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Viewing 1 to 30 of 3001
2010-04-12
Technical Paper
2010-01-0405
David A. Wagner, Stephen Logan, Kangping Wang, Timothy Skszek
Finite element analysis (FEA) predictions of magnesium beams are compared to load versus displacement test measurements. The beams are made from AM60B die castings, AM30 extrusions and AZ31 sheet. The sheet and die cast beams are built up from two top hat sections joined with toughened epoxy adhesive and structural rivets. LS-DYNA material model MAT_124 predicts the magnesium behavior over a range of strain rates and accommodates different responses in tension and compression. Material test results and FEA experience set the strain to failure limits in the FEA predictions. The boundary conditions in the FEA models closely mimic the loading and constraint conditions in the component testing. Results from quasi-static four-point bend, quasi-static axial compression and high-speed axial compression tests of magnesium beams show the beam's behavior over a range of loadings and test rates. The magnesium beams exhibit significant material cracking and splitting in all the tests.
2010-04-12
Technical Paper
2010-01-0408
Qiang Zhang, Henry Hu
In the past decade, magnesium (aluminum) alloy use in the automotive industry has increased in order to reduce vehicle weight and fuel consumption. However, their applications are usually limited to temperatures of up to 120°C. Improvements in the high-temperature mechanical properties of magnesium alloys would greatly expand their industrial applications. As compared to the unreinforced monolithic metal, metal matrix composites have been recognized to possess superior mechanical properties, such as high elastic modulus and strengths as well as enhanced wear resistance. In this study, a novel approach of making hybrid preforms with two or more types reinforcements, i.e., different size particles and fibers, for magnesium-based composites was developed. An advanced and affordable technique of fabricating hybrid magnesium-based composites called the preform-squeeze casting was employed successfully.
2010-04-12
Technical Paper
2010-01-0407
Jafar Albinmousa, Adrian Pascu, Hamid Jahed, M.F. Horstemeyer, Alan Luo, D. Chen, Steve Lambert, J. Jordon, S. Begum, Xuming Su, Q.Q. Duan, Richard Osborne, Z. Zhang, Lin Zhang, T. Luo, Yuansheng Yang
Magnesium alloys are the lightest structural metal and recently attention has been focused on using them for structural automotive components. Fatigue and durability studies are essential in the design of these load-bearing components. In 2006, a large multinational research effort, Magnesium Front End Research & Development (MFERD), was launched involving researchers from Canada, China and the US. The MFERD project is intended to investigate the applicability of Mg alloys as lightweight materials for automotive body structures. The participating institutions in fatigue and durability studies were the University of Waterloo and Ryerson University from Canada, Institute of Metal Research (IMR) from China, and Mississippi State University, Westmorland, General Motors Corporation, Ford Motor Company and Chrysler Group LLC from the United States.
2010-04-12
Technical Paper
2010-01-0410
Alan A. Luo, Joy Forsmark, Xichen Sun, Scott Shook
Magnesium alloy extrusions offer potentially more mass saving compared to magnesium castings. One of the tasks in the United States Automotive Materials Partnership (USAMP) ?Magnesium Front End Research and Development? (MFERD) project is to evaluate magnesium extrusion alloys AM30, AZ31 and AZ61 for automotive body applications. Solid and hollow sections were made by lowcost direct extrusion process. Mechanical properties in tension and compression were tested in extrusion, transverse and 45 degree directions. The tensile properties of the extrusion alloys in the extrusion direction are generally higher than those of conventional die cast alloys. However, significant tension-compression asymmetry and plastic anisotropy need to be understood and captured in the component design.
2010-04-12
Technical Paper
2010-01-0409
John Jekl, Richard D. Berkmortel, Paula Armstrong
The main objective of this paper is to demonstrate how flow and solidification simulation were used in the development of a new gating system design for three different magnesium alloys; and to determine the relative castability of each alloy based on casting trials. Prototype tooling for an existing 3-slide rear wheel drive automatic transmission case designed for aluminum A380 was provided by General Motors. Flow and solidification simulation were performed using Magmasoft on the existing runner system design using A380 (baseline), AE44, MRI153M and MRI230D. Based on the filling results, new designs were developed at Meridian for the magnesium alloys. Subsequent modeling was performed to verify the new design and the changes were incorporated into the prototype tool. Casting trials were conducted with the three magnesium alloys and the relative castability was evaluated.
