scrap chips to produce β-FeSi₂ shows promise as an eco-friendly and cost-effective production process for thermoelectric materials.

Microstructure of As-cast Co-Cr-Mo Alloy Prepared by Investment Casting

NASA Astrophysics Data System (ADS)

Park, Jong Bum; Jung, Kyung-Hwan; Kim, Kang Min; Son, Yong; Lee, Jung-Il; Ryu, Jeong Ho

2018-04-01

The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by an investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants owing to its high strength, good corrosion resistance, and excellent biocompatibility. This work focuses on the resulting microstructures arising from normal industrial environmental conditions. The characterization of the samples was carried out using optical microscopy, field emission scanning electron microscopy and energy-dispersive spectroscopy. In this study, the as-cast microstructure is an γ-Co (face-centered cubic) dendritic matrix with the presence of a secondary phase, such as M23C6 carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloy. Other minority phases, such as the σ phase, were also detected, and their presence could be linked to the manufacturing process and environment.

Metallographic assessment of Al-12Si high-pressure die casting escalator steps.

PubMed

Vander Voort, George Frederic; Suárez-Peña, Beatriz; Asensio-Lozano, Juan

2014-10-01

A microstructural characterization study was performed on high-pressure die cast specimens extracted from escalator steps manufactured from an Al-12 wt.% Si alloy designed for structural applications. Black and white, color light optical imaging and scanning electron microscopy techniques were used to conduct the microstructural analysis. Most regions in the samples studied contained globular-rosette primary α-Al grains surrounded by an Al-Si eutectic aggregate, while primary dendritic α-Al grains were present in the surface layer. This dendritic microstructure was observed in the regions where the melt did not impinge directly on the die surface during cavity filling. Consequently, microstructures in the surface layer were nonuniform. Utilizing physical metallurgy principles, these results were analyzed in terms of the applied pressure and filling velocity during high-pressure die casting. The effects of these parameters on solidification at different locations of the casting are discussed.

Microstructure and Corrosion Characterization of Squeeze Cast AM50 Magnesium Alloys

NASA Astrophysics Data System (ADS)

Sachdeva, Deepika; Tiwari, Shashank; Sundarraj, Suresh; Luo, Alan A.

2010-12-01

Squeeze casting of magnesium alloys potentially can be used in lightweight chassis components such as control arms and knuckles. This study documents the microstructural analysis and corrosion behavior of AM50 alloys squeeze cast at different pressures between 40 and 120 MPa and compares them with high-pressure die cast (HPDC) AM50 alloy castings and an AM50 squeeze cast prototype control arm. Although the corrosion rates of the squeeze cast samples are slightly higher than those observed for the HPDC AM50 alloy, the former does produce virtually porosity-free castings that are required for structural applications like control arms and wheels. This outcome is extremely encouraging as it provides an opportunity for additional alloy and process development by squeeze casting that has remained relatively unexplored for magnesium alloys compared with aluminum. Among the microstructural parameters analyzed, it seems that the β-phase interfacial area, indicating a greater degree of β network, leads to a lower corrosion rate. Weight loss was the better method for determining corrosion behavior in these alloys that contain a large fraction of second phase, which can cause perturbations to an overall uniform surface corrosion behavior.

Repair welding of cast iron coated electrodes

NASA Astrophysics Data System (ADS)

Żuk, M.; Górka, J.; Dojka, R.; Czupryński, A.

2017-08-01

Welding cast iron is a complex production procedure. Repair welding was used to repair damaged or poorly made castings. This is due to a tendency to cracking of the material during welding as well as after it. Welding cast iron can be carried out on hot or on cold. Hot welding requires high heat material and the use of welding material in the form of cast iron. In the case of cold welding, it is possible to use different materials. Mostly used filler metals are nickel and copper based. The work shows the course of research concerning repairmen of ductile iron with arc welding method. For the reparation process four types of ESAB company coated electrodes dedicated for cast iron were used with diameter 3.2 and 4 mm: ES 18-8-6B (4mm), EB 150 (4mm), OK NiCl, EŻM. In the cast iron examined during the testing grooves were made using plasma methods, in order to simulate the removed casting flaws. Then the welding process with coated electrodes was executed. The process utilized low welding current row of 100A, so there would only be a small amount of heat delivered to the heat affected zone (HAZ). Short stitches were made, after welding it was hammered, in order to remove stresses. After the repair welding the part of studies commenced which purpose was finding surface defects using visual testing (VT) and penetration testing (PT). In the second part, a series of macro and microscopic studies were executed witch the purpose of disclosuring the structure. Then the hardness tests for welds cross sections were performed. An important aspect of welding cast iron is the colour of the padding weld after welding, more precisely the difference between the base material and padding weld, the use of different materials extra gives the extra ability to select the best variant. The research of four types of coated electrode was executed, based on the demands the best option in terms of aesthetic, strength and hardness.

The Solidification Behavior of AA2618 Aluminum Alloy and the Influence of Cooling Rate

PubMed Central

Liu, Yulin; Liu, Ming; Luo, Lei; Wang, Jijie; Liu, Chunzhong

2014-01-01

In AA2618 aluminum alloy, the iron- and nickel-rich intermetallics formed during solidification are of great effect on the mechanical properties of the alloy at both room temperature and elevated temperatures. However, the solidification behavior of the alloy and the formation mechanism of the intermetallics during solidification of the alloy are not clear. This research fills the gap and contributes to understanding the intermetallic of the alloy. The results showed that cooling rate was of great influence on the formation of the intermetallics. Under the condition of slow cooling, the as-cast microstructures of the alloy were complex with many coarse eutectic compounds including Al9FeNi, Al7(CuNi)5, Si, Al2Cu and Al2CuMg. The phase Al9FeNi was the dominant intermetallic compound, which precipitated at the earlier stage of the solidification by eutectic reaction L → α-Al + Al9FeNi. Increasing the cooling rate would suppress the formation of the coarse eutectic intermetallics. Under the condition of near-rapid cooling, the as-cast microstructures of the alloy consisted of metastable intermetallics Al9FeNi and Al2Cu; the equilibrium eutectic compounds were suppressed. This research concluded that intermetallics could be refined to a great extent by near-rapid cooling. PMID:28788281

Cast B2-phase iron-aluminum alloys with improved fluidity

DOEpatents

Maziasz, Philip J.; Paris, Alan M.; Vought, Joseph D.

2002-01-01

Systems and methods are described for iron aluminum alloys. A composition includes iron, aluminum and manganese. A method includes providing an alloy including iron, aluminum and manganese; and processing the alloy. The systems and methods provide advantages because additions of manganese to iron aluminum alloys dramatically increase the fluidity of the alloys prior to solidification during casting.

Comparative study of the surface characteristics, microstructure, and magnetic retentive forces of laser-welded dowel-keepers and cast dowel-keepers for use with magnetic attachments.

PubMed

Chao, Yonglie; Du, Li; Yang, Ling

2005-05-01

Information regarding the merits and problems associated with connecting a keeper to a dowel and coping using a laser welding technique has not been explored extensively in the dental literature. This in vitro study compared the surface characteristics, microstructure, and magnetic retentive forces for a dowel and coping-keeper mechanism fabricated using a laser welding process and a cast-to casting technique. Five cast-to and 6 laser-welded dowel and coping-keeper specimens were tested. Using 5 freestanding keepers as the control group, the surface characteristics and microstructures of the specimens were examined by means of stereomicroscopy, metallographic microscopy, and scanning electron microscopy (SEM). Energy-dispersive spectroscopic (EDS) microanalysis with SEM provided elemental concentration information for the test specimens. The vertical magnetic retentive forces (N) of the 3 groups were measured using a universal testing machine. The results were statistically compared using 1-way analysis of variance and the Newman-Keuls multiple range test (alpha =.05). The laser-welded dowel-keeper generally maintained its original surface smoothness as well as the original microstructure. Elements diffused readily through the fusion zone. The surface of the cast dowel-keeper became rough with the formation of an oxide layer, the microstructure changed, and there was only limited elemental diffusion in the fusion zone. The average vertical magnetic retentive force of the laser-welded group, the cast group, and the control group were 4.2 +/- 0.2 N, 3.8 +/- 0.3 N, and 5.6 +/- 0.3 N, respectively. Statistically significant differences in vertical magnetic retentive force were found between the control group and both the laser-welded and cast groups (P <.01). Compared with the cast dowel-keepers, the average vertical magnetic retentive force of the laser-welded dowel-keepers was significantly higher (P <.05). The laser welding technique had less influence on the surface characteristics, the microstructure, and the magnetic retentive forces of keepers relative to techniques that incorporate a keeper at the time of cast dowel and coping fabrication.

POURING IRON FROM ELECTRIC FURNACE INTO BULL LADLE AFTER MAGNESIUM ...

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

POURING IRON FROM ELECTRIC FURNACE INTO BULL LADLE AFTER MAGNESIUM HAD BEEN ADDED TO GENERATE DUCTILE IRON WHEN IT COOLS IN THE MOLD. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

Advances in multi-scale modeling of solidification and casting processes

NASA Astrophysics Data System (ADS)

Liu, Baicheng; Xu, Qingyan; Jing, Tao; Shen, Houfa; Han, Zhiqiang

2011-04-01

The development of the aviation, energy and automobile industries requires an advanced integrated product/process R&D systems which could optimize the product and the process design as well. Integrated computational materials engineering (ICME) is a promising approach to fulfill this requirement and make the product and process development efficient, economic, and environmentally friendly. Advances in multi-scale modeling of solidification and casting processes, including mathematical models as well as engineering applications are presented in the paper. Dendrite morphology of magnesium and aluminum alloy of solidification process by using phase field and cellular automaton methods, mathematical models of segregation of large steel ingot, and microstructure models of unidirectionally solidified turbine blade casting are studied and discussed. In addition, some engineering case studies, including microstructure simulation of aluminum casting for automobile industry, segregation of large steel ingot for energy industry, and microstructure simulation of unidirectionally solidified turbine blade castings for aviation industry are discussed.

Experimental study of the continuous casting slab solidification microstructure by the dendrite etching method

NASA Astrophysics Data System (ADS)

Yang, X. G.; Xu, Q. T.; Wu, C. L.; Chen, Y. S.

2017-12-01

The relationship between the microstructure of the continuous casting slab (CCS) and quality defects of the steel products, as well as evolution and characteristics of the fine equiaxed, columnar, equiaxed zones and crossed dendrites of CCS were systematically investigated in this study. Different microstructures of various CCS samples were revealed. The dendrite etching method was proved to be quite efficient for the analysis of solidified morphologies, which are essential to estimate the material characteristics, especially the CCS microstructure defects.

Evaluation of the microstructure, secondary dendrite arm spacing, and mechanical properties of Al-Si alloy castings made in sand and Fe-Cr slag molds

NASA Astrophysics Data System (ADS)

Narasimha Murthy, I.; Babu Rao, J.

2017-07-01

The microstructure and mechanical properties of as-cast A356 (Al-Si) alloy castings were investigated. A356 alloy was cast into three different molds composed of sand, ferrochrome (Fe-Cr) slag, and a mixture of sand and Fe-Cr. A sodium silicate-CO2 process was used to make the necessary molds. Cylindrical-shaped castings were prepared. Cast products with no porosity and a good surface finish were achieved in all of the molds. These castings were evaluated for their metallography, secondary dendrite arm spacing (SDAS), and mechanical properties, including hardness, compression, tensile, and impact properties. Furthermore, the tensile and impact samples were analyzed by fractography. The results show that faster heat transfer in the Fe-Cr slag molds than in either the silica sand or mixed molds led to lower SDAS values with a refined microstructure in the products cast in Fe-Cr slag molds. Consistent and enhanced mechanical properties were observed in the slag mold products than in the castings obtained from either sand or mixed molds. The fracture surface of the slag mold castings shows a dimple fracture morphology with a transgranular fracture nature. However, the fracture surfaces of the sand mold castings display brittle fracture. In conclusion, products cast in Fe-Cr slag molds exhibit an improved surface finish and enhanced mechanical properties compared to those of products cast in sand and mixed molds.

10. DETAIL OF CAST IRON COLUMN BASE ON FIRST FLOOR ...

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

10. DETAIL OF CAST IRON COLUMN BASE ON FIRST FLOOR STOREFRONT, SHOWING MANUFACTURER'S STAMP: IOWA IRON WOKS CO. DUBUQUE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Dubuque Seed Company Warehouse, 169-171 Iowa Street, Dubuque, Dubuque County, IA

Corrosion Behavior of Cast Iron in Freely Aerated Stagnant Arabian Gulf Seawater

PubMed Central

Sherif, El-Sayed M.; Abdo, Hany S.; Almajid, Abdulhakim A.

2015-01-01

In this work, the results obtained from studying the corrosion of cast iron in freely aerated stagnant Arabian Gulf seawater (AGS) at room temperature were reported. The study was carried out using weight-loss (WL), cyclic potentiodynamic polarization (CPP), open-circuit potential (OCP), and electrochemical impedance spectroscopy (EIS) measurements and complemented by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) investigations. WL experiments between two and 10 days’ immersion in the test electrolyte indicated that the weight-loss the cast iron increases with increasing the time of immersion. CPP measurements after 1 h and 24 h exposure period showed that the increase of time decreases the corrosion via decreasing the anodic and cathodic currents, as well as decreasing the corrosion current and corrosion rate and increasing the polarization resistance of the cast iron. EIS data confirmed the ones obtained by WL and CPP that the increase of immersion time decreases the corrosion of cast iron by increasing its polarization resistance.

Mechanical and Microstructural Effects of Thermal Aging on Cast Duplex Stainless Steels by Experiment and Finite Element Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarm, Samuel C.; Mburu, Sarah N.; Kolli, Ratna P.

Cast duplex stainless steel piping in light water nuclear reactors expe- rience thermal aging embrittlement during operational service. Interest in extending the operational life to 80 years requires an increased understanding of the microstructural evolution and corresponding changes in mechanical behavior. We analyze the evolution of the microstructure during thermal aging of cast CF-3 and CF-8 stainless steels using electron microscopy and atom probe tomography. The evolution of the mechanical properties is measured concurrently by mechanical methods such as tensile tests, Charpy V-notch tests, and instrumented nanoinden- tation. A microstructure-based finite element method model is developed and uti- lized inmore » conjunction with the characterization results in order to correlate the local stress-strain effects in the microstructure with the bulk measurements. This work is supported by the DOE Nuclear Energy University Programs (NEUP), contract number DE-NE0000724.« less

Long-term oxidation of candidate cast iron and stainless steel exhaust system alloys from 650 to 800 °C in air with water vapor

DOE PAGES

Brady, Michael P.; Muralidharan, Govindarajan; Leonard, Donovan .; ...

2014-08-29

Here, the oxidation behavior of SiMo cast iron, Ni-resist D 5S cast iron, cast chromia-forming austenitic stainless steels of varying Cr/Ni content based on CF8C plus, HK, and HP, and a developmental cast alumina-forming austenitic (AFA) stainless steel of interest for diesel exhaust system components were studied for up to 5000 h at 650-800 °C in air with 10% H 2O. At 650 °C, the Ni-resist D5S exhibited moderately better oxidation resistance than did the SiMo cast iron. However, the D5S suffered from oxide scale spallation issues at 700 °C and higher, whereas the oxide scales formed on SiMo castmore » iron remained adherent from 700-800 °C despite oxide scales hundreds of microns thick. The oxidation of the SiMo cast iron exhibited unusual temperature dependence, with periods of slower oxidation kinetics at 750-800 °C compared to 650-700 °C due to continuous silica-rich scale formation at the higher temperatures. The oxidation of the cast chromia-forming austenitics trended with the level of Cr and Ni additions, with small mass losses consistent with Cr oxy-hydroxide volatilization processes for the higher 25Cr/25-35Ni HK and HP type alloys, and transition to rapid Fe-base oxide formation and scale spallation in the lower 19Cr/12Ni CF8C plus type alloy. In contrast, small positive mass changes consistent with protective alumina scale formation were observed for the cast AFA alloy under all conditions studied. Implications of these findings for diesel exhaust system components are discussed.« less

Does the casting mode influence microstructure, fracture and properties of different metal ceramic alloys?

PubMed

Bauer, José Roberto de Oliveira; Grande, Rosa Helena Miranda; Rodrigues-Filho, Leonardo Eloy; Pinto, Marcelo Mendes; Loguercio, Alessandro Dourado

2012-01-01

The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p < 0.05). The factors 'alloy" and 'casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property.

Metallography and microstructure interpretation of some archaeological tin bronze vessels from Iran

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oudbashi, Omid, E-mail: o.oudbashi@aui.ac.ir; Davami, Parviz, E-mail: pdavami@razi-foundation.com

2014-11-15

Archaeological excavations in western Iran have recently revealed a significant Luristan Bronzes collection from Sangtarashan archaeological site. The site and its bronze collection are dated to Iron Age II/III of western Iran (10th–7th century BC) according to archaeological research. Alloy composition, microstructure and manufacturing technique of some sheet metal vessels are determined to reveal metallurgical processes in western Iran in the first millennium BC. Experimental analyses were carried out using Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy and Optical Microscopy/Metallography methods. The results allowed reconstructing the manufacturing process of bronze vessels in Luristan. It proved that the samples have been manufacturedmore » with a binary copper–tin alloy with a variable tin content that may relates to the application of an uncontrolled procedure to make bronze alloy (e.g. co-smelting or cementation). The presence of elongated copper sulphide inclusions showed probable use of copper sulphide ores for metal production and smelting. Based on metallographic studies, a cycle of cold working and annealing was used to shape the bronze vessels. - Highlights: • Sangtarashan vessels are made by variable Cu-Sn alloys with some impurities. • Various compositions occurred due to applying uncontrolled smelting methods. • The microstructure represents thermo-mechanical process to shape bronze vessels. • In one case, the annealing didn’t remove the eutectoid remaining from casting. • The characteristics of the bronzes are similar to other Iron Age Luristan Bronzes.« less

78 FR 77421 - Certain Oil Country Tubular Goods From India: Preliminary Affirmative Countervailing Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-23

... tubing, of iron (other than cast iron) or steel (both carbon and alloy), whether seamless or welded... and tubing, of iron (other than cast iron) or steel (both carbon and alloy), whether seamless or..., United States Steel Corporation, Boomerang Tube, Energex Tube, a division of JMC Steel Group, Northwest...

Biomimetic Materials by Freeze Casting

NASA Astrophysics Data System (ADS)

Porter, Michael M.; Mckittrick, Joanna; Meyers, Marc A.

2013-06-01

Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods.

PubMed

Seikh, Asiful H; Sherif, El-Sayed M; Khan Mohammed, Sohail M A; Baig, Muneer; Alam, Mohammad Asif; Alharthi, Nabeel

2018-01-01

The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance.

Microstructure characterization and corrosion resistance properties of Pb-Sb alloys for lead acid battery spine produced by different casting methods

PubMed Central

Baig, Muneer; Alam, Mohammad Asif; Alharthi, Nabeel

2018-01-01

The aim of this study is to find out the microstructure, hardness, and corrosion resistance of Pb-5%Sb spine alloy. The alloy has been produced by high pressure die casting (HPDC), medium pressure die casting (AS) and low pressure die casting (GS) methods, respectively. The microstructure was characterized by using optical microscopy and scanning electron microscopy (SEM). The hardness was also reported. The corrosion resistance of the spines in 0.5M H2SO4 solution has been analyzed by measuring the weight loss, impedance spectroscopy and the potentiodynamic polarization techniques. It has been found that the spine produced by HPDC has defect-free fine grain structure resulting improvement in hardness and excellent corrosion resistance. PMID:29668709

Microstructure and Sliding Wear Behaviour of In-Situ TiC-Reinforced Composite Surface Layers Fabricated on Ductile Cast Iron by Laser Alloying.

PubMed

Janicki, Damian

2018-01-05

TiC-reinforced composite surface layers (TRLs) on a ductile cast iron EN-GJS-700-2 grade (DCI) substrate were synthesized using a diode laser surface alloying with a direct injection of titanium powder into the molten pool. The experimental results were compared with thermodynamic calculations. The TRLs having a uniform distribution of the TiC particles and their fraction up to 15.4 vol % were achieved. With increasing titanium concentration in the molten pool, fractions of TiC and retained austenite increase and the shape of TiC particles changes from cubic to dendritic form. At the same time, the cementite fraction decreases, lowering the overall hardness of the TRL. A good agreement between experimental and calculated results was achieved. Comparative dry sliding wear tests between the as-received DCI, the TRLs and also laser surface melted layers (SMLs) have been performed following the ASTM G 99 standard test method under contact pressures of 2.12 and 4.25 MPa. For both the as-received DCI and the SMLs, the wear rates increased with increasing contact pressure. The TRLs exhibited a significantly higher wear resistance than the others, which was found to be load independent.

Microstructure and Sliding Wear Behaviour of In-Situ TiC-Reinforced Composite Surface Layers Fabricated on Ductile Cast Iron by Laser Alloying

PubMed Central

Janicki, Damian

2018-01-01

TiC-reinforced composite surface layers (TRLs) on a ductile cast iron EN-GJS-700-2 grade (DCI) substrate were synthesized using a diode laser surface alloying with a direct injection of titanium powder into the molten pool. The experimental results were compared with thermodynamic calculations. The TRLs having a uniform distribution of the TiC particles and their fraction up to 15.4 vol % were achieved. With increasing titanium concentration in the molten pool, fractions of TiC and retained austenite increase and the shape of TiC particles changes from cubic to dendritic form. At the same time, the cementite fraction decreases, lowering the overall hardness of the TRL. A good agreement between experimental and calculated results was achieved. Comparative dry sliding wear tests between the as-received DCI, the TRLs and also laser surface melted layers (SMLs) have been performed following the ASTM G 99 standard test method under contact pressures of 2.12 and 4.25 MPa. For both the as-received DCI and the SMLs, the wear rates increased with increasing contact pressure. The TRLs exhibited a significantly higher wear resistance than the others, which was found to be load independent. PMID:29304001

DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE ...

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

DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE FABRICATING MARK OF STARBUCK IRON WORKS, TROY, NY - Bidwell Bar Suspension Bridge & Stone Toll House, Near Lake Oroville (moved from fork of Feather River), Oroville, Butte County, CA

An investigation of squeeze-cast alloy 718

NASA Technical Reports Server (NTRS)

Gamwell, W. R.

1993-01-01

Alloy 718 billets produced by the squeeze-cast process have been evaluated for use as potential replacements for propulsion engine components which are normally produced from forgings. Alloy 718 billets were produced using various processing conditions. Structural characterizations were performed on 'as-cast' billets. As-cast billets were then homogenized and solution treated and aged according to conventional heat-treatment practices for this alloy. Mechanical property evaluations were performed on heat-treated billets. As-cast macrostructures and microstructures varied with squeeze-cast processing parameters. Mechanical properties varied with squeeze-cast processing parameters and heat treatments. One billet exhibited a defect free, refined microstructure, with mechanical properties approaching those of wrought alloy 718 bar, confirming the feasibility of squeeze-casting alloy 718. However, further process optimization is required, and further structural and mechanical property improvements are expected with process optimization.

Materials Science Laboratory - Columnar-to-Equiaxed Transition in Solidification Processing and Microstructure Formation in Casting of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions

NASA Technical Reports Server (NTRS)

Gandin, Charles-Andre; Ratke, Lorenz

2008-01-01

The Materials Science Laboratory - Columnar-to-Equiaxed Transition in Solidification Processing and Microstructure Formation in Casting of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions (MSL-CETSOL and MICAST) are two investigations which supports research into metallurgical solidification, semiconductor crystal growth (Bridgman and zone melting), and measurement of thermo-physical properties of materials. This is a cooperative investigation with the European Space Agency (ESA) and National Aeronautics and Space Administration (NASA) for accommodation and operation aboard the International Space Station (ISS). Research Summary: Materials Science Laboratory - Columnar-to-Equiaxed Transition in Solidification Processing (CETSOL) and Microstructure Formation in Casting of Technical Alloys under Diffusive and Magnetically Controlled Convective Conditions (MICAST) are two complementary investigations which will examine different growth patterns and evolution of microstructures during crystallization of metallic alloys in microgravity. The aim of these experiments is to deepen the quantitative understanding of the physical principles that govern solidification processes in cast alloys by directional solidification.

Microstructures of ancient and modern cast silver–copper alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Northover, S.M., E-mail: s.m.northover@open.ac.uk; Northover, J.P., E-mail: peter.northover@materials.ox.ac.uk

The microstructures of modern cast Sterling silver and of cast silver objects about 2500 years old have been compared using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray microanalysis (EDX) and electron backscatter diffraction (EBSD). Microstructures of both ancient and modern alloys were typified by silver-rich dendrites with a few pools of eutectic and occasional cuprite particles with an oxidised rim on the outer surface. EBSD showed the dendrites to have a complex internal structure, often involving extensive twinning. There was copious intragranular precipitation within the dendrites, in themore » form of very fine copper-rich rods which TEM, X-ray diffraction (XRD), SEM and STEM suggest to be of a metastable face-centred-cubic (FCC) phase with a cube–cube orientation relationship to the silver-rich matrix but a higher silver content than the copper-rich β in the eutectic. Samples from ancient objects displayed a wider range of microstructures including a fine scale interpenetration of the adjoining grains not seen in the modern material. Although this study found no unambiguous evidence that this resulted from microstructural change produced over archaeological time, the copper supersaturation remaining after intragranular precipitation suggests that such changes, previously proposed for wrought and annealed material, may indeed occur in ancient silver castings. - Highlights: • Similar twinned structures and oxidised surfaces seen in ancient and modern cast silver • General precipitation of fine Cu-rich rods apparently formed by discontinuous precipitation is characteristic of as-cast silver. • The fine rods are cube-cube related to the matrix in contrast with the eutectic. • The silver-rich phase remains supersaturated with copper. • Possibly age-related grain boundary features seen in ancient cast silver.« less

Effect of porosity on ductility variation in investment cast 17-4PH.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Robert D.; Kilgo, Alice C.; Grant, Richard P.

2005-02-01

The stainless steel alloy 17-4PH contains a martensitic microstructure and second phase delta ({delta}) ferrite. Strengthening of 17-4PH is attributed to Cu-rich precipitates produced during age hardening treatments at 900-1150 F (H900-H1150). For wrought 17-4PH, the effects of heat treatment and microstructure on mechanical properties are well-documented [for example, Ref. 1]. Fewer studies are available on cast 17-4PH, although it has been a popular casting alloy for high strength applications where moderate corrosion resistance is needed. Microstructural features and defects particular to castings may have adverse effects on properties, especially when the alloy is heat treated to high strength. Themore » objective of this work was to outline the effects of microstructural features specific to castings, such as shrinkage/solidification porosity, on the mechanical behavior of investment cast 17-4PH. Besides heat treatment effects, the results of metallography and SEM studies showed that the largest effect on mechanical properties is from shrinkage/solidification porosity. Figure 1a shows stress-strain curves obtained from samples machined from castings in the H925 condition. The strength levels were fairly similar but the ductility varied significantly. Figure 1b shows an example of porosity on a fracture surface from a room-temperature, quasi-static tensile test. The rounded features represent the surfaces of dendrites which did not fuse or only partially fused together during solidification. Some evidence of local areas of fracture is found on some dendrite surfaces. The shrinkage pores are due to inadequate backfilling of liquid metal and simultaneous solidification shrinkage during casting. A summary of percent elongation results is displayed in Figure 2a. It was found that higher amounts of porosity generally result in lower ductility. Note that the porosity content was measured on the fracture surfaces. The results are qualitatively similar to those found by Gokhale et al. and Surappa et al. in cast A356 Al and by Gokhale et al. for a cast Mg alloys. The quantitative fractography and metallography work by Gokhale et al. illustrated the strong preference for fracture in regions of porosity in cast material. That is, the fracture process is not correlated to the average microstructure in the material but is related to the extremes in microstructure (local regions of high void content). In the present study, image analysis on random cross-sections of several heats indicated an overall porosity content of 0.03%. In contrast, the area % porosity was as high as 16% when measured on fracture surfaces of tensile specimens using stereology techniques. The results confirm that the fracture properties of cast 17-4PH cannot be predicted based on the overall 'average' porosity content in the castings.« less

Procedure for flaw detection in cast stainless steel

DOEpatents

Kupperman, David S.

1988-01-01

A method of ultrasonic flaw detection in cast stainless steel components incorporating the steps of determining the nature of the microstructure of the cast stainless steel at the site of the flaw detection measurements by ultrasonic elements independent of the component thickness at the site; choosing from a plurality of flaw detection techniques, one such technique appropriate to the nature of the microstructure as determined and detecting flaws by use of the chosen technique.

Microstructure and Mechanical Properties of a Low Alloyed MnB Cast Steel

NASA Astrophysics Data System (ADS)

Luo, Kaishuang; Bai, Bingzhe

2010-08-01

The microstructure and mechanical properties of a low alloyed MnB cast steel designed for coupler castings of trucks were studied. The results show that the microstructure of the MnB cast steel after water quenching is lath martensite and a small amount of massive islands in the matrix of lath martensite. The average size of the martensite packets is about 10 μm in length. Carbides precipitated dispersively at the tempering temperature of 450 °C. The carbides are slender and fibrous, of which the microstructure was θ-phase (Fe, Mn)3C characterized by TEM. The MnB cast steel has good hardenability and tempering stability. Excellent combination of strength, ductility and low-temperature toughness were obtained after water-quenching and 450 °C tempering: Rm = 960-1040 MPa, ReL = 880-900 MPa, A = 19-21%, Z = 56-58%. Especially, the impact energy of the Charpy V-Notch (CVN) specimens reached 70-88 J at -40 °C. The fracture mechanism is transcrystalline fracture both for ambient temperature uniaxial tensile test specimens and for CVN impact test specimens broken at -40 °C, where the whole surfaces were manifested as voids and dimples.

THE EFFECT OF CHLORIDE AND ORTHOPHOSPHATE ON THE RELEASE OF IRON FROM DRINKING WATER DISTRIBUTION SYSTEM CAST IRON MAIN

EPA Science Inventory

“Colored water” resulting from suspended iron particles is a common drinking water consumer complaint which is largely impacted by water chemistry. A bench scale study, performed on a 90 year-old corroded cast-iron pipe section removed from a drinking water distribution system, w...

Bladesmithing at South Dakota School of Mines and Technology

NASA Astrophysics Data System (ADS)

Moehring, Jack; Willman, Michael; Pulscher, Isaac; Rowe, Devin

2016-12-01

A Damascus-style layered blade was made by incorporating bloomery iron and crucible steel. A bloomery furnace was constructed and charged with Black Hills, SD bog iron ore, alloys, and hardwood charcoal. At sufficient temperature, the furnace was bottom-tapped to produce a low carbon iron bloom. A high-carbon crucible steel was made in a natural gas-fired furnace using commercial hematite pellets and coke. The steel was cast into sand molds. The two types of iron/steel were forged together using traditional blacksmithing techniques in a coke-fired forge. The forging process continued until the metal could be evenly worked, signifying the homogenization of the two metals. Once homogenized, the metal was shaped into a blade and subsequently ground into near-final shape, heat-treated, and finish-machined. The microstructure and mechanical properties of the blade were characterized using optical microscopy, hardness and tensile testing. The grain structure of the material varied widely and was not entirely homogenous at the welded layers, but the layers themselves were well-homogenized. The finished blade was compared to a common steel (1095) used for bladesmithing and was found to have similar hardness but significantly lower tensile strength.

Influence of friction stir processing on the room temperature fatigue cracking mechanisms of A356 aluminum alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelaturu, Phalgun; Jana, Saumyadeep; Mishra, Rajiv S.

Here, failure by fatigue is a common problem associated with cast aluminum alloys due to defects like shrinkage porosities, non-metallic inclusions, etc. Friction stir processing (FSP) has recently emerged as an effective technique for local modification of microstructure. This study investigates the fatigue crack initiation and growth mechanisms in cast and FSPed A356 aluminum alloy. Two sets of parameters were used to friction stir the cast alloy resulting in the complete modification the cast microstructure to a wrought microstructure. Both the FSPed microstructures exhibited severe abnormal grain growth (AGG) after heat treatment leading to a multimodal grain size distribution –more » the grain sizes ranging from a few microns to a few millimeters. One of the FSP conditions displayed an excellent improvement in fatigue life by an order of magnitude, while the other condition displayed an unexpectedly large scatter in fatigue lives. Detailed study of the fractured fatigue specimens by electron back scattered diffraction (EBSD) revealed that both, fatigue crack initiation and propagation, were intimately tied to the grain size as well as the grain misorientations in the microstructure.« less

Influence of friction stir processing on the room temperature fatigue cracking mechanisms of A356 aluminum alloy

DOE PAGES

Nelaturu, Phalgun; Jana, Saumyadeep; Mishra, Rajiv S.; ...

2018-01-11

Here, failure by fatigue is a common problem associated with cast aluminum alloys due to defects like shrinkage porosities, non-metallic inclusions, etc. Friction stir processing (FSP) has recently emerged as an effective technique for local modification of microstructure. This study investigates the fatigue crack initiation and growth mechanisms in cast and FSPed A356 aluminum alloy. Two sets of parameters were used to friction stir the cast alloy resulting in the complete modification the cast microstructure to a wrought microstructure. Both the FSPed microstructures exhibited severe abnormal grain growth (AGG) after heat treatment leading to a multimodal grain size distribution –more » the grain sizes ranging from a few microns to a few millimeters. One of the FSP conditions displayed an excellent improvement in fatigue life by an order of magnitude, while the other condition displayed an unexpectedly large scatter in fatigue lives. Detailed study of the fractured fatigue specimens by electron back scattered diffraction (EBSD) revealed that both, fatigue crack initiation and propagation, were intimately tied to the grain size as well as the grain misorientations in the microstructure.« less

Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing.

PubMed

Ding, Donghong; Pan, Zengxi; van Duin, Stephen; Li, Huijun; Shen, Chen

2016-08-03

Cast nickel aluminum bronze (NAB) alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM). Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT) are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production.

Fabricating Superior NiAl Bronze Components through Wire Arc Additive Manufacturing

PubMed Central

Ding, Donghong; Pan, Zengxi; van Duin, Stephen; Li, Huijun; Shen, Chen

2016-01-01

Cast nickel aluminum bronze (NAB) alloy is widely used for large engineering components in marine applications due to its excellent mechanical properties and corrosion resistance. Casting porosity, as well as coarse microstructure, however, are accompanied by a decrease in mechanical properties of cast NAB components. Although heat treatment, friction stir processing, and fusion welding were implemented to eliminate porosity, improve mechanical properties, and refine the microstructure of as-cast metal, their applications are limited to either surface modification or component repair. Instead of traditional casting techniques, this study focuses on developing NAB components using recently expanded wire arc additive manufacturing (WAAM). Consumable welding wire is melted and deposited layer-by-layer on substrates producing near-net shaped NAB components. Additively-manufactured NAB components without post-processing are fully dense, and exhibit fine microstructure, as well as comparable mechanical properties, to as-cast NAB alloy. The effects of heat input from the welding process and post-weld-heat-treatment (PWHT) are shown to give uniform NAB alloys with superior mechanical properties revealing potential marine applications of the WAAM technique in NAB production. PMID:28773774

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast... pipeline is disturbed: (a) That segment of the pipeline must be protected, as necessary, against damage...

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast... pipeline is disturbed: (a) That segment of the pipeline must be protected, as necessary, against damage...

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast... pipeline is disturbed: (a) That segment of the pipeline must be protected, as necessary, against damage...

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast... pipeline is disturbed: (a) That segment of the pipeline must be protected, as necessary, against damage...

Method for uniformly distributing carbon flakes in a positive electrode, the electrode made thereby and compositions

DOEpatents

Mrazek, Franklin C.; Smaga, John A.; Battles, James E.

1983-01-01

A positive electrode for a secondary electrochemical cell wherein an electrically conductive current collector is in electrical contact with a particulate mixture of gray cast iron and an alkali metal sulfide and an electrolyte including alkali metal halides or alkaline earth metal halides. Also present may be a transition metal sulfide and graphite flakes from the conversion of gray cast iron to iron sulfide. Also disclosed is a method of distributing carbon flakes in a cell wherein there is formed an electrochemical cell of a positive electrode structure of the type described and a suitable electrolyte and a second electrode containing a material capable of alloying with alkali metal ions. The cell is connected to a source of electrical potential to electrochemically convert gray cast iron to an iron sulfide and uniformly to distribute carbon flakes formerly in the gray cast iron throughout the positive electrode while forming an alkali metal alloy in the negative electrode. Also disclosed are compositions useful in preparing positive electrodes.

Technique Incorporating Cooling & Contraction / Expansion Analysis to Illustrate Shrinkage Tendency in Cast Irons

NASA Astrophysics Data System (ADS)

Stan, S.; Chisamera, M.; Riposan, I.; Neacsu, L.; Cojocaru, A. M.; Stan, I.

2017-06-01

With the more widespread adoption of thermal analysis testing, thermal analysis data have become an indicator of cast iron quality. The cooling curve and its first derivative display patterns that can be used to predict the characteristics of a cast iron. An experimental device was developed with a technique to simultaneously evaluate cooling curves and expansion or contraction of cast metals during solidification. Its application is illustrated with results on shrinkage tendency of ductile iron treated with FeSiMgRECa master alloy and inoculated with FeSi based alloys, as affected by mould rigidity (green sand and resin sand moulds). Undercooling at the end of solidification relative to the metastable (carbidic) equilibrium temperature and the expansion within the solidification sequence appear to have a strong influence on the susceptibility to macro - and micro - shrinkage in ductile iron castings. Green sand moulds, as less rigid moulds, encourage the formation of contraction defects, not only because of high initial expansion values, but also because of a higher cooling rate during solidification, and consequently, increased undercooling below the metastable equilibrium temperature up to the end of solidification.

Compacted graphite iron: Cast iron makes a comeback

NASA Astrophysics Data System (ADS)

Dawson, S.

1994-08-01

Although compacted graphite iron has been known for more than four decades, the absence of a reliable mass-production technique has resulted in relatively little effort to exploit its operational benefits. However, a proven on-line process control technology developed by SinterCast allows for series production of complex components in high-quality CGI. The improved mechanical properties of compacted graphite iron relative to conventional gray iron allow for substantial weight reduction in gasoline and diesel engines or substantial increases in horsepower, or an optimal combination of both. Concurrent with these primary benefits, CGI also provides significant emissions and fuel efficiency benefits allowing automakers to meet legislated performance standards. The operational and environmental benefits of compacted graphite iron together with its low cost and recyclability reinforce cast iron as a prime engineering material for the future.

On the damping capacity of cast irons

NASA Astrophysics Data System (ADS)

Golovin, S. A.

2012-07-01

The treatment of experimental data on the amplitude-dependent internal friction (ADIF) in terms of various theoretical models has revealed a staged character and the main mechanisms of the processes of energy dissipation in graphite with increasing amplitude of vibrations upon cyclic loading. It is shown that the level of the damping capacity of lamellar cast iron depends on the relationship between the elastic and strength characteristics of graphite and the matrix phase. In cast irons with a rigid matrix structure (pearlite, martensite), the energy dissipation is determined by the volume fraction and morphology of the initial graphite phase. In cast irons with a softer metallic phase (ferrite), the contact interaction of graphite inclusions with the matrix and the properties of the matrix introduce additional sources of high damping.

Effect of Friction Stir Processing on Microstructure and Mechanical Properties of AZ91C Magnesium Cast Alloy Weld Zone

NASA Astrophysics Data System (ADS)

Hassani, Behzad; Karimzadeh, Fathallah; Enayati, Mohammad Hossein; Sabooni, Soheil; Vallant, Rudolf

2016-07-01

In this study, friction stir processing (FSP) was applied to the GTAW (TIG)-welded AZ91C cast alloy to refine the microstructure and optimize the mechanical properties of the weld zone. Microstructural investigation of the samples was performed by optical microscopy and the phases in the microstructure were determined by x-ray diffraction (XRD). The microstructural evaluations showed that FSP destroys the coarse dendritic microstructure. Furthermore, it dissolves the secondary hard and brittle β-Mg17Al12 phase existing at grain boundaries of the TIG weld zone. The closure and decrease in amount of porosities along with the elimination of the cracks in the microstructure were observed. These changes were followed by a significant grain refinement to an average value of 11 µm. The results showed that the hardness values increased to the mean ones, respectively, for as-cast (63 Hv), TIG weld zone (67 Hv), and stir zone (79 Hv). The yield and ultimate strength were significantly enhanced after FSP. The fractography evaluations, by scanning electron microscopy (SEM), indicated to a transition from brittle to ductile fracture surface after applying FSP to the TIG weld zone.

Monitoring Stone Degradation on Coastal Structures in the Great Lakes - Summary Report

DTIC Science & Technology

2005-06-01

Iron Mountain Quarry, Iron Mountain, MI). The Iron Mountain Quarry produces taconite . c. Quarry sample microstructural analyses. Microstructural...Iron Mountain Quarry, Iron Mountain, MI. The Iron Mountain Quarry produces taconite . Also, stone from a tenth quarry (Cedarville Quarry, Cedarville, MI...Quarry, Iron Mountain, MI). The Iron Mountain Quarry produces taconite . Samples of taconite from the Iron Mountain Quarry also were evaluated by

Influence of mean stress on fatigue strength of ferritic-pearlite ductile cast iron with small defects

NASA Astrophysics Data System (ADS)

Deguchi, T.; Kim, H. J.; Ikeda, T.; Yanase, K.

2017-05-01

Because of their excellent mechanical properties, low cost and good workability, the application of ductile cast iron has been increased in various industries such as the automotive, construction and rail industries. For safety designing of the ductile cast iron component, it is necessary to understand the effect of stress ratio, R, on fatigue limit of ductile cast iron in the presence of small defects. Correspondingly in this study, rotating bending fatigue tests at R = -1 and tension-compression fatigue tests at R = -1 and 0.1 were performed by using a ferritic-pearlitic ductile cast iron. To study the effects of small defects, we introduced a small drilled hole at surface of a specimen. The diameter and depth of a drilled hole were 50, 200 and 500 μm, respectively. The non-propagating cracks emanating from graphite particles and holes edge were observed at fatigue limit, irrespective of the value of stress ratio. From the microscopic observation of crack propagation behavior, it can be concluded that the fatigue limit is determined by the threshold condition for propagation of a small crack. It was found that the effect of stress ratio on the fatigue limit of ductile cast iron with small defects can be successfully predicted based on \\sqrt {area} parameter model. Furthermore, a use of the tensile strength, σ B, instead of the Vickers hardness, HV, is effective for fatigue limit prediction.

EBSD Study on Grain Boundary and Microtexture Evolutions During Friction Stir Processing of A413 Cast Aluminum Alloy

NASA Astrophysics Data System (ADS)

Shamanian, Morteza; Mostaan, Hossein; Safari, Mehdi; Szpunar, Jerzy A.

2016-07-01

The as-cast Al alloys contain heterogeneous distributions of non-deforming particles due to non-equilibrium solidification effects. Therefore, these alloys have poor tribological and mechanical behaviors. It is well known that using friction stir processing (FSP), very fine microstructure is created in the as-cast Al alloys, while their wear resistance can be improved. In this research work, FSP is used to locally refine a surface layer of the coarse as-cast microstructure of cast A413 Al alloy. The main objective of this study is to investigate the effect of FSP on microstructure and microtexture evolutions in A413 cast Al alloy. The grain boundary character distribution, grain structure, and microtexture evolutions in as-cast and friction stir processed A413 Al alloy are analyzed by electron back scatter diffraction technique. It is found that with the FSP, the fraction of low ∑boundary such as ∑3, 7, and 9 are increased. The obtained results show that there are no deformation texture components in the structure of friction stir processed samples. However, some of the main recrystallization texture components such as BR and cubeND are formed during FSP which indicate the occurrence of dynamic recrystallization phenomenon due to the severe plastic deformation induced by the rotation of tool.

Low-Cycle Fatigue Behavior of Die-Cast Mg Alloy AZ91

NASA Astrophysics Data System (ADS)

Rettberg, Luke; Anderson, Warwick; Jones, J. Wayne

An investigation has been conducted on the influence of microstructure and artificial aging response (T6) on the low-cycle fatigue behavior of super vacuum die-cast (SVDC) AZ91. Fatigue lifetimes were determined from total strain-controlled fatigue tests for strain amplitudes of 0.2%, 0.4% and 0.6%, under fully reversed loading at a frequency of 5 Hz. Cyclic stress-strain behavior was determined using incremental step test (IST) methods. Two locations in a prototype casting with different thicknesses and, therefore, solidification rates, microstructure and porosity, were examined. In general., at all total strain amplitudes fatigue life was unaffected by microstructure refinement and was attributed to significant levels of porosity. Cyclic softening and a subsequent increased cyclic hardening rate, compared to monotonic tests, were observed, independent of microstructure. These results, fractography and damage accumulation processes, determined from metallographic sectioning, are discussed.

INTERIOR VIEW, LOOKING NORTH, TOWARDS CUPOLA WHERE SCRAP METAL AND ...

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

INTERIOR VIEW, LOOKING NORTH, TOWARDS CUPOLA WHERE SCRAP METAL AND OTHER COMPONENTS ARE MELTED TO CREATE DUCTILE IRON. BRIGHT FLASH IN BACKGROUND RESULTS FROM MOLTEN METAL (DUCTILE IRON) BEING POURED FROM CUPOLA INTO TRANSFER LADLE. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

Method for uniformly distributing carbon flakes in a positive electrode, the electrode made thereby and compositions. [Patent application

DOEpatents

Mrazek, F.C.; Smaga, J.A.; Battles, J.E.

1981-01-19

A positive electrode for a secondary electrochemical cell is described wherein an electrically conductive current collector is in electrical contact with a particulate mixture of gray cast iron and an alkali metal sulfide and an electrolyte including alkali metal halides or alkaline earth metal halides. Also present may be a transition metal sulfide and graphite flakes from the conversion of gray cast iron to iron sulfide. Also disclosed is a method of distributing carbon flakes in a cell wherein there is formed an electrochemical cell of a positive electrode structure of the type described and a suitable electrolyte and a second electrode containing a material capable of alloying with alkali metal ions. The cell is connected to a source of electrical potential to electrochemically convert gray cast iron to an iron sulfide and uniformly to distribute carbon flakes formerly in the gray cast iron throughout the positive electrode while forming an alkali metal alloy in the negative electrode. Also disclosed are compositions useful in preparing positive electrodes.

