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Viewing 1 to 30 of 430
2017-10-13
Technical Paper
2017-01-5012
Harveer Singh Pali, Shashi Prakash Dwivedi
Abstract The present work deals with the fabrication and tribological testing of an aluminium/SiC composite. Fabrication was done using two techniques; mechanical stir casting and electromagnetic stir casting. Metal matrix composite (MMC) was fabricated using aluminium as a matrix and SiC as reinforcement in varying weight percentages. The wear and frictional properties of the MMC were studied by performing dry sliding wear test using a pin-on-disc wear tester for both types of samples. Wear rate retards with the increase the percentage of reinforcement whereas it improves with the addition of normal force. At same time frictional coefficient upsurges by increasing the normal force and percentage of reinforcement. Increasing percentage of reinforcement and using electromagnetic stir casting process obtained the higher frictional coefficient and lower wear rate.
2017-03-28
Technical Paper
2017-01-1666
David Weiss, Orlando Rios
Abstract Aluminum alloys containing cerium have excellent castability and retain a substantial fraction of their room temperature strength at temperatures of 200°C and above. High temperature strength is maintained through a thermodynamically trapped, high surface energy intermetallic. Dynamic load partitioning between the aluminum and the intermetallic increases mechanical response. Complex castings have been produced in both permanent mold and sand castings. This versatile alloy system, using an abundant and inexpensive co-product of rare earth mining, is suitable for parts that need to maintain good properties when exposed to temperatures between 200 and 315°C.
2017-03-28
Technical Paper
2017-01-1665
Qigui Wang, Peggy Jones, Yucong Wang, Dale Gerard
Abstract With the increasing use of aluminum shape castings in structural applications in automobiles, assurance of cast product integrity and performance has become critical in both design and manufacturing. In this paper, the latest understanding of the relationship between casting quality and mechanical properties of aluminum castings is summarized. Examples of newly developed technologies for alloy design, melting and melt treatment, casting and heat treatment processes in aluminum casting are reviewed. Robust design and development of high integrity aluminum castings through an Integrated Computational Materials Engineering (ICME) approach is also discussed.
2017-03-28
Technical Paper
2017-01-1663
Alan Druschitz, Christopher Williams, Erin Connelly, Bob Wood
Abstract Binder jetting of sand molds and cores for metal casting provides a scalable and efficient means of producing metal components with complex geometric features made possible only by Additive Manufacturing. Topology optimization software that can mathematically determine the optimum placement of material for a given set of design requirements has been available for quite some time. However, the optimized designs are often not manufacturable using standard metal casting processes due to undercuts, backdraft and other issues. With the advent of binder-based 3D printing technology, sand molds and cores can be produced to make these optimized designs as metal castings.
2016-04-05
Technical Paper
2016-01-0406
Akihiko Asami, Tomoyuki Imanishi, Yukio Okazaki, Tomohiro Ono, Kenichi Tetsuka
Abstract High-tensile steel plates and lightweight aluminum are being employed as materials in order to achieve weight savings in automotive subframe. Closed-section structures are also in general use today in order to efficiently increase parts stiffness in comparison to open sections. Aluminum hollow-cast subframe have also been brought into practical use. Hollow-cast subframe are manufactured using sand cores in gravity die casting (GDC) or low-pressure die casting (LPDC) processes. Using these manufacturing methods, it is difficult to reduce product thickness, and the limitations of the methods therefore make the achievement of weight reductions a challenge. The research discussed in this paper developed a lightweight, hollow subframe technology employing high-pressure die casting (HPDC), a method well-suited to reducing wall thickness, as the manufacturing method. Hollow-casting using HPDC was developed as a method of forming water jackets for water-cooled automotive engines.
2016-04-05
Journal Article
2016-01-0371
Wenkai Li, Carlos Engler-Pinto, Haitao Cui, Weidong Wen, Xuming Su
Abstract In this paper, fatigue tests on a cast aluminum alloy (AS7GU-T64) were performed under different frequencies and humidity levels. Tests conducted under conventional frequency in laboratory air have been compared to tests conducted under ultrasonic frequency in dry air, saturated humidity and in distilled water. It was observed that the highest and lowest fatigue lives correspond to ultrasonic fatigue tests in dry air and in distilled water, respectively. Unlike specimens tested at conventional frequency, all of the specimens tested at ultrasonic frequency presented a large amount of slip facets on the fatigue crack propagation fracture surface.