2010-04-12
Technical Paper
2010-01-0412
Jonathan Robert Burns, Henry Hu, Xueyuan Nie, Lihong Han
Powertrain applications of alloy AJ62 arose from its comparative resistance to high temperature deformation among magnesium alloys. In this research, AJ62 permanent-mould cast in different section thicknesses was subjected to immersion corrosion in commercially-available engine coolant. The objective was to determine corrosion behaviour variation among casting thicknesses. Corrosion product accumulation suggests passive film formation, and unlike in other media, the film exhibits certain stability. Extreme thicknesses were used to generate polarization curves for their respective microstructures in engine coolant. Variation with casting section thickness was observed in the curves. These preliminary results indicate coarsened microstructures reduce corrosion resistance of the permanent mold cast AJ62 alloy.
2010-04-12
Technical Paper
2010-01-0411
Behzad Behravesh, Lei Liu, Hamid Jahed, Stephen Lambert, Grzegorz Glinka, Norman Zhou
Interest in magnesium, as the lightest engineering metal, has increased in the automotive industry as a result of requirements for lighter and cleaner vehicles. Resistance spot welding (RSW) is already the predominant mode of fabrication in this industry, and the fatigue of spot welded magnesium sheet must be studied. In this study, the tensile and fatigue strength of resistance spot welded AZ31 Mg alloy was studied. Three sets of tensile shear spot welded specimens were prepared with different welding parameters to achieve different nugget sizes. Metallographic examination revealed grain size changes from the base material (BM) to heat affected zone (HAZ) to the fusion zone (FZ). Monotonic tensile and fatigue tests were conducted and the effect of nugget size on tensile shear and fatigue strength was discussed.
2010-04-12
Technical Paper
2010-01-0403
Kumar Sadayappan, Michael Vassos
Thixomolding® is a semi-solid metal-molding process used to produce magnesium alloy components. The component quality is claimed to be high due to the low speed non-turbulent filling experienced in the thixomolding process. Parts of AM60 alloy were produced in a USAMP/DOE funded and directed project to demonstrate economic production of quality large thin wall, structural magnesium component using thixomolding. The selected application was the Ford F-150 shotgun; the structural connection between the A-pillar and the radiator support structure, and produced by G-Mag International. Test pieces were assessed through radiography and mechanical testing. The properties of the shot-gun casting were compared to those of experimental plate castings. Properties of the large casting were found to have a higher level of scatter compared to plate castings which can be attributed to the gas entrapment and oxide inclusions. The results are presented and discussed in this publication.
2010-04-12
Journal Article
2010-01-0404
Okechukwu Anopuo, Yuanding Huang, Norbert Hort, Hajo Dieringa, Karl Ulrich Kainer
Understanding the creep and bolt load retention (BLR) behavior of promising Mg-Al alloys are crucial to developing elevated temperature resistance alloys. This is especially true for elevated temperature automotive applications with a prevalence of bolted joints. In this study, creep and fastener clamp load response of Mg-Al alloy AS41 was investigated and compared to that of Mg4Al and AS41 micro-alloyed with 0.15 % Ca. A compliance-creep approach was used to model the response of these Mg-Al alloys at bolted joints. The equation prediction of the BLR response and experimental results are in good agreement. AS41+0.15 Ca shows improved creep and BLR properties up to 175°C. A correlation between the microstructures, creep and BLR results reveal that the formation of a ternary CaMgSi phase is responsible for the improved elevated temperature behavior.
2010-04-12
Journal Article
2010-01-0655
Greg Wallace, Andrew P. Jackson, Stephen P. Midson
A turbocharger essentially consists of a turbine and an impeller wheel connected on a common shaft. The turbocharger converts waste energy from the exhaust into compressed air, which is pushed into an engine to produce more power and torque, as well as improving the overall efficiency of the combustion process. The compression ratio for modern diesel engines can be up to 5:1, which can be only achieved using a complex impeller design and very high rotation speeds (up to 150,000 rpm for small impellers). The complex geometry and very high running speeds of impellers creates high stresses at locations such as blade roots and around the bore, and so impellers normally fail from fatigue. Therefore, it is vital to minimize defects while fabricating turbocharger impellers. Current methods for producing aluminum turbocharger impellers are plaster casting or by forging + machining. However, both of these current methods have serious drawbacks.