Reusability of contaminated seed crystal for cast quasi-single crystalline silicon ingots

NASA Astrophysics Data System (ADS)

Li, Zaoyang; Liu, Lijun; Zhou, Genshu

2015-04-01

Reusing seed crystal is beneficial for reducing the production costs for cast quasi-single crystalline (QSC) silicon ingots. We numerically investigate the reusability of seed crystal in the casting processes with quartz crucible and silicon feedstock of different purities. The reused seed crystal is recycled from the standard QSC ingot and has been highly contaminated by iron impurity. Transient simulations of iron transport are carried out and special attention is paid to the diffusion and distribution characteristics of iron impurity at the ingot bottom. The heights of the bottom iron contaminated region are compared for silicon ingots grown from normal and recycled seed crystals. The results show that the purity of quartz crucible can influence the reusability of seed crystal more significantly than that of the feedstock. The recycled seed crystal with high iron concentration can be reused for casting processes with standard crucible, whereas it is not recommended for reusing for processes with pure crucible.

Vacuum investment cast PH13-8Mo corrosion resistant steel. (SAE standard)

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1991-07-01

An industry-wide interest has arisen with regards to the properties and capabilities of investment cast PH 13-8Mo corrosion resistant steel. Specifically of interest are the structural applications in the aerospace industry for this product heat treated to the H1000 condition. The objective of this AMEC cooperative test program was to generate and compile useful data for aerospace structural evaluation of investment cast PH 13-8Mo heat treated to H1000. The determination was made of overall mechanical properties, fatigue, fracture toughness, and crack growth data along with basic microstructural evaluation of the investment cast material. The evaluation of mechanical property variations betweenmore » cast and machined tensile specimens and evaluation of microstructural constituents. PH 13-8Mo, H1000 investment castings for use in the aerospace industry is included.« less

Wear Resistance of Aluminum Matrix Composites Reinforced with Al2O3 Particles After Multiple Remelting

NASA Astrophysics Data System (ADS)

Klasik, Adam; Pietrzak, Krystyna; Makowska, Katarzyna; Sobczak, Jerzy; Rudnik, Dariusz; Wojciechowski, Andrzej

2016-08-01

Based on previous results, the commercial composites of A359 (AlSi9Mg) alloy reinforced with 22 vol.% Al2O3 particles were submitted to multiple remelting by means of gravity casting and squeeze-casting procedures. The studies were focused on tribological tests, x-ray phase analyses, and microstructural examinations. More promising results were obtained for squeeze-casting method mainly because of the reduction of the negative microstructural effects such as shrinkage porosity or other microstructural defects and discontinuities. The results showed that direct remelting may be treated as economically well-founded and alternative way compared to other recycling processes. It was underlined that the multiple remelting method must be analyzed for any material separately.

A novel high-strength and highly corrosive biodegradable Fe-Pd alloy: Structural, mechanical and in vitro corrosion and cytotoxicity study.

PubMed

Čapek, Jaroslav; Msallamová, Šárka; Jablonská, Eva; Lipov, Jan; Vojtěch, Dalibor

2017-10-01

Recently, iron-based materials have been considered as candidates for the fabrication of biodegradable load-bearing implants. Alloying with palladium has been found to be a suitable approach to enhance the insufficient corrosion rate of iron-based alloys. In this work, we have extensively compared the microstructure, the mechanical and corrosion properties, and the cytotoxicity of an FePd2 (wt%) alloy prepared by three different routes - casting, mechanical alloying and spark plasma sintering (SPS), and mechanical alloying and the space holder technique (SHT). The properties of the FePd2 (wt%) were compared with pure Fe prepared in the same processes. The preparation route significantly influenced the material properties. Materials prepared by SPS possessed the highest values of mechanical properties (CYS~750-850MPa) and higher corrosion rates than the casted materials. Materials prepared by SHT contained approximately 60% porosity; therefore, their mechanical properties reached the lowest values, and they had the highest corrosion rates, approximately 0.7-1.2mm/a. Highly porous FePd2 was tested in vitro according to the ISO 10993-5 standard using L929 cells, and two-fold diluted extracts showed acceptable cytocompatibility. In general, alloying with Pd enhanced both mechanical properties and corrosion rates and did not decrease the cytocompatibility of the studied materials. Copyright © 2017 Elsevier B.V. All rights reserved.

Transitions between type A flake, type D flake, and coral graphite eutectic structures in cast irons

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, J.S.; Verhoeven, J.D.

1996-09-01

Directional solidification experiments were used to measure the transition velocities between the type A and coral eutectic structures in high-purity cast irons and between the type A and type D eutectic structures in S and Te doped cast irons. Introduction of O into the gas atmosphere was found to have little effect on the A {R_arrow} D transition velocities in S doped alloys, but it produced a strong reduction in the A {R_arrow} coral transition velocities in high-purity irons. Transmission electron microscopy revealed interesting variations in the defect structures of the graphite in the flake irons vs the type ofmore » flake (A or D) and the type of doping element. Scanning Auger microscopy demonstrated that both S and Te segregate to the iron/graphite interface. In the S doped alloys, type A flakes are generally covered with a monolayer of S with patches of O in the form of iron oxide having a thickness on the order of 2 nm. A series of experiments, including examination of fracture surfaces at the quenched solid/liquid growth front, have shown that S segregates to the iron/graphite interfaces from the liquid at the growth front, but O forms at these interfaces during the cooldown. These results are discussed in relation to current models of eutectic growth in cast irons.« less

75 FR 70900 - Certain Iron Construction Castings From Brazil, Canada, and the People's Republic of China...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-19

... encase water, gas, or other valves, or water and gas meters, classifiable as light castings under HTS... systems; and valve, service, and meter boxes which are placed below ground to encase water, gas, or other valves, or water or gas meters. These articles must be of cast iron, not alloyed, and not malleable. This...

Multivariate research in areas of phosphorus cast-iron brake shoes manufacturing using the statistical analysis and the multiple regression equations

NASA Astrophysics Data System (ADS)

Kiss, I.; Cioată, V. G.; Alexa, V.; Raţiu, S. A.

2017-05-01

The braking system is one of the most important and complex subsystems of railway vehicles, especially when it comes for safety. Therefore, installing efficient safe brakes on the modern railway vehicles is essential. Nowadays is devoted attention to solving problems connected with using high performance brake materials and its impact on thermal and mechanical loading of railway wheels. The main factor that influences the selection of a friction material for railway applications is the performance criterion, due to the interaction between the brake block and the wheel produce complex thermos-mechanical phenomena. In this work, the investigated subjects are the cast-iron brake shoes, which are still widely used on freight wagons. Therefore, the cast-iron brake shoes - with lamellar graphite and with a high content of phosphorus (0.8-1.1%) - need a special investigation. In order to establish the optimal condition for the cast-iron brake shoes we proposed a mathematical modelling study by using the statistical analysis and multiple regression equations. Multivariate research is important in areas of cast-iron brake shoes manufacturing, because many variables interact with each other simultaneously. Multivariate visualization comes to the fore when researchers have difficulties in comprehending many dimensions at one time. Technological data (hardness and chemical composition) obtained from cast-iron brake shoes were used for this purpose. In order to settle the multiple correlation between the hardness of the cast-iron brake shoes, and the chemical compositions elements several model of regression equation types has been proposed. Because a three-dimensional surface with variables on three axes is a common way to illustrate multivariate data, in which the maximum and minimum values are easily highlighted, we plotted graphical representation of the regression equations in order to explain interaction of the variables and locate the optimal level of each variable for maximal response. For the calculation of the regression coefficients, dispersion and correlation coefficients, the software Matlab was used.

INTERIOR VIEW, LOOKING EAST, TOWARD BASE OF CUPOLA WITH AN ...

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

INTERIOR VIEW, LOOKING EAST, TOWARD BASE OF CUPOLA WITH AN IRON POUR IN PROCESS AS CUPOLA TENDERS, BENNY GOODMAN AND ALAN REVER, USING A ROD TO CLEAN OUT THE TAP HOLE ('RODDING THE HOLE') TO KEEP THE MOLTEN METAL FLOWING FREELY FROM THE IRON BOXES AT THE CUPOLA BASE INTO THE IRON TROUGH FOR LADLE TRANSFER TO THE MIXER AND PIPE CASTING OPERATIONS. ACIPCO'S CUPOLA (150 INCH IN DIAMETER AND 72 FEET IN HEIGHT) PRODUCED IRON THAT IS FURTHER REFINED FOR CASTING OPERATIONS. NATURAL GAS IS USED TO RESTART THE CUPOLA AFTER WHICH IT RUNS CONTINUOUSLY USING FURNACE GASES, PRODUCING AN AVERAGE OF 100 TONS OF MOLTEN METAL PER HOUR. - American Cast Iron Pipe Company, Cupola Area, 1501 Thirty-first Avenue North, Birmingham, Jefferson County, AL

25. Detail of cast iron lamp post base with fluted ...

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

25. Detail of cast iron lamp post base with fluted wooded post at top, located at north end of bridge. VIEW NORTHEAST - Chelsea Street Bridge & Draw Tender's House, Spanning Chelsea River, Boston, Suffolk County, MA

Hydrothermal conversion of graphite to carbon nanotubes (CNTs) induced by bubble collapse

NASA Astrophysics Data System (ADS)

Zhang, Yong; Liu, Fang

2016-11-01

Cu-Fe-CNTs and Ni-Fe-CNTs coatings were deposited on gray cast iron by a hydrothermal approach. It was demonstrated that, the flaky graphite of gray cast iron was exfoliated to graphene nanosheets under hydrothermal reactions, and graphene nanosheets were scrolled to CNTs. After high temperature treatments, the volume losses of Cu-Fe-CNTs and Ni-Fe-CNTs coatings were 52.6 % and 40.0 % of gray cast iron substrate at 60 min wear tests, respectively, obviously increasing the wear properties of gray cast iron. During hydrothermal reactions, water jets and shock waves were produced by bubble collapse. Induced by the water jets and shock waves, exfoliation of flaky graphite was performed, producing exfoliated graphene nanosheets. Attacked by the radially distributed water jets and shock waves, graphene nanosheets were curved, shaped to semicircle morphology and eventually scrolled to tubular CNTs.

Analytical ultrasonics for structural materials

NASA Technical Reports Server (NTRS)

Kupperman, D. S.

1986-01-01

The application of ultrasonic velocity and attenuation measurements to characterize the microstructure of structural materials is discussed. Velocity measurements in cast stainless steel are correlated with microstructural variations ranging from equiaxed (elastically isotropic) to columnar (elastically anisotropic) grain structure. The effect of the anisotropic grain structure on the deviation of ultrasonic waves in cast stainless steel is also reported. Field-implementable techniques for distinguishing equiaxed from columnar grain structures in cast strainless steel structural members are presented. The application of ultrasonic velocity measurements to characterize structural ceramics in the green state is also discussed.

Identification of a cast iron alloy containing nonstrategic elements

NASA Technical Reports Server (NTRS)

Cooper, C. V.; Anton, D. L.; Lemkey, F. D.; Nowotny, H.; Bailey, R. S.; Favrow, L. H.; Smeggil, J. G.; Snow, D. B.

1989-01-01

A program was performed to address the mechanical and environmental needs of Stirling engine heater head and regenerator housing components, while reducing the dependence on strategic materials. An alloy was developed which contained no strategic elemental additions per se. The base is iron with additions of manganese, molybdenum, carbon, silicon, niobium, and ferro-chromium. Such an alloy should be producible on a large scale at very low cost. The resulting alloy, designated as NASAUT 4G-Al, contained 15 Mn, 15 Cr, 2 Mo, 1.5 C, 1.0 Si, 1.0 Nb (in weight percent) with a balance of Fe. This alloy was optimized for chemistry, based upon tensile strength, creep-rupture strength, fracture behavior, and fatigue resistance up to 800 C. Alloys were also tested for environmental compatibility. The microstructure and mechanic properties (including hardness) were assessed in the as-cast condition and following several heat treatments, including one designed to simulate a required braze cycle. The alloy was fabricated and characterized in the form of both equiaxed and columnar-grained castings. The columnar grains were produced by directional solidification, and the properties were characterized in both the longitudinal and transverse orientations. The NASAUT 4G-Al alloy was found to be good in cyclic-oxidation resistance and excellent in both hydrogen and hot-corrosion resistance, especially in comparison to the baseline XF-818 alloy. The mechanical properties of yield strength, stress-rupture life, high-cycle-fatigue resistance, and low-cycle-fatigue resistance were good to excellent in comparison to the current alloy for this application, HS-31 (X-40), with precise results depending in a complex manner on grain orientation and temperature. If required, the ductility could be improved by lowering the carbon content.

Combination of microscopic model and VoF-multiphase approach for numerical simulation of nodular cast iron solidification

NASA Astrophysics Data System (ADS)

Subasic, E.; Huang, C.; Jakumeit, J.; Hediger, F.

2015-06-01

The ongoing increase in the size and capacity of state-of-the-art wind power plants is highlighting the need to reduce the weight of critical components, such as hubs, main shaft bearing housings, gear box housings and support bases. These components are manufactured as nodular iron castings (spheroid graphite iron, or SGI). A weight reduction of up to 20% is achievable by optimizing the geometry to minimize volume, thus enabling significant downsizing of wind power plants. One method for enhancing quality control in the production of thick-walled SGI castings, and thus reducing tolerances and, consequently, enabling castings of smaller volume is via a casting simulation of mould filling and solidification based on a combination of microscopic model and VoF-multiphase approach. Coupled fluid flow with heat transport and phase transformation kinetics during solidification is described by partial differential equations and solved using the finite volume method. The flow of multiple phases is described using a volume of fluid approach. Mass conservation equations are solved separately for both liquid and solid phases. At the micro-level, the diffusion-controlled growth model for grey iron eutectic grains by Wetterfall et al. is combined with a growth model for white iron eutectic grains. The micro-solidification model is coupled with macro-transport equations via source terms in the energy and continuity equations. As a first step the methodology was applied to a simple geometry to investigate the impact of mould-filling on the grey-to-white transition prediction in nodular cast iron.

Multi-Scale Porous Ultra High Temperature Ceramics

DTIC Science & Technology

2015-01-08

different techniques: replica, particle stabilized foams, ice templating (freeze casting) and partial sintering. The pore morphology (closed-bubble...the porosity, pore size, shape and morphology . X-Ray Tomography was used to study their 3D microstructure. The 3D microstructures captured with...four different techniques: replica, particle stabilized foams, ice templating (freeze casting) and partial sintering. The pore morphology (closed-bubble

Microstructures, Mechanical Properties, and Wear Resistances of Thixoextruded SiCp/WE43 Magnesium Matrix Composites

NASA Astrophysics Data System (ADS)

Chen, Qiang; Chen, Gang; Han, Fei; Xia, Xiangsheng; Wu, Yang

2017-07-01

Near-net shaping of Mg-RE alloy matrix composites has received increasing attention. In this work, stir casting followed by extrusion was adopted to fabricate Mg-RE alloy (WE43) matrix composites reinforced by micron-sized SiC particles. The microstructural evolutions of SiCp/WE43 composites partially remelted from as-cast and extruded states were studied. Furthermore, the thixoformability of SiCp/WE43 composites in different states was evaluated by thixoextruding a type of double-cup component. The microstructures of as-cast SiCp/WE43 composites were optimized under the comprehensive effects of SiC particles and RE elements. The SiCp/WE43 composite was fully recrystallized during hot extrusion, and the α-Mg matrix consisted of fine equiaxed grains. Although the as-cast SiCp/WE43 composite consisted of satisfactory structures and can be successfully thixoextruded into the final component with good surface quality and no evidence of internal defects, the microstructures, Vickers hardness, tensile mechanical properties, and wear resistance were still inferior to those of the component thixoextruded from extruded composite. Moreover, the thixoextrusion process was analyzed schematically, and an ideal thixoforming process that should contain two stages was proposed.

Reproducibility of ZrO2-based freeze casting for biomaterials.

PubMed

Naleway, Steven E; Fickas, Kate C; Maker, Yajur N; Meyers, Marc A; McKittrick, Joanna

2016-04-01

The processing technique of freeze casting has been intensely researched for its potential to create porous scaffold and infiltrated composite materials for biomedical implants and structural materials. However, in order for this technique to be employed medically or commercially, it must be able to reliably produce materials in great quantities with similar microstructures and properties. Here we investigate the reproducibility of the freeze casting process by independently fabricating three sets of eight ZrO2-epoxy composite scaffolds with the same processing conditions but varying solid loading (10, 15 and 20 vol.%). Statistical analyses (One-way ANOVA and Tukey's HSD tests) run upon measurements of the microstructural dimensions of these composite scaffold sets show that, while the majority of microstructures are similar, in all cases the composite scaffolds display statistically significant variability. In addition, composite scaffolds where mechanically compressed and statistically analyzed. Similar to the microstructures, almost all of their resultant properties displayed significant variability though most composite scaffolds were similar. These results suggest that additional research to improve control of the freeze casting technique is required before scaffolds and composite scaffolds can reliably be reproduced for commercial or medical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Microstructure of Friction Stir Welded AlSi9Mg Cast with 5083 and 2017A Wrought Aluminum Alloys

NASA Astrophysics Data System (ADS)

Hamilton, C.; Kopyściański, M.; Dymek, S.; Węglowska, A.; Pietras, A.

2018-03-01

Wrought aluminum alloys 5083 and 2017A were each joined with cast aluminum alloy AlSi9Mg through friction stir welding in butt weld configurations. For each material system, the wrought and cast alloy positions, i.e., the advancing side or the retreating side, were exchanged between welding trials. The produced weldments were free from cracks and discontinuities. For each alloy configuration, a well-defined nugget comprised of alternating bands of the welded alloys characterized the microstructure. The degree of mixing, however, strongly depended on which wrought alloy was present and on its position during processing. In all cases, the cast AlSi9Mg alloy dominated the weld center regardless of its position during welding. Electron backscattered diffraction analysis showed that the grain size in both alloys (bands) constituting the nugget was similar and that the majority of grain boundaries exhibited a high angle character (20°-60°). Regardless of the alloy, however, all grains were elongated along the direction of the material plastic flow during welding. A numerical simulation of the joining process visualized the material flow patterns and temperature distribution and helped to rationalize the microstructural observations. The hardness profiles across the weld reflected the microstructure formed during welding and correlated well with the temperature changes predicted by the numerical model. Tensile specimens consistently fractured in the cast alloy near the weld nugget.

10. Detail view of decorative cast and wrought iron railing ...

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

10. Detail view of decorative cast and wrought iron railing on pedestrian walkway. Jack Boucher, photographer, 1977 - Neshanic Station Lenticular Truss Bridge, State Route 567, spanning South Branch of Raritan River, Neshanic Station, Somerset County, NJ

Sculpture, cast iron lamps at northeast corner of Stephen Sitter ...

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

Sculpture, cast iron lamps at northeast corner of Stephen Sitter Avenue and Forney road, with scale - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

3. FOURTH FLOOR OF OIL HOUSE (NOTICE CAST IRON SUPPORT ...

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

3. FOURTH FLOOR OF OIL HOUSE (NOTICE CAST IRON SUPPORT POSTS AND OIL PRESS IN THE CENTER) - Wilson's Oil House, Lard Refinery, & Edible Fats Factory, Oil House, 2801 Southwest Fifteenth Street, Oklahoma City, Oklahoma County, OK

Greek "red mud" residue: a study of microwave reductive roasting followed by magnetic separation for a metallic iron recovery process.

PubMed

Samouhos, Michail; Taxiarchou, Maria; Tsakiridis, Petros E; Potiriadis, Konstantinos

2013-06-15

The present research work is focused on the development of an alternative microwave reductive roasting process of red mud using lignite (30.15 wt.%Cfix), followed by wet magnetic separation, in order to produce a raw material suitable for sponge or cast iron production. The reduction degree of iron was controlled by both the reductive agent content and the microwave heating time. The reduction followed the Fe₂O₃ → Fe₃O₄ → FeO → Fe sequence. The dielectric constants [real (ε') and imaginary (ε″) permittivities] of red mud-lignite mixture were determined at 2.45 GHz, in the temperature range of 25-1100 °C. The effect of parameters such as temperature, intensity of reducing conditions, intensity of magnetic field and dispersing agent addition rate on the result of both processes was investigated. The phase's transformations in reduction process with microwave heating were determined by X-ray diffraction analysis (XRD) in combination with thermogravimetric/differential thermal analysis (TGA/DTA). The microstructural and morphological characterization of the produced calcines was carried out by scanning electron microscopy (SEM). At the optimum conditions a magnetic concentrate with total iron concentration of 35.15 and 69.3 wt.% metallization degree was obtained. Copyright © 2013 Elsevier B.V. All rights reserved.

Effect of Ultrasonic Melt Treatment on Microstructure and Mechanical Properties of 35CrMo Steel Casting

NASA Astrophysics Data System (ADS)

Shi, Chen; Li, Fan; Liang, Gen; Mao, Daheng

2018-01-01

Effects of different power ultrasonic on microstructure and mechanical properties of 35CrMo steel casting were investigated using optical microscopy (OM), scanning electron microscopy (SEM) and hardness testing. A self-developed experiment apparatus was used for the propagation of ultrasonic vibration into the 35CrMo steel melt to carry out ultrasonic treatment. The experimental results showed that compared to the traditional casting, ultrasonic treatment can obviously change the solidification microstructure of 35CrMo steel, which is changed from coarse dendrites to fined dendrites or equiaxed grains. With the increase of ultrasonic power, equiaxed crystal is remarkably refined and its area is broadened. The micro porosity percentage of ingot casting decreases significantly and the porosity defects can be suppressed under ultrasonic treatment. The mechanical properties of 35CrMo steel ingot after heat treatment were enhanced by ultrasonic treatment: the maximum tensile strength is improved by 8.4% and the maximum elongation increased by 1.5 times.

Microstructural analysis of aluminum high pressure die castings

NASA Astrophysics Data System (ADS)

David, Maria Diana

Microstructural analysis of aluminum high pressure die castings (HPDC) is challenging and time consuming. Automating the stereology method is an efficient way in obtaining quantitative data; however, validating the accuracy of this technique can also pose some challenges. In this research, a semi-automated algorithm to quantify microstructural features in aluminum HPDC was developed. Analysis was done near the casting surface where it exhibited fine microstructure. Optical and Secondary electron (SE) and backscatter electron (BSE) SEM images were taken to characterize the features in the casting. Image processing steps applied on SEM and optical micrographs included median and range filters, dilation, erosion, and a hole-closing function. Measurements were done on different image pixel resolutions that ranged from 3 to 35 pixel/μm. Pixel resolutions below 6 px/μm were too low for the algorithm to distinguish the phases from each other. At resolutions higher than 6 px/μm, the volume fraction of primary α-Al and the line intercept count curves plateaued. Within this range, comparable results were obtained validating the assumption that there is a range of image pixel resolution relative to the size of the casting features at which stereology measurements become independent of the image resolution. Volume fraction within this curve plateau was consistent with the manual measurements while the line intercept count was significantly higher using the computerized technique for all resolutions. This was attributed to the ragged edges of some primary α-Al; hence, the algorithm still needs some improvements. Further validation of the code using other castings or alloys with known phase amount and size may also be beneficial.

Sculpture, detail view of cast iron lamps, with scale (note: ...

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

Sculpture, detail view of cast iron lamps, with scale (note: "'J.L. Mott, Ironworks, NY" stamp on the base) - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

4. DETAIL OF CAST AND WROUGHT IRON RAILING WITH SUPPORTING ...

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

4. DETAIL OF CAST AND WROUGHT IRON RAILING WITH SUPPORTING STRUCTURES AND STEEL BEAM, FROM THE NORTH BANK LOOKING SOUTHEAST AT THE WEST (UPSTREAM) SIDE - Railroad Avenue Bridge, Spanning Mispillion River on Church Street, Milford, Sussex County, DE

[Growth characteristics and control of iron bacteria on cast iron in drinking water distribution systems].

PubMed

Wang, Yang; Zhang, Xiao-Jian; Chen, Yu-Qiao; Lu, Pin-Pin; Chen, Chao

2009-11-01

This study investigated the growth characteristics of iron bacteria on cast iron and relationship between suspended and attached iron bacteria. The steady-state growth of iron bacteria would need 12 d and iron bacteria level in effluents increased 1 lg. Hydraulics influence on iron bacteria level and detachment rate of steady-state attached iron bacteria was not significant. But it could affect the time of attached iron bacteria on cast-iron coupons reaching to steady state. When the chlorine residual was 0.3 mg/L, the iron bacteria growth could be controlled effectively and suspended and attached iron bacteria levels both decreased 1 lg. When the chlorine residual was more than 1.0 mg/L, it could not inactivate the iron bacteria of internal corrosion scale yet. There was little effect on inhibiting the iron bacteria growth that the chlorine residual was 0.05 mg/L in drinking water quality standard of China. The iron bacteria on coupons reached to steady state without disinfectant and then increased the chlorine residual to 1.25 mg/L, the attached iron bacteria level could decrease 2 lg to 3 lg. Under steady-state, the suspended iron bacteria levels were linearly dependent on the attached iron bacteria. The control of iron bacteria in drinking water distribution systems was advanced: maintaining the chlorine residual (0.3 mg/L), flushing the pipeline with high dosage disinfectant, adopting corrosion-resistant pipe materials and renovating the old pipe loop.

Creep-rupture behavior of 6 candidate stirling engine iron-base superalloys in high pressure hydrogen. Volume 1: Air creep-rupture behavior

NASA Technical Reports Server (NTRS)

Bhattacharyya, S.

1982-01-01

Four wrought alloys (A-286, IN 800H, N-155, and 19-9DL) and two cast alloys (CRM-6D and XF-818) were tested to determine their creep-rupture behavior. The wrought alloys were used in the form of sheets of 0.89 mm (0.035 in.) average thickness. The cast alloy specimens were investment cast and machined to 6.35 mm (0.250 in.) gage diameter. All specimens were tested to rupture in air at different times up to 3000 h over the temperature range of 650 C to 925 C (1200 F to 1700 F). Rupture life, minimum creep rate, and time to 1% creep strain were statistically analyzed as a function of stress at different temperatures. Temperature-compensated analysis was also performed to obtain the activation energies for rupture life, time to 1% creep strain, and the minimum creep rate. Microstructural and fracture analyses were also performed. Based on statistical analyses, estimates were made for stress levels at different temperatures to obtain 3500 h rupture life and time to 1% creep strain. Test results are to be compared with similar data being obtained for these alloys under 15 MPa (2175 psi) hydrogen.

The interrelation between mechanical properties, corrosion resistance and microstructure of Pb-Sn casting alloys for lead-acid battery components

NASA Astrophysics Data System (ADS)

Peixoto, Leandro C.; Osório, Wislei R.; Garcia, Amauri

It is well known that there is a strong influence of thermal processing variables on the solidification structure and as a direct consequence on the casting final properties. The morphological microstructural parameters such as grain size and cellular or dendritic spacings will depend on the heat transfer conditions imposed by the metal/mould system. There is a need to improve the understanding of the interrelation between the microstructure, mechanical properties and corrosion resistance of dilute Pb-Sn casting alloys which are widely used in the manufacture of battery components. The present study has established correlations between cellular microstructure, ultimate tensile strength and corrosion resistance of Pb-1 wt% Sn and Pb-2.5 wt% Sn alloys by providing a combined plot of these properties as a function of cell spacing. It was found that a compromise between good corrosion resistance and good mechanical properties can be attained by choosing an appropriate cell spacing range.

Cast Iron in The 19th Century Building Equipment

NASA Astrophysics Data System (ADS)

Kwasek, Michał; Piwek, Aleksander

2017-10-01

Cast iron is a material, characteristics of which enable to receive extremely artistic elements. It maintains good strength properties at the same time. That combination of these seemingly contrary traits makes it a commodity that was widely used in the 19th century industry and architecture. These usages were not only as decorative elements, technical and structural ones. The production of new household utilities started, which made people’s lives more comfortable. Cast iron allowed for fast and cheap production while maintaining high aesthetic qualities. Useful elements, which often were ornamental parts of buildings were created. The aim of the article is to characterise elements of interior equipment of the 19th century building that are made of cast iron. As it appears from performed bibliography, archival and field studies, the ways of exploitation are very broad. Some were mounted into the building; the others were a mobile equipment. As it occurred they were most commonly used as functional items. Cast iron was used to produce the minor elements, which were only parts of the bigger wooden or stone items. Notwithstanding, there were also bigger ones casted as a whole, and frequently ones that were assembled from many elements. Nowadays, elements of an interior feature are one of the subjects of study during the restoration work of the buildings. They can provide important information about the building and the way people lived and are considered as the essential part of historical objects.

Influence of gating design on microstructure and fluidity of thin sections AA320.0 cast hypo-eutectic Al-Si alloy

NASA Astrophysics Data System (ADS)

Ramadan, Mohamed

2018-05-01

Influence of gating design especially number of ingrates on microstructure and fluidity of thin sections of 2, 4, 6 mm AA320.0 cast hypo-eutectic Al-Si alloy was evaluated for sand casting molding technique. Increasing the number of ingates improves the microstructe to be fine and more globular. About 87 μm of α-Al grain size, 0.6 α-Al grain sphericity and 37 μm dendrite arm spacing DAS are achieved by using 4 ingates in gating system. Increasing the number of ingates up to 3 increases hardness, filling area and related fluditiy of all cast samples. The minimum thickness of 2.5 mm for each ingate should be considered in order to successfully production of high quality light weight thin sections castings in sand mold.

The development of nano-modified Ti(C,N) cermets.

PubMed

Rong, Chunlan; Chen, Wenling; Zhang, Xiaobo; Liu, Ning

2007-01-01

The unique combination of mechanical properties such as excellent wear resistance and good chemical stability at elevated temperature helps titanium carbonitride based (Ti (C, N)-based) cermets to play an important roles in metal cutting operations. Nowadays, cermets cutting tools are widely used for semi-finishing and finishing works on steel and cast iron. However, their brittleness is still an unavoidable limitation for their utilization. With the development of nano-technology, nano-modified cermets have received more attention due to the high toughening enhancements. In this review, the development of nano-modified Ti(C,N) cermets is discussed including the fabrication, microstructure, mechanical properties, cutting performance and the practical applications in different fields. Many patents having important effect on the development of cermets were noticed, too.

Adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by selective laser melting technique.

PubMed

Ye, Ye; Jiao, Ting; Zhu, Jiarui; Sun, Jian

2018-01-24

The purpose of the study was to evaluate the adaptation and micro-structure of Co-Cr alloy maxillary complete denture base plates fabricated by the selective laser melting (SLM) technique. Twenty pairs of edentulous casts were randomly and evenly divided into two groups, and manufacturing of the Co-Cr alloy maxillary complete denture base was conducted either by the SLM technique or by the conventional method. The base-cast sets were transversally sectioned into three sections at the distal canines, mesial of the first molars and the posterior palatal zone. The gap between the metal base and cast was measured in these three sections with a stereoscopic microscope, and the data were analysed using t tests. A total of five specimens of 5 mm diameter were fabricated with the Co-Cr alloy by SLM and the traditional casting technology. A scanning electron microscope (SEM) was used to evaluate the differences in microstructure between these specimens. There was no statistical difference between the three sections in all four groups (P > 0.05). At the region of the canines, the clearance value for the SLM Co-Cr alloy group was larger than that of the conventional method group (P < 0.05). At the mesial of the first molar region and the posterior palatal zone, there was no statistical difference between the gaps observed in the two groups (P > 0.05). The SLM Co-Cr alloy has a denser microstructure behaviour and less casting defect than the cast Co-Cr alloy. The SLM technique showed initial feasibility for the manufacture of dental bases of complete dentures, but large sample studies are needed to prove its reliability in clinical applications. The mechanical properties and microstructure of the denture frameworks prepared by selective laser melting indicate that these dentures are appropriate for clinical use.

Development of volume deposition on cast iron by additive manufacturing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sridharan, Niyanth; Dehoff, Ryan R.; Jordan, Brian H.

2016-11-10

ORNL partnered with Cummins to demonstrate the feasibility of using additive manufacturing techniques to help develop repair techniques for refurbished cast iron engine blocks. Cummins is interested in the refurbished engine business due to the increased cost savings and reduced emissions. It is expected that by refurbishing engines could help reduce the green house gas emissions by as much as 85%. Though such repair techniques are possible in principle there has been no major industry in the automotive sector that has deployed this technology. Therefore phase-1 would seek to evaluate the feasibility of using the laser directed energy deposition techniquemore » to repair cast iron engine blocks. The objective of the phase-1 would be to explore various strategies and understand the challenges involved. During phase-1 deposits were made using Inconel-718, Nickel, Nr-Cr-B braze filler. Inconel 718 builds showed significant cracking in the heat-affected zone in the cast iron. Nickel was used to reduce the cracking in the cast iron substrate, however the Ni builds did not wet the substrate sufficiently resulting in poor dimensional tolerance. In order to increase wetting the Ni was alloyed with the Ni-Cr-B braze to decrease the surface tension of Ni. This however resulted in significant cracks in the build due to shrinkage stresses associated with multiple thermal cycling. Hence to reduce the residual stresses in the builds the DMD-103D equipment was modified and the cast iron block was pre heated using cartridge heaters. Inconel-718 alloyed with Ni was deposited on the engine block. The pre-heated deposits showed a reduced susceptibility to cracking. If awarded the phase-2 of the project would aim to develop process parameters to achieve a crack free deposit engine block.« less

Relationship between microstructure and ductility of investment cast ASTM F-75 implant alloy.

PubMed

Gómez, M; Mancha, H; Salinas, A; Rodríguez, J L; Escobedo, J; Castro, M; Méndez, M

1997-02-01

Hip replacement implants fabricated using the ASTM F-75 alloy sometimes fail in a sudden catastrophic way. In general, fractures start at microstructural defects subjected to stress-corrosion under chemical attack by body fluids. In this paper the results of a study on the effect of casting parameters on the microstructure of ASTM F-75 are presented. The preheating mold temperature and the liquid temperature were varied between 900 and 1000 degrees C, and 1410 and 1470 degrees C, respectively. Optimum static strength and ductility were obtained when shrinkage microporosity and the volume fraction of M23C6 "eutectic" carbides precipitated at grain boundaries were minimized by increasing the preheating mold temperature to 1000 degrees C and by using intermediate pouring temperatures of 1455 degrees C. Under these casting conditions, however, the solidification rates are low, leading to large grain sizes, which, in turn, reduce the strength of the material under dynamic loading conditions. The volume fraction of the M23C6 "blocky" carbides appears to be independent of the casting conditions; however, their size and spatial distributions determine the strength of the as-cast alloys.

The effect of water-soluble polymers on the microstructure and properties of freeze-cast alumina ceramics

NASA Astrophysics Data System (ADS)

Pekor, Christopher Michael

Porous ceramics can be divided into three separate classes based on their pore size: microporous ceramics with pores less than 2 nm, mesoporous ceramics with pores in the range of 2--50 nm and macroporous ceramics with pores that are greater than 50 nm. In particular, macroporous ceramics are used in a variety of applications such as refractories, molten metal filtration, diesel particulate filters, heterogeneous catalyst supports and biomedical scaffolds. Freeze casting is a novel method used to create macroporous ceramics. In this method growing ice crystals act as a template for the pores and are solidified, often directionally, through a ceramic dispersion and removed from the green body through a freeze drying procedure. This method has attracted some attention over the past few years due to its relative simplicity, flexibility and environmental friendliness. On top of this freeze casting is capable of producing materials with high pore volume fractions, which is an advantage over processing by packing and necking of particles, where the pore volume fraction is typically less than 50%. Many of the basic processing variables that affect the freeze cast microstructure, such as the temperature gradient, interfacial velocity and solid loading of the dispersion have been well established in the literature. On the other hand, areas such as the effect of additives on the microstructure and mechanical properties have not been covered in great detail. In this study the concept of constitutional supercooling from basic solidification theory is used to explain the effects of two water-soluble polymers, polyethylene glycol and polyvinyl alcohol, on the microstructure of freeze cast alumina ceramics. In addition, changes in the observed microstructure will be related to experimentally determined values of permeability and compressive strength.

Microstructures and Mechanical Properties of Co-Cr Dental Alloys Fabricated by Three CAD/CAM-Based Processing Techniques

PubMed Central

Kim, Hae Ri; Jang, Seong-Ho; Kim, Young Kyung; Son, Jun Sik; Min, Bong Ki; Kim, Kyo-Han; Kwon, Tae-Yub

2016-01-01

The microstructures and mechanical properties of cobalt-chromium (Co-Cr) alloys produced by three CAD/CAM-based processing techniques were investigated in comparison with those produced by the traditional casting technique. Four groups of disc- (microstructures) or dumbbell- (mechanical properties) specimens made of Co-Cr alloys were prepared using casting (CS), milling (ML), selective laser melting (SLM), and milling/post-sintering (ML/PS). For each technique, the corresponding commercial alloy material was used. The microstructures of the specimens were evaluated via X-ray diffractometry, optical and scanning electron microscopy with energy-dispersive X-ray spectroscopy, and electron backscattered diffraction pattern analysis. The mechanical properties were evaluated using a tensile test according to ISO 22674 (n = 6). The microstructure of the alloys was strongly influenced by the manufacturing processes. Overall, the SLM group showed superior mechanical properties, the ML/PS group being nearly comparable. The mechanical properties of the ML group were inferior to those of the CS group. The microstructures and mechanical properties of Co-Cr alloys were greatly dependent on the manufacturing technique as well as the chemical composition. The SLM and ML/PS techniques may be considered promising alternatives to the Co-Cr alloy casting process. PMID:28773718

77 FR 17119 - Pipeline Safety: Cast Iron Pipe (Supplementary Advisory Bulletin)

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-23

... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration [Docket No... national attention and highlight the need for continued safety improvements to aging gas pipeline systems... 26, 1992) covering the continued use of cast iron pipe in natural gas distribution pipeline systems...

Seal welded cast iron nuclear waste container

DOEpatents

Filippi, Arthur M.; Sprecace, Richard P.

1987-01-01

This invention identifies methods and articles designed to circumvent metallurgical problems associated with hermetically closing an all cast iron nuclear waste package by welding. It involves welding nickel-carbon alloy inserts which are bonded to the mating plug and main body components of the package. The welding inserts might be bonded in place during casting of the package components. When the waste package closure weld is made, the most severe thermal effects of the process are restricted to the nickel-carbon insert material which is far better able to accommodate them than is cast iron. Use of nickel-carbon weld inserts should eliminate any need for pre-weld and post-weld heat treatments which are a problem to apply to nuclear waste packages. Although the waste package closure weld approach described results in a dissimilar metal combination, the relative surface area of nickel-to-iron, their electrochemical relationship, and the presence of graphite in both materials will act to prevent any galvanic corrosion problem.

Effect of pressure of helium, argon, krypton, and xenon on the porosity, microstructure, and mechanical properties of commercially pure titanium castings.

PubMed

Zinelis, S

2000-11-01

Porosity is a frequently observed casting defect in dental titanium alloys. This study evaluated the effect of pressure of helium, argon, krypton, and xenon on the porosity, microstructure, and mechanical properties of commercially pure titanium (cp Ti) castings. Eight groups (A-H) of 16 rectangular wax patterns each (30 mm in length, 3 mm in width, and 1 mm in depth) were prepared. The wax patterns were invested with a magnesia-based material and cast with cp Ti (grade II). Groups A, C, E, and G were cast under a pressure of 1 atm, and groups B, D, F, and H were cast under a pressure of 0.5 atm of He, Ar, Kr, and Xe, respectively. The extent of the porosity of the cast specimens was determined radiographically and quantified by image analysis. Three specimens of each group and 3 cylinders of the as-received cp Ti used as a reference were embedded in resin and studied metallographically after grinding, polishing, and chemical etching. These surfaces were used for determination of the Vickers hardness (VHN) as well. Eight specimens from each group were fractured in the tensile mode, and the 0.2% yield strength, fracture stress, and percentage elongation were calculated. Porosity was analyzed with 2-way ANOVA and the Newman-Keuls multiple range test. VHN measurements and tensile properties for specimen groups were compared with 1-way ANOVA and the Newman-Keuls multiple range test (95% significance level). The porosity levels per group were (%): A = 5.50 +/- 4.34, B = 0.77 +/- 1.27, C = 2.44 +/- 3.68, D = 0.06 +/- 0.12, E-H = 0. Two-way ANOVA showed that there was no detectable interaction (P<.05) between gas type and applied pressure. Metallographic examination revealed no differences in microstructure among the groups studied. A finer grain size was observed in all cast groups compared with the original cp Ti. The VHN of the as-received cp Ti was significantly greater than all the cast groups tested. Groups cast under He showed the highest VHN, yield strength, and fracture stress. No significant differences were found in percentage elongation values among the groups. Porosity and mechanical properties of cp Ti castings are dependent on the gas type and pressure, whereas the microstructure remains unaffected.

Growth of Legionella anisa in a model drinking water system to evaluate different shower outlets and the impact of cast iron rust.

PubMed

van der Lugt, Wilco; Euser, Sjoerd M; Bruin, Jacob P; Den Boer, Jeroen W; Walker, Jimmy T; Crespi, Sebastian

2017-11-01

Legionella continues to be a problem in water systems. This study investigated the influence of different shower mixer faucets, and the influence of the presence of cast iron rust from a drinking water system on the growth of Legionella. The research is conducted using a model of a household containing four drinking water systems. All four systems, which contained standard plumbing components including copper pipes and a water heater, were filled with unchlorinated drinking water. Furthermore, all systems had three different shower faucets: (A) a stainless-steel faucet, (B) a brass-ceramic faucet, and (C) a brass thermostatic faucet. System 1 was solely filled with drinking water. System 2 was filled with drinking water, and cast iron rust. System 3 was contaminated with Legionella, and system 4 was contaminated with a Legionella, and cast iron rust. During a period of 34 months, 450 cold water samples were taken from 15 sample points of the four drinking water systems, and tested for Legionella according to the Dutch Standard (NEN 6265). In system 4, with added cast iron rust, the stainless-steel mixer faucet (A) had the highest concentration of Legionella at >4.3log10CFU/l (>20,000CFU/l) and was positive in 46.4% of samples. In contrast, the stainless-steel mixer faucet (A) of system 3 without cast iron rust showed 14.3% positive samples with a maximum concentration of 3.9log10CFU/l (7600CFU/l) Legionella. Additionally, both contaminated systems (3 and 4), with the brass thermostatic faucet (C), tested positive for Legionella. System 3 in 85.7% of the samples, with a maximum concentration of 4.38log10CFU/l (24,200CFU/l), and system 4 in 64.3% of the samples with a maximum concentration of 4.13log10CFU/l (13.400CFU/l). These results suggest that both the type of faucet used in a drinking water system and the presence or absence of cast iron rust influence the growth of Legionella. Copyright © 2017 Elsevier GmbH. All rights reserved.

13. INTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING NORTHEAST This ...

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

13. INTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING NORTHEAST This view, taken in the southern airway, shows the circular brick-work surrounding the air intake, the cast iron shaft support, and one of the 1883 Guibal fan cast iron spiders. Three cast iron spiders support the ten feet by eleven feet wooden paddles. Remnants of the catwalk with its screen grating lead to the inner door of the airlock. Note also the support beams and reinforced concrete roof. The concrete floor of the airway has deteriorated. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

Noise control of waste water pipes

NASA Astrophysics Data System (ADS)

Lilly, Jerry

2005-09-01

Noise radiated by waste water pipes is a major concern in multifamily housing projects. While the most common solution to this problem is to use cast-iron pipes in lieu of plastic pipes, this may not be sufficient in high-end applications. It should also be noted that many (if not most) multifamily housing projects in the U.S.A. are constructed with plastic waste piping. This paper discusses some of the measures that developers are currently using to control noise from both plastic and cast-iron waste pipes. In addition, results of limited noise measurements of transient water flow in plastic and cast-iron waste pipes will be presented.

Predictive control of thermal state of blast furnace

NASA Astrophysics Data System (ADS)

Barbasova, T. A.; Filimonova, A. A.

2018-05-01

The work describes the structure of the model for predictive control of the thermal state of a blast furnace. The proposed model contains the following input parameters: coke rate; theoretical combustion temperature, comprising: natural gas consumption, blasting temperature, humidity, oxygen, blast furnace cooling water; blast furnace gas utilization rate. The output parameter is the cast iron temperature. The results for determining the cast iron temperature were obtained following the identification using the Hammerstein-Wiener model. The result of solving the cast iron temperature stabilization problem was provided for the calculated values of process parameters of the target area of the respective blast furnace operation mode.

Modeling of the Coupling of Microstructure and Macrosegregation in a Direct Chill Cast Al-Cu Billet

NASA Astrophysics Data System (ADS)

Heyvaert, Laurent; Bedel, Marie; Založnik, Miha; Combeau, Hervé

2017-10-01

The macroscopic multiphase flow and the growth of the solidification microstructures in the mushy zone of a direct chill (DC) casting are closely coupled. These couplings are the key to the understanding of the formation of the macrosegregation and of the non-uniform microstructure of the casting. In the present paper we use a multiphase and multiscale model to provide a fully coupled picture of the links between macrosegregation and microstructure in a DC cast billet. The model describes nucleation from inoculant particles and growth of dendritic and globular equiaxed crystal grains, fully coupled with macroscopic transport phenomena: fluid flow induced by natural convection and solidification shrinkage, heat, mass, and solute mass transport, motion of free-floating equiaxed grains, and of grain refiner particles. We compare our simulations to experiments on grain-refined and non-grain-refined industrial size billets from literature. We show that a transition between dendritic and globular grain morphology triggered by the grain refinement is the key to the explanation of the differences between the macrosegregation patterns in the two billets. We further show that the grain size and morphology are strongly affected by the macroscopic transport of free-floating equiaxed grains and of grain refiner particles.

Modification of gray iron produced by induction melting with barium strontium

NASA Astrophysics Data System (ADS)

Modzelevskaya, G.; Feoktistov, A. V.; Selyanin, I. F.; Kutsenko, A. I.; Kutsenko, A. A.