2015-04-14
Technical Paper
2015-01-0524
Maniraj Perumal, Baskar Anthonysamy, Ashokkumar Sundaramoorthy
This method and its special process are particularly suited for the production of Porous free combustion chamber prototype aluminium cylinder head casting. Current methods for producing porous free combustion chamber are graphite coating and CI/Cu metal chill which are moderately effective in achieving porous free combustion chamber. However, these current methods have serious drawbacks like high rejections due to blow holes/gas porosity generated from graphite coating and fine porosity due to prolonged cooling because of slow rate of cooling while peak temperature of metal chills. The present work shows how this goal can be achieved in cylinder head casting of single cylinder high speed engine. Fundamental micro structural investigations are shown as well as the results of tensile tests, high temperature strength, corrosion behavior and static and dynamic component testing.
2015-04-14
Journal Article
2015-01-0512
Anthony D. Prescenzi
Abstract Ablation casting is an emerging technology which combines traditional sand molding techniques with rapid cooling due to the use of a water soluble binder. High cooling rates and control of solidification direction allows for exceptional mechanical properties and complex shapes. Through the use of ablation, six different body node castings have been manufactured for the 2016 NSX aluminum space frame. The high mechanical properties allowed these castings to be integrated into the crash structure for energy absorption. Using the traditional casting alloy A356, target mechanical properties were 190 Mpa Yield Strength, 280 Mpa Tensile Strength and 12% min elongation. The high elongation was achieved due to the refined eutectic microstructure produced by high cooling rates. The eutectic microstructure produced by ablation was found to be Level 5 or 6 on the AFS scale. Light weighting could also be achieved when compared to traditional GDC castings.
2015-04-14
Journal Article
2015-01-0510
Joy Hines Forsmark, Zachary Dowling, Kelsey Gibson, Caroline Mueller, Larry Godlewski, Jacob Zindel, James Boileau
Abstract Magnesium die-cast alloys are known to have a layered microstructure composed of: (1) An outer skin layer characterized by a refined microstructure that is relatively defect-free; and (2) A “core” (interior) layer with a coarser microstructure having a higher concentration of features such as porosity and externally solidified grains (ESGs). Because of the difference in microstructural features, it has been long suggested that removal of the surface layer by machining could result in reduced mechanical properties in tested tensile samples. To examine the influence of the skin layer on the mechanical properties, a series of round tensile bars of varying diameters were die-cast in a specially-designed mold using the AM60 Mg alloy. A select number of the samples were machined to different final diameters. Subsequently, all of the samples (as-cast as well as machined) were tested in tension.
2015-04-14
Journal Article
2015-01-1319
Eitaro Koya, Yukihide Fukuda, Shinya Kitagawa, Mitsunori Murakami, Atsushi Kawauchi, Sadanori Furue
Abstract When using aluminum for vehicle body parts to reduce weight, the high pressure die casting (HPDC) is widely applied due to its adaptability to thin-wall products, near-net-shape castability, and short casting cycle time. Since a hollow construction is advantageous to increase stiffness of body parts, there has been a need of development of techniques for casting of hollow parts by HPDC. So far, hollow casting by HPDC has been realized for small parts using sand cores. When applying that method to large parts, however, it is necessary to increase filling speed. When the filling speed is increased, the core tends to break. In this project, we have developed a method to estimate changes of pressure distribution when filling molten metal by the casting simulation in order to analyze damages to the core. Through the analysis, we discovered occurrence of impulsive pressure waves.
2014-04-01
Technical Paper
2014-01-1015
Dan Kraehling, David Anderson, Michael Worswick, Tim Skszek
Abstract The effect of stress triaxiality on failure strain in as-cast magnesium alloy AM60B is examined. Experiments using one uniaxial and two notched tensile geometries were used to study the effect of stress triaxiality on the quasi-static constitutive response of super vacuum die cast AM60B castings. For all tests, local strains, failure location and specimen elongation were tracked using two-dimensional digital image correlation (DIC) analysis. The uniaxial specimens were tested in two orthogonal directions to determine the anisotropy of the casting. Finite element models were developed to estimate effective plastic strain histories and stress state (triaxiality) as a function of notch severity. It was found that there is minimal, if any, anisotropy present in AM60B castings. Higher stress triaxiality levels caused increases in maximum stress and decreases in elongation and local effective plastic strain at failure.
2013-04-08
Journal Article
2013-01-0829
Alastair Long, David Thornhill, Cecil Armstrong, David Watson
Die pre-heating has a beneficial effect on die life, by reducing thermal shock and stress fluctuations on the die surface. The findings from this paper indicate that the die surface stress decreased by 44% when the die is pre-heated to 150°C, and decreases by 57% when the die is pre-heated to 200°C, in comparison to when the die is started "cold" with an initial temperature of 20°C. Changes to the die start-up procedure, by switching off the die internal water cooling for the first four casting cycles, results in the die heating to operating temperature in fewer casting cycles, resulting in fewer castings being scrapped before the die achieves steady state operating temperature. From this, a saving of four castings per start-up can be made, reducing scrap by 4.5%, leading to lower manufacturing costs, reduced energy usage and increased useful die life.