2016-09-01

The article provides analysis of results of gray iron experimental melts in induction furnace and the following melt modification with barium-strontium carbonate (BSC-2). It is shown that modification positively affects mechanical and casting properties and as-cast iron structure. It was established that BSC-2 granulated immediately prior to use has greater impact on melt than BSC-2 of the same faction, supplied by the manufacturer.

146. DETAIL VIEW, LOOKING STRAIGHT ON, OF CAST IRON LAMP ...

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

146. DETAIL VIEW, LOOKING STRAIGHT ON, OF CAST IRON LAMP STANDARD. THIS AND OTHER LAMP STANDARDS WERE REMOVED FROM THE LAMP COLUMNS ON THE PARAPET WALLS DURING WORLD WAR II AND STORED INSIDE THE DAM (January 1991) - Coolidge Dam, Gila River, Peridot, Gila County, AZ

41. Historic American Buildings Survey ORIGINAL DRAWING: CAST IRON STACKS ...

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

41. Historic American Buildings Survey ORIGINAL DRAWING: CAST IRON STACKS IN RIGGS LIBRARY (1889) (FROM THE ORIGINAL IN THE OFFICE OF THE VICE PRESIDENT FOR DEVELOPMENT AND PHYSICAL PLANT, GEORGETOWN UNIVERSITY) - Georgetown University, Healy Building, Thirty-seventh & O Streets, Northwest, Washington, District of Columbia, DC

Microstructure and Mechanical Properties of the As-Cast and As-Homogenized Mg-Zn-Sn-Mn-Ca Alloy Fabricated by Semicontinuous Casting

PubMed Central

Lu, Xing; Zhao, Guoqun; Zhou, Jixue; Zhang, Cunsheng; Yu, Junquan

2018-01-01

In this paper, a new type of low-cost Mg-3.36Zn-1.06Sn-0.33Mn-0.27Ca (wt %) alloy ingot with a diameter of 130 mm and a length of 4800 mm was fabricated by semicontinuous casting. The microstructure and mechanical properties at different areas of the ingot were investigated. The microstructure and mechanical properties of the alloy under different one-step and two-step homogenization conditions were studied. For the as-cast alloy, the average grain size and the second phase size decrease from the center to the surface of the ingot, while the area fraction of the second phase increases gradually. At one-half of the radius of the ingot, the alloy presents the optimum comprehensive mechanical properties along the axial direction, which is attributed to the combined effect of relatively small grain size, low second-phase fraction, and uniform microstructure. For the as-homogenized alloy, the optimum two-step homogenization process parameters were determined as 340 °C × 10 h + 520 °C × 16 h. After the optimum homogenization, the proper size and morphology of CaMgSn phase are conducive to improve the microstructure uniformity and the mechanical properties of the alloy. Besides, the yield strength of the alloy is reduced by 20.7% and the elongation is increased by 56.3%, which is more favorable for the subsequent hot deformation processing. PMID:29710818

Microstructure and Mechanical Properties of the As-Cast and As-Homogenized Mg-Zn-Sn-Mn-Ca Alloy Fabricated by Semicontinuous Casting.

PubMed

Lu, Xing; Zhao, Guoqun; Zhou, Jixue; Zhang, Cunsheng; Yu, Junquan

2018-04-29

In this paper, a new type of low-cost Mg-3.36Zn-1.06Sn-0.33Mn-0.27Ca (wt %) alloy ingot with a diameter of 130 mm and a length of 4800 mm was fabricated by semicontinuous casting. The microstructure and mechanical properties at different areas of the ingot were investigated. The microstructure and mechanical properties of the alloy under different one-step and two-step homogenization conditions were studied. For the as-cast alloy, the average grain size and the second phase size decrease from the center to the surface of the ingot, while the area fraction of the second phase increases gradually. At one-half of the radius of the ingot, the alloy presents the optimum comprehensive mechanical properties along the axial direction, which is attributed to the combined effect of relatively small grain size, low second-phase fraction, and uniform microstructure. For the as-homogenized alloy, the optimum two-step homogenization process parameters were determined as 340 °C × 10 h + 520 °C × 16 h. After the optimum homogenization, the proper size and morphology of CaMgSn phase are conducive to improve the microstructure uniformity and the mechanical properties of the alloy. Besides, the yield strength of the alloy is reduced by 20.7% and the elongation is increased by 56.3%, which is more favorable for the subsequent hot deformation processing.

41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND ...

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

41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND CENTRE CASTING OF CAST STEEL, MASONRY CASTING OF CAST IRON CASTING, FOR MINNEAPOLIS STEEL ARCH (4 x 5 negative) - Steel Arch Bridge, Hennepin Avenue spanning west channel of Mississippi River, Minneapolis, Hennepin County, MN

Computation material science of structural-phase transformation in casting aluminium alloys

NASA Astrophysics Data System (ADS)

Golod, V. M.; Dobosh, L. Yu

2017-04-01

Successive stages of computer simulation the formation of the casting microstructure under non-equilibrium conditions of crystallization of multicomponent aluminum alloys are presented. On the basis of computer thermodynamics and heat transfer during solidification of macroscale shaped castings are specified the boundary conditions of local heat exchange at mesoscale modeling of non-equilibrium formation the solid phase and of the component redistribution between phases during coalescence of secondary dendrite branches. Computer analysis of structural - phase transitions based on the principle of additive physico-chemical effect of the alloy components in the process of diffusional - capillary morphological evolution of the dendrite structure and the o of local dendrite heterogeneity which stochastic nature and extent are revealed under metallographic study and modeling by the Monte Carlo method. The integrated computational materials science tools at researches of alloys are focused and implemented on analysis the multiple-factor system of casting processes and prediction of casting microstructure.

The bacteriological composition of biomass recovered by flushing an operational drinking water distribution system.

PubMed

Douterelo, I; Husband, S; Boxall, J B

2014-05-01

This study investigates the influence of pipe characteristics on the bacteriological composition of material mobilised from a drinking water distribution system (DWDS) and the impact of biofilm removal on water quality. Hydrants in a single UK Distribution Management Area (DMA) with both polyethylene and cast iron pipe sections were subjected to incremental increases in flow to mobilise material from the pipe walls. Turbidity was monitored during these operations and water samples were collected for physico-chemical and bacteriological analysis. DNA was extracted from the material mobilised into the bulk water before and during flushing. Bacterial tag-encoded 454 pyrosequencing was then used to characterize the bacterial communities present in this material. Turbidity values were high in the samples from cast iron pipes. Iron, aluminium, manganese and phosphate concentrations were found to correlate to observed turbidity. The bacterial community composition of the material mobilised from the pipes was significantly different between plastic and cast iron pipe sections (p < 0.5). High relative abundances of Alphaproteobacteria (23.3%), Clostridia (10.3%) and Actinobacteria (10.3%) were detected in the material removed from plastic pipes. Sequences related to Alphaproteobacteria (22.8%), Bacilli (16.6%), and Gammaproteobacteria (1.4%) were predominant in the samples obtained from cast iron pipes. The highest species richness and diversity were found in the samples from material mobilised from plastic pipes. Spirochaeta spp., Methylobacterium spp. Clostridium spp. and Desulfobacterium spp., were the most represented genera in the material obtained prior to and during the flushing of the plastic pipes. In cast iron pipes a high relative abundance of bacteria able to utilise different iron and manganese compounds were found such as Lysinibacillus spp., Geobacillus spp. and Magnetobacterium spp. Copyright © 2014 Elsevier Ltd. All rights reserved.

Feasibility of producing cast-refractory metal-fiber superalloy composites

NASA Technical Reports Server (NTRS)

Mcintyre, R. D.

1973-01-01

A study was conducted to evaluate the feasibility of direct casting as a practical method for producing cast superalloy tungsten or columbium alloy fiber composites while retaining a high percentage of fiber strength. Fourteen nickel base, four cobalt, and three iron based matrices were surveyed for their degree of reaction with the metal fibers. Some stress-rupture results were obtained at temperatures of 760, 816, 871, and 1093 C for a few composite systems. The feasibility of producing acceptable composites of some cast nickel, cobalt, and iron matrix alloys with tungsten or columbium alloy fibers was demonstrated.

Novel technologies for the lost foam casting process

NASA Astrophysics Data System (ADS)

Jiang, Wenming; Fan, Zitian

2018-03-01

Lost foam casting (LFC) is a green precision casting process categorized as a near net forming technology. Yet, despite its popularity, it still suffers from some technological problems, such as poor filling ability of the castings, coarse and non-dense microstructure, low mechanical properties for the Al and Mg LFC processes, and defective carburization for the low carbon steel LFC process. These drawbacks restrict the development and widespread application of the LFC process. To solve these problems, the present study developed several novel LFC technologies, namely, LFC technologies under vacuum and low pressure, vibration solidification, and pressure solidification conditions; expendable shell casting technology; and preparation technology of bimetallic castings based on the LFC process. The results showed that the LFC under vacuum and low pressure evidently improved the filling ability and solved the oxidization problem of the alloys, which is suitable for producing complex and thinwall castings. The vibration and pressure solidifications increased the compactness of the castings and refined the microstructure, significantly improving the mechanical properties of the castings. The expendable shell casting technology could solve the pore, carburization, and inclusion defects of the traditional LFC method, obtaining castings with acceptable surface quality. Moreover, the Al/Mg and Al/Al bimetallic castings with acceptable metallurgical bonding were successfully fabricated using the LFC process. These proposed novel LFC technologies can solve the current technological issues and promote the technological progress of the LFC process.

Mechanical strength and microstructure of laser-welded Ti-6Al-7Nb alloy castings.

PubMed

Srimaneepong, Viritpon; Yoneyama, Takayuki; Kobayashi, Equo; Doi, Hisashi; Hanawa, Takao

2005-12-01

Mechanical properties of laser-welded castings of Ti-6Al-7Nb alloy, CP Ti, and Co-Cr alloy were investigated and compared to the unwelded castings using a tensile test. Dumbbell-shaped specimens were cut at the center, and two halves of the specimens were welded with an Nd:YAG laser welding machine at 220 or 260 V of laser voltage. The mechanical strength of 260 V groups was higher than that of 220 V groups for Ti-6Al-7Nb and Co-Cr alloys except for CP Ti. All 260 V laser-welded castings of Ti-6Al-7Nb alloy and CP Ti, which fractured outside the welded joints, exhibited ductile characteristics, while all laser-welded Co-Cr alloy castings, which fractured within the welded joints, showed brittle characteristics. This study proved that the mechanical strength of laser-welded Ti-6Al-7Nb alloy and CP Ti castings was as high as that of unwelded castings, while the mechanical properties of laser-welded alloy joints were influenced by microstructural changes.

Ceramic port shields cast in an iron engine head

NASA Technical Reports Server (NTRS)

Hakim, Nabil S.; Groeneweg, Mark A.

1989-01-01

Silicon nitride exhaust and intake port shields have been successfully cast into a gray iron cylinder head of a heavy duty diesel single cylinder research engine. Careful design considerations, finite element, and probability of survival analyses indicated viability of the design. Foundry experience, NDE, and failure investigations are reported.

Causes of Cracking in Quenching of the Parts Made of Steels and Cast Iron and Recommendations for Their Removal: A Review

NASA Astrophysics Data System (ADS)

Kuznetsov, A. A.; Rudnev, V. I.

2017-12-01

The domestic and foreign experience on revealing the causes of quenching cracking and its prevention is generalized. We consider the works performed on the machine parts made of carbon and alloyed pearlitic steel and quenchable cast irons.

Effect of Cold Forging on Microstructure and MechanicalProperties of Al/SiC Composites

NASA Astrophysics Data System (ADS)

Hanamantraygouda, M. B.; Shivakumar, B. P., Dr; Siddappa, P. N.; Sampathkumar, L.; Prashanth, L.

2018-02-01

The objective of this work was to investigate the effect of cold forging on mechanical properties and microstructural study of Al MMCs, at different wt% of SiC and forging cycle. The Al-SiC composite material was fabricated by stir casting method at different weight percentage of SiC such as 2.5, 5, 7.5 and 10%. Further, the deformation characteristics during open-die forging of Al-SiC composite at cold conditions was investigated. Cast and forged composite material was subjected to hardness test, tensile test and impact test. The grain size, microstructure behaviour was investigated using optical microscope. The results show that hardness and strength of Al-SiC composite increases and ductility decreases as compared to Al alloy in both as-cast and forged conditions. Optical microscope images showed that the distribution of SiC in Al matrix was more homogeneous in a forged composite as compared to cast one and reduction of porosity was found. Further, it showed that due to forging cycle the grain size was reduced by 30% to 35% from initial size.

Effects of heat treatment on mechanical properties of h13 steel

NASA Astrophysics Data System (ADS)

Guanghua, Yan; Xinmin, Huang; Yanqing, Wang; Xingguo, Qin; Ming, Yang; Zuoming, Chu; Kang, Jin

2010-12-01

Heat treatment on the mechanical properties of H13 hot working die steel for die casting is discussed. The H13 steel for die casting was treated by different temperatures of vacuum quenching, tempering, and secondary tempering to investigate its mechanical properties. Strength, plasticity, hardness, and impact toughness of the H13 hot working die steel for die casting were measured. Microstructure, grain size, and carbide particle size after heat treatment have a great impact on the mechanical properties of H13 hot working die steel for die casting. The microstructure of the H13 was analyzed by scanning electron microscopy (SEM) and by a metallographic microscope. It is found that H13 exhibits excellent mechanical properties after vacuum quenching at 1050°C and twice tempering at 600°C.

Micro-structure and Air-tightness of Squeeze Casting Motor housing for New Energy Vehicle

NASA Astrophysics Data System (ADS)

Jiang, Y. F.; Kang, Z. Q.; Jiang, W. F.; Wang, K. W.; Sha, D. L.; Li, M. L.; Sun, J.

2018-05-01

In order to improve the performance of automobile parts, the influence of squeeze casting process parameters on casting defects, material structure and air-tightness of aluminum alloy motor housing for new energy vehicle was studied. The results show that the density of the castings increases with the increase in pressure and mold temperature. With increase in pouring temperature, it increases first and then decreases. Pressure has the greatest influence on the density of the castings. Under a certain pressure, with moderate increase in casting temperature and mold temperature, the grain growth begins to increase; the dendrites become less, the new α - Al grains are spherical and granular, the micro-structure is uniform. Also, with increase in pressure, this effect is more pronounced, the air-tightness of castings improve. In conclusion, when the pressure is 110MPa, pouring temperature is 680° C, mold temperature is 280° C, pressure holding for 30s, and punch speed of 0.1m/s, there is no clear shrinkage in the casting, the structure is uniform, the qualified rate of air-tightness of production reaches 86%, and the performance is excellent.

Characterization of Newly Developed Semisolid Stir Joining Method for Cast Cu Base Alloy (Cu-Al-Si-Fe) and Effect of Stirrer Type on Uniformity of Microstructure

NASA Astrophysics Data System (ADS)

Ferasat, Keyvan; Aashuri, Hossein; Kokabi, Amir Hossein; Nikzad, Siamak; Shafizadeh, Mahdi

2015-02-01

In this research, the semisolid stir joining method was used to overcome the problem of hot cracking in welding aluminum and silicon bronzes. Moreover, the effects of grooved and cylindrical tools on the microstructure and mechanical properties of samples were examined. After welding specimens, mechanical tests were carried out to find differences between the cast and welded samples. Optical microscopy and scanning electron microscopy were used to study microstructure. X-ray diffraction was used to investigate compounds formed during casting and welding. The solidus and liquidus temperatures of the alloy were measured by differential scanning calorimetry. In this study, the temperature of the work pieces was raised to 1203 K (930 °C) that is in the semisolid region, and the weld seams were stirred by two different types of tools at the speed of 1600 rpm. Macro and micro-structural analyses show uniformity in the phase distribution for specimens welded by cylindrical tool. Desirable and uniform mechanical properties obtained when the cylindrical tool was used.

Corrosion Resistance of a Cast-Iron Material Coated With a Ceramic Layer Using Thermal Spray Method

NASA Astrophysics Data System (ADS)

Florea, C. D.; Bejinariu, C.; Munteanu, C.; Istrate, B.; Toma, S. L.; Alexandru, A.; Cimpoesu, R.

2018-06-01

Cast-iron 250 used for breake systems present many corrosion signs after a mean usage time based on the environment conditions they work. In order to improve them corrosion resistance we propose to cover the active part of the material using a ceramic material. The deposition process is an industrial deposition system based on thermal spraying that can cover high surfaces in low time. In this articol we analyze the influence of a ceramic layer (40-50 µm) on the corrosion resistance of FC250 cast iron. The results were analyzed using scanning electron microscopy (SEM), X-ray energy dispersive (EDS) and linear and cyclic potentiometry.

Evolution of microstructure, texture and inhibitor along the processing route for grain-oriented electrical steels using strip casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Hai-Tao, E-mail: liuht@ral.neu.edu.cn; Institute of Research of Iron and Steel, Shasteel, Zhangjiagang 215625, Jiangsu; Yao, Sheng-Jie

2015-08-15

In the present work, a regular grade GO sheet was produced successively by strip casting, hot rolling, normalizing annealing, two-stage cold rolling with intermediate annealing, primary recrystallization annealing, secondary recrystallization annealing and purification. The aim of this paper was to characterize the evolution of microstructure, texture and inhibitor along the new processing route by comprehensive utilization of optical microscopy, X-ray diffraction and transmission electron microscopy. It was found that a fine microstructure with the ferrite grain size range of 7–12 μm could be obtained in the primary recrystallization annealed sheet though a very coarse microstructure was produced in the initialmore » as-cast strip. The main finding was that the “texture memory” effect on Goss texture started on the through-thickness intermediate annealed strip after first cold rolling, which was not similar to the “texture memory” effect on Goss texture starting on the surface layers of the hot rolled strip in the conventional production route. As a result, the origin of Goss nuclei capable of secondary recrystallization lied in the grains already presented in Goss orientation in the intermediate annealed strip after first cold rolling. Another finding was that fine and dispersive inhibitors (mainly AlN) were easy to be produced in the primary recrystallization microstructure due to the initial rapid solidification during strip casting and the subsequent rapid cooling, and the very high temperature reheating usually used before hot rolling in the conventional production route could be avoided. - Highlights: • A regular grade grain-oriented electrical steel was produced. • Evolution of microstructure, texture and inhibitor was characterized. • Origin of Goss nuclei lied in the intermediate annealed strip. • A fine primary recrystallization microstructure could be produced. • Effective inhibitors were easy to be obtained in the new processing route.« less

46 CFR 56.50-95 - Overboard discharges and shell connections.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., or ductile cast iron specification listed in Table 56.60-1(a). Lead or other heat sensitive materials... flooding. Brittle materials such as cast iron shall not be used in such service. Where nonmetallic... inch, except that the use of suitable corrosion-resistant material of lesser thickness will be given...

46 CFR 56.50-95 - Overboard discharges and shell connections.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., or ductile cast iron specification listed in Table 56.60-1(a). Lead or other heat sensitive materials... flooding. Brittle materials such as cast iron shall not be used in such service. Where nonmetallic... inch, except that the use of suitable corrosion-resistant material of lesser thickness will be given...

FIELD DEMONSTRATION OF EMERGING PIPE WALL INTEGRITY ASSESSMENT TECHNOLOGIES FOR LARGE CAST IRON WATER MAINS

EPA Science Inventory

The U.S. Environmental Protection Agency sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,500-ft long, cement-lined, 24-in. cast iron water main in Louisville, KY from July through Septembe...

Field Demonstration of Emerging Pipe Wall Integrity Assessment Technologies for Large Cast Iron Water Mains - Paper

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) sponsored a large-scale field demonstration of innovative leak detection/location and condition assessment technologies on a 76-year old, 2,000-ft long, cement-lined, 24-in. cast-iron water main in Louisville, KY from July through Se...

Statistical experiments using the multiple regression research for prediction of proper hardness in areas of phosphorus cast-iron brake shoes manufacturing

NASA Astrophysics Data System (ADS)

Kiss, I.; Cioată, V. G.; Ratiu, S. A.; Rackov, M.; Penčić, M.

2018-01-01

Multivariate research is important in areas of cast-iron brake shoes manufacturing, because many variables interact with each other simultaneously. This article focuses on expressing the multiple linear regression model related to the hardness assurance by the chemical composition of the phosphorous cast irons destined to the brake shoes, having in view that the regression coefficients will illustrate the unrelated contributions of each independent variable towards predicting the dependent variable. In order to settle the multiple correlations between the hardness of the cast-iron brake shoes, and their chemical compositions several regression equations has been proposed. Is searched a mathematical solution which can determine the optimum chemical composition for the hardness desirable values. Starting from the above-mentioned affirmations two new statistical experiments are effectuated related to the values of Phosphorus [P], Manganese [Mn] and Silicon [Si]. Therefore, the regression equations, which describe the mathematical dependency between the above-mentioned elements and the hardness, are determined. As result, several correlation charts will be revealed.

Structural and compositional analysis of a casting mold sherd from ancient China.

PubMed

Zong, Yunbing; Yao, Shengkun; Lang, Jianfeng; Chen, Xuexiang; Fan, Jiadong; Sun, Zhibin; Duan, Xiulan; Li, Nannan; Fang, Hui; Zhou, Guangzhao; Xiao, Tiqiao; Li, Aiguo; Jiang, Huaidong

2017-01-01

Casting had symbolic significance and was strictly controlled in the Shang dynasty of ancient China. Vessel casting was mainly distributed around the Shang capital, Yin Ruins, which indicates a rigorous centralization of authority. Thus, for a casting mold to be excavated far from the capital region is rare. In addition to some bronze vessel molds excavated at the Buyao Village site, another key discovery of a bronze vessel mold occurred at Daxinzhuang. The Daxinzhuang site was a core area in the east of Shang state and is an important site to study the eastward expansion of the Shang. Here, combining synchrotron X-rays and other physicochemical analysis methods, nondestructive three-dimensional structure imaging and different elemental analyses were conducted on this mold sherd. Through high penetration X-ray tomography, we obtained insights on the internal structure and discovered some pores. We infer that the generation of pores inside the casting mold sherd was used to enhance air permeability during casting. Furthermore, we suppose that the decorative patterns on the surface were carved and not pasted onto it. Considering the previous compositional studies of bronze vessels, the copper and iron elements were analyzed by different methods. Unexpectedly, a larger amount of iron than of copper was detected on the surface. According to the data analysis and archaeological context, the source of iron on the casting mold sherd could be attributed to local soil contamination. A refined compositional analysis confirms that this casting mold was fabricated locally and used for bronze casting.

Evolution of Constitution, Structure, and Morphology in FeCo-Based Multicomponent Alloys

NASA Astrophysics Data System (ADS)

Li, R.; Stoica, M.; Liu, G.; Eckert, J.

2010-07-01

Constituent phases, melting behaviors, and microstructure of multicomponent (Fe0.5Co0.5) x (Mo0.1C0.2B0.5Si0.2)100- x alloys ( x = 95, 90, 85, 80, and 70) produced by copper mold casting were evaluated by various analysis techniques, i.e., X-ray diffractometry, scanning electronic microscopy with energy dispersive X-ray spectrometry, and differential scanning calorimetry. Metastable Fe3C- and Cr23C6-type phases were identified in the chill-cast alloys. A schematic illustration was proposed to explain the evolution of constituent phases and microstructure for the alloys with x = 95, 90, and 85 during the solidification process, which could be applicable to controlling microstructural formation of other multicomponent alloys with similar microstructures by artificially adjusting the composition.

Heat Treatment Development for a Rapidly Solidified Heat Resistant Cast Al-Si Alloy

NASA Astrophysics Data System (ADS)

Kasprzak, W.; Chen, D. L.; Shaha, S. K.

2013-07-01

Existing heat treatment standards do not properly define tempers for thin-walled castings that solidified with high solidification rates. Recently emerged casting processes such as vacuum high pressure die casting should not require long solution treatment times due to the fine microstructures arising from rapid solidification rates. The heat treatment studies involving rapidly solidified samples with secondary dendrite arm spacing between 10 and 35 μm were conducted for solution times between 30 min and 9 h and temperatures of 510 and 525 °C and for various aging parameters. The metallurgical analysis revealed that an increase in microstructure refinement could enable a reduction of solution time up to 88%. Solution treatment resulted in the dissolution of Al2Cu and Al5Mg8Si6Cu2, while Fe- and TiZrV-based phases remained partially in the microstructure. The highest strength of approximately 351 ± 9.7 and 309 ± 3.4 MPa for the UTS and YS, respectively, was achieved for a 2-step solution treatment at 510 and 525 °C in the T6 peak aging conditions, i.e., 150 °C for 100 h. The T6 temper did not yield dimensionally stable microstructure since exceeding 250 °C during in-service operation could result in phase transformation corresponding to the over-aging reaction. The microstructure refinement had a statistically stronger effect on the alloy strength than the increase in solutionizing time. Additionally, thermal analysis and dilatometer results were presented to assess the dissolution of phases during solution treatment, aging kinetics as well as dimensional stability.

The Effect of Rare-Earth Metals on Cast Steels

DTIC Science & Technology

1954-04-01

as the 1-inch section is also illustrated in Figure 23 and consists of tempered bainite and tempered martensite. Both of the control steels (AE-1...section Tempered bainite and tempered martensite 4 inch section Figure 23 Microstructure ol the Mn-Cr-Mo base control steels . Etched with... bainite 4-inch Section Figure 25—Microstructures of the MnCr-Mo + Rare Earths f B cast steels . Etched with picral, SOOX - .1 €. Figure 26

Pore- and micro-structural characterization of a novel structural binder based on iron carbonation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Das, Sumanta, E-mail: Sumanta.Das@asu.edu; Stone, David, E-mail: dajstone@gmail.com; Convey, Diana, E-mail: Diana.Convey@asu.edu

2014-12-15

The pore- and micro-structural features of a novel binding material based on the carbonation of waste metallic iron powder are reported in this paper. The binder contains metallic iron powder as the major ingredient, followed by additives containing silica and alumina to facilitate favorable reaction product formation. Compressive strengths sufficient for a majority of concrete applications are attained. The material pore structure is investigated primarily through mercury intrusion porosimetry whereas electron microscopy is used for microstructural characterization. Reduction in the overall porosity and the average pore size with an increase in carbonation duration from 1 day to 4 days ismore » noticed. The pore structure features are used in predictive models for gas and moisture transport (water vapor diffusivity and moisture permeability) through the porous medium which dictates its long-term durability when used in structural applications. Comparisons of the pore structure with those of a Portland cement paste are also provided. The morphology of the reaction products in the iron-based binder, and the distribution of constituent elements in the microstructure are also reported. - Highlights: • Carbonation of iron produces a dense microstructure. • Pore volume in iron carbonate lower, critical size higher than those in OPC pastes • Reaction product contains iron, carbon, silicon, aluminum and calcium. • Power-law for porosity-moisture permeability relationship was established.« less

35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE ...

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

35. GREY IRON TUMBLERS, IN THE GREY IRON FOUNDRY ROTATE CASTINGS WITH SHOT TO REMOVE AND SURFACE OXIDES AND REMAINING EXCESS METALS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Deformation Behavior and Microstructure Evolution of As-Cast 42CrMo Alloy in Isothermal and Non-isothermal Compression

NASA Astrophysics Data System (ADS)

Qin, Fangcheng; Li, Yongtang; Qi, Huiping; Lv, Zhenhua

2016-11-01

The isothermal and non-isothermal multi-pass compression tests of centrifugal casting 42CrMo steel were conducted on a Gleeble-3500 thermal simulation machine. The effects of compression passes and finishing temperatures on deformation behavior and microstructure evolution were investigated. It is found that the microstructure is homogeneous with equiaxed grains, and the flow stress does not show significant change with the increase in passes, while the peak softening coefficient increases first and then decreases during inter-pass. Moreover, the dominant mechanisms of controlled temperature and accumulated static recrystallization for grain refinement and its homogeneous distribution are found after 5 passes deformation. As the finishing temperature increases, the flow stress decreases gradually, but the dynamic recrystallization accelerates and softening effect increases, resulting in the larger grain size and homogeneous microstructure. The microhardness decreases sharply because the sufficient softening occurs in microstructure. When the finishing temperature is 890 °C, the carbide particles are precipitated in the vicinity of the grain boundaries, thus inhibiting the dislocation motion. Thus, the higher finishing temperature (≥970 °C) for centrifugal casting 42CrMo alloy should be avoided in non-isothermal multi-pass deformation, which is beneficial to grain refinement and properties improvement.

Thermal Microstructural Stability of AZ31 Magnesium after Severe Plastic Deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, John P.; Askari, Hesam A.; Hovanski, Yuri

2015-03-01

Both equal channel angular pressing and friction stir processing have the ability to refine the grain size of twin roll cast AZ31 magnesium and potentially improve its superplastic properties. This work used isochronal and isothermal heat treatments to investigate the microstructural stability of twin roll cast, equal channel angular pressed and friction stir processed AZ31 magnesium. For both heat treatment conditions, it was found that the twin roll casted and equal channel angular pressed materials were more stable than the friction stir processed material. Calculations of the grain growth kinetics showed that severe plastic deformation processing decreased the activation energymore » for grain boundary motion with the equal channel angular pressed material having the greatest Q value of the severely plastically deformed materials and that increasing the tool travel speed of the friction stir processed material improved microstructural stability. The Hollomon-Jaffe parameter was found to be an accurate means of identifying the annealing conditions that will result in substantial grain growth and loss of potential superplastic properties in the severely plastically deformed materials. In addition, Humphreys’s model of cellular microstructural stability accurately predicted the relative microstructural stability of the severely plastically deformed materials and with some modification, closely predicted the maximum grain size ratio achieved by the severely plastically deformed materials.« less

The effects of different types of investments on the alpha-case layer of titanium castings.

PubMed

Guilin, Yu; Nan, Li; Yousheng, Li; Yining, Wang

2007-03-01

Different types of investments affect the formation of the alpha-case (alpha-case) layer on titanium castings. This alpha-case layer may possibly alter the mechanical properties of cast titanium, which may influence the fabrication of removable and fixed prostheses. The formation mechanism for the alpha-case layer is not clear. The aim of this study was to evaluate the effect of 3 types of investments on the microstructure, composition, and microhardness of the alpha-case layer on titanium castings. Fifteen wax columns with a diameter of 5 mm and a length of 40 mm were divided into 3 groups of 5 patterns each. Patterns were invested using 3 types of investment materials, respectively, and were cast in pure titanium. The 3 types of materials tested were SiO(2)-, Al(2)O(3)-, and MgO-based investments. All specimens were sectioned and prepared for metallographic observation. The microstructure and composition of the surface reaction layer of titanium castings were investigated by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). The surface microhardness (VHN) for all specimens was measured using a hardness testing machine, and a mean value for each group was calculated. The alpha-case layer on titanium castings invested with SiO(2)-, Al(2)O(3)-, and MgO-based investments consisted of 3 layers-namely, the oxide layer, alloy layer, and hardening layer. In this study, the oxide layer and alloy layer were called the reaction layer. The thickness of the reaction layer for titanium castings using SiO(2)-, Al(2)O(3)-, and MgO-based investments was approximately 80 microm, 50 microm, and 14 microm, respectively. The surface microhardness of titanium castings made with SiO(2)-based investments was the highest, and that with MgO-based investments was the lowest. The type of investment affects the microstructure and microhardness of the alpha-case layer of titanium castings. Based on the thickness of the surface reaction layer and the surface microhardness of titanium castings, MgO-based investment materials may be the best choice for casting these materials.

Microstructure and Porosity of Laser Welds in Cast Ti-6Al-4V with Addition of Boron

NASA Astrophysics Data System (ADS)

Tolvanen, Sakari; Pederson, Robert; Klement, Uta

2018-03-01

Addition of small amounts of boron to cast Ti-6Al-4V alloy has shown to render a finer microstructure and improved mechanical properties. For such an improved alloy to be widely applicable for large aerospace structural components, successful welding of such castings is essential. In the present work, the microstructure and porosity of laser welds in a standard grade cast Ti-6Al-4V alloy as well as two modified alloy versions with different boron concentrations have been investigated. Prior-β grain reconstruction revealed the prior-β grain structure in the weld zones. In fusion zones of the welds, boron was found to refine the grain size significantly and rendered narrow elongated grains. TiB particles in the prior-β grain boundaries in the cast base material restricted grain growth in the heat-affected zone. The TiB particles that existed in the as cast alloys decreased in size in the fusion zones of welds. The hardness in the weld zones was higher than in the base material and boron did not have a significant effect on hardness of the weld zones. The fusion zones were smaller in the boron-modified alloys as compared with Ti-6Al-4V without boron. Computed tomography X-ray investigations of the laser welds showed that pores in the FZ of the boron modified alloys were confined to the lower part of the welds, suggesting that boron addition influences melt pool flow.

Comparative study on the mechanical and microstructural characterisation of AA 7075 nano and hybrid nanocomposites produced by stir and squeeze casting.

PubMed

Kannan, C; Ramanujam, R

2017-07-01

In this research work, a comparative evaluation on the mechanical and microstructural characteristics of aluminium based single and hybrid reinforced nanocomposites was carried out. The manufacture of a single reinforced nanocomposite was conducted with the distribution of 2 wt.% nano alumina particles (avg. particle size 30-50 nm) in the molten aluminium alloy of grade AA 7075; while the hybrid reinforced nanocomposites were produced with of 4 wt.% silicon carbide (avg. particle size 5-10 µm) and 2 wt.%, 4 wt.% nano alumina particles. Three numbers of single reinforced nanocomposites were manufactured through stir casting with reinforcements preheated to different temperatures viz. 400 °C, 500 °C, and 600 °C. The stir cast procedure was extended to fabricate two hybrid reinforced nanocomposites with reinforcements preheated to 500 °C prior to their inclusion. A single reinforced nanocomposite was also developed by squeeze casting with a pressure of 101 MPa. Mechanical and physical properties such as density, hardness, ultimate tensile strength, and impact strength were evaluated on all the developed composites. The microstructural observation was carried out using optical and scanning electron microscopy. On comparison with base alloy, an improvement of 63.7% and 81.1% in brinell hardness was observed for single and hybrid reinforced nanocomposites respectively. About 16% higher ultimate tensile strength was noticed with the squeeze cast single reinforced nanocomposite over the stir cast.

Fatigue in a heat treatable high silicon containing aluminium alloy

NASA Astrophysics Data System (ADS)

González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael

2017-05-01

The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

NASA Astrophysics Data System (ADS)

Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

2016-02-01

The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

Application of Al-2La-1B Grain Refiner to Al-10Si-0.3Mg Casting Alloy

NASA Astrophysics Data System (ADS)

Jing, Lijun; Pan, Ye; Lu, Tao; Li, Chenlin; Pi, Jinhong; Sheng, Ningyue

2018-05-01

This paper reports the application and microstructure refining effect of an Al-2La-1B grain refiner in Al-10Si-0.3Mg casting alloy. Compared with the traditional Al-5Ti-1B refiner, Al-2La-1B refiner shows better performances on the grain refinement of Al-10Si-0.3Mg alloy. Transmission electron microscopy analysis suggests that the crystallite structure features of LaB6 are beneficial to the heterogeneous nucleation of α-Al grains. Regarding the mechanical performances, tensile properties of Al-10Si-0.3Mg casting alloy are prominently improved, due to the refined microstructures.

25. "CAST IRON HOWE TRUSS CARRYING PENNA STATE HIGHWAY ...

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

25. "CAST IRON HOWE TRUSS - CARRYING PENNA STATE HIGHWAY ROUTE #83 OVER READING CO. TRACKS - SOUTH OF READING, PENNA, Dwg. #6 - Sht. #1", dated November 20, 1956, shows partial side elevation of bridge truss, beginning at end post - Reading-Halls Station Bridge, U.S. Route 220, spanning railroad near Halls Station, Muncy, Lycoming County, PA

Method of Estimating the Principal Characteristics of an Infantry Fighting Vehicle from Basic Performance Requirements

DTIC Science & Technology

2013-08-01

Balliett, “Investigation of Cast Austempered Ductile Iron ( CADI ) Trackshoes in T-158 Configuration,” US TACOM Report 13575 (Warren, MI: US Army Tank...Engineers, 11th Ed. New York, NY: McGraw Hill, 2007. Balliett, T. “Investigation of Cast Austempered Ductile Iron ( CADI ) Trackshoes in T-158

Implementation Analysis of Cutting Tool Carbide with Cast Iron Material S45 C on Universal Lathe

NASA Astrophysics Data System (ADS)

Junaidi; hestukoro, Soni; yanie, Ahmad; Jumadi; Eddy

2017-12-01

Cutting tool is the tools lathe. Cutting process tool CARBIDE with Cast Iron Material Universal Lathe which is commonly found at Analysiscutting Process by some aspects numely Cutting force, Cutting Speed, Cutting Power, Cutting Indication Power, Temperature Zone 1 and Temperatur Zone 2. Purpose of this Study was to determine how big the cutting Speed, Cutting Power, electromotor Power,Temperatur Zone 1 and Temperatur Zone 2 that drives the chisel cutting CARBIDE in the Process of tur ning Cast Iron Material. Cutting force obtained from image analysis relationship between the recommended Component Cuting Force with plane of the cut and Cutting Speed obtained from image analysis of relationships between the recommended Cutting Speed Feed rate.

Microstructure and Properties of Cobalt-and Zinc-Containing Magnetic Magnesium Alloys Processed by High-Pressure Die Casting

NASA Astrophysics Data System (ADS)

Klose, Christian; Demminger, Christian; Maier, Hans Jürgen

The inherent magnetic properties of lightweight alloys based on magnesium and cobalt offer a novel way in order to measure mechanical loads throughout the entire structural component using the magnetoelastic effect. Because the solubility of cobalt in the magnesium matrix is negligible, the magnetic properties mainly originate from Co-rich precipitates. Thus, the size and distribution of Co-containing phases within the alloy's microstructure wields a major influence on the amplitude of the load-sensitive properties which can be measured by employing the harmonic analysis of eddy-current signals. In this study, Mg-Co-based alloys are produced by several casting methods which allow the application of different cooling rates, e.g. gravity die casting and high-pressure die casting. The differences between the manufactured alloys' micro- and phase structures are compared depending on the applied cooling rate and the superior magnetic and mechanical properties of the high-pressure die cast material are demonstrated.

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... the cast heel, toe cap, cast support, and walking iron. (b) Classification. Class I (general controls...

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... the cast heel, toe cap, cast support, and walking iron. (b) Classification. Class I (general controls...

Modeling of microstructure evolution of magnesium alloy during the high pressure die casting process

NASA Astrophysics Data System (ADS)

Wu, Mengwu; Xiong, Shoumei

2012-07-01

Two important microstructure characteristics of high pressure die cast magnesium alloy are the externally solidified crystals (ESCs) and the fully divorced eutectic which form at the filling stage of the shot sleeve and at the last stage of solidification in the die cavity, respectively. Both of them have a significant influence on the mechanical properties and performance of magnesium alloy die castings. In the present paper, a numerical model based on the cellular automaton (CA) method was developed to simulate the microstructure evolution of magnesium alloy during cold-chamber high pressure die casting (HPDC) process. Modeling of dendritic growth of magnesium alloy with six-fold symmetry was achieved by defining a special neighbourhood configuration and calculating of the growth kinetics from complete solution of the transport equations. Special attention was paid to establish a nucleation model considering both of the nucleation of externally solidified crystals in the shot sleeve and the massive nucleation in the die cavity. Meanwhile, simulation of the formation of fully divorced eutectic was also taken into account in the present CA model. Validation was performed and the capability of the present model was addressed by comparing the simulated results with those obtained by experiments.

Effect of Rotating Mold Speed on Microstructure of Al LM6 Hollow Cylinder Fabricated Using Centrifugal Method

NASA Astrophysics Data System (ADS)

Kohnizio Mahli, Maximus; Jamian, Saifulnizan; Ismail, Al Emran; Nor, Nik Hisyamudin Muhd; Nor, Mohd Khir Mohd; Azhar Kamarudin, Kamarul

2017-10-01

Al LM6 hollow cylinder is fabricated using horizontal centrifugal casting which produce a very fine grain on the outer surface of the structure. In this study, the effect of motor speed and pouring temperature on the microstructure of Al LM6 hollow cylinder is determined. The speed of the motor used during casting are 1300rpm, 1500rpm and 1700rpm and the pouring temperature are 690°C, 710°C and 725°C. The Al LM6 hollow cylinder is produced by pouring the molten Al LM6 into a cylindrical casting mold which is connected with a shaft and it is rotated by motor until it is solidified. Then, the cross-section is observed using OM and SEM/EDS. From the microstructure observation, the distributions of Si are more concentrated at the inner parts and the size of Si is bigger at the inner parts. The result shows that the Si particles at the inner part which is fabricated at the highest motor speed (1700rpm) have the most Si particles compared with the Si particles that are casted with other motor speeds.

Precision cast vs. wrought superalloys

NASA Technical Reports Server (NTRS)

Tien, J. K.; Borofka, J. C.; Casey, M. E.

1986-01-01

While cast polycrystalline superalloys recommend themselves in virtue of better 'buy-to-fly' ratios and higher strengthening gamma-prime volume fractions than those of wrought superalloys, the expansion of their use into such critical superalloy applications as gas turbine hot section components has been slowed by insufficient casting process opportunities for microstructural control. Attention is presently drawn, however, to casting process developments facilitating the production of defect-tolerant superalloy castings having improved fracture reliability. Integrally bladed turbine wheel and thin-walled turbine exhaust case near-net-shape castings have been produced by these means.

Structural and compositional analysis of a casting mold sherd from ancient China

PubMed Central

Zong, Yunbing; Yao, Shengkun; Lang, Jianfeng; Chen, Xuexiang; Fan, Jiadong; Sun, Zhibin; Duan, Xiulan; Li, Nannan; Fang, Hui; Zhou, Guangzhao; Xiao, Tiqiao; Li, Aiguo; Jiang, Huaidong

2017-01-01

Casting had symbolic significance and was strictly controlled in the Shang dynasty of ancient China. Vessel casting was mainly distributed around the Shang capital, Yin Ruins, which indicates a rigorous centralization of authority. Thus, for a casting mold to be excavated far from the capital region is rare. In addition to some bronze vessel molds excavated at the Buyao Village site, another key discovery of a bronze vessel mold occurred at Daxinzhuang. The Daxinzhuang site was a core area in the east of Shang state and is an important site to study the eastward expansion of the Shang. Here, combining synchrotron X-rays and other physicochemical analysis methods, nondestructive three-dimensional structure imaging and different elemental analyses were conducted on this mold sherd. Through high penetration X-ray tomography, we obtained insights on the internal structure and discovered some pores. We infer that the generation of pores inside the casting mold sherd was used to enhance air permeability during casting. Furthermore, we suppose that the decorative patterns on the surface were carved and not pasted onto it. Considering the previous compositional studies of bronze vessels, the copper and iron elements were analyzed by different methods. Unexpectedly, a larger amount of iron than of copper was detected on the surface. According to the data analysis and archaeological context, the source of iron on the casting mold sherd could be attributed to local soil contamination. A refined compositional analysis confirms that this casting mold was fabricated locally and used for bronze casting. PMID:28296963

CASTING DEFECT MODELING IN AN INTEGRATED COMPUTATIONAL MATERIALS ENGINEERING APPROACH

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabau, Adrian S

2015-01-01

To accelerate the introduction of new cast alloys, the simultaneous modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. The required models related to casting defects, such as microporosity and hot tears, are reviewed. Three aluminum alloys are considered A356, 356 and 319. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Examples are given for predicting microporosity defects and microstructure distribution for a plate casting. Models to predict fatigue life and yield stress are briefly highlighted here for the sake ofmore » completion and to illustrate how the length scales of the microstructure features as well as porosity defects are taken into account for modeling the mechanical properties. Thus, the data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the component. ACKNOWLEDGEMENTS This work was performed under a Cooperative Research and Development Agreement (CRADA) with the Nemak Inc., and Chrysler Co. for the project "High Performance Cast Aluminum Alloys for Next Generation Passenger Vehicle Engines. The author would also like to thank Amit Shyam for reviewing the paper and Andres Rodriguez of Nemak Inc. Research sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Office, as part of the Propulsion Materials Program under contract DE-AC05-00OR22725 with UT-Battelle, LLC. Part of this research was conducted through the Oak Ridge National Laboratory's High Temperature Materials Laboratory User Program, which is sponsored by the U. S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Vehicle Technologies Program.« less

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

NASA Astrophysics Data System (ADS)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-06-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.

Magnetically assisted slip casting of bioinspired heterogeneous composites

NASA Astrophysics Data System (ADS)

Le Ferrand, Hortense; Bouville, Florian; Niebel, Tobias P.; Studart, André R.

2015-11-01

Natural composites are often heterogeneous to fulfil functional demands. Manufacturing analogous materials remains difficult, however, owing to the lack of adequate and easily accessible processing tools. Here, we report an additive manufacturing platform able to fabricate complex-shaped parts exhibiting bioinspired heterogeneous microstructures with locally tunable texture, composition and properties, as well as unprecedentedly high volume fractions of inorganic phase (up to 100%). The technology combines an aqueous-based slip-casting process with magnetically directed particle assembly to create programmed microstructural designs using anisotropic stiff platelets in a ceramic, metal or polymer functional matrix. Using quantitative tools to control the casting kinetics and the temporal pattern of the applied magnetic fields, we demonstrate that this approach is robust and can be exploited to design and fabricate heterogeneous composites with thus far inaccessible microstructures. Proof-of-concept examples include bulk composites with periodic patterns of microreinforcement orientation, and tooth-like bilayer parts with intricate shapes exhibiting site-specific composition and texture.

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

NASA Astrophysics Data System (ADS)

Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

2018-04-01

This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity (H c > 10 kOe) can be achieved without any microstructural refinement.

Predictive Capabilities of Multiphysics and Multiscale Models in Modeling Solidification of Steel Ingots and DC Casting of Aluminum

NASA Astrophysics Data System (ADS)

Combeau, Hervé; Založnik, Miha; Bedel, Marie

2016-08-01

Prediction of solidification defects, such as macrosegregation and inhomogeneous microstructures, constitutes a key issue for industry. The development of models of casting processes needs to account for several imbricated length scales and different physical phenomena. For example, the kinetics of the growth of microstructures needs to be coupled with the multiphase flow at the process scale. We introduce such a state-of-the-art model and outline its principles. We present the most recent applications of the model to casting of a heavy steel ingot and to direct chill casting of a large Al alloy sheet ingot. Their ability to help in the understanding of complex phenomena, such as the competition between nucleation and growth of grains in the presence of convection of the liquid and of grain motion is shown, and its predictive capabilities are discussed. Key issues for future developments and research are addressed.

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

NASA Astrophysics Data System (ADS)

Perrier, Frédéric; Desrayaud, Christophe; Bouvier, Véronique

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

Further studies on gold alloys used in fabrication of porcelain-fused-to-metal restorations.

PubMed

Civjan, S; Huget, E F; Dvivedi, N; Cosner, H J

1975-03-01

Composition, microstructure, castability, mechanical properties, and heat treatment characteristics of two gold-palladium-silver-based alloys were studied. The materials exhibited compositional as well as microstructural differences. Clinically acceptable castings could not be obtained when manufacturers' recommended casting temperatures were used. Ultimate tensile strength, yield strength, modulus of elasticity, and Brinell hardness values for the alloys were comparable. The elastic limit of Cameo, however, was significantly higher than that of vivo-star. Maximum rehardening of annealed castings occurred on reheat treatment at temperatures between 1,200 and 1,300 F. As-cast specimens, however, were not heat hardenable. The sequence of heat treatments used in the application of porcelain reduced slightly the hardness of both alloys. Hardness of the metal substructures was not increased by return of porcelain-coated specimens to a 1,250 F oven for final heat treatment.

Changes Found on Run-In and Scuffed Surfaces of Steel Chrome Plate, and Cast Iron

NASA Technical Reports Server (NTRS)

Good, J. N.; Godfrey, Douglas

1947-01-01

A study was made of run-in and scuffed steel, chrome-plate, and cast-iron surfaces. X-ray and electron diffraction techniques, micro-hardness determinations, and microscopy were used. Surface changes varied and were found to include three classes: chemical reaction, hardening, and crystallite-size alteration. The principal chemical reactions were oxidation and carburization.

Cast Iron Versus Creativity: Fostering Balanced Thinking in Military Professionals

DTIC Science & Technology

2015-06-01

CREATIVITY: FOSTERING BALANCED THINKING IN MILITARY PROFESSIONALS by Michael H. Laplante June 2015 Thesis Advisor: Leo Blanken Co...AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE CAST IRON VERSUS CREATIVITY: FOSTERING BALANCED THINKING IN MILITARY PROFESSIONALS 5...utilizes multivariant experimentation with military officers. The research analyzes the impact of how a commander frames a problem to a subordinate. More

Coliform culturability in over- versus undersaturated drinking waters.

PubMed

Grandjean, D; Fass, S; Tozza, D; Cavard, J; Lahoussine, V; Saby, S; Guilloteau, H; Block, J-C

2005-05-01

The culturability of Escherichia coli in undersaturated drinking water with respect to CaCO3 (corrosive water) or in oversaturated water (non-corrosive water) was tested in different reactors: glass flasks (batch, "non-reactive" wall); glass reactors (chemostat, "non-reactive" wall) versus a corroded cast iron Propella reactor (chemostat, "reactive" wall) and a 15-year-old distribution system pilot (chemostat, "reactive" wall with 1% corroded cast iron and 99% cement-lined cast iron). The E. coli in E. coli-spiked drinking water was not able to maintain its culturability and colonize the experimental systems. It appears from our results that the optimal pH for maintaining E. coli culturability was around 8.2 or higher. However, in reactors with a reactive wall (corroded cast iron), the decline in E. coli culturability was slower when the pH was adjusted to 7.9 or 7.7 (i.e. a reactor fed with corrosive water; pHpHs). We tentatively deduce that corrosion products coming from chemical reactions driven by corrosive waters on the pipe wall improve E. coli culturability.

Method of fabricating a prestressed cast iron vessel

DOEpatents

Lampe, Robert F.

1982-01-01

A method of fabricating a prestressed cast iron vessel wherein double wall cast iron body segments each have an arcuate inner wall and a spaced apart substantially parallel outer wall with a plurality of radially extending webs interconnecting the inner wall and the outer wall, the bottom surface and the two exposed radial side surfaces of each body segment are machined and eight body segments are formed into a ring. The top surfaces and outer surfaces of the outer walls are machined and keyways are provided across the juncture of adjacent end walls of the body segments. A liner segment complementary in shape to a selected inner wall of one of the body segments is mounted to each of the body segments and again formed into a ring. The liner segments of each ring are welded to form unitary liner rings and thereafter the cast iron body segments are prestressed to complete the ring assembly. Ring assemblies are stacked to form the vessel and adjacent unitary liner rings are welded. A top head covers the top ring assembly to close the vessel and axially extending tendons retain the top and bottom heads in place under pressure.

Precise Analysis of Microstructural Effects on Mechanical Properties of Cast ADC12 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Okayasu, Mitsuhiro; Takeuchi, Shuhei; Yamamoto, Masaki; Ohfuji, Hiroaki; Ochi, Toshihiro

2015-04-01

The effects of microstructural characteristics (secondary dendrite arm spacing, SDAS) and Si- and Fe-based eutectic structures on the mechanical properties and failure behavior of an Al-Si-Cu alloy are investigated. Cast Al alloy samples are produced using a special continuous-casting technique with which it is easy to control both the sizes of microstructures and the direction of crystal orientation. Dendrite cells appear to grow in the casting direction. There are linear correlations between SDAS and tensile properties (ultimate tensile strength σ UTS, 0.2 pct proof strength σ 0.2, and fracture strain ɛ f). These linear correlations, however, break down, especially for σ UTS vs SDAS and ɛ f vs SDAS, as the eutectic structures become more than 3 μm in diameter, when the strength and ductility ( σ UTS and ɛ f) decrease significantly. For eutectic structures larger than 3 μm, failure is dominated by the brittle eutectic phases, for which SDAS is no longer strongly correlated with σ UTS and ɛ f. In contrast, a linear correlation is obtained between σ 0.2 and SDAS, even for eutectic structures larger than 3 μm, and the eutectic structure does not have a strong effect on yield behavior. This is because failure in the eutectic phases occurs just before final fracture. In situ failure observation during tensile testing is performed using microstructural and lattice characteristics. From the experimental results obtained, models of failure during tensile loading are proposed.

Effect of Al-TiB Addition on the Mechanical Properties and Microstructure of Al-ADC12/NanoSiC Produced by Stir Casting Methods

NASA Astrophysics Data System (ADS)

Dhaneswara, D.; Zulfia, A.; Pramudita, T. P.; Ferdian, D.; Utomo, B. W.

2018-03-01

Addition of Ti-B grain refiner in Al-ADC12/nanoSiC composite results in improvement of tensile strength, hardness, and wear resistance through grain refinement. In this research, composite of Al-ADC12/nano SiC (0.15 %vf) with variations of TiB respectively (0.0), (0.02), (0.04), (0.06), dan (0.08) wt% were produced by stir casting. 10% of Mg were added to promote wettability between reinforce and matrix. It was found the best addition of TiB is 0.04 wt% Ti-B which results 135,9 MPa in tensile strength, 46 HRB in hardness, and 1.47x10-5 mm3/s as wear rate. The increase in mechanical properties of composites mainly because of Al3Ti acts as nucleants which initiates the grain refinement and the existence of MgAl2O4 phase indicates an interphase between nano SiC and ADC12 matrix. However, the increase of Ti-B addition after optimum number gives no significant results. High composition of iron and magnesium addition will form intermetallic phase β-Fe, π-Fe, and Mg2Si.

An Electron Microscopy Study of Graphite Growth in Nodular Cast Irons

NASA Astrophysics Data System (ADS)

Laffont, L.; Jday, R.; Lacaze, J.

2018-04-01

Growth of graphite during solidification and high-temperature solid-state transformation has been investigated in samples cut out from a thin-wall casting which solidified partly in the stable (iron-graphite) and partly in the metastable (iron-cementite) systems. Transmission electron microscopy has been used to characterize graphite nodules in as-cast state and in samples having been fully graphitized at various temperatures in the austenite field. Nodules in the as-cast material show a twofold structure characterized by an inner zone where graphite is disoriented and an outer zone where it is well crystallized. In heat-treated samples, graphite nodules consist of well-crystallized sectors radiating from the nucleus. These observations suggest that the disoriented zone appears because of mechanical deformation when the liquid contracts during its solidification in the metastable system. During heat-treatment, the graphite in this zone recrystallizes. In turn, it can be concluded that nodular graphite growth mechanism is the same during solidification and solid-state transformation.

Investigation of Wear and Friction Properties Under Sliding Conditions of Some Materials Suitable for Cages of Rolling-Contact Bearings

NASA Technical Reports Server (NTRS)

Johnson, Robert L; Swikert, Max A; Bisson, Edmond E

1952-01-01

An investigation of wear and friction properties of a number of materials sliding against SAE 52100 steel was conducted. These materials included brass, bronze, beryllium copper, monel, nichrome v, 24s-t aluminum, nodular iron, and gray cast iron. The metals investigated may be useful as possible cage (separator or retainer) materials for rolling-contact bearings of high-speed turbine engines. The ability of materials to form surface films that prevent welding is a most important factor in both dry friction and boundary lubrication. On the basis of wear and resistance to welding only, the cast irons were the most promising materials investigated; they showed the least wear and the least tendency to surface failure when run dry, and when boundary lubricated they showed the highest load capacity. On the basis of mechanical properties, nodular iron is superior to gray cast iron. Bronze had the lowest friction coefficient under dry sliding conditions. The results with brass, beryllium copper, and aluminum were poor and these materials do not appear, with regard to friction and wear, to be suitable for cages.

Effect of powder reactivity on fabrication and properties of NiAl/Al2O3 composite coated on cast iron using spark plasma sintering

NASA Astrophysics Data System (ADS)

Beyhaghi, Maryam; Kiani-Rashid, Ali-Reza; Kashefi, Mehrdad; Khaki, Jalil Vahdati; Jonsson, Stefan

2015-07-01

Powder mixtures of Ni, NiO and Al are ball milled for 1 and 10 h. X-ray diffractometry and differential thermal analysis show that while ball milling for 1 h produced mechanically activated powder; 10 h ball milling produced NiAl and Al2O3 phases. Dense NiAl/Al2O3 composite coatings are formed on gray cast iron substrate by spark plasma sintering (SPS) technique. The effect of powder reactivity on microstructure, hardness and scratch hardness of NiAl/Al2O3 coatings after SPS is discussed. Results show that in the coating sample made of mechanically activated powder in situ synthesis of NiAl/Al2O3 composite coating is fulfilled and a thicker well-formed diffusion bond layer at the interface between coating and substrate is observed. The diffusion of elements across the bond layers and phase evolution in the bond layers were investigated. No pores or cracks were observed at the interface between coating layer and substrate in any of samples. Higher Vickers hardness and scratch hardness values in coating made of 10 h ball milled powder than in coating fabricated from 1 h ball milled powder are attributed to better dispersion of Al2O3 reinforcement particles in NiAl matrix and nano-crystalline structure of NiAl matrix. Scratched surface of coatings did not reveal any cracking or spallation at coating-substrate interface indicating their good adherence at test conditions.

Microstructure and corrosion behavior of die-cast AM60B magnesium alloys in a complex salt solution. A slow positron beam study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y. F.; Yang, W.; Qin, Q. L.

2013-12-15

The microstructure and corrosion behavior of high pressure die-cast (HPDC) and super vacuum die-cast (SVDC) AM60B magnesium alloys were investigated in a complex salt solution using slow positron beam technique and potentiodynamic polarization tests. The experiments revealed that a CaCO 3 film was formed on the surface of the alloys and that the rate of CaCO 3 formation for the SVDC alloy with immersion time was slower than that of the HPDC alloy. The larger volume fraction of b-phase in the skin layer of the SVDC alloy than that of the HPDC alloy was responsible for the better corrosion resistance.

Crystallography and Morphology of MC Carbides in Niobium-Titanium Modified As-Cast HP Alloys

NASA Astrophysics Data System (ADS)

Buchanan, Karl G.; Kral, Milo V.; Bishop, Catherine M.

2014-07-01

The microstructures of two as-cast heats of HP alloy stainless steels modified with niobium and titanium were examined with particular attention paid to the interdendritic niobium-titanium-rich carbides formed during solidification of these alloys. Generally, these precipitates obtain a blocky morphology in the as-cast condition. However, the (NbTi)C precipitates may obtain a nodular morphology. To provide further insight to the origin of the two different morphologies obtained by the (NbTi)C precipitates in the HP-NbTi alloy, the microstructure and crystallography of each have been studied in detail using scanning electron microscopy, transmission electron microscopy, various electron diffraction methods (EBSD, SAD, and CBED), and energy-dispersive X-ray spectroscopy.

[Corrosion resistance of casted titanium by compound treatments in the artificial saliva with different fluoride concentrations].

PubMed

Wang, Xian-li; Guo, Tian-wen

2012-09-01

To study the corrosion resistance of casted titanium by plasma nitriding and TiN-coated compound treatments in the artificial saliva with different fluoride concentrations and to investigate whether compound treatments can increase the corrosion resistance of casted titanium. Potentiodynamic polarization technique was used to depict polarization curve and to measured the current density of corrosion (Icorr) and the electric potential of corrosion (Ecorr) of casted titanium (Group A) and casted titanium by compound treatments (Group B) in the artificial saliva with different fluoride concentrations. After electrochemical experiment, the microstructure was observed by scanning electron microscope (SEM). The Icorrs of Group A and B in the artificial saliva of different fluoride concentrations were (1530.23 ± 340.12), (2290.36 ± 320.10), (4130.52 ± 230.17) nA and (2.62 ± 0.64), (7.37 ± 3.59), (10.76 ± 6.05) nA, respectively. The Ecorrs were (-0.93 ± 0.10), (-0.89 ± 0.21), (-0.57 ± 0.09) V and (-0.21 ± 0.04), (-0.17 ± 0.03), (-0.22 ± 0.03) V, respectively.The Icorrs of Group B were significantly lower (P < 0.01)than that of Group A. The Icorrs increased significantly with the increasing of fluoride concentrations (P < 0.01). The Ecorrs of Group B were significantly higher than that of Group A (P < 0.01). The SEM confirmed the microstructure in the casted titanium was much severely than that in Group B, the microstructure in Group A and B corroded more and more heavily with increasing of fluoride concentrations. The increase of fluoride concentrations influence the corrosion resistance of both treated and untreated casted titanium negatively, but plasma nitriding and TiN-coated compound treatments can significantly increase the corrosion resistance of casted titanium.

Effect of scandium on the microstructure and ageing behaviour of cast Al-6Mg alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaiser, M.S.; Datta, S.; Roychowdhury, A.

2008-11-15

Microstructural modification and grain refinement due to addition of scandium in Al-6Mg alloy has been studied. Transmission electron microscopy is used to understand the microstructure and precipitation behaviour in Al-6Mg alloy doped with scandium. It is seen from the microstructure that the dendrites of the cast Al-6Mg alloy have been refined significantly due to addition of scandium. Increasing amount of scandium leads to a greater dendrite refinement. The age hardening effect in scandium added Al-6Mg alloys has been studied by subjecting the alloys containing varying amount of scandium ranging from 0.2 wt.% to 0.6 wt.% to isochronal and isothermal ageingmore » at various temperatures for different times. It is observed that significant hardening takes place in the aged alloys due to the precipitation of scandium aluminides.« less

Effect of Binder and Mold parameters on Collapsibility and Surface Finish of Gray Cast Iron No-bake Sand Molds

NASA Astrophysics Data System (ADS)

Srinivasulu Reddy, K.; Venkata Reddy, Vajrala; Mandava, Ravi Kumar

2017-08-01

Chemically bonded no-bake molds and cores have good mechanical properties and produce dimensionally accurate castings compared to green sand molds. Poor collapsibility property of CO2 hardened sodium silicate bonded sand mold and phenolic urethane no-bake (PUN) binder system, made the reclamation of the sands more important. In the present work fine silica sand is mixed with phenolic urethane no-bake binder and the sand sets in a very short time within few minutes. In this paper it is focused on optimizing the process parameters of PUN binder based sand castings for better collapsibility and surface finish of gray cast iron using Taguchi design. The findings were successfully verified through experiments.

Metallographic Characterization of Wrought Depleted Uranium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Forsyth, Robert Thomas; Hill, Mary Ann

Metallographic characterization was performed on wrought depleted uranium (DU) samples taken from the longitudinal and transverse orientations from specific locations on two specimens. Characterization of the samples included general microstructure, inclusion analysis, grain size analysis, and microhardness testing. Comparisons of the characterization results were made to determine any differences based on specimen, sample orientation, or sample location. In addition, the characterization results for the wrought DU samples were also compared with data obtained from the metallographic characterization of cast DU samples previously characterized. No differences were observed in microstructure, inclusion size, morphology, and distribution, or grain size in regard tomore » specimen, location, or orientation for the wrought depleted uranium samples. However, a small difference was observed in average hardness with regard to orientation at the same locations within the same specimen. The longitudinal samples were slightly harder than the transverse samples from the same location of the same specimen. This was true for both wrought DU specimens. Comparing the wrought DU sample data with the previously characterized cast DU sample data, distinct differences in microstructure, inclusion size, morphology and distribution, grain size, and microhardness were observed. As expected, the microstructure of the wrought DU samples consisted of small recrystallized grains which were uniform, randomly oriented, and equiaxed with minimal twinning observed in only a few grains. In contrast, the cast DU microstructure consisted of large irregularly shaped grains with extensive twinning observed in most grains. Inclusions in the wrought DU samples were elongated, broken and cracked and light and dark phases were observed in some inclusions. The mean inclusion area percentage for the wrought DU samples ranged from 0.08% to 0.34% and the average density from all wrought DU samples was 1.62E+04/cm 2. Inclusions in the cast DU samples were equiaxed and intact with light and dark phases observed in some inclusions. The mean inclusion area percentage for the cast DU samples ranged from 0.93% to 1.00% and the average density from all wrought DU samples was 2.83E+04/cm 2. The average mean grain area from all wrought DU samples was 141 μm 2 while the average mean grain area from all cast DU samples was 1.7 mm2. The average Knoop microhardness from all wrought DU samples was 215 HK and the average Knoop microhardness from all cast DU samples was 264 HK.« less

The Effects of Dy Addition on Microstructure and Mechanical Properties of the As-Cast Mg-5Al-3Ca-2Nd Alloys.

PubMed

Son, Hyeon-Taek; Kim, Yong-Ho; Yoo, Hyo-Sang

2018-03-01

The microstructure of the as-cast Mg-5Al-3Ca-2Nd-xDy alloys consists of α-Mg matrix, (Mg, Al)2Ca eutectic phase, Al-Nd and Al-Dy intermetallic compounds. α-Mg matrix morphology was changed from dendritic to equiaxed with the increase Dy addition. And grain size was remarkably refined. As Dy content was increased, yield strength was improved due to the refined grains and the homogeneous distribution of Al-Dy phase.

Physical metallurgy of BATMAN II Ti-bearing martensitic steels

NASA Astrophysics Data System (ADS)

Pilloni, L.; Attura, F.; Calza-Bini, A.; De Santis, G.; Filacchioni, G.; Carosi, A.; Amato, S.

1998-10-01

Seven laboratory experimental casts of 7-9% Cr Ti-bearing martensitic steels were obtained via VIM process. Plates of 25 mm thickness were produced by hot rolling. On each cast CCT diagrams and critical temperatures were determined. Several austenitizing treatments were performed to study the grain size evolution. The effect of microstructure on impact properties were finally investigated. This paper discusses the role of chemical composition on microstructural and physical properties and shows the beneficial effect either of low-temperature austenitizing or double-austenitizing steps on impact properties.

Evaluation of the mechanical properties and porcelain bond strength of cobalt-chromium dental alloy fabricated by selective laser melting.

PubMed

Wu, Lin; Zhu, Haiting; Gai, Xiuying; Wang, Yanyan

2014-01-01

Limited information is available regarding the microstructure and mechanical properties of dental alloy fabricated by selective laser melting (SLM). The purpose of this study was to evaluate the mechanical properties of a cobalt-chromium (Co-Cr) dental alloy fabricated by SLM and to determine the correlation between its microstructure and mechanical properties and its porcelain bond strength. Five metal specimens and 10 metal ceramic specimens were fabricated to evaluate the mechanical properties of SLM Co-Cr dental alloy (SLM alloy) with a tensile test and its porcelain bond strength with a 3-point bending test. The relevant properties of the SLM alloy were compared with those of the currently used Co-Cr dental alloy fabricated with conventional cast technology (cast alloy). The Student t test was used to compare the results of the SLM alloy and the cast alloy (α=.05). The microstructure of the SLM alloy was analyzed with a metallographic microscope; the metal ceramic interface of the SLM porcelain bonded alloy was studied with scanning electron microscopy, energy dispersive x-ray spectroscopy, and an electron probe microanalyzer. Both the mean (standard deviation) yield strength (884.37 ± 8.96 MPa) and tensile strength (1307.50 ±10.65 MPa) of the SLM alloy were notably higher than yield strength (568.10 ± 30.94 MPa) and tensile strength (758.73 ± 25.85 MPa) of the currently used cast alloy, and the differences were significant (P<.05). The porcelain bond strength of the SLM alloy was 55.78 ± 3.02 MPa, which was similar to that of the cast alloy, 54.17 ± 4.96 MPa (P>.05). Microstructure analysis suggested that the SLM alloy had a dense and obviously orientated microstructure, which led to excellent mechanical properties. Analysis from scanning electron microscopy, energy dispersive x-ray spectroscopy, and the electron probe microanalyzer indicated that the SLM alloy had an intermediate layer with elemental interpenetration between the alloy and the porcelain, which resulted in an improved bonding interface. Compared with the currently used cast alloy, SLM alloy possessed improved mechanical properties and similar porcelain bond strength. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Grain Refinement and Improvement of Solidification Defects in Direct-Chill Cast Billets of A4032 Alloy by Melt Conditioning

NASA Astrophysics Data System (ADS)

Li, Hu-Tian; Zhao, Pizhi; Yang, Rongdong; Patel, Jayesh B.; Chen, Xiangfu; Fan, Zhongyun

2017-10-01

Melt-conditioned, direct-chill (MC-DC) casting is an emerging technology to manipulate the solidification process by melt conditioning via intensive shearing in the sump during DC casting to tailor the solidification microstructure and defect formation. When using MC-DC casting technology in an industrial scale DC cast billet of an A4032 aluminum alloy, significant grain refinement and uniform microstructure can be achieved in the primary α-Al phase with fine secondary dendritic arm spacing (SDAS). Improved macrosegregation is quantitatively characterized and correlated with the suppression of channel segregation. The mechanisms for the prevention of channel segregation are attributed to the increased local cooling rate in the liquid-solid phase region in the sump and the formation of fine equiaxed dendritic grains under intensive melt shearing during MC-DC casting. A critical cooling rate has been identified to be around 0.5 to 1 K/s (°C/s) for the channel segregation to happen in the investigated alloy based on quantitative metallographic results of SDAS. Reduction and refinement of microporosity is attributed to the improved permeability in the liquid-solid phase region estimated by the Kozeny-Carman relationship. The potential improvement in the mechanical properties achievable in MC-DC cast billets is indicated by the finer and more uniform forging streamline in the forgings of MC-DC cast billet.

Method and apparatus for in-situ drying investigation and optimization of slurry drying methodology

DOEpatents

Armstrong, Beth L.; Daniel, Claus; Howe, Jane Y.; Kiggans, Jr, James O.; Sabau, Adrian S.; Wood, III, David L.; Kalnaus, Sergiy

2016-05-10

A method of drying casted slurries that includes calculating drying conditions from an experimental model for a cast slurry and forming a cast film. An infrared heating probe is positioned on one side of the casted slurry and a thermal probe is positioned on an opposing side of the casted slurry. The infrared heating probe may control the temperature of the casted slurry during drying. The casted slurry may be observed with an optical microscope, while applying the drying conditions from the experimental model. Observing the casted slurry includes detecting the incidence of micro-structural changes in the casted slurry during drying to determine if the drying conditions from the experimental model are optimal.

Thermal analysis on Al7075/Al2O3 metal matrix composites fabricated by stir casting process

NASA Astrophysics Data System (ADS)

Jacob, S.; Shajin, S.; Gnanavel, C.

2017-03-01

Metal matrix Composites (MMC’s) have evoked a keen interest in recent times for various applications in aerospace, renewable energy and automotive industries due to their superior strength, low cost, easy availability and high temperature resistance [1]. The crack and propagation occurs in conventional materials without any appreciable indication in a short span. Hence composite materials are preferred nowadays to overcome this problem [2]. The process of metal matrix composites (MMC’s) is to unite the enviable attributes of metals and ceramics. The Stir casting method is used for producing aluminium metal matrix composites (AMC’s). A key challenge of the process is to spread the ceramic particles to achieve a defect free microstructure [2]. By carefully selecting stir casting processing specification, such as stirring time, temperature of the melt and blade angle, the desired microstructure can be obtained. The focus of this work is to develop a high strength particulate strengthen aluminium metal matrix composites, and Al7075 was selected which can offer high strength without much disturbing ductility of metal matrix [4]. The composites will be examined using standard metallurgical and mechanical tests. The cast composites are analysed to Laser flash analysis (LFA) to determine Thermal conductivity [5]. Also changes in microstructure are determined by using SEM analysis.

Impacts of water quality on the corrosion of cast iron pipes for water distribution and proposed source water switch strategy.

PubMed

Hu, Jun; Dong, Huiyu; Xu, Qiang; Ling, Wencui; Qu, Jiuhui; Qiang, Zhimin

2018-02-01

Switch of source water may induce "red water" episodes. This study investigated the impacts of water quality on iron release, dissolved oxygen consumption (ΔDO), corrosion scale evolution and bacterial community succession in cast iron pipes used for drinking water distribution at pilot scale, and proposed a source water switch strategy accordingly. Three sets of old cast iron pipe section (named BP, SP and GP) were excavated on site and assembled in a test base, which had historically transported blended water, surface water and groundwater, respectively. Results indicate that an increasing Cl - or SO 4 2- concentration accelerated iron release, but alkalinity and calcium hardness exhibited an opposite tendency. Disinfectant shift from free chlorine to monochloramine slightly inhibited iron release, while the impact of peroxymonosulfate depended on the source water historically transported in the test pipes. The ΔDO was highly consistent with iron release in all three pipe systems. The mass ratio of magnetite to goethite in the corrosion scales of SP was higher than those of BP and GP and kept almost unchanged over the whole operation period. Siderite and calcite formation confirmed that an increasing alkalinity and hardness inhibited iron release. Iron-reducing bacteria decreased in the BP but increased in the SP and GP; meanwhile, sulfur-oxidizing, sulfate-reducing and iron oxidizing bacteria increased in all three pipe systems. To avoid the occurrence of "red water", a source water switch strategy was proposed based on the difference between local and foreign water qualities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Preparation of glass-ceramics from molten steel slag using liquid-liquid mixing method.

PubMed

Zhang, Kai; Liu, Jianwen; Liu, Wanchao; Yang, Jiakuan

2011-10-01

A novel approach to prepare glass-ceramics from molten steel slag (MSS) was proposed. In laboratory, the water-quenched steel slag was melted at 1350 °C to simulate the MSS. A mixture of additive powders in wt.% (55 quartz powder, 5 Na2O, 16 emery powder, 15 CaO, 8 MgO, 1 TiO2) were melted into liquid at 1350 °C separately. Then the MSS and the molten additives were mixed homogeneously in order to obtain parent glass melt. The proportion of MSS in the melt was 50 wt.%. The melt was subsequently cast, annealed, heat-treated and transformed into glass-ceramics. Their microstructure and crystallization behavior were analyzed. The samples exhibited excellent properties and displayed bulk crystallization. The major crystallized phase was diopside ((Fe0.35Al0.20Mg0.44)Ca0.96(Fe0.08Si0.70Al0.20)2O6.12), which was uniformly distributed in the microstructure. The novel approach may help iron and steel industry achieve zero disposal of steel slag with utilization of the heat energy of the MSS. Copyright © 2011 Elsevier Ltd. All rights reserved.

1. Historic American Buildings Survey E. W. Russell, Photographer, February ...

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

1. Historic American Buildings Survey E. W. Russell, Photographer, February 6, 1936 WROUGHT IRON GATE WITH CAST IRON ORNAMENTS, FRONT OF 605 GOVERNMENT STREET - 605 Government Street (Iron Gate), Mobile, Mobile County, AL

The mutual co-regulation of extracellular polymeric substances and iron ions in biocorrosion of cast iron pipes.

PubMed

Jin, Juntao; Guan, Yuntao

2014-10-01

New insights into the biocorrosion process may be gained through understanding of the interaction between extracellular polymeric substances (EPS) and iron. Herein, the effect of iron ions on the formation of biofilms and production of EPS was investigated. Additionally, the impact of EPS on the corrosion of cast iron coupons was explored. The results showed that a moderate concentration of iron ions (0.06 mg/L) promoted both biofilm formation and EPS production. The presence of EPS accelerated corrosion during the initial stage, while inhibited corrosion at the later stage. The functional groups of EPS acted as electron shuttles to enable the binding of iron ions. Binding of iron ions with EPS led to anodic dissolution and promoted corrosion, while corrosion was later inhibited through oxygen reduction and availability of phosphorus from EPS. The presence of EPS also led to changes in crystalline phases of corrosion products. Copyright © 2014 Elsevier Ltd. All rights reserved.

Iron and copper release in drinking-water distribution systems.

PubMed

Shi, Baoyou; Taylor, James S

2007-09-01

A large-scale pilot study was carried out to evaluate the impacts of changes in water source and treatment process on iron and copper release in water distribution systems. Finished surface waters, groundwaters, and desalinated waters were produced with seven different treatment systems and supplied to 18 pipe distribution systems (PDSs). The major water treatment processes included lime softening, ferric sulfate coagulation, reverse osmosis, nanofiltration, and integrated membrane systems. PDSs were constructed from PVC, lined cast iron, unlined cast iron, and galvanized pipes. Copper pipe loops were set up for corrosion monitoring. Results showed that surface water after ferric sulfate coagulation had low alkalinity and high sulfates, and consequently caused the highest iron release. Finished groundwater treated by conventional method produced the lowest iron release but the highest copper release. The iron release of desalinated water was relatively high because of the water's high chloride level and low alkalinity. Both iron and copper release behaviors were influenced by temperature.

Microstructure of bentonite in iron ore green pellets.

PubMed

Bhuiyan, Iftekhar U; Mouzon, Johanne; Schröppel, Birgit; Kaech, Andres; Dobryden, Illia; Forsmo, Seija P E; Hedlund, Jonas

2014-02-01

Sodium-activated calcium bentonite is used as a binder in iron ore pellets and is known to increase strength of both wet and dry iron ore green pellets. In this article, the microstructure of bentonite in magnetite pellets is revealed for the first time using scanning electron microscopy. The microstructure of bentonite in wet and dry iron ore pellets, as well as in distilled water, was imaged by various imaging techniques (e.g., imaging at low voltage with monochromatic and decelerated beam or low loss backscattered electrons) and cryogenic methods (i.e., high pressure freezing and plunge freezing in liquid ethane). In wet iron ore green pellets, clay tactoids (stacks of parallel primary clay platelets) were very well dispersed and formed a voluminous network occupying the space available between mineral particles. When the pellet was dried, bentonite was drawn to the contact points between the particles and formed solid bridges, which impart strength to the solid compact.

European Scientific Notes. Volume 36, Number 4.

DTIC Science & Technology

1982-03-30

de of gray cast iron, Mampaey demonstrated that Recherches Scientifiques et Techniques de the minimum riser dimensions needed to obtain I’lndustrie...through the nonprofit He is now making a similar study of ’nodular Industrial association Fabrimetal (Fdlration des cast iron. entreprises de I’industrie...SCIENTIFIC NOTES April 6. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(&) II. CONTRACT OR GRANT NUMBER(e) 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10

Power supplies for dual-frequency induction melting of metals

NASA Astrophysics Data System (ADS)

Lusgin, V. I.; Koptyakov, A. S.; Petrov, A. U.; Zinovev, K. A.; Kamaev, D. A.

2018-02-01

The article discusses the benefits of multi frequency induction melting in the production of synthetic cast iron, structural (electric circuit) principles of dual frequency Power supplies of melting systems. The ways of electric power regulation of low frequency and high frequency components of the current in the inductor sections of furnace are demonstrated, namely power rescheduling at the metal melting stage, alloying stage and decarburizing of synthetic cast iron.

Evaluation of Changes in Iron Interfacial Composition Using Surface Spectroscopy

NASA Astrophysics Data System (ADS)

Vikesland, P. J.; Kohn, T.; Ball, W. P.; Fairbrother, D.; Roberts, A.

2001-12-01

Although the ability of granular cast iron permeable reactive barriers to attenuate many persistent groundwater contaminants is well established, many uncertainties remain about the interactions that occur between cast iron and contaminant species. To better understand these interactions we set out to evaluate how various inorganic species and organic contaminants affect the interfacial composition of the iron over time. Column studies using granular iron enable us to observe changes in iron interfacial composition as a function of distance along the column as well as of column "age". The spectroscopic evaluations reported here are for ten columns that were fed continuously with simulated anoxic groundwaters of different chemistries. Nine of these columns were packed with untreated sieved cast iron and one was packed with a mixture of cast iron and the aluminosilicate mineral albite. Of the ten columns, seven have been continually fed chlorinated hydrocarbons (CHCs), one has been continually fed nitroaromatic compounds (NACs), and two have only periodically been fed CHCs in their influent. Six of these ten columns were operated for 1100 days and the remaining four were operated for 475 days. In an anaerobic glovebox, sample grains were extracted for surface spectroscopic characterization using solid sampling ports drilled into the columns. At each port, several iron grains were removed and immediately put into headspace free vials containing porewater obtained from the nearest aqueous sampling port. Samples were then analyzed using in-situ Raman analysis, Auger electron spectroscopy (AES), and transmission electron microscopy (TEM). Raman spectra indicate that the interfacial composition of the iron grains changes substantially between the inlet and the outlet of a given column. Near the inlet, Raman bands corresponding to the iron oxides goethite and magnetite are prevalent, whereas grains from a port near the column outlet exhibit bands at 425 and 504 cm-1, corresponding to the Fe2+-OH stretch and the Fe3+-OH stretch, respectively, of the redox-active mineral green rust. Comparisons at two different times (308 and 921 days) suggest that the interfacial composition of the iron grains also changed as the columns aged, with the longer-term downgradient compositions becoming more like those observed upgradient at earlier times. These in-situ Raman observations were supported by both AES and TEM. The observed spatial and temporal changes in the interfacial composition of the iron indicate that the iron grains become more passivated as the columns age. Initially, this passivation is most notable near the influent end of the columns, since that region receives the largest influx of reducible material. As the columns age, the passivated region slowly expands into the distal regions of the columns. This presentation will address the use of surface spectroscopy to analyze these changes in interfacial composition and will relate the observations to feed solution properties and to concurrent observations of reactivity changes. The implications of these results on the design and longevity of cast iron barriers will also be discussed.

Health implications of PAH release from coated cast iron drinking water distribution systems in The Netherlands.

PubMed

Blokker, E J Mirjam; van de Ven, Bianca M; de Jongh, Cindy M; Slaats, P G G Nellie

2013-05-01

Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. We estimated the potential human cancer risk from PAHs in coated cast iron water mains. In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations.

Health Implications of PAH Release from Coated Cast Iron Drinking Water Distribution Systems in the Netherlands

PubMed Central

van de Ven, Bianca M.; de Jongh, Cindy M.

2013-01-01

Background: Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. Objective: We estimated the potential human cancer risk from PAHs in coated cast iron water mains. Method: In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. Results: During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. Conclusions: The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations. PMID:23425894

Microstructure and Dynamic Failure Properties of Freeze-Cast Materials for Thermobaric Warhead Cases

DTIC Science & Technology

2012-12-01

Function LLNL Lawrence Livermore National Laboratory PDF Probability Density Function PMMA Poly(Methyl Methacrylate) RM Reactive Materials SEM...FREEZE CAST MATERIALS Freeze casting technology combines compounds such as aluminum oxide and poly(methyl methacrylate) ( PMMA ) to develop a...Subsequently, the porous structure can be infiltrated with a variety of materials, such as a standard polymer like PMMA . This hybrid material is believed

Effect of Heat Treatment on the Hardness and Wear of Grinding Balls

NASA Astrophysics Data System (ADS)

Aissat, Sahraoui; Sadeddine, Abdelhamid; Bradai, Mohand Amokrane; Younes, Rassim; Bilek, Ali; Benabbas, Abderrahim

2017-09-01

The effect quenching and tempering by different regimes on Rockwell hardness and wear processes of grinding balls 50 and 70 mm in diameter made of two melts of chromium-molybdenum cast iron is studied. The heating temperature for quenching is 850, 950, and 1050°C; the tempering temperature is 250, 400, and 600°C. Iron is analyzed in an electron microscope. Diffraction patterns are obtained. A model of cast iron wear is suggested and compared to the Davis model and to experimental results. An optimum heat treatment regime is proposed.

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

DOE PAGES

Meng, F.; Chaudhary, R. P.; Gandha, K.; ...

2018-04-23

Here, this work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu) 5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5–20 at.%) and Co (60–45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure andmore » phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu) 5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.« less

Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, F.; Chaudhary, R. P.; Gandha, K.

Here, this work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu) 5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5–20 at.%) and Co (60–45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure andmore » phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu) 5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.« less

The development of ultrahigh strength low alloy cast steels with increased toughness

NASA Astrophysics Data System (ADS)

Lynch, Paul C.

This work describes the initial work on the development of the next generation of ultrahigh strength low alloy (UHSLA) cast steels. These UHSLA cast steels have both ultrahigh strength levels and good impact toughness. The influence of heat treatment, secondary processing using hot isostatic processing (HIP), and chemical composition on the microstructure and properties of UHSLA cast steels have been evaluated. The extent of microsegregation reduction expected during the heat treatment of UHSLA cast steels has also been estimated by diffusion modeling. This new family of UHSLA cast steels is similar in composition and properties to UHSLA wrought steels. However, the heat treatment and secondary processing of the UHSLA cast steels is used to develop microstructures and properties typically developed through thermomechanical processing and heat treatment for wrought UHSLA steels. Two martensitic UHSLA steels, 4340+ (silicon modified 4340) and ES-1 were investigated for this study. For the 4340+ alloy, heat treatment variables evaluated include homogenization temperature and time, tempering temperature, and austempering temperature and time. For the ES-1 alloy, heat treatment variables evaluated include homogenization temperature and time, austenization temperature, cryogenic treatment, and tempering temperature. The effect of high temperature hot isostatic processing (HIP) on the 4340+ and ES- 1 alloys was also investigated. Tensile properties, charpy v-notch impact toughness (CVN), microstructures, and fractographs have all been characterized after heat treatment. The effects of HIP on microporosity reduction in the ES-1 alloy were also investigated. The experiments carried out on the investment cast 4340+ alloy have shown that increasing the homogenization temperature can increase CVN without changing the ultimate tensile strength (UTS) or yield strength (YS) of the cast material. By replacing the homogenization step in the conventional heat treatment process with a high temperature HIP treatment, both the CVN and ductility of the alloy was found to increase while maintaining comparable ultimate tensile strength (UTS) and yield strength (YS) levels as compared to the original homogenization treatment. Austempering the (IC) 4340+ material led to a significant increase in CVN and ductility at the expense of UTS and yield strength as the primarily martensitic microstructure was converted to a mixed martensitic-bainitic structure. An initial heat of induction melted, aluminum deoxidized investment cast ES-1 with 0.06 wt % of aluminum showed that the average -40°F and +72°F impact toughness, % elongation, and UTS and YS of the fully heat treated investment cast + HIP ES-1 material lagged significantly behind that of the vacuum degassed cast + HIP ES-1 ingot material. Even though the % elongation and impact toughness of the investment cast ES-1 material changed between heat treatment conditions, the average UTS and YS values remained relatively unchanged throughout the heat treatments for the investment cast study. Etched micrographs of the investment cast ES-1 material showed evidence of significant differences in microsegregation reduction between the samples homogenized at 2125°F for 4 hours and those not homogenized at 2125°F for 4 hours. SEM fracture surface work performed on the investment cast material clearly showed that the induction melted investment and aluminum killed cast material contained significant amounts of MnS and Al2O3 inclusions that were not discovered in the vacuum degassed cast ingot material. Lastly, the results of a third heat of induction melted, aluminum deoxidized investment cast ES-1 material possessing just 0.01wt% of aluminum showed that the decrease in aluminum content from the first experimental heat did not improve the mechanical properties of the investment cast material. (Abstract shortened by UMI.)

Castable high-temperature Ce-modified Al alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rios, Orlando; King, Alexander H.; McCall, Scott K.

2018-05-08

A cast alloy includes aluminum and from about 5 to about 30 weight percent of at least one material selected from the group consisting of cerium, lanthanum, and mischmetal. The cast alloy has a strengthening Al 11X 3 intermetallic phase in an amount in the range of from about 5 to about 30 weight percent, wherein X is at least one of cerium, lanthanum, and mischmetal. The Al 11X 3 intermetallic phase has a microstructure that includes at least one of lath features and rod morphological features. The morphological features have an average thickness of no more than 700 ummore » and an average spacing of no more than 10 um, the microstructure further comprising an eutectic microconstituent that comprises more than about 10 volume percent of the microstructure.« less

Microstructure and tensile properties after thermohydrogen processing of Ti-6 Al-4V.

PubMed

Guitar, A; Vigna, G; Luppo, M I

2009-04-01

Thermohydrogen processing (THP), a technique in which hydrogen is used as a temporary alloying element, can refine the microstructure and improve the final mechanical properties of the Ti-6 Al-4V alloy. THP allows microstructural modification of titanium alloys near net shape such as biomaterial components obtained by powder metallurgy and castings, since it does not require mechanical working. Two THP, called THP-A and THP-B, have been evaluated in samples of Ti-6Al-4V with a coarse and lamellar microstructure typical of castings and powder metallurgy. The THP-A is based in the eutectoid decomposition of the beta(H) phase to alpha phase and hydride phase. The THP-B is based in the isothermal decomposition of alpha('') martensite phase, obtained by quenching of hydrogenated samples. The refinement of the microstructure due to THP has been evaluated by means of optical and electron microscopy. Tensile tests showed that while both processes were able to increase the strength of the alloy as compared with the starting material, the ductility in samples subjected to THP-B was severely reduced.

8. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACES ...

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

8. INTERIOR VIEW, LOOKING WEST, WITH GREY IRON HOLDING FURNACES AND AN IRON POUR IN PROCESS, CUPOLA TENDER RICHARD SLAUGHTER SUPERVISING THE POUR. MOLTEN DUCTILE IRON IS POURED FROM THIS 25-TON HOLDING FURNACE INTO LADLES FOR TRANSPORT TO CASTING STATIONS. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Corrosion Inhibition of Cast Iron in Arabian Gulf Seawater by Two Different Ionic Liquids

PubMed Central

Sherif, El-Sayed M.; Abdo, Hany S.; Zein El Abedin, Sherif

2015-01-01

In this paper we report on the corrosion inhibition of cast iron in Arabian Gulf seawater by two different ionic liquids namely, 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-butyl-1-methylpyrrolidinium chloride ([Py1,4]Cl). The inhibiting influence of the employed ionic liquids was investigated by weight loss, open circuit potential electrochemical impedance spectroscopy, and cyclic potentiodynamic polarization. The results show the corrosion inhibition impact of the employed ionic liquids (ILs). Compared with [Py1,4]Cl, [EMIm]Cl shows a higher inhibition efficiency at a short immersion time, for the examined ILs concentrations. However, [Py1,4]Cl exhibits a higher efficiency upon increasing the immersion time indicating the persistence of the inhibiting influence. The corrosion inhibition of the employed ionic liquids is attributed to the adsorption of the cations of the ionic liquids onto the surface of cast iron forming a corrosion barrier. PMID:28793413

Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components

DOEpatents

Ripley, Edward B.; Hallman, Russell L.

2015-11-10

Disclosed are methods and systems for controlling of the microstructures of a soldered, brazed, welded, plated, cast, or vapor deposited manufactured component. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. Such systems and processes may be used with components consisting of only materials that are conventionally characterized as be uninfluenced by magnetic forces.

Phosphoric acid addition effect on the microstructure and magnetic properties of iron-based soft magnetic composites

NASA Astrophysics Data System (ADS)

Hsiang, Hsing-I.; Fan, Liang-Fang; Hung, Jia-Jing

2018-02-01

The phosphoric acid addition effect on phosphate insulation coating microstructure was investigated in this study. The relationships between the phosphate insulation coating microstructure and temperature resistance, corrosion resistance and magnetic properties of iron-based soft magnetic composites (SMCs) were studied by using SEM, TEM/EDS and FTIR. It was observed that an iron phosphate/carbonyl iron core/shell structure is formed with carbonyl iron powder after phosphatizing treatment. The iron phosphate phase was identified as amorphous and its thickness increased from 30 nm to 60 nm as the phosphoric acid concentration was increased from 1 wt% to 2 wt%. When the phosphoric acid concentration was further increased to 5 wt%, the excess iron phosphate precipitates between the soft magnetic composite particles. The temperature and corrosion resistance and resistivity of the iron-based SMCs can be effectively improved using carbonyl iron powders after phosphatizing. The initial permeability of the iron-based SMCs decreased with increasing phosphoric acid concentration due to thicker insulation layer formation. However, the imaginary permeability below the domain wall displacement resonance frequency decreased with increasing phosphoric acid concentration. The DC-bias superposition characteristic can also be improved by increasing the phosphoric acid concentration. Iron-based SMCs with superior temperature and corrosion resistance, initial permeability, magnetic loss and DC-bias superposition characteristics can be obtained by controlling the phosphoric acid concentration during phosphatizing to adjust the iron phosphate precipitate thickness on the iron powder surface.