2013-04-08
Journal Article
2013-01-1026
Meng Wang, Henry Hu
Recently, joining of cast aluminum components with wrought and/or cast similar metals becomes an urgent task for the auto industry to develop light-weight complex and large-scale chassis and body structures for further reduction in vehicle weight. In this study, fusion-joining of vacuum high pressure die cast (VHPDC) alloy A356 subjected to T5 heat treatment and wrought alloy 6061 with the Gas Metal Arc Welding (GMAW-MIG) process was experimented in an effort to understand the effect of the MIG process on the microstructure development and tensile behaviors of the base alloys (T5 A356 and 6061), Heat Affected Zone (HAZ) and Fusion Zone (filler metal ER4043). The results of tensile testing indicated that the ultimate tensile strength (UTS), yield strength (YS) and elongation (Ef) of VHPDC T5 A356 were relatively high, compared to both wrought alloy 6061 and the filler metal (ER 4043).
2013-04-08
Technical Paper
2013-01-0979
Yuichi Ienaga, Kenshi Inoue, Tokuteru Uesugi, Kenji Higashi
In order to develop large-scale (100 mm in diameter) Mg-Zn-Y alloys with high strength beyond that of 4032-T6 alloy, we considered a novel casting process to produce large ingots with homogeneous microstructure, and investigated the mechanical properties of the extruded alloys. First, ingots (335 mm in diameter and 850 mm in height) were produced by a novel stir casting process in the ingot case. Then large-scale extruded alloys (100 mm in diameter) were prepared with an extrusion ratio of 10. The Mg-Zn-Y alloys exhibited higher yield and fatigue strengths than those of 4032-T6 aluminum alloy. The yield strengths of the aluminum alloy decreased drastically above 473 K, whereas those of the Mg-Zn-Y alloys did not. It is noteworthy that the yield strength (274 MPa) and fatigue strength (100 MPa) of the Mg-Zn-Y alloys at 473 K were about 1.3 and 1.2 times respectively as high as those of aluminum alloys.
2013-04-08
Technical Paper
2013-01-0644
Kyoo Sil Choi, Dongsheng Li, Xin Sun, Mei Li, John Allison
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 to induce the fracture by element removal, leading to the prediction of ductility.
2012-04-16
Technical Paper
2012-01-0770
Joy H. Forsmark, Jacob Zindel, Larry Godlewski, Ari Caliskan
A demonstration structure was cast in AM60. The structure, known as the Generic Frame Casting or GFC, was designed specifically to mimic features seen in castings for closure applications. Excised samples were subsequently removed from different areas of the casting and tested under axial loading conditions. Component level tests were also conducted. Comparison of the excised sample results and the component level testing indicated the influence of local properties on the component level deformation. It was shown that varying the casting processing conditions could change the local ductility and yield strength in different areas of casting with the same geometry. Lowering the local ductility decreased the total displacement in a component level test and lowered the amount of energy absorption. Therefore, understanding the processing conditions and their influence on the local properties is important for predicting behavior in a component level test.
2012-04-16
Technical Paper
2012-01-0540
Xingfu Chen, Carlos Engler-Pinto, Michael King, Mei Li, Eben Prabhu, Xuming Su
High cycle fatigue material properties are not uniformly distributed on cylinder heads due to the casting process. Virtual Aluminum Casting (VAC) tools have been developed within Ford Motor Company to simulate the effects of the manufacturing process on the mechanical properties of cast components. One of VAC features is the ability to predict the high cycle fatigue strength distribution. Residual stresses also play an important role in cylinder head high cycle fatigue, therefore they are also simulated and used in the head high cycle fatigue analysis. Cylinder head assembly, thermal and operating stresses are simulated with ABAQUS™. The operating stresses are combined with the residual stresses for high cycle fatigue calculations. FEMFAT™ is used for the high cycle fatigue analysis. A user-defined Haigh diagram is built based on the local material properties obtained from the VAC simulation.