Initial Microstructure Evaluation of a U3Si2 + W Fuel Pin Fabricated Via Arc Melt Gravity Drop Casting

NASA Astrophysics Data System (ADS)

Hoggan, Rita E.; Harp, Jason M.

2018-02-01

Injection casting has historically been used to fabricate metallic nuclear fuel on a large scale. Casting of intermetallic fuel forms, such as U3Si2, may be an alternative pathway for fabrication of fuel pins to powder metallurgy. To investigate casting on a small scale, arc melt gravity drop casting was employed to cast a one-off pin of U3Si2 for evaluation as a fabrication method for U3Si2 as a light water reactor fuel. The pin was sectioned and examined via optical microscopy and scanning electron microscopy equipped with energy dispersive x-ray spectroscopy (EDS). Image analysis was used to estimate the volume fraction of phase impurities as well as porosity. The primary phase determined by EDS was U3Si2 with U-O and U-Si-W phase impurities. Unusually high levels of tungsten were observed because of accidental tungsten introduction during arc melting. No significant changes in microstructure were observed after annealing a section of the pin at 800°C for 72 h. The average density of the sectioned specimens was 12.4 g/cm3 measured via Archimedes principle immersion density and He gas displacement.

Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation

PubMed Central

Shen, Yan; Yu, Baihong; Lv, Yutao; Li, Bin

2017-01-01

A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe) cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS), and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM) is compared at different nominal pressures (40~100 MPa) and temperatures (180~250 °C). With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL), the cast iron liner enters into a “polish wear” stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs. PMID:29036911

Microstructure, Tensile and Fatigue Properties of Al-5 wt.%Mg Alloy Manufactured by Twin Roll Strip Casting

NASA Astrophysics Data System (ADS)

Heo, Joon-Young; Baek, Min-Seok; Euh, Kwang-Jun; Lee, Kee-Ahn

2018-04-01

This study investigated the microstructure, tensile and fatigue properties of Al-5 wt.%Mg alloy manufactured by twin roll strip casting. Strips cast as a fabricated (F) specimen and a specimen heat treated (O) at 400 °C/5 h were produced and compared. In the F specimen, microstructural observation discovered clustered precipitates in the center area, while in the O specimen precipitates were relatively more evenly distributed. Al, Al6(Mn, Fe), Mg2Al3 and Mg2Si phases were observed. However, most of the Mg2Al3 phase in the heat-treated O specimen was dissolved. A room temperature tensile test measured yield strength of 177.7 MPa, ultimate tensile strength of 286.1 MPa and elongation of 11.1% in the F specimen and 167.7 MPa (YS), 301.5 MPa (UTS) and 24.6% (EL) in the O specimen. A high cycle fatigue test measured a fatigue limit of 145 MPa in the F specimen and 165 MPa in the O specimen, and the O specimen achieved greater fatigue properties in all fatigue stress conditions. The tensile and fatigue fracture surfaces of the above-mentioned specimens were observed, and this study attempted to investigate the tensile and fatigue deformation behavior of strip cast Al-5 wt.%Mg based on the findings.

Advanced single crystal for SSME turbopumps

NASA Technical Reports Server (NTRS)

Fritzemeier, L. G.

1989-01-01

The objective of this program was to evaluate the influence of high thermal gradient casting, hot isostatic pressing (HIP) and alternate heat treatments on the microstructure and mechanical properties of a single crystal nickel base superalloy. The alloy chosen for the study was PWA 1480, a well characterized, commercial alloy which had previously been chosen as a candidate for the Space Shuttle Main Engine high pressure turbopump turbine blades. Microstructural characterization evaluated the influence of casting thermal gradient on dendrite arm spacing, casting porosity distribution and alloy homogeneity. Hot isostatic pressing was evaluated as a means of eliminating porosity as a preferred fatigue crack initiation site. The alternate heat treatment was chosen to improve hydrogen environment embrittlement resistance and for potential fatigue life improvement. Mechanical property evaluation was aimed primarily at determining improvements in low cycle and high cycle fatigue life due to the advanced processing methods. Statistically significant numbers of tests were conducted to quantitatively demonstrate life differences. High thermal gradient casting improves as-cast homogeneity, which facilitates solution heat treatment of PWA 1480 and provides a decrease in internal pore size, leading to increases in low cycle and high cycle fatigue lives.

High coercivity microcrystalline Nd-rich Nd-Fe-Co-Al-B bulk magnets prepared by direct copper mold casting

NASA Astrophysics Data System (ADS)

Zhao, L. Z.; Hong, Y.; Fang, X. G.; Qiu, Z. G.; Zhong, X. C.; Gao, X. S.; Liu, Z. W.

2016-06-01

High coercivity Nd25Fe40Co20Al15-xBx (x=7-15) hard magnets were prepared by a simple process of injection casting. Different from many previous investigations on nanocomposite compositions, the magnets in this work contain hard magnetic Nd2(FeCoAl)14B, Nd-rich, and Nd1+ε(FeCo)4B4 phases. The magnetic properties, phase evolution, and microstructure of the as-cast and annealed magnets were investigated. As the boron content increased from 7 to 11 at%, the intrinsic coercivity Hcj of the as-cast magnet increased from 816 to 1140 kA/m. The magnets annealed at 750 °C have shown more regular and smaller grains than the as-cast alloys, especially for the x=11 alloy. The high intrinsic coercivities for the annealed alloys with x=8~11 result from the presence of small-sized grains in the microstructure. The highest Hcj of 1427 kA/m was obtained for the heat treated alloy with x=10. This work provides an alternative approach for preparing fully dense Nd-rich bulk hard magnets with relatively good properties.

THE EFFECT OF CHLORIDE AND ORTHOPHOSPHATE ON THE RELEASE OF IRON FROM A DRINKING WATER DISTRIBUTION SYSTEM CAST IRON PIPE

EPA Science Inventory

"Colored water" describes the appearance of drinking water that contains suspended particulate iron although the actual suspension color may be light yellow to red depending on water chemistry and particle properties. The release of iron from distribution system materials such a...

THE EFFECT OF CHLORIDE AND ORTHOPHOSPHATE ON THE RELEASE OF IRON FROM A DRINKING WATER DISTRIBUTION SYSTEM CAST IRON PIPE

EPA Science Inventory

Colored water" describes the appearance of drinking water that contains suspended particulate iron although the actual suspension color may be light yellow to red depending on water chemistry and particle properties. The release of iron from distribution system materials such as...

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL ...

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

22. INTERIOR VIEW WITH INTERIOR VIEW OF MOLDING SANDS CONTROL AND TEST LAB FOR UNIT NO. 2 GREY IRON DISAMATIC. SAND CASTING TECHNICIAN, ROY BATES, TESTS THE WEIGHT OF THE SAND, DRYS IT, AND WEIGHT IT AGAINST STANDARDS TO CALCULATE THE CORRECT MOISTURE NEEDED FOR DIFFERENT MOLDS. THE SAND MIX VARY WITH THE SIZE AND COMPOSITION OF THE CASTING. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

Molecular analysis of long-term biofilm formation on PVC and cast iron surfaces in drinking water distribution system.

PubMed

Liu, Ruyin; Zhu, Junge; Yu, Zhisheng; Joshi, DevRaj; Zhang, Hongxun; Lin, Wenfang; Yang, Min

2014-04-01

To understand the impacts of different plumbing materials on long-term biofilm formation in water supply system, we analyzed microbial community compositions in the bulk water and biofilms on faucets with two different materials-polyvinyl chloride (PVC) and cast iron, which have been frequently used for more than10 years. Pyrosequencing was employed to describe both bacterial and eukaryotic microbial compositions. Bacterial communities in the bulk water and biofilm samples were significantly different from each other. Specific bacterial populations colonized on the surface of different materials. Hyphomicrobia and corrosion associated bacteria, such as Acidithiobacillus spp., Aquabacterium spp., Limnobacter thiooxidans, and Thiocapsa spp., were the most dominant bacteria identified in the PVC and cast iron biofilms, respectively, suggesting that bacterial colonization on the material surfaces was selective. Mycobacteria and Legionella spp. were common potential pathogenic bacteria occurred in the biofilm samples, but their abundance was different in the two biofilm bacterial communities. In contrast, the biofilm samples showed more similar eukaryotic communities than the bulk water. Notably, potential pathogenic fungi, i.e., Aspergillus spp. and Candida parapsilosis, occurred in similar abundance in both biofilms. These results indicated that microbial community, especially bacterial composition was remarkably affected by the different pipe materials (PVC and cast iron). Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Effect of Heat Treatment Parameters on the Characteristics of Thin Wall Austempered Ductile Iron Casting

NASA Astrophysics Data System (ADS)

Upadhyaya, Rajat; Singh, K. K.; Kumar, Rajeev

2018-03-01

The technology of thin parts is necessary steps to designers for energy consuming equipment to choose accurate material based on material properties. Here austempering treatment process was utilized to acquire thin wall austempered ductile iron castings. The plate thickness (2-5) mm were austenitized at 900 °C for, 30 minutes took after by holding at 350°C, 400°C and 450°C inoculated by Ce-Ca-Al-S-O-FeSi,Zr-Mn-Ca-Al-Ba-FeSi and Sr-Al-Ca-FeSi at 0.2wt%,0.4wt% and 0.6wt% for 2,5 and 10 minutes for every temperature.The austempered samples are comparatively harder than the as-cast ductile iron plates. The micro hardness(HV20) also decreases with increase in austempering temperature for a given austempering time for thinner plates and also the micro hardness(HV20) is more for the samples treated at 350°C than those treated at 400°C and 450°C at 0.4wt% for a given austempering time. The yield strength and ultimate tensile strength of 2 mm thin wall austempered ductile iron are higher and ductility and impact strength are lower than that of as-cast 2 mm thin plate ductile iron inoculated by Ce-Ca-Al-S-O-FeSi compare to Zr-Mn-Ca-Al-Ba-FeSi and Sr-Al-Ca-FeSi at 0.4wt%. This may be attributed to the change in the structure change from ferrite-pearlite to austenite-bainite.

Phase Transformation and Creep of Mg-Al-Ca Based Die-Cast Alloys

NASA Astrophysics Data System (ADS)

Suzuki, Akane; Saddock, Nicholas D.; Jones, J. Wayne; Pollock, Tresa M.

The microstructure and microstructural stability of die-cast AC53 (Mg-5Al-3Ca) and AXJ530 (Mg-5Al-3Ca-0.15Sr) have been investigated in detail by transmission electron microscopy (TEM). Both alloys have an as-cast microstructure of α-Mg with (Mg, Al)2Ca (dihexagonal C36) eutectic at grain boundaries. During aging at 573 K, the C36 phase transforms to Al2Ca (cubic Cl5) phase. These two phases have a crystallographic orientation relationship of (0001)C36//{111}C15 and [2110]C36//[011]C15, and the transformation from C36 to C15 occurs by a shear-assisted process. Despite this change in the phase constitution, the network structure of the intermetallic compound(s) surrounding α-Mg grains is fairly stable, morphologically, even after prolonged exposure at elevated temperature. In the α-Mg matrix phase, precipitation of Al2Ca was observed after aging for 360 ks at 573 K. The precipitates are disc-shaped with a habit plane of {111}C15//(0001)α. AXJ530 shows higher creep resistance than AC53. The dislocation substructure that evolved during creep deformation was investigated in both alloys, and the basal and non-basal slip of a-dislocation and other slip modes of a+c- dislocations were observed. The relationship between creep properties and microstructure is discussed.

Low-Temperature Aging of Delta-Ferrite in 316L SS Welds; Changes in Mechanical Properties and Etching Properties

NASA Astrophysics Data System (ADS)

Abe, Hiroshi; Shimizu, Keita; Watanabe, Yutaka

Thermal aging embrittlement of LWR components made of stainless cast (e.g. CF-8 and CF-8M) is a potential degradation issue, and careful attention has been paid on it. Although welds of austenitic stainless steels (SSs) have γ-δ duplex microstructure, which is similar to that of the stainless cast, examination on thermal aging characteristics of the SS welds is very limited. In order to evaluate thermal aging behavior of weld metal of austenitic stainless steel, the 316L SS weld metal has been prepared and changes in mechanical properties and in etching properties at isothermal aging at 335°C have been investigated. The hardness of the ferrite phase has increased with aging, while the hardness of austenite phase has stayed same. It has been suggested that spinodal decomposition has occurred in δ-ferrite by the 335°C aging. The etching rates of δ-ferrite at immersion test in 5wt% hydrochloric acid solution have been also investigated using an AFM technique. The etching rate of ferrite phase has decreased consistently with the increase in hardness of ferrite phase. It has been thought that this characteristic is also caused by spinodal decomposition of ferrite into chromium-rich (α') and iron-rich (α).

[Case study of red water phenomenon in drinking water distribution systems caused by water source switch].

PubMed

Wang, Yang; Zhang, Xiao-jian; Chen, Chao; Pan, An-jun; Xu, Yang; Liao, Ping-an; Zhang, Su-xia; Gu, Jun-nong

2009-12-01

Red water phenomenon occurred in some communities of a city in China after water source switch in recent days. The origin of this red water problem and mechanism of iron release were investigated in the study. Water quality of local and new water sources was tested and tap water quality in suffered area had been monitored for 3 months since red water occurred. Interior corrosion scales on the pipe which was obtained from the suffered area were analyzed by XRD, SEM, and EDS. Corrosion rates of cast iron under the conditions of two source water were obtained by Annular Reactor. The influence of different source water on iron release was studied by pipe section reactor to simulate the distribution systems. The results indicated that large increase of sulfate concentration by water source shift was regarded as the cause of red water problem. The Larson ratio increased from about 0.4 to 1.7-1.9 and the red water problem happened in the taps of some urban communities just several days after the new water source was applied. The mechanism of iron release was concluded that the stable shell of scales in the pipes had been corrupted by this kind of high-sulfate-concentration source water and it was hard to recover soon spontaneously. The effect of sulfate on iron release of the old cast iron was more significant than its effect on enhancing iron corrosion. The rate of iron release increased with increasing Larson ratio, and the correlation of them was nonlinear on the old cast-iron. The problem remained quite a long time even if the water source re-shifted into the blended one with only small ratio of the new source and the Larson ratio reduced to about 0.6.

Microstructural characterization of as-cast biocompatible Co-Cr-Mo alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giacchi, J.V., E-mail: jgiacchi@exa.unicen.edu.ar; Instituto de Fisica de Materiales Tandil; Morando, C.N.

2011-01-15

The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by the investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants because of its high strength, good corrosion resistance and excellent biocompatibility properties. This work focuses on the resulting microstructures arising from samples poured under industrial environment conditions, of three different Co-Cr-Mo alloys. For this purpose, we used: 1) an alloy built up from commercial purity constituents, 2) a remelted alloy and 3) a certified alloy for comparison. The characterization of the samples was achieved by using opticalmore » microscopy (OM) with a colorant etchant to identify the present phases and scanning electron microscopy (SE-SEM) and energy dispersion spectrometry (EDS) techniques for a better identification. In general the as-cast microstructure is a Co-fcc dendritic matrix with the presence of a secondary phase, such as the M{sub 23}C{sub 6} carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloys. Other minority phases were also reported and their presence could be linked to the cooling rate and the manufacturing process variables and environment. - Research Highlights: {yields}The solidification microstructure of an ASTM-F75 type alloy were studied. {yields}The alloys were poured under an industrial environment. {yields}Carbides and sigma phase identified by color metallography and scanning microscopy (SEM and EDS). {yields}Two carbide morphologies were detected 'blocky type' and 'pearlite type'. {yields}Minority phases were also detected.« less

42. Casting floor, "B" furnace, pour in progress; mudgun is ...

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

42. Casting floor, "B" furnace, pour in progress; mudgun is to right of furnace; operator takes temperature of iron in trough during pout. Looking south - Rouge Steel Company, 3001 Miller Road, Dearborn, MI

Microstructural evolution during the homogenization heat treatment of 6XXX and 7XXX aluminum alloys

NASA Astrophysics Data System (ADS)

Priya, Pikee

Homogenization heat treatment of as-cast billets is an important step in the processing of aluminum extrusions. Microstructural evolution during homogenization involves elimination of the eutectic morphology by spheroidisation of the interdendritic phases, minimization of the microsegregation across the grains through diffusion, dissolution of the low-melting phases, which enhances the surface finish of the extrusions, and precipitation of nano-sized dispersoids (for Cr-, Zr-, Mn-, Sc-containing alloys), which inhibit grain boundary motion to prevent recrystallization. Post-homogenization cooling reprecipitates some of the phases, changing the flow stress required for subsequent extrusion. These precipitates, however, are deleterious for the mechanical properties of the alloy and also hamper the age-hardenability and are hence dissolved during solution heat treatment. Microstructural development during homogenization and subsequent cooling occurs both at the length scale of the Secondary Dendrite Arm Spacing (SDAS) in micrometers and dispersoids in nanometers. Numerical tools to simulate microstructural development at both the length scales have been developed and validated against experiments. These tools provide easy and convenient means to study the process. A Cellular Automaton-Finite Volume-based model for evolution of interdendritic phases is coupled with a Particle Size Distribution-based model for precipitation of dispersoids across the grain. This comprehensive model has been used to study the effect of temperature, composition, as-cast microstructure, and cooling rates during post-homogenization quenching on microstructural evolution. The numerical study has been complimented with experiments involving Scanning Electron Microscopy, Energy Dispersive Spectroscopy, X-Ray Diffraction and Differential Scanning Calorimetry and a good agreement has with numerical results has been found. The current work aims to study the microstructural evolution during homogenization heat treatment at both length scales which include the (i) dissolution and transformation of the as-cast secondary phases; (ii) precipitation of dispersoids; and (iii) reprecipitation of some of the secondary phases during post-homogenization cooling. The kinetics of the phase transformations are mostly diffusion controlled except for the eta to S phase transformation in 7XXX alloys which is interface reaction rate controlled which has been implemented using a novel approach. Recommendations for homogenization temperature, time, cooling rates and compositions are made for Al-Si-Mg-Fe-Mn and Al-Zn-Cu-Mg-Zr alloys. The numerical model developed has been applied for a through process solidification-homogenization modeling of a Direct-Chill cast AA7050 cylindrical billet to study the radial variation of microstructure after solidification, homogenization and post-homogenization cooling.

Mineral resource of the month: manganese

USGS Publications Warehouse

Corathers, Lisa A.

2012-01-01

Manganese is a silver-colored metal resembling iron and often found in conjunction with iron. The earliest-known human use of manganese compounds was in the Stone Age, when early humans used manganese dioxide as pigments in cave paintings. In ancient Rome and Egypt, people started using it to color or remove the color from glass - a practice that continued to modern times. Today, manganese is predominantly used in metallurgical applications as an alloying addition, particularly in steel and cast iron production. Steel and cast iron together provide the largest market for manganese (historically 85 to 90 percent), but it is also alloyed with nonferrous metals such as aluminum and copper. Its importance to steel cannot be overstated, as almost all types of steel contain manganese and could not exist without it.

CONTROLLING ODOROUS EMISSIONS FROM IRON FOUNDRIES

EPA Science Inventory

The report discusses the control of odorous emissions from iron foundries. he main process sources of odors in iron foundries are mold and core making, casting, and sand shakeout. he odors are usually caused by chemicals, which may be present as binders and other additives to the...

Wear Resistance of Austempered Ductile Iron with Nanosized Additives

NASA Astrophysics Data System (ADS)

Kaleicheva, J. K.; Mishev, V.

2018-01-01

The wear resistance, microstructure and mechanical properties of austempered ductile iron (ADI) with nanosized additives of cubic boron nitride cBN are investigated. Samples of ductile iron are put under austhempering at the following conditions: heating at 900°С, 1 h and isothermal retention at 280оС, 2 h and 380°С, 2 h with the aim to achieve a lower bainitic structure and an upper bainitic structure. The experimental wear testing of austempered ductile irons is performed in friction conditions of a fixed abrasive by a cinematic scheme „pin - disc” using an accelerated testing method and device. The microstructure of the ADI is investigated by metallographic and X-Ray analyses. The Vickers hardness testing and impact strength examination are carried out. The influence of the nanosized additives of cBN on the wear resistance, microstructure, impact strength and hardness of the ADI is investigated.

New sulphiding method for steel and cast iron parts

NASA Astrophysics Data System (ADS)

Tarelnyk, V.; Martsynkovskyy, V.; Gaponova, O.; Konoplianchenko, Ie; Dovzyk, M.; Tarelnyk, N.; Gorovoy, S.

2017-08-01

A new method for sulphiding steel and cast iron part surfaces by electroerosion alloying (EEA) with the use of a special electrode is proposed, which method is characterized in that while manufacturing the electrode, on its surface, in any known manner (punching, threading, pulling, etc.), there is formed at least a recess to be filled with sulfur as a consistent material, and then there is produced EEA by the obtained electrode without waiting for the consistent material to become dried.

Micromechanical Characterization and Texture Analysis of Direct Cast Titanium Alloys Strips

NASA Technical Reports Server (NTRS)

2000-01-01

This research was conducted to determine a post-processing technique to optimize mechanical and material properties of a number of Titanium based alloys and aluminides processed via Melt Overflow Solidification Technique (MORST). This technique was developed by NASA for the development of thin sheet titanium and titanium aluminides used in high temperature applications. The materials investigated in this study included conventional titanium alloy strips and foils, Ti-1100, Ti-24Al-11Nb (Alpha-2), and Ti-48Al-2Ta (Gamma). The methodology used included micro-characterization, heat-treatment, mechanical processing and mechanical testing. Characterization techniques included optical, electron microscopy, and x-ray texture analysis. The processing included heat-treatment and mechanical deformation through cold rolling. The initial as-cast materials were evaluated for their microstructure and mechanical properties. Different heat-treatment and rolling steps were chosen to process these materials. The properties were evaluated further and a processing relationship was established in order to obtain an optimum processing condition. The results showed that the as-cast material exhibited a Widmanstatten (fine grain) microstructure that developed into a microstructure with larger grains through processing steps. The texture intensity showed little change for all processing performed in this investigation.

Effects of N/C Ratio on Solidification Behaviors of Novel Nb-Bearing Austenitic Heat-Resistant Cast Steels for Exhaust Components of Gasoline Engines

NASA Astrophysics Data System (ADS)

Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

2017-03-01

In order to comply with more stringent environmental and fuel consumption regulations, novel Nb-bearing austenitic heat-resistant cast steels that withstand exhaust temperatures as high as 1,323 K (1,050 °C) is urgently demanded from automotive industries. In the current research, the solidification behavior of these alloys with variations of N/C ratio is investigated. Directional solidification methods were carried out to examine the microstructural development in mushy zones. Computational thermodynamic calculations under partial equilibrium conditions were performed to predict the solidification sequence of different phases. Microstructural characterization of the mushy zones indicates that N/C ratio significantly influenced the stability of γ-austenite and the precipitation temperature of NbC/Nb(C,N), thereby altering the solidification path, as well as the morphology and distribution of NbC/Nb(C,N) and γ-ferrite. The solidification sequence of different phases predicted by thermodynamic software agreed well with the experimental results, except the specific precipitation temperatures. The generated data and fundamental understanding will be helpful for the application of computational thermodynamic methods to predict the as-cast microstructure of Nb-bearing austenitic heat-resistant steels.

46 CFR 56.60-15 - Ductile iron.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A 395 (incorporated by reference, see 46 CF...

46 CFR 56.60-15 - Ductile iron.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A 395 (incorporated by reference, see 46 CF...

46 CFR 56.60-15 - Ductile iron.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A 395 (incorporated by reference, see 46 CF...

46 CFR 56.60-15 - Ductile iron.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A 395 (incorporated by reference, see 46 CF...

46 CFR 56.60-15 - Ductile iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Ductile iron. 56.60-15 Section 56.60-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Materials § 56.60-15 Ductile iron. (a) Ductile cast iron components made of material conforming to ASTM A 395 (incorporated by reference, see 46 CF...

Microstructure and properties of pure iron/copper composite cladding layers on carbon steel

NASA Astrophysics Data System (ADS)

Wan, Long; Huang, Yong-xian; Lü, Shi-xiong; Huang, Ti-fang; Lü, Zong-liang

2016-08-01

In the present study, pure iron/copper composite metal cladding was deposited onto carbon steel by tungsten inert gas welding. The study focused on interfacial morphological, microstructural, and mechanical analyses of the composite cladding layers. Iron liquid-solid-phase zones were formed at copper/steel and iron interfaces because of the melting of the steel substrate and iron. Iron concentrated in the copper cladding layer was observed to exhibit belt, globule, and dendrite morphologies. The appearance of iron-rich globules indicated the occurrence of liquid phase separation (LPS) prior to solidification, and iron-rich dendrites crystallized without the occurrence of LPS. The maximum microhardness of the iron/steel interface was lower than that of the copper/steel interface because of the diffusion of elemental carbon. All samples fractured in the cladding layers. Because of a relatively lower strength of the copper layer, a short plateau region appeared when shear movement was from copper to iron.

Geopolymer Porous Nanoceramics for Structural, for Smart and Thermal Shock Resistant Applications

DTIC Science & Technology

2011-02-02

porous membranes and foams, ceramic armor composites , iron-based geopolymer analogues, geopolymer composites reinforced with chopped polypropylene...the microstructure of geopolymers and geopolymer composites , as fabricated and upon conversion to ceramics with heating. The microstructure consisted...porous membranes and foams, ceramic armor composites , iron-based geopolymer analogues, geopolymer composites reinforced with chopped polypropylene or

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ahmed, A.; Chadwick, T.; Makhlouf, M.

This paper deals with the effects of various solidification variables such as cooling rate, temperature gradient, solidification rate, etc. on the microstructure and shrinkage defects in aluminum alloy (A356) castings. The effects are first predicted using commercial solidification modeling softwares and then verified experimentally. For this work, the authors are considering a rectangular bar cast in a sand mold. Simulation is performed using SIMULOR, a finite volume based casting simulation program. Microstructural variables such as dendritic arm spacing (DAS) and defects (percentage porosity) are calculated from the temperature fields, cooling rate, solidification time, etc. predicted by the computer softwares. Themore » same variables are then calculated experimentally in the foundry. The test piece is cast in a resin (Sodium Silicate) bonded sand mold and the DAS and porosity variables are calculated using Scanning Electron Microscopy and Image Analysis. The predictions from the software are compared with the experimental results. The results are presented and critically analyzed to determine the quality of the predicted results. The usefulness of the commercial solidification modeling softwares as a tool for the foundry are also discussed.« less

Microstructural and mechanical investigation of aluminium alloy (Al 1050) melted by microwave hybrid heating

NASA Astrophysics Data System (ADS)

Shashank Lingappa, M.; Srinath, M. S.; Amarendra, H. J.

2017-07-01

Microwave processing of metals is an emerging area. Melting of bulk metallic materials through microwave irradiation is still immature. In view of this, the present paper discusses the melting of bulk Al 1050 metallic material through microwave irradiation. The melting process is carried out successfully in a domestic microwave oven with 900 W power at 2450 MHz frequency. Metallurgical and mechanical characterization of the processed and as-received material is carried out. Aluminium phase is found to be dominant in processed material when tested through x-ray diffraction (XRD). Microstructure study of as-cast metal through scanning electron microscopy (SEM) reveals the formation of uniform hexagonal grain structure free from pores and cavities. The average tensile strength of the cast material is found to be around 21% higher, when compared to as-received material. Vickers’ microhardness of the as-cast metal is measured and is 10% higher than that of the as-received metal. Radiography on as-cast metal shows no significant defects. Al 1050 material melted through microwave irradiation has exhibited superior properties than the as-received Al 1050.

Microstructure, Tensile and Creep Properties of Ta20Nb20Hf20Zr20Ti20 High Entropy Alloy

PubMed Central

Larianovsky, Natalya; Katz-Demyanetz, Alexander; Eshed, Eyal; Regev, Michael

2017-01-01

This paper examines the microstructure and mechanical properties of Ta20Nb20Hf20Zr20Ti20. Two casting processes, namely, gravity casting and suction-assisted casting, were applied, both followed by Hot Isostatic Pressing (HIP). The aim of the current study was to investigate the creep and tensile properties of the material, since the literature review revealed no data whatsoever regarding these properties. The main findings are that the HIP process is responsible for the appearance of a Hexagonal Close Packed (HCP) phase that is dispersed differently in these two castings. The HIP process also led to a considerable increase in the mechanical properties of both materials under compression, with values found to be higher than those reported in the literature. Contrary to the compression properties, both materials were found to be highly brittle under tension, either during room temperature tension tests or creep tests conducted at 282 °C. Fractography yielded brittle fracture without any evidence of plastic deformation prior to fracture. PMID:28773245

Chemically bonded phosphate ceramics of trivalent oxides of iron and manganese

DOEpatents

Wagh, Arun S.; Jeong, Seung-Young

2002-01-01

A new method for combining elemental iron and other metals to form an inexpensive ceramic to stabilize arsenic, alkaline red mud wastes, swarfs, and other iron or metal-based additives, to create products and waste forms which can be poured or dye cast.

UPTAKE OF HEAVY METALS IN BATCH SYSTEMS BY A RECYCLED IRON-BEARING MATERIAL

EPA Science Inventory

An iron-bearing material deriving from surface finishing operations in the manufacturing of cast-iron components demonstrates potential for removal of heavy metals from aqueous waste streams. Batch isotherm and rate experiments were conducted for uptake of cadmium, zinc, and lead...

Influence of Cu on modifying the beta phase and enhancing the mechanical properties of recycled Al-Si-Fe cast alloys.

PubMed

Basak, C B; Babu, N Hari

2017-07-18

High iron impurity affects the castability and the tensile properties of the recycled Al-Si alloys due to the presence of the Fe containing intermetallic β-Al 9 Fe 2 Si 2 phase. To date only Mn addition is known to transform the β-Al 9 Fe 2 Si 2 phase in the Al-Si-Fe system. However, for the first time, as reported here, it is shown that β-phase transforms to the ω-Al 7 Cu 2 Fe phase in the presence of Cu, after solutionization at 793 K. The ω-phase decomposes below 673 K resulting into the formation of θ-Al 2 Cu phase. However, the present thermodynamic description of the Al-Si-Fe-Cu system needs finer tuning to accurately predict the stability of the ω-phase in these alloys. In the present study, an attempt was made to enhance the strength of Al-6wt%Si-2wt%Fe model recycled cast alloy with different amount of Cu addition. Microstructural and XRD analysis were carried out in detail to show the influence of Cu and the stability range of the ω-phase. Tensile properties and micro-hardness values are also reported for both as-cast and solutionized alloys with different amount of Cu without and with ageing treatment at 473 K. The increase in strength due to addition of Cu, in Fe-rich Al-Si alloys is promising from the alloy recyclability point of view.

Increased corrosion resistance of the AZ80 magnesium alloy by rapid solidification.

PubMed

Aghion, E; Jan, L; Meshi, L; Goldman, J

2015-11-01

Magnesium (Mg) and Mg-alloys are being considered as implantable biometals. Despite their excellent biocompatibility and good mechanical properties, their rapid corrosion is a major impediment precluding their widespread acceptance as implantable biomaterials. Here, we investigate the potential for rapid solidification to increase the corrosion resistance of Mg alloys. To this end, the effect of rapid solidification on the environmental and stress corrosion behavior of the AZ80 Mg alloy vs. its conventionally cast counterpart was evaluated in simulated physiological electrolytes. The microstructural characteristics were examined by optical microscopy, SEM, TEM, and X-ray diffraction analysis. The corrosion behavior was evaluated by immersion, salt spraying, and potentiodynamic polarization. Stress corrosion resistance was assessed by Slow Strain Rate Testing. The results indicate that the corrosion resistance of rapidly solidified ribbons is significantly improved relative to the conventional cast alloy due to the increased Al content dissolved in the α-Mg matrix and the correspondingly reduced presence of the β-phase (Mg17 Al12 ). Unfortunately, extrusion consolidated solidified ribbons exhibited a substantial reduction in the environmental performance and stress corrosion resistance. This was mainly attributed to the detrimental effect of the extrusion process, which enriched the iron impurities and increased the internal stresses by imposing a higher dislocation density. In terms of immersion tests, the average corrosion rate of the rapidly solidified ribbons was <0.4 mm/year compared with ∼2 mm/year for the conventionally cast alloy and 26 mm/year for the rapidly solidified extruded ribbons. © 2014 Wiley Periodicals, Inc.

Effect of heavy ion irradiation on microstructural evolution in CF8 cast austenitic stainless steel

DOE PAGES

Chen, Wei-Ying; Li, Meimei; Kirk, Marquis A.; ...

2015-08-21

The microstructural evolution in ferrite and austenitic in cast austenitic stainless steel (CASS) CF8, as received or thermally aged at 400 °C for 10,000 h, was followed under TEM with in situ irradiation of 1 MeV Kr ions at 300 and 350 °C to a fluence of 1.9 × 10 15 ions/cm 2 (~3 dpa) at the IVEM-Tandem Facility. For the unaged CF8, the irradiation-induced dislocation loops appeared at a much lower dose in the austenite than in the ferrite. At the end dose, the austenite formed a well-developed dislocation network microstructure, while the ferrite exhibited an extended dislocation structuremore » as line segments. Compared to the unaged CF8, the aged specimen appeared to have lower rate of damage accumulation. The rate of microstructural evolution under irradiation in the ferrite was significantly lower in the aged specimen than in the unaged. Finally, we attributed this difference to the different initial microstructures in the unaged and aged specimens, which implies that thermal aging and irradiation are not independent but interconnected damage processes.« less

High-Throughput Study of Diffusion and Phase Transformation Kinetics of Magnesium-Based Systems for Automotive Cast Magnesium Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Alan A; Zhao, Ji-Cheng; Riggi, Adrienne

The objective of the proposed study is to establish a scientific foundation on kinetic modeling of diffusion, phase precipitation, and casting/solidification, in order to accelerate the design and optimization of cast magnesium (Mg) alloys for weight reduction of U.S. automotive fleet. The team has performed the following tasks: 1) study diffusion kinetics of various Mg-containing binary systems using high-throughput diffusion multiples to establish reliable diffusivity and mobility databases for the Mg-aluminum (Al)-zinc (Zn)-tin (Sn)-calcium (Ca)-strontium (Sr)-manganese (Mn) systems; 2) study the precipitation kinetics (nucleation, growth and coarsening) using both innovative dual-anneal diffusion multiples and cast model alloys to provide largemore » amounts of kinetic data (including interfacial energy) and microstructure atlases to enable implementation of the Kampmann-Wagner numerical model to simulate phase transformation kinetics of non-spherical/non-cuboidal precipitates in Mg alloys; 3) implement a micromodel to take into account back diffusion in the solid phase in order to predict microstructure and microsegregation in multicomponent Mg alloys during dendritic solidification especially under high pressure die-casting (HPDC) conditions; and, 4) widely disseminate the data, knowledge and information using the Materials Genome Initiative infrastructure (http://www.mgidata.org) as well as publications and digital data sharing to enable researchers to identify new pathways/routes to better cast Mg alloys.« less

Thermophysical and Electronic Properties of Foreign Nonstainless Alloy Steels, Carbon Steels, and Cast Irons, A Comprehensive Survey of the World Literature,

DTIC Science & Technology

1981-11-01

PHYSICAL P;OPkRTIES CF ANTIMONY CAST IRONS. LONDON UNIV.. LONOCN. ENGLAND, PH.O. THESIS PI#UI.,V M K VAfAGIN MA M 1-79 1938 RU.IAN ATIAb PUOflsCTION 1...SURFACE TENCIC. PF LYCUIE ’ CFt AELC5. i𔄀-iC, ±9717 FOR OMZINAL ZEE T74161 I K.INl. V. CC. ANT. CONE. C. TECHP-OL. IRON STEEL IT ?4󈧏 1FT. 1 1 ~-i 971...978. A7 .-IG- PRESSURES 4143 TME EAIHS-.S COME. T4’%Lov. G. 10950617 Ur.;V. ;ALIFORNIA, LIVERMORE. PP-. JI. THESIS EFFECT OF TEMPERING ON GNINDING

A new large-volume metal reference standard for radioactive waste management.

PubMed

Tzika, F; Hult, M; Stroh, H; Marissens, G; Arnold, D; Burda, O; Kovář, P; Suran, J; Listkowska, A; Tyminski, Z

2016-03-01

A new large-volume metal reference standard has been developed. The intended use is for calibration of free-release radioactivity measurement systems and is made up of cast iron tubes placed inside a box of the size of a Euro-pallet (80 × 120 cm). The tubes contain certified activity concentrations of (60)Co (0.290 ± 0.006 Bq g(-1)) and (110m)Ag (3.05 ± 0.09 Bq g(-1)) (reference date: 30 September 2013). They were produced using centrifugal casting from a smelt into which (60)Co was first added and then one piece of neutron irradiated silver wire was progressively diluted. The iron castings were machined to the desirable dimensions. The final material consists of 12 iron tubes of 20 cm outer diameter, 17.6 cm inner diameter, 40 cm length/height and 245.9 kg total mass. This paper describes the reference standard and the process of determining the reference activity values. © The Author 2015. Published by Oxford University Press.

Freeze cast porous barium titanate for enhanced piezoelectric energy harvesting

NASA Astrophysics Data System (ADS)

Roscow, J. I.; Zhang, Y.; Kraśny, M. J.; Lewis, R. W. C.; Taylor, J.; Bowen, C. R.

2018-06-01

Energy harvesting is an important developing technology for a new generation of self-powered sensor networks. This paper demonstrates the significant improvement in the piezoelectric energy harvesting performance of barium titanate by forming highly aligned porosity using freeze casting. Firstly, a finite element model demonstrating the effect of pore morphology and angle with respect to poling field on the poling behaviour of porous ferroelectrics was developed. A second model was then developed to understand the influence of microstructure-property relationships on the poling behaviour of porous freeze cast ferroelectric materials and their resultant piezoelectric and energy harvesting properties. To compare with model predictions, porous barium titanate was fabricated using freeze casting to form highly aligned microstructures with excellent longitudinal piezoelectric strain coefficients, d 33. The freeze cast barium titanate with 45 vol.% porosity had a d 33  =  134.5 pC N‑1 compared to d 33  =  144.5 pC N‑1 for dense barium titanate. The d 33 coefficients of the freeze cast materials were also higher than materials with uniformly distributed spherical porosity due to improved poling of the aligned microstructures, as predicted by the models. Both model and experimental data indicated that introducing porosity provides a large reduction in the permittivity () of barium titanate, which leads to a substantial increase in energy harvesting figure of merit, , with a maximum of 3.79 pm2 N‑1 for barium titanate with 45 vol.% porosity, compared to only 1.40 pm2 N‑1 for dense barium titanate. Dense and porous barium titanate materials were then used to harvest energy from a mechanical excitation by rectification and storage of the piezoelectric charge on a capacitor. The porous barium titanate charged the capacitor to a voltage of 234 mV compared to 96 mV for the dense material, indicating a 2.4-fold increase that was similar to that predicted by the energy harvesting figures of merit.

Irradiation Microstructure of Austenitic Steels and Cast Steels Irradiated in the BOR-60 Reactor at 320°C

NASA Astrophysics Data System (ADS)

Yang, Yong; Chen, Yiren; Huang, Yina; Allen, Todd; Rao, Appajosula

Reactor internal components are subjected to neutron irradiation in light water reactors, and with the aging of nuclear power plants around the world, irradiation-induced material degradations are of concern for reactor internals. Irradiation-induced defects resulting from displacement damage are critical for understanding degradation in structural materials. In the present work, microstructural changes due to irradiation in austenitic stainless steels and cast steels were characterized using transmission electron microscopy. The specimens were irradiated in the BOR-60 reactor, a fast breeder reactor, up to 40 dpa at 320°C. The dose rate was approximately 9.4x10-7 dpa/s. Void swelling and irradiation defects were analyzed for these specimens. A high density of faulted loops dominated the irradiated-altered microstructures. Along with previous TEM results, a dose dependence of the defect structure was established at 320°C.

40 CFR 420.60 - Applicability; description of the continuous casting subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING POINT SOURCE CATEGORY... owned treatment works resulting from the continous casting of molten steel into intermediate or semi-finished steel products through water cooled molds. ...

Microstructure, Mechanical and Surface Morphological Properties of Al5Ti5Cr Master Alloy as Friction Material Prepared by Stir Die Casting

NASA Astrophysics Data System (ADS)

Ahmed, Syed Faisal; Srivastava, Sanjay; Agarwal, Alka Bani

2018-04-01

Metal matrix composite offers outstanding properties for better performance of disc brakes. In the present study, the composite of AlTiCr master alloy was prepared by stir die casting method. The developed material was reinforced with (0-10 wt%) silicon carbide (SiC) and boron carbide (B4C). The effects of SiC reinforcement from 0 to 10 wt% on mechanical, microstructure and surface morphological properties of Al MMC was investigated and compared with B4C reinforcement. Physical properties like density and micro Vickers hardness number show an increasing trend with an increase in the percentage of SiC and B4C reinforcement. Mechanical properties viz. UTS, yield strength and percentage of elongation are improved with increasing the fraction of reinforcement. The surface morphology and phase were identified from scanning electron microscopy (SEM) and X-ray diffraction analysis and the oxidized product formed during the casting was investigated by Fourier transformation infrared spectroscopy. This confirms the presence of crystallization of corundum (α-Al2O3) in small traces as one of the alumina phases, within casting sample. Micro-structural characterization by SEM depicted that the particles tend to be more agglomerated more and more with the percentage of the reinforcement. The AFM results reveal that the surface roughness value shows a decreasing trend with SiC reinforcement while roughness increases with increase the percentage of B4C.

Microstructure of Haynes® 282® Superalloy after Vacuum Induction Melting and Investment Casting of Thin-Walled Components.

PubMed

Matysiak, Hubert; Zagorska, Malgorzata; Andersson, Joel; Balkowiec, Alicja; Cygan, Rafal; Rasinski, Marcin; Pisarek, Marcin; Andrzejczuk, Mariusz; Kubiak, Krzysztof; Kurzydlowski, Krzysztof J

2013-11-01

The aim of this work was to characterize the microstructure of the as-cast Haynes ® 282 ® alloy. Observations and analyses were carried out using techniques such as X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray spectroscopy (EDS), wave length dispersive X-ray spectroscopy (WDS), auger electron spectroscopy (AES) and electron energy-loss spectrometry (EELS). The phases identified in the as-cast alloy include: γ (gamma matrix), γ' (matrix strengthening phase), (TiMoCr)C (primary carbide), TiN (primary nitride), σ (sigma-TCP phase), (TiMo)₂SC (carbosulphide) and a lamellar constituent consisting of molybdenum and chromium rich secondary carbide phase together with γ phase. Within the dendrites the γ' appears mostly in the form of spherical, nanometric precipitates (74 nm), while coarser (113 nm) cubic γ' precipitates are present in the interdendritic areas. Volume fraction content of the γ' precipitates in the dendrites and interdendritic areas are 9.6% and 8.5%, respectively. Primary nitrides metallic nitrides (MN), are homogeneously dispersed in the as-cast microstructure, while primary carbides metallic carbides (MC), preferentially precipitate in interdendritic areas. Such preference is also observed in the case of globular σ phase. Lamellar constituents characterized as secondary carbides/γ phases were together with (TiMo)₂SC phase always observed adjacent to σ phase precipitates. Crystallographic relations were established in-between the MC, σ, secondary carbides and γ/γ' matrix.

Effects of Yttrium Addition on Microstructure and Mechanical Properties of AZ80-2Sn Magnesium Alloys

NASA Astrophysics Data System (ADS)

Xue, Hansong; Yang, Gang; Li, Di; Xing, Zhihui; Pan, Fusheng

2015-12-01

The effects of Y on microstructure and mechanical properties of as-cast AZ80-2Sn magnesium alloys were investigated by optical microscopy, scanning electron microscopy and X-ray diffraction. Y addition not only changes the as-cast microstructure but also influences the mechanical properties of AZ80-2Sn alloy. Unmodified AZ80-2Sn alloys under casting state show that Mg17Al12 eutectic phase is semicontinuous and reticulated shape and distributes mainly at grain boundaries. Moreover, there are numerous Mg2Sn precipitate particles dispersing in Mg17Al12 eutectic phases. Y addition to as-cast AZ80-2Sn alloys has an important influence on the precipitation phase. But there has no obvious effect on grain refinement with Y addition. The results show that the AZ80-2Sn alloys with variable Y contents all contain Al2Y phase. By adding Y, the amount of Mg17Al12 is decreased and the dimension of that is reduced. Mg17Al12 eutectic phase turns to discontinuous, and the more disperse phases occur with the increase of Y content. The tensile tests indicate that a minor addition of Y can contribute to the formation of the dispersed small polygonal Al2Y particles and the improvement in the room-temperature strength. However, excessive Y addition leads to the coarsening of Al2Y phases, and thus results in the decline of strength and ductility.

Fouling communities and degradation of archeological metals in the coastal sea of the Southwestern Gulf of Mexico.

PubMed

López Garrido, Pedro H; González-Sánchez, J; Escobar Briones, Elva

2015-01-01

Corrosion and biofouling phenomena of cast iron and brass were evaluated under natural conditions to determine the degradation process of archeological artifacts. Field exposure studies of experimental materials were conducted over 15 months at an offshore position in the sea of Campeche in the Gulf of Mexico. Corrosion was determined by gravimetric measurements. The community structure of the benthic assemblage inhabiting the surfaces of both materials was evaluated. A total of 53 species was identified. The community in both cases was composed of a small number of species. Encrusting, attached and erect life forms were dominant on iron. Attached life forms were dominant on brass. Biofouling produced a decrease in the weight loss measurements of cast iron samples. Biofouling provided a beneficial factor for in situ preservation of iron archeological artifacts in wreck sites.

Development of Advanced High Strength Cast Alloys for Heavy Duty Engines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barlow, James

Gray iron has been the primary alloy for heavy duty diesel engine core castings for decades. During recent decades the limitations of gray iron have been reached in some applications, leading to the use of compacted graphite iron in engine blocks and heads. Caterpillar has had compacted graphite designs in continuous production since the late 1980’s. Due to the drive for higher power density, decreased emissions and increased fuel economy, cylinder pressures and temperatures continue to increase. Currently no viable replacement for today’s compacted graphite irons exist at an acceptable cost level. This project explored methods to develop the nextmore » generation of heavy duty diesel engine materials as well as demonstrated some results on new alloy designs although cost targets will likely not be met.« less

Effect of severe plastic deformation on microstructure of squeeze-cast magnesium alloy AZ31 plate

NASA Astrophysics Data System (ADS)

Fong, Kai Soon; Tan, Ming Jen; Atsushi, Danno; Chua, Beng Wah; Ho, Meng Kwong

2016-10-01

High cost and poor room temperature formability of magnesium alloy sheet are the key factors that limit its application as a feedstock material for press forming. Production of Mg plates by squeeze casting with further processing by severe plastic deformation (SPD) is a potential method to reduce cost and improve formability. In this study, AZ31 Mg plate of dimension 96×96×4 mm was successfully produced by squeeze casting, using a novel melt transfer technique, at a forging force and speed of 180 Ton and 200 mm/sec respectively. The effect of severe plastic deformation (SPD) using groove pressing on the mechanical properties of squeeze-casted Mg plate after partial homogenization was subsequently investigated. Observation of the microstructure after two cycles of groove pressing, under decreasing temperature from 543K to 493K, shows a significant grain refinement from 39 to 4.7 µm. The Vickers hardness increased by approximately 25% from 56 to 74.1 which suggests an improvement in mechanical strength as a result of both the grain refinement and work hardening. The result shows that squeeze casting combined with groove pressing is potentially an effective method for preparation of thin magnesium alloy plate with fine-grained structure and improved mechanical properties.

Microstructure, microstructural stability and mechanical properties of sand-cast Mg–4Al–4RE alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rzychoń, Tomasz, E-mail: tomasz.rzychon@polsl.pl; Kiełbus, Andrzej; Lityńska-Dobrzyńska, Lidia

2013-09-15

This paper presents a methodology for assessing the phase composition and the results of structural stability tests of the sand-cast Mg–4Al–4RE alloy after annealing it at 175 and 250 °C for 3000 h. The microstructure was analyzed with optical, scanning electron, and transmission electron microscopy. The phase composition was determined with X-ray diffraction. The structure of the Mg–4Al–4RE (AE44) alloy is composed of large grains of α-Mg solid solution, needle-shaped precipitates of the Al{sub 11}RE{sub 3}phase, polyhedral precipitates of the Al{sub 2}RE phase and Al{sub 10}RE{sub 2}Mn{sub 7} phase. After annealing at 175 °C for 3000 h, no changes inmore » the alloy structure are observed, whereas after annealing at 250 °C the precipitates of the Al{sub 11}RE{sub 3} phase are found to be in the initial stages of spheroidization. The coarse-grained structure and unfavorable morphology of the intermetallic phases in the sand-cast AE44 alloy, which are caused by low solidification rates, result in low creep resistance up to 200 °C and low mechanical properties at ambient temperature and at 175 °C. - Highlights: • Complement the knowledge about the microstructure of Mg-Al-RE alloys. • Clarify the mechanism of formation of Mg17Al12 phase above 180 °C. • Applying a chemical dissolution of the α-Mg in order to phase identification. • Applying a statistical test to assess the spheroidization of precipitates. • Quantitative description of microstructure of Mg-Al-RE alloys.« less

Phase-field modelling of microstructure formation during the solidification of continuously cast low carbon and HSLA steels

NASA Astrophysics Data System (ADS)

Böttger, B.; Apel, M.; Santillana, B.; Eskin, D. G.

2012-07-01

Cracking in continuous casting of steels has been one of the main problems for decades. Many of the cracks that occur during solidification are hot tears. To better understand the factors leading to this defect, microstructure formation is simulated for a low carbon (LCAK) and two high strength low alloyed (HSLA) steel grades during the initial stage of the process where the first solidified shell is formed inside the mould and where breakouts typically occur. 2D simulation is performed using the multiphase-field software MICRESS [1], which is coupled to the thermodynamic database TCFE6 [2] and the mobility database MOB2 [2], taking into account all elements which may have a relevant effect on the mechanical properties and structure formation during or subsequent to solidification. The use of a moving-frame boundary condition allows travelling through the entire solidification history starting from the slab surface, and tracking the morphology changes during growth of the shell. A heterogeneous nucleation model is included to permit the description of morphological transitions between the initial solidification and the subsequent columnar growth region. Furthermore, a macroscopic one-dimensional temperature solver is integrated to account for the transient and nonlinear temperature field during the initial stage of continuous casting. The external heat flux boundary conditions for this process were derived from thermal process data of the industrial slab caster. The simulation results for the three steel grades have been validated by thickness measurements of breakout shells and microstructure observation of the corresponding grades. Furthermore, the primary dendrite spacing has been measured across the whole thickness of the shell and compared with the simulated microstructures. Significant microstructure differences between the steel grades are discussed and correlated with their hot-cracking behavior.

Combined effects of cerium and cooling rate on microstructure and mechanical properties of AZ91 magnesium alloy

NASA Astrophysics Data System (ADS)

Cai, Huisheng; Guo, Feng; Su, Juan

2018-01-01

The specimens of AZ91-xCe(x = 0, 0.3, 0.6, 0.9, 1.2, mass fraction wt%) with different thicknesses were prepared by die casting process, their as-cast microstructure and room temperature mechanical properties were investigated to analyze the change rule of microstructure and mechanical properties of AZ91 magnesium alloy under combined effects of cooling rate and cerium content. The results show that, the microstructure and mechanical properties of AZ91 magnesium alloy were twofold influenced by cooling rate and cerium content. With the increase of cooling rate and Ce content, the average as-cast grain size is evidently refined; the amount of β-Mg17Al12 decreases and distribution becomes discrete. While decreasing cooling rate or increasing Ce content, Al4Ce phase is more and the morphology tends to strip and needle from granular and short rod-like. The tensile strength and elongation of AZ91-xCe magnesium alloy are improved with increasing cooling rate. With the increase of Ce content, the tensile strength and elongation of AZ91-xCe magnesium alloy increased first and decreased afterwards, besides the action of Ce to improve tensile strength and elongation is more evident under faster cooling rate. Mechanical properties of samples are optimal in this work, when Ce content is 0.96% and cooling rate is 39.6 K s-1, tensile strength (259.7 MPa) and elongation (5.5%) are reached maximum, respectively.

A new magnesium alloy system: TEXAS

NASA Astrophysics Data System (ADS)

Wiese, Björn; Mendis, Chamini; Blawert, Carsten; Nyberg, Eric; Kainer, Karl Ulrich; Hort, Norbert

A new TEXAS alloy system (Mg-Sn-Nd-Ca-Al-Si) is presented in order to extend the range of applications for magnesium alloys. The alloy has been produced by permanent mould direct chill casting, a process that provides a homogenous distribution of alloying elements throughout the entire casting. This work presents microstructural features and a new Mg-Sn-Ca phase with the morphology of hexagonal platelets. Additionally mechanical properties and the corrosion behaviour of TEXAS alloys are presented in as cast and heat treated conditions.

Understanding the Interaction between a Steel Microstructure and Hydrogen

PubMed Central

Depover, Tom; Laureys, Aurélie; Wallaert, Elien

2018-01-01

The present work provides an overview of the work on the interaction between hydrogen (H) and the steel’s microstructure. Different techniques are used to evaluate the H-induced damage phenomena. The impact of H charging on multiphase high-strength steels, i.e., high-strength low-alloy (HSLA), transformation-induced plasticity (TRIP) and dual phase (DP) is first studied. The highest hydrogen embrittlement resistance is obtained for HSLA steel due to the presence of Ti- and Nb-based precipitates. Generic Fe-C lab-cast alloys consisting of a single phase, i.e., ferrite, bainite, pearlite or martensite, and with carbon contents of approximately 0, 0.2 and 0.4 wt %, are further considered to simplify the microstructure. Finally, the addition of carbides is investigated in lab-cast Fe-C-X alloys by adding a ternary carbide forming element to the Fe-C alloys. To understand the H/material interaction, a comparison of the available H trapping sites, the H pick-up level and the H diffusivity with the H-induced mechanical degradation or H-induced cracking is correlated with a thorough microstructural analysis. PMID:29710803

Effects of the Strain Rate and Temperature on the Microstructural Evolution of Twin-Rolled Cast Wrought AZ31B Alloys Sheets

NASA Astrophysics Data System (ADS)

Rodriguez, A. K.; Kridli, G.; Ayoub, G.; Zbib, H.

2013-10-01

This article investigates the effects of the strain rate and temperature on the microstructural evolution of twin-rolled cast wrought AZ31B sheets. This was achieved through static heating and through tensile test performed at strain rates from 10-4 to 10-1 s-1 and temperatures between room temperature (RT) and 300 °C. While brittle fracture with high stresses and limited elongation was observed at the RT, ductile behavior was obtained at higher temperatures with low strain rates. The strain rate sensitivity and activation energy calculations indicate that grain boundary diffusion and lattice diffusion are the two rate-controlling mechanisms at warm and high temperatures, respectively. An analysis of the evolution of the microstructure provided some indications of the most probable deformation mechanisms in the material: twinning operates at lower temperatures, and dynamic recrystallization dominates at higher temperatures. The static evolution of the microstructure was also studied, proving a gradual static grain growth of the AZ31B with annealing temperature and time.

Microstructure and degradation performance of biodegradable Mg-Si-Sr implant alloys.

PubMed

Gil-Santos, Andrea; Marco, Iñigo; Moelans, Nele; Hort, Norbert; Van der Biest, Omer

2017-02-01

In this work the microstructure and degradation behavior of several as-cast alloy compositions belonging to the Mg rich corner of the Mg-Si-Sr system are presented and related. The intermetallic phases are identified and analyzed describing the microstructure evolution during solidification. It is intended in this work to obtain insight in the behavior of the ternary alloys in in vitro tests and to analyze the degradation behavior of the alloys under physiologically relevant conditions. The as-cast specimens have been exposed to immersion tests, both mass loss (ML) and potentiodynamic polarization (PDP). The degradation rate (DR) have been assessed and correlated to microstructure features, impurity levels and alloy composition. The initial reactions resulted to be more severe while the degradation stabilizes with time. A higher DR is related with a high content of the Mg 17 Sr 2 phase and with the presence of coarse particles of the intermetallics Mg 2 Si, MgSiSr and MgSi 2 Sr. Specimens with a higher DR typically have higher levels of impurities and alloy contents. Copyright © 2016 Elsevier B.V. All rights reserved.

Computational Multi-Scale Modeling of the Microstructure and Segregation of Cast Mg Alloys at Low Superheat

NASA Astrophysics Data System (ADS)

Nastac, Laurentiu; El-Kaddah, Nagy

It is well known that casting at low superheat has a strong influence on the solidification structures of the cast alloy. Recent studies on casting magnesium AZ alloys at low superheat using the Magnetic Suspension Melting (MSM) process have shown that the cast alloy exhibit a fine globular grain structure, and the grain size depend on the cooling rate. This paper describes a stochastic mesoscopic model for predicting the grain structure and segregation in cast alloys at low superheat. This model was applied to predict the globular solidification morphology and solute redistribution of Al in cast Mg AZ31B alloy at different cooling rates. The predictions were found to be in good agreement with the observed grain structure and Al segregation. This makes the model a very useful tool for optimizing the solidification structure of cast magnesium alloys.

46 CFR 162.018-3 - Materials.

Code of Federal Regulations, 2011 CFR

2011-10-01

... where susceptible to attack by the lading. (d) The seats and disks shall be of suitable corrosion resistant material. Seats and disks of cast iron or malleable iron shall not be used. Springs shall be of...

46 CFR 162.018-3 - Materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

... resistant material. Seats and disks of cast iron or malleable iron shall not be used. Springs shall be of best quality spring steel consistent with the design of the valve and the service requirement. [CGFR 52...

46 CFR 162.018-3 - Materials.

Code of Federal Regulations, 2012 CFR

2012-10-01

... resistant material. Seats and disks of cast iron or malleable iron shall not be used. Springs shall be of best quality spring steel consistent with the design of the valve and the service requirement. [CGFR 52...

46 CFR 162.018-3 - Materials.

Code of Federal Regulations, 2014 CFR

2014-10-01

... resistant material. Seats and disks of cast iron or malleable iron shall not be used. Springs shall be of best quality spring steel consistent with the design of the valve and the service requirement. [CGFR 52...

Sixty Years of Casting Research

NASA Astrophysics Data System (ADS)

Campbell, John

2015-11-01

The 60 years of solidification research since the publication of Chalmer's constitutional undercooling in 1953 has been a dramatic advance of understanding which has and continues to be an inspiration. In contrast, 60 years of casting research has seen mixed fortunes. One of its success stories relates to improvements in inoculation of gray irons, and another to the discovery of spheroidal graphite iron, although both of these can be classified as metallurgical rather than casting advances. It is suggested that true casting advances have dated from the author's lab in 1992 when a critical surface turbulence condition was defined for the first time. These last 20 years have seen the surface entrainment issues of castings developed to a sufficient sophistication to revolutionize the performance of light alloy and steel foundries. However, there is still a long way to go, with large sections of the steel and Ni-base casting industries still in denial that casting defects are important or even exist. The result has been that special ingots are still cast poorly, and shaped casting operations have suffered massive losses. For secondary melted and cast materials, electro-slag remelting has the potential to be much superior to expensive vacuum arc remelting, which has cost our aerospace and defense industries dearly over the years. This failure to address and upgrade our processing of liquid metals is a serious concern, since the principle entrainment defect, the bifilm, is seen as the principle initiator of cracks in metals; in general, bifilms are the Griffith cracks that initiate failures by cracking. A new generation of crack resistant metals and engineering structures can now be envisaged.

Investigation on Simultaneous Effects of Shot Peen and Austenitizing Time and Temperature on Grain Size and Microstructure of Austenitic Manganese Steel (Hadfield)

NASA Astrophysics Data System (ADS)

Beheshti, M.; Zabihiazadboni, M.; Ismail, M. C.; Kakooei, S.; Shahrestani, S.

2018-03-01

Optimal conditions to increase life time of casting parts have been investigated by applying various cycles of heat treatment and shot peening on Hadfield steel surface. Metallographic and SEM microstructure examinations were used to determine the effects of shot peen, austenitizing time and temperature simultaneously. The results showed that with increasing austenitizing time and temperature of casting sample, carbides resolved in austenite phase and by further increase of austenitizing temperature and time, the austenite grain size becomes larger. Metallographic images illustrated that shot peening on Hadfield steel surface; Austenite - Martensite transformation has not occurred, but its matrix hardened through twining formation process.

Modeling wear of cast Ti alloys.

PubMed

Chan, Kwai S; Koike, Marie; Okabe, Toru

2007-05-01

The wear behavior of Ti-based alloys was analyzed by considering the elastic-plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an alpha, alpha+beta or beta microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability.

Modeling wear of cast Ti alloys

PubMed Central

Chan, Kwai S.; Koike, Marie; Okabe, Toru

2007-01-01

The wear behavior of Ti-based alloys was analyzed by considering the elastic–plastic fracture of individual alloys in response to the relevant contact stress field. Using the contact stresses as the process driving force, wear was computed as the wear rate or volume loss as a function of hardness and tensile ductility for Ti-based cast alloys containing an α, α+β or β microstructure with or without the intermetallic precipitates. Model predictions indicated that wear of Ti alloys increases with increasing hardness but with decreasing fracture toughness or tensile ductility. The theoretical results are compared with experimental data to elucidate the roles of microstructure in wear and contrasted against those in grindability. PMID:17224314

Alloy Microstructure Dictates Corrosion Modes in THA Modular Junctions.

PubMed

Pourzal, Robin; Hall, Deborah J; Ehrich, Jonas; McCarthy, Stephanie M; Mathew, Mathew T; Jacobs, Joshua J; Urban, Robert M

2017-12-01

Adverse local tissue reactions (ALTRs) triggered by corrosion products from modular taper junctions are a known cause of premature THA failure. CoCrMo devices are of particular concern because cobalt ions and chromium-orthophosphates were shown to be linked to ALTRs, even in metal-on-polyethylene THAs. The most common categories of CoCrMo alloy are cast and wrought alloy, which exhibit fundamental microstructural differences in terms of grain size and hard phases. The impact of implant alloy microstructure on the occurring modes of corrosion and subsequent metal ion release is not well understood. The purpose of this study was to determine whether (1) the microstructure of cast CoCrMo alloy varies broadly between manufacturers and can dictate specific corrosion modes; and whether (2) the microstructure of wrought CoCrMo alloy is more consistent between manufacturers and has low implications on the alloy's corrosion behavior. The alloy microstructure of four femoral-stem and three femoral-head designs from four manufacturers was metallographically and electrochemically characterized. Three stem designs were made from cast alloy; all three head designs and one stem design were made from wrought alloy. Alloy samples were sectioned from retrieved components and then polished and etched to visualize grain structure and hard phases such as carbides (eg, M 23 C 6 ) or intermetallic phases (eg, σ phase). Potentiodynamic polarization (PDP) tests were conducted to determine the corrosion potential (E corr ), corrosion current density (I corr ), and pitting potential (E pit ) for each alloy. Four devices were tested within each group, and each measurement was repeated three times to ensure repeatable results. Differences in PDP metrics between manufacturers and between alloys with different hard phase contents were compared using one-way analysis of variance and independent-sample t-tests. Microstructural features such as twin boundaries and slip bands as well as corrosion damage features were viewed and qualitatively assessed in a scanning electron microscope. We found broad variability in implant alloy microstructure for both cast and wrought alloy between manufacturers, but also within the same implant design. In cast alloys, there was no difference in PDP metrics between manufacturers. However, coarse hard phases and clusters of hard phases (mainly intermetallic phases) were associated with severe phase boundary corrosion and pitting corrosion. Furthermore, cast alloys with hard phases had a lower E pit than those without (0.46 V, SD 0.042; 0.53 V, SD 0.03, respectively; p = 0.015). Wrought alloys exhibited either no hard phases or numerous carbides (M 23 C 6 ). However, the corrosion behavior was mainly affected by lattice defects and banded structures indicative of segregations that appear to be introduced during bar stock manufacturing. Alloys with banding had a lower E corr (p = 0.008) and higher I corr (p = 0.028) than alloys without banding (-0.76 V, SD 0.003; -0.73 V, SD 0.009; and 1.14 × 10 -4 mA/cm 2 , SD 1.47 × 10 -5 ; 5.2 × 10 -5 mA/cm 2 , SD 2.57 × 10 -5 , respectively). Alloys with carbides had a slightly higher E corr (p = 0.046) than those without (-0.755 V, SD 0.005; -0.761 V, SD 0.004); however, alloys with carbides exhibited more severe corrosion damage as a result of phase boundary corrosion, hard phase detachment, and subsequent local crevice corrosion. The observed variability in CoCrMo alloy microstructure of both cast and wrought components in this study appears to be an important issue to address, perhaps through better standards, to minimize in vivo corrosion. The finding of the banded structures within wrought alloys is especially concerning because it unfavorably influences the corrosion behavior independent of the manufacturer. The findings suggest that a homogeneous alloy microstructure with a minimal hard phase fraction exhibits more favorable corrosion behavior within the in vivo environment of modular taper junctions, thus lowering metal ion release and subsequently the risk of ALTRs to corrosion products. Also, the question arises if hard phases fulfill a useful purpose in metal-on-polyethylene bearings, because they may come with a higher risk of phase boundary corrosion and pitting corrosion and the benefit they provide by adding strength is not needed (unlike in metal-on-metal bearings). Implant failure resulting from corrosion processes within modular junctions is a major concern in THA. Our results suggest that implant alloy microstructure is not sufficiently standardized and may also dictate specific corrosion modes and subsequent metal ion release.

Features of Wear-Resistant Cast Iron Coating Formation During Plasma-Powder Surfacing

NASA Astrophysics Data System (ADS)

Vdovin, K. N.; Emelyushin, A. N.; Nefed'ev, S. P.

2017-09-01

The structure of coatings deposited on steel 45 by plasma-powder surfacing of white wear-resistant cast iron is studied. The effects of surfacing regime and additional production effects on the welding bath during surfacing produced by current modulation, accelerated cooling of the deposited beads by blowing with air, and accelerated cooling of the substrate with running water on the structure, are determined. A new composition is suggested for powder material for depositing wear-resistant and corrosion-resistant coatings on a carbon steel by the plasma-powder process.

27. Bollinger twinchain tandem, pigcasting machine, located at the north ...

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

27. Bollinger twin-chain tandem, pig-casting machine, located at the north end of the plant. Prior to closing, approximately 40 percent of the plant's: iron production was cast into pigs and sold to foundry customers. The pig-casting machine employed a controller, lime man, trough man, and crane operator. - Central Furnaces, 2650 Broadway, east bank of Cuyahoga River, Cleveland, Cuyahoga County, OH

Cast Iron Inoculation Enhanced by Supplementary Oxy-sulfides Forming Elements

NASA Astrophysics Data System (ADS)

Riposan, Iulian; Stan, Stelian; Uta, Valentin; Stefan, Ion

2017-09-01

Inoculation is one of the most important metallurgical treatments applied to the molten cast iron immediately prior to casting, to promote solidification without excessive eutectic undercooling, which favors carbides formation usually with undesirable graphite morphologies. The paper focused on the separate addition of an inoculant enhancer alloy [S, O, oxy-sulfides forming elements] with a conventional Ca-FeSi alloy, in the production of gray and ductile cast irons. Carbides formation tendency decreased with improved graphite characteristics as an effect of the [Ca-FeSi + Enhancer] inoculation combination, when compared to other Ca/Ca, Ba/Ca, RE-FeSi alloy treatments. Adding an inoculant enhancer greatly enhances inoculation, lowers inoculant consumption up to 50% or more and avoids the need to use more costly inoculants, such as a rare earth bearing alloy. The Inoculation Specific Factor [ISF] was developed as a means to more realistically measure inoculant treatment efficiency. It compares the ratio between the improved characteristic level and total inoculant consumption for this effect. Addition of any of the commercial inoculants plus the inoculant enhancer offered outstanding inoculation power [increased ISF] even at higher solidification cooling rates, even though the total enhancer addition was at a small fraction of the amount of commercial inoculant used.

Statistical Study to Evaluate the Effect of Processing Variables on Shrinkage Incidence During Solidification of Nodular Cast Irons

NASA Astrophysics Data System (ADS)

Gutiérrez, J. M.; Natxiondo, A.; Nieves, J.; Zabala, A.; Sertucha, J.

2017-04-01

The study of shrinkage incidence variations in nodular cast irons is an important aspect of manufacturing processes. These variations change the feeding requirements on castings and the optimization of risers' size is consequently affected when avoiding the formation of shrinkage defects. The effect of a number of processing variables on the shrinkage size has been studied using a layout specifically designed for this purpose. The β parameter has been defined as the relative volume reduction from the pouring temperature up to the room temperature. It is observed that shrinkage size and β decrease as effective carbon content increases and when inoculant is added in the pouring stream. A similar effect is found when the parameters selected from cooling curves show high graphite nucleation during solidification of cast irons for a given inoculation level. Pearson statistical analysis has been used to analyze the correlations among all involved variables and a group of Bayesian networks have been subsequently built so as to get the best accurate model for predicting β as a function of the input processing variables. The developed models can be used in foundry plants to study the shrinkage incidence variations in the manufacturing process and to optimize the related costs.

Arsenic Accumulation and Release Studies Using a Cast Iron Pipe Section from a Drinking Water Distribution System

EPA Science Inventory

The tendency of iron solid surfaces to adsorb arsenic and other ions is well known and has become the basis for several drinking water treatment approaches that remove these contaminants. It is reasonable to assume that iron-based solids, such as corrosion deposits present in dri...

Standard methods for chemical analysis of steel, cast iron, open-hearth iron, and wrought iron

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1973-01-01

Methods are described for determining manganese, phosphorus, sulfur, selenium, copper, nickel, chromium, vanadium, tungsten, titanium, lead, boron, molybdenum ( alpha -benzoin oxime method), zirconium (cupferron --phosphate method), niobium and tantalum (hydrolysis with perchloric and sulfurous acids (gravimetric, titrimetric, and photometric methods)), and beryllium (oxide method). (DHM)

Analysis of four dental alloys following torch/centrifugal and induction/ vacuum-pressure casting procedures.

PubMed

Thompson, Geoffrey A; Luo, Qing; Hefti, Arthur

2013-12-01

Previous studies have shown casting methodology to influence the as-cast properties of dental casting alloys. It is important to consider clinically important mechanical properties so that the influence of casting can be clarified. The purpose of this study was to evaluate how torch/centrifugal and inductively cast and vacuum-pressure casting machines may affect the castability, microhardness, chemical composition, and microstructure of 2 high noble, 1 noble, and 1 base metal dental casting alloys. Two commonly used methods for casting were selected for comparison: torch/centrifugal casting and inductively heated/ vacuum-pressure casting. One hundred and twenty castability patterns were fabricated and divided into 8 groups. Four groups were torch/centrifugally cast in Olympia (O), Jelenko O (JO), Genesis II (G), and Liberty (L) alloys. Similarly, 4 groups were cast in O, JO, G, and L by an inductively induction/vacuum-pressure casting machine. Each specimen was evaluated for casting completeness to determine a castability value, while porosity was determined by standard x-ray techniques. Each group was metallographically prepared for further evaluation that included chemical composition, Vickers microhardness, and grain analysis of microstructure. Two-way ANOVA was used to determine significant differences among the main effects. Statistically significant effects were examined further with the Tukey HSD procedure for multiple comparisons. Data obtained from the castability experiments were non-normal and the variances were unequal. They were analyzed statistically with the Kruskal-Wallis rank sum test. Significant results were further investigated statistically with the Steel-Dwass method for multiple comparisons (α=.05). The alloy type had a significant effect on surface microhardness (P<.001). In contrast, the technique used for casting did not affect the microhardness of the test specimen (P=.465). Similarly, the interaction between the alloy and casting technique was not significant (P=.119). A high level of castability (98.5% on average) was achieved overall. The frequency of casting failures as a function of alloy type and casting method was determined. Failure was defined as a castability index score of <100%. Three of 28 possible comparisons between alloy and casting combinations were statistically significant. The results suggested that casting technique affects the castability index of alloys. Radiographic analysis detected large porosities in regions near the edge of the castability pattern and infrequently adjacent to noncast segments. All castings acquired traces of elements found in the casting crucibles. The grain size for each dental casting alloy was generally finer for specimens produced by the induction/vacuum-pressure method. The difference was substantial for JO and L. This study demonstrated a relation between casting techniques and some physical properties of metal ceramic casting alloys. Copyright © 2013 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Magnetic characteristics of ultrafine Fe particles reduced from uniform iron oxide particles

NASA Astrophysics Data System (ADS)

Bridger, K.; Watts, J.; Tadros, M.; Xiao, Gang; Liou, S. H.; Chien, C. L.

1987-04-01

Uniform, cubic 0.05-μm iron oxide particles were formed by forced hydrolysis of ferric perchlorate. These particles were reduced to α-Fe by heating in hydrogen at temperatures between 300 and 500 °C. The effect of reduction temperature and various prereduction treatments on the microstructure of the iron particles will be discussed. Complete reduction to α-Fe was established by 57Fe Mössbauer spectroscopy and x-ray diffraction. Magnetic measurements on epoxy and polyurethane films containing these particles with various mass fractions gave coercivities as high as 1000 Oe. The relationship between the magnetic measurements and the microstructure will be discussed. Na2SiO3 is found to be the best coating material for the process of reducing iron oxide particles to iron.

The influence of various cooling rates during laser alloying on nodular iron surface layer

NASA Astrophysics Data System (ADS)

Paczkowska, Marta; Makuch, Natalia; Kulka, Michał

2018-06-01

The results of research referring to modification of the nodular iron surface layer by laser alloying with cobalt were presented. The aim of this study was to analyze the possibilities of cobalt implementation into the surface layer of nodular iron in various laser heat treatment conditions (by generating different cooling rates of melted surface layer). The modified surface layer of nodular iron was analyzed with OM, SEM, TEM, XRD, EDS and Vickers microhardness tester. The modified surface layer of nodular iron after laser alloying consisted of: the alloyed zone (melted with cobalt), the transition zone and the hardened zone from solid state. The alloyed zone was characterized by higher microstructure homogeneity - in contrast to the transition and the hardened zones. All the alloyed zones contained a dendritic microstructure. Dendrites consisted of martensite needles and retained austenite. Cementite was also detected. It was stated, that due to similar dimension of iron and cobalt atoms, their mutual replacement in the crystal lattice could occur. Thus, formation of phases based on α solution: Co-Fe (44-1433) could not be excluded. Although cobalt should be mostly diluted in solid solutions (because of its content in the alloyed zone), the other newly formed phases as Co (ε-hex.), FeC and cobalt carbides: Co3C, CoC0.25 could be present in the alloyed zones as a result of unique microstructure creation during laser treatment. Pearlite grains were observed in the zone, formed using lower power density of the laser beam and its longer exposition time. Simply, such conditions resulted in the cooling rate which was lower than critical cooling rate. The alloyed zones, produced at a higher cooling rate, were characterized by better microstructure homogeneity. Dendrites were finer in this case. This could result from a greater amount of crystal nuclei appearing at higher cooling rate. Simultaneously, the increased amount of γ-Fe and Fe3C precipitates was expected in the alloyed zone formed at higher cooling rates. The hardness of nodular iron surface layer, alloyed with cobalt, was up to 4-times higher than the hardness of core material. The hardness of alloyed zones strongly depended on laser treatment conditions. In the case of lower cooling rate, lower hardness was observed due to more coarse-grained microstructure and a presence of pearlite. The hardness of the alloyed zone increased (from 850 to 950HV0.1) together with the increasing cooling rate (from 2 · 103 to nearly 9 · 103 °C/s). Laser treatment enabled a formation of surface layers on nodular iron, alloyed with cobalt. The microstructure of such a surface layer could be controlled by the laser processing parameters. High hardness and fine microstructure of the laser-alloyed nodular iron with cobalt should result in higher resistance to wear, corrosion and even (due to effect of cobalt addition) elevated temperatures during operation conditions of machine parts.

Effects of Pore Distributions on Ductility of Thin-Walled High Pressure Die-Cast Magnesium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Kyoo Sil; Li, Dongsheng; Sun, Xin

2013-06-01

In this paper, a microstructure-based three-dimensional (3D) finite element modeling method is adopted to investigate the effects of porosity in thin-walled high pressure die-cast (HPDC) Magnesium alloys on their ductility. For this purpose, the cross-sections of AM60 casting samples are first examined using optical microscope and X-ray tomography to obtain the general information on the pore distribution features. The experimentally observed pore distribution features are then used to generate a series of synthetic microstructure-based 3D finite element models with different pore volume fractions and pore distribution features. Shear and ductile damage models are adopted in the finite element analyses tomore » induce the fracture by element removal, leading to the prediction of ductility. The results in this study show that the ductility monotonically decreases as the pore volume fraction increases and that the effect of ‘skin region’ on the ductility is noticeable under the condition of same local pore volume fraction in the center region of the sample and its existence can be beneficial for the improvement of ductility. The further synthetic microstructure-based 3D finite element analyses are planned to investigate the effects of pore size and pore size distribution.« less

Effects of Sn addition on the microstructure and tensile properties of AX55 alloys

NASA Astrophysics Data System (ADS)

Qiu, K. Q.; Huang, P.

2018-04-01

The microstructures and tensile properties at both room and elevated temperatures for both the as-cast and as-aged Mg-5Al-5Ca (AX55) alloy with 0–2 wt% Sn addition were studied. The results indicate that the α-Mg dendrite is gradually refined and the interdendritic Al2Ca and Mg2Ca intermetallics become more connected with Sn addition. The as-cast AX55-1Sn alloy shows optimal ultimate tensile strength (UTS) at testing temperature from 25 to 225 °C. After T61 and T62 heat treatment, the eutectic-lamellar microstructure of the as-cast alloys tends to be spheroidized and distributed uniformly along the grain boundaries. While the alloys with higher Sn content show higher density of granulated and needle-shaped Al2Ca phases precipitated into α-Mg matrix, which results in the increase of UTS, yield strength (YS), elongation and microhardness with Sn addition. The morphology of CaMgSn phase can be improved by T62 treatment, which makes as-aged AX55-2.0Sn alloy exhibit a smaller decrease rate of the UTS at temperature up to 225 °C. The heat resistance of different heat-resistant magnesium alloys were compared and discussed by using the decrease rate of the UTS.

Microstructure Characterization Of Lead-Free Solders Depending On Alloy Composition

NASA Astrophysics Data System (ADS)

Panchenko, Iuliana; Mueller, Maik; Wolter, Klaus-Juergen

2010-11-01

Fatigue and crack nucleation in solder joints is basically associated with changes in the microstructure. Therefore the microstructure evolution of SnAgCu solder joints during solidification and subsequent application is an important subject for reliability investigations and physics of failure analysis. The scope of this study is a systematic overview of the as-cast microstructures in small sized lead-free SnAgCu solder spheres after solidification. A total of 32 alloy compositions have been investigated with varying Ag content from 0 to 5 wt.% and varying Cu content from 0 to 1.2 wt.%. The solder spheres had a diameter of approx. 270 μm and were all manufactured under the similar conditions. Subsequent cross-sectioning was carried out in order to analyze the microstructure by optical and electron microscopy as well as Electron Backscatter Diffraction and Energy Dispersive X-ray Spectroscopy. The results allow a comprehensive overview of the dependence of the as-cast microstructure on the solder composition. It is shown that strong changes in microstructure can be caused by small changes in solder composition. In addition, a solidification phenomenon known as cyclic twinning has been found in the samples. Three different microstructures related to that phenomenon will be presented and detailed characterizations of these structures are given in this study. These microstructures differ in their appearance by solidification morphology, phase distribution as well as grain structure and can be described as follows: 1. large dentritic areas of different grain orientations which are characterized by approx. 60° twin boundaries; 2. areas of small β-Sn cells with approx. 60° twin relation and larger intermetallic precipitates; 3. large grains consisting of a β-Sn matrix with very fine intermetallic precipitates and high angle grain boundaries between adjacent grains.

Freeze Tape Casting of Functionally Graded Porous Ceramics

NASA Technical Reports Server (NTRS)

Sofie, Stephen W.

2007-01-01

Freeze tape casting is a means of making preforms of ceramic sheets that, upon subsequent completion of fabrication processing, can have anisotropic and/or functionally graded properties that notably include aligned and graded porosity. Freeze tape casting was developed to enable optimization of the microstructures of porous ceramic components for use as solid oxide electrodes in fuel cells: Through alignment and grading of pores, one can tailor surface areas and diffusion channels for flows of gas and liquid species involved in fuel-cell reactions. Freeze tape casting offers similar benefits for fabrication of optimally porous ceramics for use as catalysts, gas sensors, and filters.

Processing of IN-718 Lattice Block Castings

NASA Technical Reports Server (NTRS)

Hebsur, Mohan G.

2002-01-01

Recently a low cost casting method known as lattice block casting has been developed by JAM Corporation, Wilmington, Massachusetts for engineering materials such as aluminum and stainless steels that has shown to provide very high stiffness and strength with only a fraction of density of the alloy. NASA Glenn Research Center has initiated research to investigate lattice block castings of high temperature Ni-base superalloys such as the model system Inconel-718 (IN-718) for lightweight nozzle applications. Although difficulties were encountered throughout the manufacturing process , a successful investment casting procedure was eventually developed. Wax formulation and pattern assembly, shell mold processing, and counter gravity casting techniques were developed. Ten IN-718 lattice block castings (each measuring 15-cm wide by 30-cm long by 1.2-cm thick) have been successfully produced by Hitchiner Gas Turbine Division, Milford, New Hampshire, using their patented counter gravity casting techniques. Details of the processing and resulting microstructures are discussed in this paper. Post casting processing and evaluation of system specific mechanical properties of these specimens are in progress.

13. Bottom floor, tower interior showing concrete floor and cast ...

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

13. Bottom floor, tower interior showing concrete floor and cast iron bases for oil butts (oil butts removed when lighthouse lamp was converted to electric power.) - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

15. TAKING A CAST AT FURNACE NO. 1 HOT SLAG, ...

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

15. TAKING A CAST AT FURNACE NO. 1 HOT SLAG, BY-PRODUCT IN SMELTING OF PIG IRON, CAN BE SEEN FLOWING INTO THE SLAG YARD. VIEW IS LOOKING SOUTH. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

Influence of Sc on microstructure and mechanical properties of Al-Si-Mg-Cu-Zr alloy

NASA Astrophysics Data System (ADS)

Li, Yukun; Du, Xiaodong; Zhang, Ya; Zhang, Zhen; Fu, Junwei; Zhou, Shi'ang; Wu, Yucheng

2018-02-01

In the present study, the effects of Mg, Cu, Sc and Zr combined additions on the microstructure and mechanical properties of hypoeutectic Al-Si cast alloy were systematically investigated. Characterization techniques such as optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron back-scatter diffraction (EBSD), atomic force microscopy (AFM), transmission electron microscope (TEM), Brinell hardness tester and universal testing machine were employed to analyze the microstructure and mechanical properties. The results showed that Sc served as modifier on the microstructure of Al-3Si-0.45Mg-0.45Cu-0.2Zr alloys, including modification of eutectic Si and grains. Extraordinarily, grain refinement was found to be related to the primary particles, which exhibited a close orientation to matrix. After T6 heat treatment, the grain structures were composed of nano-scaled secondary Al3(Sc, Zr) precipitates and spherical eutectic Si. Combined with T6 heat treatment, the highest hardness, yield strength, ultimate tensile strength and elongation were achieved in 0.56 wt.% Sc-modified alloy. Interestingly, the strength and ductility had a similar tendency. This paper demonstrated that combined additions of Mg, Cu, Sc and Zr could significantly improve the microstructure and performance of the hypoeutectic Al-Si cast alloy.

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

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.

Predicting Stress vs. Strain Behaviors of Thin-Walled High Pressure Die Cast Magnesium Alloy with Actual Pore Distribution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Kyoo Sil; Barker, Erin; Cheng, Guang

2016-01-06

In this paper, a three-dimensional (3D) microstructure-based finite element modeling method (i.e., extrinsic modeling method) is developed, which can be used in examining the effects of porosity on the ductility/fracture of Mg castings. For this purpose, AM60 Mg tensile samples were generated under high-pressure die-casting in a specially-designed mold. Before the tensile test, the samples were CT-scanned to obtain the pore distributions within the samples. 3D microstructure-based finite element models were then developed based on the obtained actual pore distributions of the gauge area. The input properties for the matrix material were determined by fitting the simulation result to themore » experimental result of a selected sample, and then used for all the other samples’ simulation. The results show that the ductility and fracture locations predicted from simulations agree well with the experimental results. This indicates that the developed 3D extrinsic modeling method may be used to examine the influence of various aspects of pore sizes/distributions as well as intrinsic properties (i.e., matrix properties) on the ductility/fracture of Mg castings.« less

Influence of heat treatment and hot extrusion on the microstructure and tensile properties of rare earth modified Mg-Zn based alloy

NASA Astrophysics Data System (ADS)

Sheng, L. Y.; Wang, B. J.; Du, B. N.; Lai, C.; Xi, T. F.

2018-01-01

In the present paper, the Mg-Zn-Y-Nd alloy was prepared by casting, heat treatment and hot extrusion. The microstructure and mechanical properties of the alloys were tested by OM, SEM, TEM and tensile test. The results showed that the Mg3Zn2Y3 phase is the main strengthening phase and forms the eutectic structure with α-Mg matrix in the as cast alloy. The strengthening phases semi-continuously connect and separate the α-Mg matrix into cell structure. The average grain size of the as cast alloy is about 60 μm. The heat treatment promotes the solid solution of the strengthening phase and precipitation of small particles inside grain.Compared with the as cast alloy, the heat treatment increases grain size a little and mechanical properties more than 30%. The hot extrusion refines the grain and strengthening phase, which increase the mechanical properties significantly. Moreover, the great deformation by the hot extrusion results in the ultrafine structure and abundant of crystal defects. The intersection of micro-twins lead to the special region with nanometer size.

Microstructure, Texture, and Mechanical Behavior of As-cast Ni-Fe-W Matrix Alloy

NASA Astrophysics Data System (ADS)

Rao, A. Sambasiva; Manda, Premkumar; Mohan, M. K.; Nandy, T. K.; Singh, A. K.

2018-04-01

This article describes the tensile properties, flow, and work-hardening behavior of an experimental alloy 53Ni-29Fe-18W in as-cast condition. The microstructure of the alloy 53Ni-29Fe-18W displays single phase (fcc) in as-cast condition along with typical dendritic features. The bulk texture of the as-cast alloy reveals the triclinic sample symmetry and characteristic nature of coarse-grained materials. The alloy exhibits maximum strength ( σ YS and σ UTS) values along the transverse direction. The elongation values are maximum and minimum along the transverse and longitudinal directions, respectively. Tensile fracture surfaces of both the longitudinal and transverse samples display complete ductile fracture features. Two types of slip lines, namely, planar and intersecting, are observed in deformed specimens and the density of slip lines increases with increasing the amount of deformation. The alloy displays moderate in-plane anisotropy ( A IP) and reasonably low anisotropic index ( δ) values, respectively. The instantaneous or work-hardening rate curves portray three typical stages (I through III) along both the longitudinal and transverse directions. The alloy exhibits dislocation-controlled strain hardening during tensile testing, and slip is the predominant deformation mechanism.

Effects of Annular Electromagnetic Stirring Coupled with Intercooling on Grain Refinement and Homogeneity During Direct Chill Casting of Large-Sized 7005 Alloy Billet

NASA Astrophysics Data System (ADS)

Luo, Yajun; Zhang, Zhifeng; Li, Bao; Gao, Mingwei; Qiu, Yang; He, Min

2017-12-01

To obtain a large-sized, high-quality aluminum alloy billet, an advanced uniform direct chill (UDC) casting method was developed by combining annular electromagnetic stirring (A-EMS) with intercooling in the sump. The 7005 alloy was chosen to investigate the effect of UDC on grain refinement and homogeneity during normal direct chill (NDC) casting. It was concluded that the microstructure consisting of both primary α-Al phase and secondary phases becomes finer and more homogeneous for the billets prepared with UDC casting compared to those prepared with NDC casting, and the forced cooling from both the inner and outer melt under A-EMS has a measurable effect on grain refinement and homogeneity.

An Integrated Study on the Evolution of Inclusions in EH36 Shipbuilding Steel with Mg Addition: From Casting to Welding

NASA Astrophysics Data System (ADS)

Zou, Xiaodong; Zhao, Dapeng; Sun, Jincheng; Wang, Cong; Matsuura, Hiroyuki

2018-04-01

Inclusion evolution behaviors, in terms of composition, size, and number density, and associated influence on the microstructures of the as-cast slabs, rolled plates, and simulated welded samples of plain EH36 and EH36-Mg shipbuilding steels have been systematically investigated. The results indicate that the inclusions in the as-cast plain EH36 are almost Al-Ca-S-O-(Mn) complex oxides with sizes ranging from 1.0 to 2.0 μm. After Mg addition, a large amount of individually fine MnS precipitates and Mg-containing Ti-Al-Mg-O-(Mn-S) complex inclusions are generated, which significantly refine the microstructure and are conducive to the nucleation of acicular ferrite in the rolled and welded sample. Moreover, after rolling and welding thermal simulation, the number of individual MnS decreases gradually due to its precipitation on the surface of Ti-Al-Mg-O oxides.

Effects of microbial redox cycling of iron on cast iron pipe corrosion in drinking water distribution systems.

PubMed

Wang, Haibo; Hu, Chun; Zhang, Lili; Li, Xiaoxiao; Zhang, Yu; Yang, Min

2014-11-15

Bacterial characteristics in corrosion products and their effect on the formation of dense corrosion scales on cast iron coupons were studied in drinking water, with sterile water acting as a reference. The corrosion process and corrosion scales were characterized by electrochemical and physico-chemical measurements. The results indicated that the corrosion was more rapidly inhibited and iron release was lower due to formation of more dense protective corrosion scales in drinking water than in sterile water. The microbial community and denitrifying functional genes were analyzed by pyrosequencing and quantitative polymerase chain reactions (qPCR), respectively. Principal component analysis (PCA) showed that the bacteria in corrosion products played an important role in the corrosion process in drinking water. Nitrate-reducing bacteria (NRB) Acidovorax and Hydrogenophaga enhanced iron corrosion before 6 days. After 20 days, the dominant bacteria became NRB Dechloromonas (40.08%) with the protective corrosion layer formation. The Dechloromonas exhibited the stronger corrosion inhibition by inducing the redox cycling of iron, to enhance the precipitation of iron oxides and formation of Fe3O4. Subsequently, other minor bacteria appeared in the corrosion scales, including iron-respiring bacteria and Rhizobium which captured iron by the produced siderophores, having a weaker corrosion-inhibition effect. Therefore, the microbially-driven redox cycling of iron with associated microbial capture of iron caused more compact corrosion scales formation and lower iron release. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microstructure and magnetism of Co2FeAl Heusler alloy prepared by arc and induction melting compared with planar flow casting

NASA Astrophysics Data System (ADS)

Titov, A.; Jiraskova, Y.; Zivotsky, O.; Bursik, J.; Janickovic, D.

2018-04-01

This paper is devoted to investigations of the structural and magnetic properties of the Co2FeAl Heusler alloy produced by three technologies. The alloys prepared by arc and induction melting have resulted in coarse-grained samples in contrast to the fine-grained ribbon-type sample prepared by planar flow casting. Scanning electron microscopy completed by energy dispersive X-ray spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and magnetic methods sensitive to both bulk and surface were applied. The chemical composition was slightly different from the nominal only for the ribbon sample. From the viewpoint of magnetic properties, the bulk coercivity and remnant magnetization have followed the structure influenced by the technology used. Saturation magnetization was practically the same for samples prepared by arc and induction melting, whereas the magnetization of ribbon is slightly lower due to a higher Al content at the expense of iron and cobalt. The surface magnetic properties were markedly influenced by anisotropy, grain size, and surface roughness of the samples. The surface roughness and brittleness of the ribbon-type sample did not make domain structure observation possible. The other two samples could be well polished and their highly smooth surface has enabled domain structure visualization by both magneto-optical Kerr microscopy and magnetic force microscopy.