2012-04-16
Journal Article
2012-01-0549
Yumi Kubota, Jun Kubo, Keitaro Ishida, Akinori Okada, Minoru Yoshida, Toru Saito, Hiroshi Suzuki
When designing engine parts of motor vehicles, it is important to evaluate internal residual stresses that cause crack growth and influence the strength of parts. Internal stresses can be measured nondestructively by the neutron diffraction method. However, it is difficult to apply this method to aluminum alloy castings because they consist of coarse crystal grains. As for cylinder heads, the grain size ranges up to approximately 400 μm and there are few grains contributing to intensity of diffraction in each gauge volume. In the case of X-ray diffraction, "the oscillation method" has been employed for materials with coarse grains. In this study, the applicability of the oscillation method to aluminum alloy castings was investigated with the aim of establishing a method of measuring internal stresses and strains. A related objective was to determine the accuracy of stresses.
2011-11-08
Technical Paper
2011-32-0504
Youji Yamada, Hiroshi Yoshii, Satoshi Mochizuki, Yuuta Bannai, Jun Yaokawa, Koichi Anzai, Katsunari Oikawa
The relationship of J factor and internal casting quality in high pressure die casting was investigated by leakage testing conducted after the machining process. The trial die, used for motorcycle engine applications, was a single closed-deck-type liner-less cylinder block with an expendable salt core. The J factor was calculated by using the VanRens equation with varied gate thickness, gate speed, plunger diameter, and casting pressure. To confirm casting quality by leakage testing, we conducted X-ray computerized tomography (XRC), micro-focus XRC, and thermal decomposition gas chromatographic determination analysis. In addition, XRC was used to calculate the total shrinkage volume. A strong correlation was found between the J factor and tightness against pressure leakage.
2011-10-04
Technical Paper
2011-36-0004
Edison Marcelo Serbino, Jairo Cândido, Ely Roberto Benedicto
This paper describes the development of a low pressure die casting process for cylinder heads, with focus on the minimization and control of the micro-constituents in an aluminum alloy. The increasing demand for new designs of auto-parts which are interchangeable among platform and global powertrain, confirm the need for good quality equalization in a globalized market. However, in the specific case of engine aggregates, there is a strong complicating factor which is the fuel mixture variation used in several regions of the world, which create distinct combustion rates and thermo-mechanical efforts. In view of such scenario, a Low Pressure Die Casting process (LPDC) was developed as an alternative for the current process by Gravity Sand process (GS). Their objective is to fulfill the material requirements, focusing on the minimization of the Secondary Dendrite Arm Spacing (SDAS), which exert a significant influence on the most critical mechanical properties.
2011-04-12
Technical Paper
2011-01-0426
Mark E. DeBruin, S. E. Jordan
Significant research has been conducted with the goal of obtaining thin walled ductile iron for use in lighter weight designs. A review is made of the past efforts to achieve thin walled ductile iron. Most past efforts resorted to costly processes or non-standard production practices. Lost Foam Casting (LFC) is an alternate foundry process which used in conjunction with standard melt shop practices results in a massive carbide free structure when used with thin section size. Chemistry, hardness tests, microstructures, and design improvements of a case study are reviewed.
2011-04-12
Journal Article
2011-01-0193
Qigui Wang, Peggy Jones
Cast aluminum alloys are increasingly used in cyclically loaded automotive structural applications for light weight and fuel economy. The fatigue resistance of aluminum castings strongly depends upon the presence of casting flaws and characteristics of microstructural constituents. The existence of casting flaws significantly reduces fatigue crack initiation life. In the absence of casting flaws, however, crack initiation occurs at the fatigue-sensitive microstructural constituents. Cracking and debonding of large silicon (Si) and Fe-rich intermetallic particles and crystallographic shearing from persistent slip bands in the aluminum matrix play an important role in crack initiation. This paper presents fatigue life models for aluminum castings free of casting flaws, which complement the fatigue life models for aluminum castings containing casting flaws published in [1].
2011-04-12
Technical Paper
2011-01-1085
Douglas Rourke
Many new surface finishes have been proposed for zinc die casting. In many cases these are intended to replace the traditional processes of solvent-based painting, electroplating and hexavalent chromium. Twenty new coatings were offered by suppliers and were subjected to cyclic corrosion testing (CCT). A wide variation in results was seen, suggesting the need for further development in come cases. However, several of the new environmentally friendly finishes are of interest for current application.
2011-04-12
Technical Paper
2011-01-1088
Frank E. Goodwin, Martin Gagné
Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were tested at five temperatures between −40 C and room temperature to determine impact properties. Izod impact energy data was obtained in accordance with ASTM D256. Unlike ASTM E23, these samples were tested with a milled notch in order to compare with plastic samples. In addition, flexural data was obtained for design use. Fatigue stress-life (S-N) curves and fatigue limits of die cast zinc Alloy 2, Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were determined using the rotating bend test. Fatigue limits for Alloy 3, Alloy 5, and ACuZinc 5 appeared to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. The improvement in properties for Alloy 3, Alloy 5 and ACuZinc 5 is related to the presence of the die cast skin.