Relationship between notch strengthening threshold and mechanical property for ductile cast iron

NASA Astrophysics Data System (ADS)

Ikeda, T.; Noda, N.-A.; Sano, Y.; Umetani, T.; Kai, N.

2018-06-01

In this study, dynamic tensile tests were conducted at the various strain rates and temperatures for traditional ductile cast iron. Then, the notch strength {σ }{{B}}{{noth}} and the static tensile strength at room temperature {σ }{{B,}\\quad {{RT}}}{{smooth}} were discussed in terms of the strain rate- temperature parameter R, which is known to be useful for evaluating the combined influence of strain rate and temperature. This study focuses on the notch strengthening threshold R ≧ R th where {σ }{{B}}{{noth}} is larger than {σ }{{B,}\\quad {{RT}}}{{smooth}} and therefore notched components can be used safely. In other words, if R ≧ R th, {σ }{{B,}\\quad {{RT}}}{{smooth}} can be used to evaluate notched components in mechanical design to prevent the instantaneous fracture. In this study, it was found that the R th value can be predicted from the static tensile property and Brinell hardness. Since the traditional ductile cast iron considered in this paper has a broad range of mechanical properties, the present approach and discussion can be applied to evaluate other materials under various temperature and strain rate.

Process for forming unusually strong joints between metals and ceramics by brazing at temperatures that do not exceed 750/sup 0/C

DOEpatents

Hammond, J.P.; David, S.A.; Woodhouse, J.J.

1984-12-04

This invention is a process for joining metals to ceramics to form very strong bonds using low brazing temperature, i.e., less than 750/sup 0/C, and particularly for joining nodular cast iron to partially stabilized zirconia. The process provides that the ceramic be coated with an active metal, such as titanium, that can form an intermetallic with a low melting point brazing alloy such as 60Ag-30Cu-10Sn. The nodular cast iron is coated with a noncarbon containing metal, such as copper, to prevent carbon in the nodular cast iron from dissolving in the brazing alloy. These coated surfaces can be brazed together with the brazing alloy between at less than 750/sup 0/C to form a very strong joint. An even stronger bond can be formed if a transition piece is used between the metal and ceramic. It is preferred for the transition piece to have a coefficient of thermal expansion compatible with the coefficient of thermal expansion of the ceramic, such as titanium.

Process for forming unusually strong joints between metals and ceramics by brazing at temperatures that do no exceed 750 degree C.

DOEpatents

Hammond, Joseph P.; David, Stan A.; Woodhouse, John J.

1986-01-01

This invention is a process for joining metals to ceramics to form very strong bonds using low brazing temperature, i.e., less than 750.degree. C., and particularly for joining nodular cast iron to partially stabilized zirconia. The process provides that the ceramic be coated with an active metal, such as titanium, that can form an intermetallic with a low melting point brazing alloy such as 60Ag-30Cu-10Sn. The nodular cast iron is coated with a noncarbon containing metal, such as copper, to prevent carbon in the nodular cast iron from dissolving in the brazing alloy. These coated surfaces can be brazed together with the brazing alloy between at less than 750.degree. C. to form a very strong joint. An even stronger bond can be formed if a transition piece is used between the metal and ceramic. It is preferred for the transition piece to have a coefficient of thermal compatible with the coefficient of thermal expansion of the ceramic, such as titanium.

Pulsed Eddy Current Sensing for Critical Pipe Condition Assessment.

PubMed

Ulapane, Nalika; Alempijevic, Alen; Vidal Calleja, Teresa; Valls Miro, Jaime

2017-09-26

Pulsed Eddy Current (PEC) sensing is used for Non-Destructive Evaluation (NDE) of the structural integrity of metallic structures in the aircraft, railway, oil and gas sectors. Urban water utilities also have extensive large ferromagnetic structures in the form of critical pressure pipe systems made of grey cast iron, ductile cast iron and mild steel. The associated material properties render NDE of these pipes by means of electromagnetic sensing a necessity. In recent years PEC sensing has established itself as a state-of-the-art NDE technique in the critical water pipe sector. This paper presents advancements to PEC inspection in view of the specific information demanded from water utilities along with the challenges encountered in this sector. Operating principles of the sensor architecture suitable for application on critical pipes are presented with the associated sensor design and calibration strategy. A Gaussian process-based approach is applied to model a functional relationship between a PEC signal feature and critical pipe wall thickness. A case study demonstrates the sensor's behaviour on a grey cast iron pipe and discusses the implications of the observed results and challenges relating to this application.

Raising the Reliability of Forming Rolls by Alloying Their Core with Copper

NASA Astrophysics Data System (ADS)

Zhizhkina, N. A.

2016-11-01

The mechanical properties and the structure of forming rolls from cast irons of different compositions are studied. A novel iron including a copper additive that lowers its chilling and raises the homogeneity of the structure is suggested for the roll cores. The use of such iron should raise the reliability of the rolls in operation.

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ~315 °C to 0.08 dpa (5.6 × 10more » 19 n/cm 2 E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10 -9 dpa/s was found to induce spinod,al decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. Lastly, The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.« less

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

DOE PAGES

Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren; ...

2015-08-08

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ~315 °C to 0.08 dpa (5.6 × 10more » 19 n/cm 2 E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10 -9 dpa/s was found to induce spinod,al decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. Lastly, The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.« less

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.

Microstructure, Friction and Wear of Aluminum Matrix Composites

NASA Astrophysics Data System (ADS)

Florea, R. M.

2018-06-01

MMCs are made by dispersing a reinforcing material into a metal matrix. They are prepared by casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. The aluminum alloy composite materials consist of high strength, high stiffness, more thermal stability, more corrosion and wear resistance, and more fatigue life. Aluminum alloy materials found to be the best alternative with its unique capacity of designing the materials to give required properties. In this work a composite is developed by adding silicon carbide in Aluminum metal matrix by mass ratio 5%, 10% and 15%. Mechanical tests such as hardness test and microstructure test are conducted.

Solidification and Microstructure of Ni-Containing Al-Si-Cu Alloy

NASA Astrophysics Data System (ADS)

Fang, Li; Ren, Luyang; Geng, Xinyu; Hu, Henry; Nie, Xueyuan; Tjong, Jimi

2018-01-01

2 wt. % nickel (Ni) addition was introduced into a conventional cast aluminum alloy A380. The influence of transition alloying element nickel on the solidification behavior of cast aluminum alloy A380 was investigated via thermal analyses based on temperature measurements recorded on cooling curves. The corresponding first and second derivatives of the cooling curves were derived to reveal the details of phase changes during solidification. The nucleation of the primary α-Al phase and eutectic phases were analyzed. The microstructure analyses by scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) indicate that different types and amount of eutectic phases are present in the tested two alloys. The introduction of Ni forms the complex Ni-containing intermetallic phases with Cu and Al.

Surface modification of investment cast-316L implants: microstructure effects.

PubMed

El-Hadad, Shimaa; Khalifa, Waleed; Nofal, Adel

2015-03-01

Artificial femur stem of 316L stainless steel was fabricated by investment casting using vacuum induction melting. Different surface treatments: mechanical polishing, thermal oxidation and immersion in alkaline solution were applied. Thicker hydroxyapatite (HAP) layer was formed in the furnace-oxidized samples as compared to the mechanically polished ones. The alkaline treatment enhanced the precipitation of HAP on the samples. It was also observed that the HAP precipitation responded differently to the different phases of the microstructure. The austenite phase was observed to have more homogeneous and smoother layer of HAP. In addition, the growth of HAP was sometimes favored on the austenite phase rather than on ferrite phase. Copyright © 2014 Elsevier B.V. All rights reserved.

Gold nanotriangles decorated with superparamagnetic iron oxide nanoparticles: a compositional and microstructural study

DOE PAGES

Hachtel, J. A.; Yu, S.; Lupini, A. R.; ...

2016-03-11

The combination of iron oxide and gold in a single nanoparticle results in both magnetic and plasmonic properties that can stimulate novel applications in bio-sensing, medical imaging, or therapeutics. Microwave assisted heating allows the fabrication of multi-component, multi-functional nanostructures by promoting selective heating at desired sites. Recently, we reported a microwave-assisted polyol route yielding gold nanotriangles decorated with iron oxide nanoparticles. Here, we present an in-depth microstructural and compositional characterization of the system by using scanning transmission electron microscopy (STEM) and electron energy loss (EELS) spectroscopy. A method to remove the iron oxide nanoparticles from the gold nanocrystals and somemore » insights on crystal nucleation and growth mechanisms are also provided.« less

Effects of silicon on the oxidation, hot-corrosion, and mechanical behavior of two cast nickel-base superalloys

NASA Technical Reports Server (NTRS)

Miner, R. V., Jr.

1977-01-01

Cast specimens of nickel-base superalloys 713C and Mar-M200 with nominal additions of 0, 0.5, and 1 wt% Si were evaluated for oxidation and corrosion resistance, tensile and stress-rupture properties, microstructure, and phase relations. Results are compared with those of an earlier study of the effects of Si in B-1900. Si had similar effects on all three superalloys. It improves oxidation resistance but the improvement in 713C and Mar-M200 was considerably less than in B-1900. Hot-corrosion resistance is also improved somewhat. Si is, however, detrimental to mechanical properties, in particular, rupture strength and tensile ductility. Si has two obvious microstructural effects. It increases the amount of gamma-prime precipitated in eutectic nodules and promotes a Mo(Ni,Si)2 Laves phase in the alloys containing Mo. These microstructural effects do not appear responsible for the degradation of mechanical properties, however.

Microstructure evolution and mechanical properties degradation of HPNb alloy after a five-year service

NASA Astrophysics Data System (ADS)

Guo, Jingfeng; Cao, Tieshan; Cheng, Congqian; Meng, Xianming; Zhao, Jie

2018-04-01

The microstructure and mechanical properties of ethylene cracking furnace tube (HPNb alloy) are investigated by scanning electronic microscopy (SEM), tensile tests and Charpy impact tests at room temperature, tensile tests and creep tests at high temperature in this paper. The primary carbides of HPNb alloy coarsened and formed a continuous network after a five-year service. Furthermore, a lot of fine secondary carbides precipitated in the dendrite interior. The primary carbides M7C3 and NbC transformed into M23C6 and G phase after service, respectively. The furnace tube after service exhibits higher yield strength, lower tensile strength, worse ductility and toughness than as-cast tube at room temperature. At high temperature, the tensile strength and yield strength of service tube are higher than as-cast tube, but its tensile elongation is lower. The creep strength of HPNb alloy at high temperature decreases after a five-year service. Both microstructure and mechanical properties of ethylene cracking furnace tube have deteriorated after a five-year service.

An innovative approach to sampling complex industrial emissions for use in animal toxicity tests: application to iron casting operations.

PubMed

Palmer, W G; Scholz, R C; Moorman, W J

1983-03-01

Sampling of complex mixtures of airborne contaminants for chronic animal toxicity tests often involves numerous sampling devices, requires extensive sampling time, and yields forms of collected materials unsuitable for administration to animals. A method is described which used a high volume, wet venturi scrubber for collection of respirable fractions of emissions from iron foundry casting operations. The construction and operation of the sampler are presented along with collection efficiency data and its application to the preparation of large quantities of samples to be administered to animals by intratracheal instillation.

Creep-rupture behavior of a developmental cast-iron-base alloy for use up to 800 deg C

NASA Technical Reports Server (NTRS)

Titran, Robert H.; Scheuermann, Coulson M.

1987-01-01

A promising iron-base cast alloy is being developed as part of the DOE/NASA Stirling Engine Systems Project under contract DEN 3-282 with the United Technologies Research Center. This report presents the results of a study at the Lewis Research Center of the alloy's creep-rupture properties. The alloy was tested under a variety of conditions and was found to exhibit the normal 3-stage creep response. The alloy compared favorably with others being used or under consideration for the automotive Stirling engine cylinder/regenerator housing.

Comparison of the microstructure and phase stability of as-cast, CAD/CAM and powder metallurgy manufactured Co-Cr dental alloys.

PubMed

Li, Kai Chun; Prior, David J; Waddell, J Neil; Swain, Michael V

2015-12-01

The objective of this study was to identify the different microstructures produced by CC, PM and as-cast techniques for Co-Cr alloys and their phase stability following porcelain firings. Three bi-layer porcelain veneered Co-Cr specimens and one monolithic Co-Cr specimen of each alloy group [cast, powder metallurgy (PM), CAD/CAM (CC)] were manufactured and analyzed using electron backscatter diffraction (EBSD), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD). Specimens were treated to incremental numbers of porcelain firings (control 0, 5, 15) with crystallographic data, grain size and chemical composition subsequently obtained and analyzed. EBSD datasets of the cast alloy indicated large grains >200 μm whereas PM and CC alloy consisted of mean arithmetic grain sizes of 29.6 μm and 19.2 μm respectively. XRD and EBSD results both indicated the highest increase in hcp content (>13vol%) for cast Co-Cr alloy after treatment with porcelain firing while PM and CC indicated <2vol% hcp content. A fine grain interfacial layer developed on all surfaces of the alloy after porcelain firing. The depth of this layer increased with porcelain firings for as-cast and PM but no significant increase (p>.05) was observed in CC. EDS line scans indicated an increase in Cr content at the alloy surface after porcelain firing treatment for all three alloys. PM and CC produced alloy had superior fcc phase stability after porcelain firings compared to a traditional cast alloy. It is recommended that PM and CC alloys be used for porcelain-fused-to-metal restorations. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Microstructures and Mechanical Properties of Two-Phase Alloys Based on NbCr(2)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cady, C.M.; Chen, K.C.; Kotula, P.G.

A two-phase, Nb-Cr-Ti alloy (bee+ C15 Laves phase) has been developed using several alloy design methodologies. In effort to understand processing-microstructure-property relationships, diffment processing routes were employed. The resulting microstructure and mechanical properties are discussed and compared. Plasma arc-melted samples served to establish baseline, . . . as-cast properties. In addition, a novel processing technique, involving decomposition of a supersaturated and metastable precursor phase during hot isostatic pressing (HIP), was used to produce a refined, equilibrium two-phase microstructure. Quasi-static compression tests as a ~ function of temperature were performed on both alloy types. Different deformation mechanisms were encountered based uponmore » temperature and microstructure.« less

Development of the Electromagnetic Continuous Casting Technology for of Magnesium Alloys

NASA Astrophysics Data System (ADS)

Park, Joon-Pyo; Kim, Myoung-Gyun; Kim, Jong-Ho; Lee, Gyu-Chang

Currently, magnesium billets produced by ingot casting or direct chill casting process, result in low-quality surfaces and low productivity, Continuous casting technology to solve these problem has not only high-quality surface billets with fine-grained and homogeneous microstructure but also cost down. The latent heat of fusion per weight (J/g) of magnesium is similar to other metals, however, considering the heat emitted to the mold surface during continuous casting in meniscus region and converting it to the latent heat of fusion per volume, magnesium will be rapidly solidified in the mold during continuous casting, which induces subsequent surface defect formation. In this study, electromagnetic casting and stirring (EMC and EMS) techniques are proposed to control solidification process conveniently by compensating the low latent heat of solidification by volume and to fabricate magnesium billet with high-quality surface. This technique was extended to large scale billets up to 300 mm diameter and continuous casting was successfully conducted. Then magnesium billet was used for the fabrication of prototype automobile pulley.

The effects of microstructural stability on the compressive response of two cast aluminum alloys up to 300 °C

DOE PAGES

Shower, Patrick T.; Roy, Shibayan; Hawkins, Charles Shane; ...

2017-06-08

Here in this study, the high temperature compressive response of cast aluminum alloys 319 and RR350 is compared in light of their microstructures. The 319 alloy is widely used in thermally critical automotive applications and provides a baseline for comparison with the RR350 alloy, whose microstructural stability at high homologous temperatures was recently reported. Cylindrical compression samples from each alloy were tested at four temperatures up to 300 °C at a constant true strain rate that was varied over four orders of magnitude. Although both alloys are strengthened by metastable precipitates (nominally Al 2Cu) in the as-aged condition, their mechanicalmore » response diverges at temperatures greater than 250 °C as the strengthening precipitates evolve in the 319 alloy and retain their as-aged morphology in the RR350 alloy. Deformation mechanisms of each alloy are examined using microstructural analysis and empirical activation energy calculations. The stability of the θ' phase in the RR350 alloy leads to effective precipitation hardening at homologous temperatures up to 0.6 and an extensive regime of grain boundary controlled deformation.« less

The Effect of Ca Content on the Microstructure, Hardness and Tensile Properties of AZ81 Mg Cast Alloy

NASA Astrophysics Data System (ADS)

Allameh, S. H.; Emamy, M.

2017-05-01

The effects of various Ca contents (0.1-4 wt.%) on the microstructure and tensile properties of AZ81 magnesium alloy were investigated with the contribution of an analytical method. Ca addition (up to 1.0 wt.%) refined the alloy microstructure but further addition of Ca resulted in a coarse structure and introduced large dendrites within the grains. The changes in the microstructures revealed that Al4Ca, Al2Ca, τ-Mg32(A1,Zn)49 and ɛ-MgZn intermetallics are formed in the alloy as a result of Ca addition and Al consumption. The assessment of tensile properties of AZ81-1.0 wt.%Ca alloy showed the optimum values of yield strength and ultimate tensile strength, while AZ81-0.7 wt.%Ca alloy showed maximum elongation. The reduction in tensile properties of the cast alloy by the addition of more Ca was attributed to grain coarsening and evolution of a network of intermetallic compounds. FF study of tensile fractured surfaces indicated that Ca addition encourages brittle mode of fracture propagating through precipitated intermetallics in the structure.

Mechanical property degradation and microstructural evolution of cast austenitic stainless steels under short-term thermal aging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lach, Timothy G.; Byun, Thak Sang; Leonard, Keith J.

Mechanical testing and microstructural characterization were performed on short-term thermally aged cast austenitic stainless steels (CASS) to understand the severity and mechanisms of thermal-aging degradation experienced during extended operation of light water reactor (LWR) coolant systems. Four CASS materials – CF3, CF3M, CF8, and CF8M – were thermally aged for 1500 hours at 290 °C, 330 °C, 360 °C, and 400 °C. All four alloys experienced insignificant change in strength and ductility properties but a significant reduction in absorbed impact energy. The primary microstructural and compositional changes during thermal aging were spinodal decomposition of the δ-ferrite into α/ α`, precipitationmore » of G-phase in the δ-ferrite, segregation of solute to the austenite/ ferrite interphase boundary, and growth of M23C6 carbides on the austenite/ferrite interphase boundary. These changes were shown to be highly dependent on chemical composition, particularly the concentration of C and Mo, and aging temperature. A comprehensive model is being developed to correlate the microstructural evolution with mechanical behavior and simulation for predictive evaluations of LWR coolant system components.« less

20. TAKING A CAST AT BLAST FURNACE NO. 1. WORKERS, ...

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

20. TAKING A CAST AT BLAST FURNACE NO. 1. WORKERS, LIKE THE ONE STANDING ON THE BRIDGE ABOVE THE 'BOTTLE' INTO WHICH THE HOT IRON FLOWS, ARE PROTECTED BY HEAVY FIREPROOF GARMENTS. - Corrigan, McKinney Steel Company, 3100 East Forty-fifth Street, Cleveland, Cuyahoga County, OH

Cast Ductile Iron 155mm M804 Bodies

DTIC Science & Technology

1990-07-12

for the final delivery. The balance of the parts were returned to Wagner Castings for analysis, scrap, or de-militarization. The radiographic...as possible to avoid pre-cure. Mixing/ mulling time should be consistent with the system " worklife " or poor composite properties will result. Tensile...Burn-in on castings is caused by poor sand density, poor mixing, out of balance mix or improper drying of the wash. Long set times are an indication

Toughness Properties of Nodular Iron

NASA Astrophysics Data System (ADS)

Bradley, Walter L.

1985-01-01

The German government recently certified ductile iron for construction of nuclear waste transport containers. This approved use of ductile iron for such a critical application represents the culmination of ten years worth of research bringing to light the surprising toughness of ductile iron. This article explains how modern fracture mechanics and microstructure/property relationships have altered the stereotype of ductile iron as a low toughness material.

75 FR 20335 - Certain Oil Country Tubular Goods from the People's Republic of China: Final Determination of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-19

... tubing, of iron (other than cast iron) or steel (both carbon and alloy), whether seamless or welded... Seamless Tube Mill of Inner Mongolia Baotou Steel 29.94 and Trading Co., Ltd Union Co., Ltd.\\27\\ Benxi... Century Machinery Co. Ltd.;Tianjin Seamless Steel Pipe Plant; Baoshan Iron & Steel Co. Ltd Shengli...

Thermal cooling effects in the microstructure and properties of cast cobalt-base biomedical alloys

NASA Astrophysics Data System (ADS)

Vega Valer, Vladimir

Joint replacement prosthesis is widely used in the biomedical field to provide a solution for dysfunctional human body joints. The demand for orthopedic knee and hip implants motivate scientists and manufacturers to develop novel materials or to increase the life of service and efficiency of current materials. Cobalt-base alloys have been investigated by various researchers for biomedical implantations. When these alloys contain Chromium, Molybdenum, and Carbon, they exhibit good tribological and mechanical properties, as well as excellent biocompatibility and corrosion resistance. In this study, the microstructure of cast Co-Cr-Mo-C alloy is purposely modified by inducing rapid solidification through fusion welding processes and solution annealing heat treatment (quenched in water at room temperature. In particular the effect of high cooling rates on the athermal phase transformation FCC(gamma)↔HCP(epsilon) on the alloy hardness and corrosion resistance is investigated. The Co-alloy microstructures were characterized using metallography and microscopy techniques. It was found that the as cast sample typically dendritic with dendritic grain sizes of approximately 150 microm and containing Cr-rich coarse carbide precipitates along the interdendritic boundaries. Solution annealing gives rise to a refined microstructure with grain size of 30 microm, common among Co-Cr-Mo alloys after heat treating. Alternatively, an ultrafine grain structure (between 2 and 10 microm) was developed in the fusion zone for specimens melted using Laser and TIG welding methods. When laser surface modification treatments were implemented, the developed solidification microstructure shifted from dendritic to a fine cellular morphology, with possible nanoscale carbide precipitates along the cellular boundaries. In turn, the solidified regions exhibited high hardness values (461.5HV), which exceeds by almost 110 points from the alloy in the as-cast condition. The amount of developed athermal epsilon-martensite phase was determined using X-ray diffractrometry. It was found that the amount of epsilon-martensite increases significantly from 2% for the Laser surface processing to 13% in the as cast specimen, 24% in the annealed specimen, and 51% for the TIG surface processing. Moreover, the corrosion rate in Ringer solution was calculated by applying the Tafel extrapolation method on each alloy condition. The lowest corrosion rate (0.435 microm/year) was achieved in the Laser treated alloy and it is attributed to the lack of appreciable athermal epsilon-martensite. The highest corrosion rate (15.5 microm/year) was found to occur in the TIG treated alloy, which possesses the largest amount of epsilon-martensite. In turn, this suggests that surface modification through melting induces variable amounts of athermal epsilon-martensite in the as-cast Co-Cr-Mo-C alloys. Apparently, rapid solidification of melted surfaces in the Co-alloy is highly effective in modifying the induced amounts of HCP phase, and hence, the exhibited properties.

Sensitivity of Austempering Heat Treatment of Ductile Irons to Changes in Process Parameters

NASA Astrophysics Data System (ADS)

Boccardo, A. D.; Dardati, P. M.; Godoy, L. A.; Celentano, D. J.

2018-06-01

Austempered ductile iron (ADI) is frequently obtained by means of a three-step austempering heat treatment. The parameters of this process play a crucial role on the microstructure of the final product. This paper considers the influence of some process parameters ( i.e., the initial microstructure of ductile iron and the thermal cycle) on key features of the heat treatment (such as minimum required time for austenitization and austempering and microstructure of the final product). A computational simulation of the austempering heat treatment is reported in this work, which accounts for a coupled thermo-metallurgical behavior in terms of the evolution of temperature at the scale of the part being investigated (the macroscale) and the evolution of phases at the scale of microconstituents (the microscale). The paper focuses on the sensitivity of the process by looking at a sensitivity index and scatter plots. The sensitivity indices are determined by using a technique based on the variance of the output. The results of this study indicate that both the initial microstructure and the thermal cycle parameters play a key role in the production of ADI. This work also provides a guideline to help selecting values of the appropriate process parameters to obtain parts with a required microstructural characteristic.

A Study on the Physical Properties and Interfacial Reactions with Cu Substrate of Rapidly Solidified Sn-3.5Ag Lead-Free Solder

NASA Astrophysics Data System (ADS)

Ma, Hai-Tao; Wang, Jie; Qu, Lin; Zhao, Ning; Kunwar, A.

2013-08-01

A rapidly solidified Sn-3.5Ag eutectic alloy produced by the melt-spinning technique was used as a sample in this research to investigate the microstructure, thermal properties, solder wettability, and inhibitory effect of Ag3Sn on Cu6Sn5 intermetallic compound (IMC). In addition, an as-cast Sn-3.5Ag solder was prepared as a reference. Rapidly solidified and as-cast Sn-3.5Ag alloys of the same size were soldered at 250°C for 1 s to observe their instant melting characteristics and for 3 s with different cooling methods to study the inhibitory effect of Ag3Sn on Cu6Sn5 IMC. Experimental techniques such as scanning electron microscopy, differential scanning calorimetry, and energy-dispersive spectrometry were used to observe and analyze the results of the study. It was found that rapidly solidified Sn-3.5Ag solder has more uniform microstructure, better wettability, and higher melting rate as compared with the as-cast material; Ag3Sn nanoparticles that formed in the rapidly solidified Sn-3.5Ag solder inhibited the growth of Cu6Sn5 IMC during aging significantly much strongly than in the as-cast material because their number in the rapidly solidified Sn-3.5Ag solder was greater than in the as-cast material with the same soldering process before aging. Among the various alternative lead-free solders, this study focused on comparison between rapidly solidified and as-cast solder alloys, with the former being observed to have better properties.

[Mineral migration from stainless steel, cast iron and soapstone (steatite) Brazilian pans to food preparations].

PubMed

Quintaes, Késia Diego; Farfan, Jaime Amaya; Tomazini, Fernanda Mariana; Morgano, Marcelo Antônio

2006-09-01

Culinary utensils may release some inorganic elements during food preparation. Mineral migration can be beneficial for as long as it occurs in amounts adequate to the needs of the consumer or no toxicological implications are involved. In this study, the migrations of Fe, Mg, Mn, Cr, Ni and Ca, along seven cooking cycles were evaluated for two food preparations (polished rice and commercial tomato sauce, the latter as an acid food), performed in unused stainless steel, cast iron and soapstone pans, taking refractory glass as a blank. Minerals were determined by inductively coupled plasma optical emission spectrometry (ICP OES). The utensils studied exhibited different rates, patterns and variability of migration depending on the type of food. Regression analysis of the data revealed that, as a function of the number of cycles, the iron pans released increasing amounts of iron when tomato sauce was cooked (y = 70.76x + 276.75; R2 = 0.77). The soapstone pans released calcium (35 and 26 mg/kg), magnesium (25 and 15 mg/kg) into the tomato sauce and rice preparations, respectively. Additionally, the commercial tomato sauce drew manganese (3.9 and 0.6 mg/kg) and some undesirable nickel (1.0 mg/kg) from the soapstone material, whereas the stainless steel pans released nickel at a lower rate than steatite and in a diminishing fashion with the number o cooking cycles, while still transferring some iron and chromium to the food. We conclude that while cast iron and glass could be best for the consumer's nutritional health, stainless steel and steatite can be used with relatively low risk, provided acid foods are not routinely prepared in those materials.

Characterization of biofilm and corrosion of cast iron pipes in drinking water distribution system with UV/Cl2 disinfection.

PubMed

Zhu, Ying; Wang, Haibo; Li, Xiaoxiao; Hu, Chun; Yang, Min; Qu, Jiuhui

2014-09-01

The effect of UV/Cl2 disinfection on the biofilm and corrosion of cast iron pipes in drinking water distribution system were studied using annular reactors (ARs). Passivation occurred more rapidly in the AR with UV/Cl2 than in the one with Cl2 alone, decreasing iron release for higher corrosivity of water. Based on functional gene, pyrosequencing assays and principal component analysis, UV disinfection not only reduced the required initial chlorine dose, but also enhanced denitrifying functional bacteria advantage in the biofilm of corrosion scales. The nitrate-reducing bacteria (NRB) Dechloromonas exhibited the greatest corrosion inhibition by inducing the redox cycling of iron to enhance the precipitation of iron oxides and formation of Fe3O4 in the AR with UV/Cl2, while the rhizobia Bradyrhizobium and Rhizobium, and the NRB Sphingomonas, Brucella producing siderophores had weaker corrosion-inhibition effect by capturing iron in the AR with Cl2. These results indicated that the microbial redox cycling of iron was possibly responsible for higher corrosion inhibition and lower effect of water Larson-Skold Index (LI) changes on corrosion. This finding could be applied toward the control of water quality in drinking water distribution systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Magnetite-hematite transformation: correlation between natural and synthetic features

NASA Astrophysics Data System (ADS)

Barbosa, Paola F.; Lagoeiro, Leonardo; Scholz, Ricardo; Graça, Leonardo M.; Mohallem, Nelcy

2015-06-01

The iron-oxide system can be used as a marker of oxidized and reduced conditions in closed systems. However, natural rocks with iron oxide minerals also exhibit such reactions, although the natural system is typically open. To understand the behaviour of this natural system, some similarities were investigated, in terms of crystallographic textures, between the microstructures of two systems: natural open system and synthetic closed system of iron oxide phase transformation. Particular cases of phase transformation in iron oxide minerals, described as natural reactions of magnetite to hematite and synthetic reactions of hematite to magnetite, were chosen. It is observed, in both scenarios, that the transformation obeys the topotaxial and epitaxial relationship, which are well described for the iron oxide system. However, in natural open systems, the precipitation of a new phase during the in situ transformation modifies the microstructures and must be taken into account as an important factor to describe them.

Study of grain structure evolution during annealing of a twin-roll-cast Mg alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, A.; Department of Metallurgical Engineering and Materials Science, IIT Bombay; Department of Materials Engineering, Monash University

2016-04-15

The evolution of microstructure under static annealing was studied for mid-thickness section of a twin-roll-cast (TRC) magnesium alloy. Annealing was performed at 300 °C and 500 °C for different times. Microstructural evolution was quantitatively analyzed, from optical micrographs, using grain path envelope analysis. Additional information from electron backscatter diffraction (EBSD) was used for addressing the possible mechanism(s). It was found that the TRC structure had a bimodal grain size, which was preserved even after annealing at 300 °C. However, the annealing at 500 °C led to a unimodal grain size. This difference in the grain size distribution created a contrastingmore » behavior in the normalized standard deviations. This was primarily attributed to a competition between recovery and recrystallization, and their respective dominance at 300° and 500 °C. A deformation induced recrystallization recovery (DIRR) model was proposed. The proposed model could successfully address the experimental microstructural evolution. - Highlights: • Annealing of twin roll cast (TRC) magnesium alloy was done at temperatures of 300 °C and 500 °C. • TRC had bimodal structure. Bimodality preserved for annealing at 300 °C. Annealing at 500 °C led to unimodal structure. • Grain evolution was described based on the competition between recovery and recrystallization. • Deformation induced recrystallization recovery (DIRR) mechanistic model was developed.« less

Effect of Grain Refining on Defect Formation in DC Cast Al-Zn-Mg-Cu Alloy Billet

NASA Astrophysics Data System (ADS)

Nadella, Ravi; Eskin, Dmitry; Katgerman, Laurens

In direct chill (DC) casting, the effect of grain refining on the prominent defects such as hot cracking and macrosegregation remains poorly understood, especially for multi-component commercial aluminum alloys. In this work, DC casting experiments were conducted on a 7075 alloy with and without grain refining at two casting speeds. The grain refiner was introduced either in the launder or in the furnace. The concentration profiles of Zn, Cu and Mg, measured along the billet diameter, showed that the increasing casting speed raises the segregation levels but grain refining does not seem to have a noticeable effect. However, hot cracking tendency is significantly reduced with grain refining and it is observed that crack is terminated with the introduction of grain refiner at a lower casting speed. These experimental results are correlated with microstructural observations such as grain size and morphology, and the occurrence of floating grains.

Modeling of interdendritic porosity defects in an integrated computational materials engineering approach for metal casting

DOE PAGES

Sabau, Adrian S.

2016-04-22

Modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components in order to accelerate the introduction of new cast alloys. The data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the component. Here in this paper, the required models for the prediction of interdendritic casting defects, such as microporosity and hot tears, are reviewed. The data on calculated solidification shrinkage is presented and its effects on microporosity levels discussed. Numerical simulation results for microporosity are presented for A356, 356 and 319 aluminummore » alloys using ProCAST TM software. The calculated pressure drop of the interdendritic liquid was observed to be quite significant and the regions of high-pressure drop can be used as an indicator of the severity of interdendritic microporosity defects.« less

Structure and properties of stir-cast zinc alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

LeHuy, H.; Blain J.; Masounave, J.

Stir casting (or rheocasting) of ZA-27 zinc alloys was investigated experimentally. By vigorously agitating the alloys during cooling, the dendrites that were forming were fragmented giving a unique structure composed of spherical and rosette shaped particles suspended in the remaining liquid. Under high shear rates ({center dot}{gamma} = 300s{sup {minus}1} or more) the slurries with primary particle concentrations as high as 60% displayed viscosities as low as 20 poises and could easily be casted. The effects of processing variables such as shearing and cooling rates and casting temperatures were studied. Their relative importance on the rheological and microstructural behavior ofmore » the stir cast alloys are discussed. Results from viscosity measurements on slurries show that non-dendritical ZA-27 alloys obey a power law fluid model. Finally, results from mechanical and compressive studies carried out on solidified slurries are discussed and compared to conventional casted and wrought alloy properties.« less

Fabrication of Ti-0.48Al Alloy by Centrifugal Casting.

PubMed

Park, Jong Bum; Lee, Jung-Il; Ryu, Jeong Ho

2018-09-01

Many of the unique properties of TiAl alloys that make are attractive for use in high-temperature structural applications also make it challenging to process them into useful products. Cast TiAl is rapidly nearing commercialization, particularly in the vehicle industry, owing to its low production cost. In this study, the centrifugal casting of a TiAl (Ti-48%Al, mole fraction) turbocharger was simulated and an experimental casting was created in vacuum using an induction melting furnace coupled to a ceramic composite mold. Numerical simulation results agreed with the experiment. The crystal structure, microstructure, and chemical composition of the TiAl prepared by centrifugal casting were studied by X-ray diffractometry, optical microscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). FE-SEM and EDS examinations of the TiAl casting revealed that the thickness of the oxide layer (α-case) was typically less than 35 μm.

49 CFR 192.369 - Service lines: Connections to cast iron or ductile iron mains.

Code of Federal Regulations, 2010 CFR

2010-10-01

... by a mechanical clamp, by drilling and tapping the main, or by another method meeting the requirements of § 192.273. (b) If a threaded tap is being inserted, the requirements of § 192.151 (b) and (c...

Austempered ductile iron (ADI) for railroad wheels : final report.

DOT National Transportation Integrated Search

2017-01-31

The purpose of this project is to investigate the potential for austempered ductile iron (ADI) to be used as an alternative material for the production of rail wheels, which are currently cast or forged steel which is commonly heat treated. ADI has s...

Reductive dehalogenation of endosulfan by cast iron: Kinetics, pathways and modeling.

PubMed

Lama, Yangdup; Sinha, Alok; Singh, Gurdeep; Masto, Reginald E

2016-05-01

Cast iron has been a material of choice for in-situ remediation of groundwater. In this study interaction of endosulfan with High Carbon Iron Filings (HCIF) was studied in batch reactors. Decline in total concentration (Ct) could be related to aqueous concentration (Ca) by equation dCt/dt = k1.M.Ca(n), where reaction rate constant (k1) and order (n) were found to be 1.246 × 10(-4) L g(-1) iron h(-1) and 1.47, respectively. Partitioning of endosulfan to HCIF could be explained by Freundlich isotherm. The process of simultaneous reductive dehalogenation and adsorption/desorption was successfully modelled. The reductive dehalogenation of endosulfan resulted in by-products identified as [(3a, alpha,7beta,7a alpha,8s)-4,5,6,7,8 Pentachloro 3a,4,7,7a-tetrahydro] (C9H3Cl5O3) and Benzofuran,4,5,7-trichloro-2,3-dihydro-2-methyl (C9H7Cl3O). Copyright © 2015 Elsevier Ltd. All rights reserved.

Microstructure and Phase Stability of Single Crystal NiAl Alloyed with Hf and Zr

NASA Technical Reports Server (NTRS)

Locci, I. E.; Dickerson, R. M.; Garg, A.; Noebe, R. D.; Whittenberger, J. D.; Nathal, M. V.; Darolia, R.

1996-01-01

Six near stoichiometric, NiAl single-crystal alloys, with 0.05-1.5 at.% of Hf and Zr additions plus Si impurities, were microstructurally analyzed in the as-cast, homogenized, and aged conditions. Hafnium-rich interdendritic regions, containing the Heusler phase (Ni2AlHf), were found in all the as-cast alloys containing Hf. Homogenization heat treatments partially reduced these interdendritic segregated regions. Transmission electron microscopy (TEM) observations of the as-cast and homogenized microstructures revealed the presence of a high density of fine Hf (or Zr) and Si-rich precipitates. These were identified as G-phase, Nil6X6Si7, or as an orthorhombic NiXSi phase, where X is Hf or Zr. Under these conditions the expected Heusler phase (beta') was almost completely absent. The Si responsible for the formation of the G and NiHfSi phases is the result of molten metal reacting with the Si-containing crucible used during the casting process. Varying the cooling rates after homogenization resulted in the refinement or complete suppression of the G and NiHfSi phases. In some of the alloys studied, long-term aging heat treatments resulted in the formation of Heusler precipitates, which were more stable at the aging temperature and coarsened at the expense of the G-phase. In other alloys, long-term aging resulted in the formation of the NiXSi phase. The stability of the Heusler or NiXSi phases can be traced to the reactive element (Hf or Zr) to silicon ratio. If the ratio is high, then the Heusler phase appears stable after long time aging. If the ratio is low, then the NiHfSi phase appears to be the stable phase.

Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au; Wood, Kathleen; Taylor, Adam

2016-02-15

A high strength low alloy steel composition has been melted and processed by two different routes: simulated direct strip casting and slow cooled ingot casting. The microstructures were examined with scanning and transmission electron microscopy, atom probe tomography and small angle neutron scattering (SANS). The formation of cementite (Fe{sub 3}C), manganese sulphides (MnS) and niobium carbo-nitrides (Nb(C,N)) was investigated in both casting conditions. The sulphides were found to be significantly refined by the higher cooling rate, and developed an average diameter of only 100 nm for the fast cooled sample, and a diameter too large to be measured with SANSmore » in the slow cooled condition (> 1.1 μm). Slow cooling resulted in the development of classical Nb(C,N) precipitation, with an average diameter of 7.2 nm. However, after rapid cooling both the SANS and atom probe tomography data indicated that the Nb was retained in the matrix as a random solid solution. There was also some evidence that O, N and S are also retained in solid solution in levels not found during conventional processing. - Highlights: • The influence of cooling rate on microstructure is investigated in a HSLA steel. • SANS, TEM and APT are used to characterise the sulphides and Nb(C,N) precipitates. • The slow cooling rate result in the formation of Nb(C,N) precipitates. • The fast cooling rate results in a microstructure supersaturated in Nb, C and N. • The sulphides are 100 nm in the fast cooled sample and > 1 μm in the slow cooled one.« less

Microstructure and hydrogenation properties of a melt-spun non-stoichiometric Zr-based Laves phase alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Tiebang, E-mail: tiebangzhang@nwpu.edu.cn; Zhang, Yunlong; Li, Jinshan

2016-01-15

Alloy with composition of Zr{sub 0.9}Ti{sub 0.1}V{sub 1.7} off normal stoichiometric proportion is selected to investigate the effect of defects introduced by non-stoichiometry on hydrogenation kinetics of Zr–Ti–V Laves phase alloys. Microstructure and phase constituent of melt-spun ribbons have been investigated in this work. The activation process, hydrogenation kinetics, thermodynamics characteristics and hydride phase constituent of as-cast alloy and melt-spun ribbons are also compared. Comparing with the as-cast alloy, the dominant Laves phase ZrV{sub 2} is preserved, V-BCC phase is reduced and α-Zr phase is replaced by a small amount of Zr{sub 3}V{sub 3}O phase in melt-spun ribbons. Melt-spun ribbonsmore » exhibit easy activation and fast initial hydrogen absorption on account of the increased specific surface area. However, the decrease in unit cell volume of the dominant phase leads to the decrease in hydrogen absorption capacity. Melt-spinning technique raises the equilibrium pressure and decreases the stability of hydride due to the decrease of unit cell volume and the elimination of α-Zr phase, respectively. Melt-spun ribbons with fine grains show improved hydrogen absorption kinetics comparing with that of the as-cast alloy. Meanwhile, the prevalent micro twins observed within melt-spun ribbons are believed to account for the improved hydrogen absorption kinetics. - Highlights: • Role of defects on hydrogenation kinetics of Zr-based alloys is proposed. • Microstructure and hydrogenation properties of as-cast/melt-spun alloy are compared. • Melt-spinning technique improves the hydrogenation kinetics of Zr{sub 0.9}Ti{sub 0.1}V{sub 1.7} alloy. • Refined grains and twin defects account for improved hydrogen absorption kinetics.« less

A Comparative Study of Hot Deformation Behaviors for Sand Casting and Centrifugal Casting Q235B Flange Blanks

NASA Astrophysics Data System (ADS)

Qin, Fangcheng; Li, Yongtang; Ju, Li

2017-03-01

Hot compression tests of sand casting and centrifugal casting Q235B flange blanks were performed at strain rate range of 0.01-5 s-1 and temperature range of 850-1,150 °C. The evolutions of microstructure and texture were revealed. The constitutive models based on Arrhenius constitutive modeling were proposed by considering the effects of strain on material constants. The results show that recrystallization in centrifugal casting Q235B is more apparent than that in sand casting, resulting in the finer grains and lower flow stress for centrifugal casting Q235B. The intensities of textures slightly weaken with the increase of temperature. At 1,050 °C and 5 s-1, the textures of sand casting are characterized by strong {001}<100> and {001}<110>, which are related with severe deformation, while the textures of centrifugal casting are composed of {110}<110> and {111}<112>, which are related with dynamic recovery and shear deformation. A good agreement between the predicted and experimental flow stress is achieved and demonstrates that the proposed constitutive models are reliable.

Development of a new casting method to fabricate U–Zr alloy containing minor actinides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jong Hwan Kim; Hoon Song; Hyung Tae Kim

2014-01-01

Metal fuel slugs of U–Zr alloys for a sodium-cooled fast reactor (SFR) have conventionally been fabricated using an injection casting method. However, casting alloys containing volatile radioactive constituents, such as Am, are problematic in a conventional injection casting method. As an alternative fabrication method, low pressure gravity casting has been developed. Casting soundness, microstructural characteristics, alloying composition, density, and fuel losses were evaluated for the following as-cast fuel slugs: U–10 wt% Zr, U–10 wt% Zr–5 wt% RE, and U–10 wt% Zr–5 wt% RE–5 wt% Mn. The U and Zr contents were uniform throughout the matrix, and impurities such as oxyen,more » carbon, and nitrogen satisfied the specification of total impurities less than 2,000 ppm. The appearance of the fuel slugs was generally sound, and the internal integrity was shown to be satisfactory based on gamma-ray radiography. In a volatile surrogate casting test, the U–Zr–RE–Mn fuel slug showed that nearly all of the manganese was retained when casting was done under an inert atmosphere.« less

A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties.

PubMed

Zhang, Xuezheng; Chen, Tijun; Qin, He; Wang, Chong

2016-05-24

Microstructural and mechanical characterization of 10 vol% SiC particles (SiC p ) reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF) was investigated in comparison with the PTF and permanent mold cast (PMC) 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiC p , which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa) of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

The effects of annealing on the microstructure and mechanical properties of Fe 28Ni 18Mn 33Al 21

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Fanling; Qiu, Jingwen; Baker, Ian

In this paper, As-cast Fe 28Ni 18Mn 33Al 21, which consists of aligned, 50 nm, (Ni, Al)-rich B2, and (Fe, Mn)-rich f.c.c. phases, was annealed at a variety of temperatures up to 1423 K and the microstructure and mechanical properties were examined. It was shown that the as-cast microstructure arises from a eutectoid transformation at ~1300 K. Annealing at temperatures ≤1073 K produces β-Mn-structured precipitates and hardness values up to 816 HV, while annealing at temperatures >1073 K leads to dramatic coarsening of the two-phase B2/f.c.c. microstructure (up to 5.5 µm after 50 h at 1273 K), but does notmore » lead to β-Mn precipitation. Interestingly, annealing at temperatures >1073 K delays the onset of β-Mn precipitation during subsequent anneals at lower temperatures. Coarsening the B2/f.c.c. lamellar structure by annealing at higher temperatures softens it and leads to increases in ductility from fracture before yield to ~8 % elongation. Finally, the presence of β-Mn precipitates makes the very fine, brittle B2/f.c.c. microstructures even more brittle, but significant ductility (8.4 % elongation) is possible even with β-Mn precipitates present if the B2/f.c.c. matrix is coarse and, hence, more ductile.« less

The effects of annealing on the microstructure and mechanical properties of Fe 28Ni 18Mn 33Al 21

DOE PAGES

Meng, Fanling; Qiu, Jingwen; Baker, Ian; ...

2015-08-20

In this paper, As-cast Fe 28Ni 18Mn 33Al 21, which consists of aligned, 50 nm, (Ni, Al)-rich B2, and (Fe, Mn)-rich f.c.c. phases, was annealed at a variety of temperatures up to 1423 K and the microstructure and mechanical properties were examined. It was shown that the as-cast microstructure arises from a eutectoid transformation at ~1300 K. Annealing at temperatures ≤1073 K produces β-Mn-structured precipitates and hardness values up to 816 HV, while annealing at temperatures >1073 K leads to dramatic coarsening of the two-phase B2/f.c.c. microstructure (up to 5.5 µm after 50 h at 1273 K), but does notmore » lead to β-Mn precipitation. Interestingly, annealing at temperatures >1073 K delays the onset of β-Mn precipitation during subsequent anneals at lower temperatures. Coarsening the B2/f.c.c. lamellar structure by annealing at higher temperatures softens it and leads to increases in ductility from fracture before yield to ~8 % elongation. Finally, the presence of β-Mn precipitates makes the very fine, brittle B2/f.c.c. microstructures even more brittle, but significant ductility (8.4 % elongation) is possible even with β-Mn precipitates present if the B2/f.c.c. matrix is coarse and, hence, more ductile.« less

VIEW FROM THE SOUTH OF THE #2 BLAST FURNACE AND ...

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

VIEW FROM THE SOUTH OF THE #2 BLAST FURNACE AND CASTING SEED ON THE LEFT, THE #1 BLAST FURNACE AND CASTING SHED ON THE RIGHT, AND THE STOVES, BOILERS, AND AUXILIARY EQUIPMENT IN THE CENTER. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

Effect of Al on Grain Refinement and Mechanical Properties of Mg-3Nd Casting Alloy

NASA Astrophysics Data System (ADS)

Wang, Lei; Feng, Yicheng; Wang, Liping; Chen, Yanhong; Guo, Erjun

2018-05-01

The effect of Al on the grain refinement and mechanical properties of as-cast Mg-3Nd alloy was investigated systematically by a series of microstructural analysis, solidification analysis and tensile tests. The results show that Al has an obvious refining effect on the as-cast Mg-3Nd alloy. With increasing Al content, the grain size of the as-cast Mg-3Nd alloy decreases firstly, then increases slightly after the Al content reaching 3 wt.%, and the minimum grain size of the Mg-3Nd alloy is 48 ± 4.0 μm. The refining mechanism can be attributed to the formation of Al2Nd particles, which play an important role in the heterogeneous nucleation. The strength and elongation of the Mg-3Nd alloy refined by Al also increase with increasing Al content and slightly decrease when the Al content is more than 3 wt.%, and the strengthening mechanism is attributed to the grain refinement as well as dispersed intermetallic particles. Furthermore, the microstructural thermal stability of the Mg-3Nd-3Al alloy is higher than that of the Mg-3Nd-0.5Zr alloy. Overall, the Mg-3Nd alloy with Al addition is a novel alloy with wide and potential application prospects.

Cast iron-base alloy for cylinder/regenerator housing

NASA Technical Reports Server (NTRS)

Witter, Stewart L.; Simmons, Harold E.; Woulds, Michael J.

1985-01-01

NASACC-1 is a castable iron-base alloy designed to replace the costly and strategic cobalt-base X-40 alloy used in the automotive Stirling engine cylinder/generator housing. Over 40 alloy compositions were evaluated using investment cast test bars for stress-rupture testing. Also, hydrogen compatibility and oxygen corrosion resistance tests were used to determine the optimal alloy. NASACC-1 alloy was characterized using elevated and room temperature tensile, creep-rupture, low cycle fatigue, heat capacity, specific heat, and thermal expansion testing. Furthermore, phase analysis was performed on samples with several heat treated conditions. The properties are very encouraging. NASACC-1 alloy shows stress-rupture and low cycle fatigue properties equivalent to X-40. The oxidation resistance surpassed the program goal while maintaining acceptable resistance to hydrogen exposure. The welding, brazing, and casting characteristics are excellent. Finally, the cost of NASACC-1 is significantly lower than that of X-40.

Development of cast alumina-forming austenitic stainless steels

DOE PAGES

Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; ...

2016-09-06

Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt. % are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt. % Ni with good creep strength and the ability to form a protective alumina scale for use atmore » temperatures up to 800 C - 850 C in H 2O-, S-, and C- containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloy along with improved oxidation resistance typical of alumina-forming alloys. Lastly, challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.« less

Development of Cast Alumina-Forming Austenitic Stainless Steels

NASA Astrophysics Data System (ADS)

Muralidharan, G.; Yamamoto, Y.; Brady, M. P.; Walker, L. R.; Meyer, H. M., III; Leonard, D. N.

2016-11-01

Cast Fe-Ni-Cr chromia-forming austenitic stainless steels with Ni levels up to 45 wt.% are used at high temperatures in a wide range of industrial applications that demand microstructural stability, corrosion resistance, and creep strength. Although alumina scales offer better corrosion protection at these temperatures, designing cast austenitic alloys that form a stable alumina scale and achieve creep strength comparable to existing cast chromia-forming alloys is challenging. This work outlines the development of cast Fe-Ni-Cr-Al austenitic stainless steels containing about 25 wt.% Ni with good creep strength and the ability to form a protective alumina scale for use at temperatures up to 800-850°C in H2O-, S-, and C-containing environments. Creep properties of the best alloy were comparable to that of HK-type cast chromia-forming alloys along with improved oxidation resistance typical of alumina-forming alloys. Challenges in the design of cast alloys and a potential path to increasing the temperature capability are discussed.

Thin Gauge Twin-Roll Casting, Process Capabilities and Product Quality

NASA Astrophysics Data System (ADS)

Daaland, O.; Espedal, A. B.; Nedreberg, M. L.; Alvestad, I.

Traditionally industrial twin roll casters have been operated at gauges 6-10 mm, depending on the type of caster and the final product requirements. Over the past few years it has become apparent that a significant increase in productivity can be achieved when the casting gauge is reduced. Hydro Aluminium embarked on an extensive research and development, thin gauge casting programme, in the beginning of the 1990's and this paper presents some results from a five year lasting project (joint programme between Hydro Aluminium a.s. and Lauener Engineering). Based on more than 400 casting trials the major benefits and limitations of casting at reduced gauge and increased speed are outlined. Important aspects related to process development and product quality are discussed including: productivity and limitations, surface defects, microstructural characteristics, cooling rates and dendrite structure, segregation behaviour and mechanical properties after thermo-mechanical processing. Results for casting of several alloys are given. Additionally, numerical modelling results of the strip casting process are included.

Influence of rotational speed of centrifugal casting process on appearance, microstructure, and sliding wear behaviour of Al-2Si cast alloy

NASA Astrophysics Data System (ADS)

Mukunda, P. G.; Shailesh, Rao A.; Rao, Shrikantha S.

2010-02-01

Although the manner in which the molten metal flows plays a major role in the formation of the uniform cylinder in centrifugal casting, not much information is available on this topic. The flow in the molten metal differs at various rotational speeds, which in turn affects the final casting. In this paper, the influence of the flow of molten metal of hyper eutectic Al-2Si alloys at various rotational speeds is discussed. At an optimum speed of 800 rpm, a uniform cylinder was formed. For the rotational speeds below and above these speeds, an irregular shaped casting was formed, which is mainly due to the influence of melt. Primary á-Al particles were formed in the tube periphery at low rotational speed, and their sizes and shapes were altered with changes in rotational speeds. The wear test for the inner surface of the casting showed better wear properties for the casting prepared at the optimum speed of rotation.

Effect of intermediate annealing on the microstructure and mechanical property of ZK60 magnesium alloy produced by twin roll casting and hot rolling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Hongmei, E-mail: hmchen@just.edu.cn; Zang, Qianhao; Yu, Hui

2015-08-15

Twin roll cast (designated as TRC in short) ZK60 magnesium alloy strip with 3.5 mm thickness was used in this paper. The TRC ZK60 strip was multi-pass rolled at different temperatures, intermediate annealing heat treatment was performed when the thickness of the strip changed from 3.5 mm to 1 mm, and then continued to be rolled until the thickness reached to 0.5 mm. The effect of intermediate annealing during rolling process on microstructure, texture and room temperature mechanical properties of TRC ZK60 strip was studied by using OM, TEM, XRD and electronic universal testing machine. The introduction of intermediate annealingmore » can contribute to recrystallization in the ZK60 sheet which was greatly deformed, and help to reduce the stress concentration generated in the rolling process. Microstructure uniformity and mechanical properties of the ZK60 alloy sheet were also improved; in particular, the room temperature elongation was greatly improved. When the TRC ZK60 strip was rolled at 300 °C and 350 °C, the room temperature elongation of the rolled sheet with 0.5 mm thickness which was intermediate annealed during the rolling process was increased by 95% and 72% than that of no intermediate annealing, respectively. - Highlights: • Intermediate annealing was introduced during hot rolling process of twin roll cast ZK60 alloy. • Intermediate annealing can contribute to recrystallization and reduce the stress concentration in the deformed ZK60 sheet. • Microstructure uniformity and mechanical properties of the ZK60 sheet were improved, in particular, the room temperature elongation. • The elongation of the rolled ZK60 sheet after intermediate annealed was increased by 95% and 72% than that of no intermediate annealing.« less

Development of ceramic matrix composites for application in the ceramic technology for Advanced Heat Engines Project: Phase 2a, Development of in-situ toughened silicon nitride. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pollinger, J.; Newson, D.; Yeh, H.

1992-06-01

The objective of this program was to develop a net shape forming process for an in-situ reinforced Si{sub 3}N{sub 4} (AS-700). AS-700 was initially developed using cold isostatic pressing (CIP) of alcohol milled powders. The CIP`ed AS-700 material exhibited a moderate strength (690 MPa) and high toughness (9 MPa{radical}m) at room temperature. In addition to net-shape process development, optimization of AS-700 properties was also investigated through the refinement of densification processes, and evaluation of the effect of Si{sub 3}N{sub 4} powder properties on resulting microstructure and mechanical properties. Slip casting was chosen as the net-shape forming process. A slip castingmore » process was successfully developed for forming green parts ranging from thin plates to thick cylinders, and to large complex shaped turbine rotors. The densification cycle was optimized to achieve full density parts without any cracks or warpage, and with comparable properties and microstructure to the CIP`ed baseline AS-700 material. The evaluation of six (6) alternate Si{sub 3}N{sub 4} powders indicated that Si{sub 3}N{sub 4} powders have a very strong influence on the development of resulting AS-700 in-situ microstructures and mechanical properties. The AS-700 slip casting process and optimized densification process were then combined and a number of test specimens were fabricated. The mechanical properties and microstructure of the optimized slip cast AS-700 Si{sub 3}N{sub 4} were then fully characterized. The key property values are: 695 MPa at room temperature, 446 MPa at 1370{degree}C flexural strengths and 8.25 MPa{radical}m toughness.« less

Microstructure characterization of LAE442 magnesium alloy processed by extrusion and ECAP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minárik, Peter; Král, Robert; Pešička, Josef

2016-02-15

The magnesium alloy LAE442 was processed by extrusion and equal channel angular pressing (ECAP) to achieve ultrafine grained microstructure. Detailed characterization of the microstructure was performed by scanning electron microscope, electron back scattered diffraction (EBSD) and transmission electron microscope. The initial, as-cast, microstructure consisted of large grains of ~ 1 mm. The grain refinement due to the processing by severe plastic deformation led to a decrease of the average grain size to ~ 1.7 μm after the final step of ECAP. A detailed characterization of secondary phases showed the precipitation of Al{sub 11}RE{sub 3}, Al{sub 2}Ca and Al{sub 10}RE{sub 2}Mn{submore » 7} intermetallic phases. X-ray diffraction measurements proved that Li is dissolved within the magnesium matrix in the as-cast condition. Newly formed Al{sub 3}Li phase was observed after ECAP. The texture formation due to the extrusion and ECAP was different from that in the other magnesium alloys due to the activation of non-basal slip systems as a result of the decrease of the c/a ratio. - Highlights: • Combined extrusion and equal channel angular pressing results in significant grain refinement by factor 1000 approximately. • Al{sub 11}RE{sub 3}, Al{sub 2}Ca and Al{sub 10}RE{sub 2}Mn{sub 7} secondary phases are present in the as-cast material while Li was dissolved in the Mg matrix. • Extrusion and ECAP have no effect on the composition of the secondary phases but they influence strongly their distribution. • Texture evolution is affected by decrease of c/a ratio due to the presence of Li and resulting activation of non-basal slip.« less

The Particle Distribution in Liquid Metal with Ceramic Particles Mould Filling Process

NASA Astrophysics Data System (ADS)

Dong, Qi; Xing, Shu-ming

2017-09-01

Adding ceramic particles in the plate hammer is an effective method to increase the wear resistance of the hammer. The liquid phase method is based on the “with the flow of mixed liquid forging composite preparation of ZTA ceramic particle reinforced high chromium cast iron hammer. Preparation method for this system is using CFD simulation analysis the particles distribution of flow mixing and filling process. Taking the 30% volume fraction of ZTA ceramic composite of high chromium cast iron hammer as example, by changing the speed of liquid metal viscosity to control and make reasonable predictions of particles distribution before solidification.

Discussion on the application of high additional value of high purity and high quality direct reduced iron

NASA Astrophysics Data System (ADS)

Yue, Chongfeng; Bai, Lu; Hong, Yicheng; Xu, Lijun

2018-03-01

The high purity and high quality direct reduced iron(DRI) products which were produced by high grade and high quality iron powder, with a high grade and low impurity characteristics. This article introduced the application of high purity and high quality DRI in the fields of amorphous base material, atomized iron powder, powder superalloy, high purity and ultra-low carbon special metallurgy products, precision casting, super alloy and various iron-based alloys. It provides a reference for the high added value utilization of DRI.

Pulsed Eddy Current Sensing for Critical Pipe Condition Assessment

PubMed Central

2017-01-01

Pulsed Eddy Current (PEC) sensing is used for Non-Destructive Evaluation (NDE) of the structural integrity of metallic structures in the aircraft, railway, oil and gas sectors. Urban water utilities also have extensive large ferromagnetic structures in the form of critical pressure pipe systems made of grey cast iron, ductile cast iron and mild steel. The associated material properties render NDE of these pipes by means of electromagnetic sensing a necessity. In recent years PEC sensing has established itself as a state-of-the-art NDE technique in the critical water pipe sector. This paper presents advancements to PEC inspection in view of the specific information demanded from water utilities along with the challenges encountered in this sector. Operating principles of the sensor architecture suitable for application on critical pipes are presented with the associated sensor design and calibration strategy. A Gaussian process-based approach is applied to model a functional relationship between a PEC signal feature and critical pipe wall thickness. A case study demonstrates the sensor’s behaviour on a grey cast iron pipe and discusses the implications of the observed results and challenges relating to this application. PMID:28954392

Improving friction performance of cast iron by laser shock peening

NASA Astrophysics Data System (ADS)

Feng, Xu; Zhou, Jianzhong; Huang, Shu; Sheng, Jie; Mei, Yufen; Zhou, Hongda

2015-05-01

According to different purpose, some high or low friction coefficient of the material surface is required. In this study, micro-dent texture was fabricated on cast iron specimens by a set of laser shock peening (LSP) experiments under different laser energy, with different patterns of micro dimples in terms of the depth over diameter. The mechanism of LSP was discussed and surface morphology of the micro dimples were investigated by utilizing a Keyence KS-1100 3D optical surface profilometer. The tests under the conditions of dry and lubricating sliding friction were accomplished on the UMT-2 apparatus. The performance of treated samples during friction and wear tests were characterized and analyzed. Based on theoretical analysis and experimental study, friction performance of textured and untextured samples were studied and compared. Morphological characteristics were observed by scanning electron microscope (SEM) and compared after friction tests under dry condition. The results showed that friction coefficient of textured samples were obvious changed than smooth samples. It can be seen that LSP is an effective way to improve the friction performance of cast iron by fabricating high quality micro dimples on its surface, no matter what kind of engineering application mentioned in this paper.

Detonation Initiation of Heterogeneous Melt-Cast High Explosives

NASA Astrophysics Data System (ADS)

Chuzeville, Vincent; Baudin, Gerard; Lefrancois, Alexandre; Boulanger, Remi; Catoire, Laurent

2015-06-01

The melt-cast explosives' shock initiation mechanisms are less investigated than pressed and cast-cured ones. If the existence of hot-spots is widely recognized, their formation mechanism is not yet established. We study here two melt-cast explosives, NTO-TNT 60:40 and RDX-TNT 60:40 in order to establish a relation between the microstructure and the reaction rate using a two-phase model based on a ZND approach. Such a model requires the reaction rate, the equations of state of the unreacted phase and of the detonation products and an interaction model between the two phases to describe the reaction zone thermodynamics. The reaction rate law can be written in a factorized form including the number of initiation sites, the explosive's deflagration velocity around hot spots and a function depending on gas volume fraction produced by the deflagration front propagation. The deflagration velocity mainly depends on pressure and is determined from pop-plot tests using the hypothesis of the single curve build-up. This hypothesis has been verified for our two melt-cast explosives. The function depending on gas volume fraction is deduced from microstructural observations and from an analogy with the solid nucleation and growth theory. It has been established for deflagration fronts growing from grain's surface and a given initial grain size distribution. The model requires only a few parameters, calibrated thanks to an inversion method. A good agreement is obtained between experiments and numerical simulations.

Microstructural and microtextural characterization of oxide scale on steel using electron backscatter diffraction.

PubMed

Birosca, S; Dingley, D; Higginson, R L

2004-03-01

High-temperature oxidation of steel has been extensively studied. The microstructure of iron oxides is, however, not well understood because of the difficulty in imaging it using conventional methods, such as optical or electron microscopy. A knowledge of the oxide microstructure and texture is critical in understanding how the oxide film behaves during high-temperature deformation of steels and more importantly how it can be removed following processing. Recently, electron back-scatter diffraction (EBSD) has proved to be a powerful technique for distinguishing the different phases in scales. This technique gives valuable information both on the microstructure and on the orientation relationships between the steel and the scale layers. In the current study EBSD has been used to investigate the microstructure and microtexture of iron oxide layers grown on interstitial free steel at different times and temperatures. Heat treatments have been carried out under normal oxidation conditions in order to relate the results to real steel manufacturing in industry. The composition, morphologies, microstructure and microtexture of selected conditions have been studied using EBSD.

10. VIEW UPSTREAM OF PIPELINE SECTION AT JUNCTION OF HUME ...

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

10. VIEW UPSTREAM OF PIPELINE SECTION AT JUNCTION OF HUME CEMENT PIPE AND CAST-IRON (460'). NOTE CYLINDRICAL COLLAR OF CEMENT SECTIONS AND BELL JUNCTIONS OF IRON PIPE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

Spray Characteristics and Tribo-Mechanical Properties of High-Velocity Arc-Sprayed WC-W2C Iron-Based Coatings

NASA Astrophysics Data System (ADS)

Tillmann, W.; Hagen, L.; Kokalj, D.

2017-10-01

In terms of arc-sprayed coatings, the lamellar coating microstructure is mainly affected by the atomization behavior of the molten electrode tips. When using compressed air, oxide formations occur during atomization, across the particle-laden spray plume and when the molten droplets splash onto the substrate. Within the scope of this study, the potential of a high-velocity arc-spraying process due to elevated atomization gas pressures and its effect on the spray and coating characteristics was analyzed using a cast tungsten carbide (CTC)-reinforced FeCMnSi cored wire. Since the atomization behavior corresponds with the electrode phenomena, the power spectrum and the droplet formation were observed during spraying. The tribo-mechanical properties of CTC-FeCMnSi coatings were examined in dry sliding experiments and indentation tests. In addition, adhesion tests and metallographic investigations were carried out to analyze the bonding strength, cohesive behavior, and lamellar microstructure. The occurrence of oxide phases was evaluated by x-ray diffraction and electron microscopy. Moreover, the oxygen content was determined by using glow discharge optical emission spectroscopy as well as energy-dispersive x-ray spectroscopy. With respect to elevated atomization gas pressures, a dense microstructure with improved adhesion to the substrate and reduced surface roughness was observed. Dry sliding experiments revealed an advanced wear behavior of specimens, when using above average increased atomization gas pressures. Analytic methods verified the existence of oxide phases, which were generated during spraying. A significant change of the extent and type of oxides, when applying an increased flow rate of the atomization gas, cannot be observed. Besides an enhanced coating quality, the use of increased atomization gas pressure exhibited good process stability.

DE-NE0000724 - Research Performance Final Report - Investigation of Thermal Aging Effects on the Evolution of Microstructure and Mechanical Properties of Cast Duplex Stainless Steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ankem, Sreeramamurthy; Perea, Daniel E.; Kolli, R. Prakash

This report details the research activities carried out under DOE-NEUP award number DE-NE0000724 concerning the evolution of structural and mechanical properties during thermal aging of CF–3 and CF–8 cast duplex stainless steels (CDSS). The overall objective of this project was to use state-of-the-art characterization techniques to elucidate trends and phenomena in the mechanical and structural evolution of cast duplex stainless steels (CDSS) during thermal aging. These steels are commonly used as structural materials in commercial light water nuclear power plants, undergoing aging for decades in operation as cooling water pipes, pump casings, valve bodies, etc. During extended exposure to thesemore » conditions, CDSS are known to undergo a change in mechanical properties resulting in a loss of ductility, i.e. embrittlement. While it is generally accepted that structural changes within the ferrite phase, such as decomposition into iron (Fe)-rich and chromium (Cr)-rich domains, lead to the bulk embrittlement of the steels, many questions remain as to the mechanisms of embrittlement at multiple length scales. This work is intended to shed insight into the atomic level composition changes, associated kinetic mechanisms, and effects of changing phase structure on micro- and nano-scale deformation that lead to loss of impact toughness and tensile ductility in these steels. In general, this project provides a route to answer some of these major questions using techniques such as 3-dimensional (3-D) atom probe tomography (APT) and real-microstructure finite element method (FEM) modeling, which were not readily available when these steels were originally selected for service in light water reactors. Mechanical properties evaluated by Charpy V-notch impact testing (CVN), tensile testing, and microhardness and nanohardness measurements were obtained for each condition and compared with the initial baseline properties to view trends in deformation behavior during aging. Concurrent analysis of the microstructure and nanostructure by atom probe tomography (APT) and transmission electron microscopy (TEM) provide mechanistic insight into the kinetic and mechanical behavior occurring on the nano-scale. The presence and morphology of the ferrite, austenite, and carbide phases have been characterized, and formation of new phases during aging, including spinodal decomposition products (α- and α'-ferrite) and G-phase, have been observed. The mechanical and structural characterization have been used to create accurate FEM models based on the real micro- and nano-structures of the systems. These models provide new insight into the local deformation behavior of these steels and the effects of each individual phase (including ferrite, austenite, carbides, and spinodal decomposition products) on the evolving bulk mechanical behavior of the system. The project was divided into three major tasks: 1. Initial Microstructure and Mechanical Property Survey and Initiate Heat Treatment; 2. Microstructural Characterization and Mechanical Property Testing During Aging; and 3. Microstructure-based Finite Element Modeling. Each of these tasks was successfully executed, resulting in reliable data and analysis that add to the overall body of work on the CDSS materials. Baseline properties and aging trends in mechanical data confirm prior observations and add new insights into the mechanical behavior of the steels. Structural characterization on multiple length scales provides new information on phase changes occurring during aging and sheds light on the kinetic processes occurring at the atomic scale. Furthermore, a combination of mechanical testing and microstructural characterization techniques was utilized to design FEM models of local deformation behavior of the ferrite and austenite phases, providing valuable new information regarding the effects of each of the microstructural components on the hardening and embrittlement processes. The data and analysis presented in this report and the publication associated with this project (§V) increase the understanding of aging and deformation in CF–3 and CF–8 steels. These results provide valuable information that can be utilized to aid in making informed decisions regarding the ongoing use of these steels in commercial nuclear infrastructure.« less

Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous α-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds.

PubMed

Rowthu, Sriharitha; Böhlen, Karl; Bowen, Paul; Hoffmann, Patrik

2015-11-11

Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. Here, we present a route to obtain intricate surface structures through in situ slip casting using polydimethylsiloxane (PDMS) negative molds which are replicated from excimer laser ablated polycarbonate (PC) master molds. PC sheets are ablated with a nanosecond KrF (λ = 248 nm) excimer laser mask projection system to obtain micron-scale 3D surface features over a large area of up to 3 m(2). Complex surface structures that include 3D free forms such as 3D topography of Switzerland, shallow structures such as diffractive optical elements (60 nm step) and conical micropillars have been obtained. The samples are defect-free produced with thicknesses of up to 10 mm and 120 mm diameter. The drying process of the slip cast alumina slurry takes place as a one-dimensional process, through surface evaporation and water permeation through the PDMS membrane. This allows homogeneous one-dimensional shrinkage during the drying process, independent of the sample's lateral dimensions. A linear mass diffusion model has been proposed to predict and explain the drying process of these ceramic colloidal suspensions. The calculated drying time is linearly proportional to the height of the slurry and the thickness of the negatively structured PDMS and is validated by the experimental results. An experimentally observed optimum Sylgard PDMS thickness range of ∼400 μm to 1 mm has achieved the best quality microstructured green compacts. Further, the model predicts that the drying time is independent of the microstructured areas and was validated using experimental observations carried out with microstructured areas of 300 mm(2), 1200 mm(2), and 120 cm(2). Therefore, in principle, the structures can be further replicated in areas up to 3 m(2) with the same drying time for the same slurry height. The surface-structured ceramics display interesting wetting properties, for example, eicosane-coated mesoporous microstructured alumina shows superhydrophobic behavior. Additionally, ceramic bulk samples could be further used as second-generation very hard and low-wear molds for further microfabrication.

Evaluating the Tensile Properties of Aluminum Foundry Alloys through Reference Castings-A Review.

PubMed

Anilchandra, A R; Arnberg, Lars; Bonollo, Franco; Fiorese, Elena; Timelli, Giulio

2017-08-30

The tensile properties of an alloy can be exploited if detrimental defects and imperfections of the casting are minimized and the microstructural characteristics are optimized through several strategies that involve die design, process management and metal treatments. This paper presents an analysis and comparison of the salient characteristics of the reference dies proposed in the literature, both in the field of pressure and gravity die-casting. The specimens produced with these reference dies, called separately poured specimens, are effective tools for the evaluation and comparison of the tensile and physical behaviors of Al-Si casting alloys. Some of the findings of the present paper have been recently developed in the frame of the European StaCast project whose results are complemented here with some more recent outcomes and a comprehensive analysis and discussion.

Fabrication and Characterization of Porous MgAl₂O₄ Ceramics via a Novel Aqueous Gel-Casting Process.

PubMed

Yuan, Lei; Liu, Zongquan; Liu, Zhenli; He, Xiao; Ma, Beiyue; Zhu, Qiang; Yu, Jingkun

2017-11-30

A novel and aqueous gel-casting process has been successfully developed to fabricate porous MgAl₂O₄ ceramics by using hydratable alumina and MgO powders as raw materials and deionized water as hydration agent. The effects of different amounts of deionized water on the hydration properties, apparent porosity, bulk density, microstructure, pore size distribution and compressive strength of the samples were investigated. The results indicated that the porosity and the microstructure of porous MgAl₂O₄ ceramics were governed by the amounts of deionized water added. The porous structure was formed by the liberation of physisorbed water and the decomposition of hydration products such as bayerite, brucite and boehmite. After determining the addition amounts of deionized water, the fabricated porous MgAl₂O₄ ceramics had a high apparent porosity (52.5-65.8%), a small average pore size structure (around 1-3 μm) and a relatively high compressive strength (12-28 MPa). The novel aqueous gel-casting process with easy access is expected to be a promising candidate for the preparation of Al₂O₃-based porous ceramics.

Flame-resistant Ca-containing AZ31 magnesium alloy sheets with good mechanical properties fabricated by a combination of strip casting and high-ratio differential speed rolling methods

NASA Astrophysics Data System (ADS)

Kim, Y. H.; Kim, W. J.

2015-03-01

This study reported that a combination of strip casting and high-ratio differential speed rolling (HRDSR) can produce flame-resistant Mg alloy sheets (0.7 wt%Ca-AZ31: 0.7Ca-AZ31) with good room-temperature mechanical properties and high-temperature formability. HRDSR effectively refined the coarse microstructure of the strip-casting processed 0.7Ca-AZ31 alloy. As the result, the (true) grain size was reduced to as small as 2.7 μm and the (Mg, Al)2Ca phase was broken up to fine particles with an average sizes of 0.5 μm. Due to the advantage of having such a highly refined microstructure, the HRDSR-processed 0.7Ca-AZ31 alloy sheet exhibited a high yield stress over 300 MPa and good superplasticity at elevated temperatures. The deformation mechanism of the fine-grained 0.7Ca-AZ31 alloy in the superplastic regime was identified to be grainboundary-diffusion or lattice-diffusion controlled grain boundary sliding.

A visual approach to efficient analysis and quantification of ductile iron and reinforced sprayed concrete.

PubMed

Fritz, Laura; Hadwiger, Markus; Geier, Georg; Pittino, Gerhard; Gröller, M Eduard

2009-01-01

This paper describes advanced volume visualization and quantification for applications in non-destructive testing (NDT), which results in novel and highly effective interactive workflows for NDT practitioners. We employ a visual approach to explore and quantify the features of interest, based on transfer functions in the parameter spaces of specific application scenarios. Examples are the orientations of fibres or the roundness of particles. The applicability and effectiveness of our approach is illustrated using two specific scenarios of high practical relevance. First, we discuss the analysis of Steel Fibre Reinforced Sprayed Concrete (SFRSpC). We investigate the orientations of the enclosed steel fibres and their distribution, depending on the concrete's application direction. This is a crucial step in assessing the material's behavior under mechanical stress, which is still in its infancy and therefore a hot topic in the building industry. The second application scenario is the designation of the microstructure of ductile cast irons with respect to the contained graphite. This corresponds to the requirements of the ISO standard 945-1, which deals with 2D metallographic samples. We illustrate how the necessary analysis steps can be carried out much more efficiently using our system for 3D volumes. Overall, we show that a visual approach with custom transfer functions in specific application domains offers significant benefits and has the potential of greatly improving and optimizing the workflows of domain scientists and engineers.

A Directionally Solidified Iron-chromium-aluminum-tantalum Carbide Eutectic Alloy

NASA Technical Reports Server (NTRS)

Harf, F. H.

1977-01-01

A eutectic alloy, Fe-13.6CR-3.7Al+9TaC, was directionally solidified in a high gradient furnace, producing a microstructure of alined TaC fibers in an oxidation resistant alpha-iron matrix. Tensile and stress rupture properties, thermal cycling resistance, and microstructures were evaluated. The alloy displays at 1000 C an ultimate tensile strength of 58 MPa and a 100-hour rupture life at a stress of 21 MPa. Thermal cycling to 1100 C induces faceting in the TaC fibers.

Microstructures and Mechanical Properties of a Wear-Resistant Alloyed Ductile Iron Austempered at Various Temperatures

NASA Astrophysics Data System (ADS)

Cui, Junjun; Chen, Liqing

2015-08-01

To further improve the mechanical performance of a new type of alloyed bainitic wear-resistant ductile iron, the effects of the various austempering temperatures have been investigated on microstructure and mechanical behaviors of alloyed ductile iron Fe-3.50C-1.95Si-3.58Ni-0.71Cu-0.92Mo-0.65Cr-0.36Mn (in weight percent). This alloyed ductile iron were firstly austenitized at 1123 K (850 °C) for 1 hour and then austempered in a salt bath at 548 K, 573 K, and 598 K (275 °C, 300 °C, and 325 °C) for 2 hours according to time-temperature-transformation diagram calculated by JMatPro software. The microstructures of austempered wear-resistant ductile irons consist of matrix of dark needle-like ferrite plus bright etching austenite and some amount of martensite and some dispersed graphite nodules. With increasing the austempering temperature, the amount of ferrite decreases in austempered ductile iron, while the amount of austenite and carbon content of austenite increases. There is a gradual decrease in hardness and increase in compressive strength with increasing austempering temperature. The increased austenite content and coarsened austenite and ferrite can lead to a hardness decrease as austempering temperature is increased. The increased compressive strength can be attributed to a decreased amount of martensitic transformation. The alloyed ductile iron behaves rather well wear resistance when the austempering is carried out at 598 K (325 °C) for 2 hours. Under the condition of wear test by dry sand/rubber wheel, the wear mechanisms of austempered ductile irons are both micro-cutting and plastic deformation.

Regulation of DMT1 on Bone Microstructure in Type 2 Diabetes

PubMed Central

Zhang, Wei-Lin; Meng, Hong-Zheng; Yang, Mao-Wei

2015-01-01

Diabetic osteoporosis is gradually attracted people's attention. However, the process of bone microstructure changes in diabetic patients, and the exact mechanism of osteoblast iron overload are unclear. Therefore, the present study aimed to explore the function of DMT1 in the pathological process of diabetic osteoporosis. We build the type two diabetes osteoporosis models with SD rats and Belgrade rats, respectively. Difference expression of DMT1 was detected by using the method of immunohistochemistry and western blotting. Detection of bone microstructure and biomechanics and iron content for each group of samples. We found that DMT1 expression in type 2 diabetic rats was higher than that in normal rats. The bone biomechanical indices and bone microstructure in the rat model deficient in DMT1 was significantly better than that in the normal diabetic model. The loss of DMT1 can reduce the content of iron in bone. These findings indicate that DMT1 expression was enhanced in the bone tissue of type 2 diabetic rats, and plays an important role in the pathological process of diabetic osteoporosis. Moreover, DMT1 may be a potential therapeutic target for diabetic osteoporosis. PMID:26078704

Influence of Processing Techniques on Microstructure and Mechanical Properties of a Biodegradable Mg-3Zn-2Ca Alloy

PubMed Central

Doležal, Pavel; Zapletal, Josef; Fintová, Stanislava; Trojanová, Zuzanka; Greger, Miroslav; Roupcová, Pavla; Podrábský, Tomáš

2016-01-01

New Mg-3Zn-2Ca magnesium alloy was prepared using different processing techniques: gravity casting as well as squeeze casting in liquid and semisolid states. Materials were further thermally treated; thermal treatment of the gravity cast alloy was additionally combined with the equal channel angular pressing (ECAP). Alloy processed by the squeeze casting in liquid as well as in semisolid state exhibit improved plasticity; the ECAP processing positively influenced both the tensile and compressive characteristics of the alloy. Applied heat treatment influenced the distribution and chemical composition of present intermetallic phases. Influence of particular processing techniques, heat treatment, and intermetallic phase distribution is thoroughly discussed in relation to mechanical behavior of presented alloys. PMID:28774000

Numerical simulation and optimization of casting process for complex pump

NASA Astrophysics Data System (ADS)

Liu, Xueqin; Dong, Anping; Wang, Donghong; Lu, Yanling; Zhu, Guoliang

2017-09-01

The complex shape of the casting pump body has large complicated structure and uniform wall thickness, which easy give rise to casting defects. The numerical simulation software ProCAST is used to simulate the initial top gating process, after analysis of the material and structure characteristics of the high-pressure pump. The filling process was overall smooth, not there the water shortage phenomenon. But the circular shrinkage defects appear at the bottom of casting during solidification process. Then, the casting parameters were optimized and adding cold iron in the bottom. The shrinkage weight was reduced from 0.00167g to 0.0005g. The porosity volume was reduced from 1.39cm3 to 0.41cm3. The optimization scheme is simulated and actual experimented. The defect has been significantly improved.

DETAIL VIEW OF INTERIOR SHOWING TWO 3,000POUND STEAM HAMMERS, CA. ...

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

DETAIL VIEW OF INTERIOR SHOWING TWO 3,000-POUND STEAM HAMMERS, CA. 1905, CONVERTED TO COMPRESSED AIR 1985 (MANUFACTURED BY CHAMBERSBURG ENGINEERING COMPANY, CHAMBERSBURG, PENNSYLVANIA), LOCATED ON EITHER SIDE OF CAST-IRON CENTRAL SUPPORT COLUMN. - Cambria Iron Company, Blacksmith Shop, Lower Works, Johnstown, Cambria County, PA

Prediction model of austenite growth and the role of MnS inclusions in non-quenched and tempered steel

NASA Astrophysics Data System (ADS)

Jiang, Bo; Wu, Meng; Sun, He; Wang, Zhilin; Zhao, Zhigang; Liu, Yazheng

2018-01-01

The austenite growth behavior of non-quenched and tempered steels (casted by continuous casting and molding casting processes) was studied. The austenite grain size of steel B casted by continuous casting process is smaller than that of steel A casted by molding casting process at the same heating parameters. The abnormal austenite growth temperature of the steels A and B are 950 °C and 1000 °C, respectively. Based on the results, the models for the austenite grain growth below and above the abnormal austenite growth temperature of the investigated steels were established. The dispersedly distributed fine particles MnS in steel B is the key factor refining the austenite grain by pinning the migration of austenite grain boundary. The elongated inclusions MnS are ineffective in preventing the austenite grain growth at high heating temperature. For the non-quenched and tempered steel, the continuous casting process should be adopted and the inclusion MnS should be elliptical, smaller in size and distributed uniformly in order to refine the final microstructure and also improve the mechanical properties.

Comparative evaluation of cast aluminum alloys for automotive cylinder heads: Part I Microstructure evolution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roy, Shibayan; Allard, Jr, Lawrence Frederick; Rodriguez, Andres

The present study stages a comparative evaluation of microstructure and associated mechanical and thermal response for common cast aluminum alloys that are used for manufacturing automotive cylinder heads. The systems considered are Al-Cu (206-T6), Al-Si-Cu (319-T7), and Al-Si (356-T6, A356-T6, and A356 + 0.5Cu-T6). The focus of the present manuscript is on the evaluation of microstructure at various length scales after aging, while the second manuscript will deal with the mechanical and thermal response of these alloys due to short-term (aging) and long-term (pre-conditioning) heat treatments. At the grain-scale, the Al-Cu alloy possessed an equiaxed microstructure as opposed to themore » dendritic structure for the Al-Si-Cu or Al-Si alloys which is related to the individual solidification conditions for these alloy systems. The composition and morphology of intermetallic precipitates within the grain and at the grain/dendritic boundary are dictated by the alloy chemistry, solidification, and heat treatment conditions. At the nanoscale, these alloys contain various metastable strengthening precipitates (GPI and θ''θ'' in Al-Cu alloy, θ'θ' in Al-Si-Cu alloy, and β'β' in Al-Si alloys) with varying size, morphology, coherency, and thermal stability.« less

Comparative evaluation of cast aluminum alloys for automotive cylinder heads: Part I Microstructure evolution

DOE PAGES

Roy, Shibayan; Allard, Jr, Lawrence Frederick; Rodriguez, Andres; ...

2017-03-06

The present study stages a comparative evaluation of microstructure and associated mechanical and thermal response for common cast aluminum alloys that are used for manufacturing automotive cylinder heads. The systems considered are Al-Cu (206-T6), Al-Si-Cu (319-T7), and Al-Si (356-T6, A356-T6, and A356 + 0.5Cu-T6). The focus of the present manuscript is on the evaluation of microstructure at various length scales after aging, while the second manuscript will deal with the mechanical and thermal response of these alloys due to short-term (aging) and long-term (pre-conditioning) heat treatments. At the grain-scale, the Al-Cu alloy possessed an equiaxed microstructure as opposed to themore » dendritic structure for the Al-Si-Cu or Al-Si alloys which is related to the individual solidification conditions for these alloy systems. The composition and morphology of intermetallic precipitates within the grain and at the grain/dendritic boundary are dictated by the alloy chemistry, solidification, and heat treatment conditions. At the nanoscale, these alloys contain various metastable strengthening precipitates (GPI and θ''θ'' in Al-Cu alloy, θ'θ' in Al-Si-Cu alloy, and β'β' in Al-Si alloys) with varying size, morphology, coherency, and thermal stability.« less

Friction Stir Welding in Wrought and Cast Aluminum Alloys: Weld Quality Evaluation and Effects of Processing Parameters on Microstructure and Mechanical Properties

NASA Astrophysics Data System (ADS)

Pan, Yi; Lados, Diana A.

2017-04-01

Friction stir welding (FSW) is a solid-state process widely used for joining similar and dissimilar materials for critical applications in the transportation sector. Understanding the effects of the process on microstructure and mechanical properties is critical in design for structural integrity. In this study, four aluminum alloy systems (wrought 6061-T651 and cast A356, 319, and A390) were processed in both as-fabricated and pre-weld heat-treated (T6) conditions using various processing parameters. The effects of processing and heat treatment on the resulting microstructures, macro-/micro-hardness, and tensile properties were systematically investigated and mechanistically correlated to changes in grain size, characteristic phases, and strengthening precipitates. Tensile tests were performed at room temperature both along and across the welding zones. A new method able to evaluate weld quality (using a weld quality index) was developed based on the stress concentration calculated under tensile loading. Optimum processing parameter domains that provide both defect-free welds and good mechanical properties were determined for each alloy and associated with the thermal history of the process. These results were further related to characteristic microstructural features, which can be used for component design and materials/process optimization.

Microstructure and hot compression deformation of the as-cast Mg-5.0Sn-1.5Y-0.1Zr alloy

NASA Astrophysics Data System (ADS)

Luo, Xiaoping; Kang, Li; Li, Qiushu; Chai, Yuesheng

2015-08-01

The hot compression deformation behavior and microstructure of as-cast Mg-5.0Sn-1.5Y-0.1Zr alloy were investigated by performing isothermal hot compression tests. The tests were conducted using a thermal mechanical simulator at 250-450 °C and strain rates ranging from 0.002 to 2 s-1, with a maximum deformation strain of 50 %. The effects of the deformation parameters on the microstructure evolution of the Mg-5.0Sn-1.5Y-0.1Zr alloy were discussed. The study revealed the flow behavior and the deformation mechanism of the Mg-5.0Sn-1.5Y-0.1Zr alloy. The dependence of flow stress on temperature and strain rate was described by a hyperbolic sine constitutive equation. Through regression analysis, the activation energy of 223.26 kJ mol-1 for plastic deformation was determined by considering flow stress at a strain rate of 0.2. Microstructure observation showed that dynamic recrystallization occurred extensively along grain boundaries at temperatures higher than 300 °C and strain rates lower than 0.02 s-1. This observation provides a theoretical basis for the manufacture and application of the Mg-5.0Sn-1.5Y-0.1Zr alloy.

Comparative Evaluation of Cast Aluminum Alloys for Automotive Cylinder Heads: Part I—Microstructure Evolution

NASA Astrophysics Data System (ADS)

Roy, Shibayan; Allard, Lawrence F.; Rodriguez, Andres; Watkins, Thomas R.; Shyam, Amit

2017-05-01

The present study stages a comparative evaluation of microstructure and associated mechanical and thermal response for common cast aluminum alloys that are used for manufacturing automotive cylinder heads. The systems considered are Al-Cu (206-T6), Al-Si-Cu (319-T7), and Al-Si (356-T6, A356-T6, and A356 + 0.5Cu-T6). The focus of the present manuscript is on the evaluation of microstructure at various length scales after aging, while the second manuscript will deal with the mechanical and thermal response of these alloys due to short-term (aging) and long-term (pre-conditioning) heat treatments. At the grain-scale, the Al-Cu alloy possessed an equiaxed microstructure as opposed to the dendritic structure for the Al-Si-Cu or Al-Si alloys which is related to the individual solidification conditions for these alloy systems. The composition and morphology of intermetallic precipitates within the grain and at the grain/dendritic boundary are dictated by the alloy chemistry, solidification, and heat treatment conditions. At the nanoscale, these alloys contain various metastable strengthening precipitates (GPI and θ^'' in Al-Cu alloy, θ^' in Al-Si-Cu alloy, and β^' in Al-Si alloys) with varying size, morphology, coherency, and thermal stability.

The role of processing route on the microstructure of 14YWT nanostructured ferritic alloy

DOE PAGES

Mazumder, B.; Parish, C. M.; Bei, H.; ...

2015-06-03

Nanostructured ferritic alloys (NFAs) have outstanding high temperature creep properties and extreme tolerance to radiation damage. To achieve these properties, NFAs are fabricated by mechanical alloying of metallic and yttria powders. Atom probe tomography has demonstrated that milling times of at least 40 h are required to produce a uniform distribution of solutes in the flakes. After milling and hot extrusion, the microstructure consists of -Fe, high number densities of Ti-Y-O-vacancy-enriched nanoclusters, and coarse Y2Ti2O7 and Ti(O,C,N) precipitates on the grain boundaries. In contrast, the as-cast condition consists of -Fe with 50-100 m irregularly-shaped Y2Ti2O7 pyrochlore precipitates with smaller embeddedmore » precipitates with the Al5Y3O12 (yttrium-aluminum garnet) crystal structure indicating that this traditional processing route is not a viable approach to achieve the desired microstructure. The nano-hardnesses were also substantially different, i.e., 4 and 8 GPa for the as-cast and as-extruded conditions, respectively. These differences can be explained by the differences in the microstructure and the effects of the high vacancy content introduced by mechanical alloying, and the strong binding energy of vacancies with O, Ti, and Y atoms retarding diffusion.« less

Synthesize and microstructure characterization of Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} Heusler alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elwindari, Nastiti; Manaf, Azwar, E-mail: azwar@ui.ac.id

2016-06-17

The ferromagnetic heusler alloys are promising materials in many technical applications due to their multifunctional properties such as shape memory effect, magnetocaloric effect, giant magnetoresistance, etc. In this work, synthesize and characterization of polycrystalline Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} (NMCS) alloy are reported. Alloy preparation was conducted by melting the constitute elements under an innert Argon (Ar) atmosphere in a vacuum mini arc-melting furnace. Homogenization of the microstructure of the as-cast ingot was obtained after annealing process at 750°C for 48 hours. It is shown that the dendrites structure has changed to equaixed grains morphology after homogenization. Microstructure characteristics ofmore » material by x-ray diffraction revealed that the alloy has a L{sub 21}-type cubic crystal structure as the main phase at room temperature. In order to induce the shape anisotropy, a forging treatment was applied to show the shape orientation of material. Various enhancements of magnetic properties in a longitudinal direction were observed at various degree of anisotropy. The microstructure changes of as-cast NMCS and effects of homogenization treatments as studied by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) are discussed in details.« less