2011-04-12
Technical Paper
2011-01-1087
Martin Gagné
Zinc die casting products and metal casting processes continue to evolve for the benefit of end users. Through cooperative global research programs continuous improvements are still being made to the broad range of excellent mechanical properties, easy castability and the wide choice of finishes available for zinc die castings. Recent advances will be highlighted with case histories specific to automotive applications.
2011-04-12
Journal Article
2011-01-1082
Frank E. Goodwin, Lothar Kallien
Most creep studies are conducted to determine steady state creep rate and time to failure. However, the priority for the designer is to predict the amount of total creep, being the sum of primary and secondary creep elongations, for a given service life under given loads and temperatures, for example 0.5% elongation after 3000h. An assessment of total creep behavior of industrially important zinc alloys has been conducted, and correlation/prediction curves produced. Another important property, related to creep, is stability after ageing, both for unloaded and also loaded castings. Recently developed relationships between natural and artificial ageing, and the correlation of mechanical property changes for different periods of artificial ageing with natural ageing will be presented.
2011-04-12
Technical Paper
2011-01-1089
Ehab Samuel, Michel Garat, Fred Major
Cast aluminum-silicon alloys have witnessed a notable increase in use in the automotive and transport industry. The ability of these alloys to be easily cast into complex shapes coupled with a favorable strength-to-weight ratio has given them an edge over cast irons. One particular area of casting which has received further and further attention is the area of semi-solid casting, where an alloy casting is prepared as slurry with flow properties that resemble both solid and liquid. In the present work, the effects of iron additions on the mechanical properties of a 319 semi-solid alloy were studied. This alloy was prepared using the SEED process, as developed by Rio Tinto Alcan in collaboration with the Aluminum Technology Centre of NRC Canada. The SEED (Swirled Enthalpy Equilibration Device) process is a novel rheocasting method which yields a semi-solid slurry from the mechanical stirring and cooling of the molten aluminum.
2011-04-12
Technical Paper
2011-01-1090
Mark E. DeBruin, S. Jordan
Despite the embrace of aluminum and other nonferrous materials, steel is still a widely used material in the vehicle industry. However, it is not produced in the vehicle industry by the lost foam casting (LFC) method despite the tremendous potential benefits. These include the elimination of machining due to tolerances equal to investment casting and part consolidation which allows for the elimination of components and joining technologies. Both of these are financially and operationally beneficial by allowing for the creation of a leaner supply chain. With proper lost foam casting technology adjustments to compensate for the higher melting point of steel, there appear to be no degradation in cast steel as compared to when cast by green sand or resin bonded sand (no -bake) methods. In fact the opposite is true as the LFC benefits of improved surface roughness and dimensionality are maintained.
2011-04-12
Journal Article
2011-01-0036
Dimitry Sediako, Francesco D'Elia, Anthony Lombardi, Alan Machin, C. (Ravi) Ravindran, Camden Hubbard, Robert Mackay
Continuous efforts to develop a lightweight alloy suitable for the most demanding applications in automotive industry resulted in a number of advanced aluminum (Al) and magnesium alloys and manufacturing routes. One example of this is the application of 319 Al alloy for production of 3.6L V6 gasoline engine blocks. Aluminum is sand cast around Fe-liner cylinder inserts, prior to undergoing the T7 heat treatment process. One of the critical factors determining the quality of the final product is the type, level, and profile of residual stresses along the Fe liners (or extent of liner distortion) that are always present in a cast component. In this study, neutron diffraction was used to characterize residual stresses along the Al and the Fe liners in the web region of the cast engine block. The strains were measured both in Al and Fe in hoop, radial, and axial orientations. The stresses were subsequently determined using generalized Hooke's law.
2011-04-12
Technical Paper
2011-01-0537
Minsoo Kim, Taesung Lim, Kwangmin yoon, Youngjin Ko, Jong Myung Kim, Kihoon Kwak
Aluminum steering knuckles are widely employed for weight reduction and improvement of ride & handling performance. In this study, a high strength aluminum alloy for cast-forged knuckle was designed to achieve higher mechanical properties than those of the conventional foundry alloy. Using this alloy, high strength knuckles were manufactured and performed test of mechanical properties, suspension module strength and durability. The strength and the elongation of the developed knuckle were increased by 20% and 40%, respectively, as compared with the conventional alloy. Also this knuckle passed the static strength and durability test of the front suspension module.
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