2010-04-12
Journal Article
2010-01-0657
William (Jud) Dunlap, Alan Druschitz
Exhaust manifolds and turbocharger housings require good elevated temperature strength, good resistance to thermal fatigue and a stable microstructure. High silicon ductile iron, high silicon-molybdenum ductile iron and Ni-resist (a high nickel ductile iron) are the cast materials of choice. Unfortunately, molybdenum and nickel are expensive. In this study, a lower cost, high silicon-titanium, compacted graphite iron was developed and compared to high silicon ductile iron and higher cost, high silicon-molybdenum ductile iron. Room and elevated temperature strength data is presented.
2010-04-12
Journal Article
2010-01-0652
Christopher A. Bixler, Kathy L. Hayrynen, John Keough, George Pfaffmann, Scott Gledhill
There are numerous component applications that would benefit from localized austempering (heat treating only a portion of the component) for either improved wear properties or fatigue strength. Currently available methods for “surface austempering” of ductile iron are often expensive and not as well controlled as would be desired. This study was undertaken to find a better process. Locally Austempered Ductile Iron (LADI) is the result of those efforts. LADI is a surface hardening heat treatment process that will produce a localized case depth of an ausferrite microstructure (ADI) in a desired area of a component. This process has been jointly developed by Ajax Tocco Magnethermic Corporation (ATM) and Applied Process, Inc.- Technologies Division (AP) with support and collaboration from ThyssenKrupp Waupaca, Inc. (TKW). This paper describes the outcome of using this patent pending process (US #65/195,131).
2010-04-12
Journal Article
2010-01-0654
Delin Li, Clayton Sloss
There is a wide spectrum of cast ferrous heat resistant alloys available for exhaust component applications such as exhaust manifolds and turbocharger housings. Generally speaking, the ferrous alloys can be divided into four groups including: ferritic cast irons, austenitic cast irons, ferritic stainless steels, and austenitic stainless steels. Selection of a suitable alloy usually depends on a number of material properties meeting the requirements of a specific application. Ferritic cast irons continue to be an important alloy for exhaust manifolds and turbocharger housings due to their relatively low cost. A better understanding of the alloying effects and graphite morphologies of ferritic cast irons are discussed and their effect on material behavior such as the brittleness at medium temperatures is provided. The nickel-alloyed austenitic cast irons, also known as Ni-resist, exhibit stable structure and improved high-temperature strength compared to the ferritic cast irons.
2000-03-06
Technical Paper
2000-01-0679
Alan P. Druschitz, David C. Fitzgerald
The use of aluminum to produce lightweight automotive castings has gained wide acceptance despite significant cost penalties. Lightweight iron and steel casting designs have been largely ignored despite their obvious cost and property advantages. This paper reviews and discusses the following: 1) various processes for producing lightweight iron and steel castings, 2) examples of lightweight components in high-volume production, 3) examples of conversions from aluminum to iron, 4) material properties of interest to designers, 5) examples of concept components and 6) efforts to improve the design and manufacturing processes for lightweight iron and steel castings. In summary, the potential for low-cost, lightweight iron and steel castings to aid the automotive industry in achieving both cost and weight objectives has been demonstrated and continues to expand. In general, however, automotive designers and engineers have not yet fully taken advantage of these technologies.
2000-03-06
Technical Paper
2000-01-0677
Mitsuru Adachi, Satoru Sato
The New Rheocasting process will provide excellent mechanical properties with a positive solution for the cost of material that has been the weakness of the semi-solid casting process. The process is a kind of batch system. It uses a cup for each shot and a conventional automatic ladling system, which pours molten metal into the cup. This process produces semi-liquid slurry including globular crystals directly from molten metal without a stirring technique. The products made by this process have shown good mechanical properties. The solidification rate of a rheocasting sample is so high that the microstructures of the products are uniform and fine.
2000-03-06
Technical Paper
2000-01-0763
Brian Baker, Samuel Kiser, Peter Chen, Brian Skinn, Rick Williams
The demands of modern society continue to drive automotive design to greater efficiency and cleaner operation at lower cost. Higher operating temperatures are now typically required to meet these demands, making the use of more robust materials and joining techniques a necessity. This paper describes how the benefits of reduced emissions and greater fuel economy along with quieter operation are achieved by using silicon-molybdenum modified ductile iron exhaust manifolds welded to close-coupled 400 series stainless steel catalyst cans. This weldment is made possible by using a newly-developed stabilized Ni-Fe-Mn-Cr-Cb welding wire called NI-ROD® Filler Metal 44HT. Durability testing of fabricated exhaust components under extreme dynamometer testing has shown that this welding material provides successful higher temperature performance by the ductile iron than that provided by previous weldments of the same iron.
2000-03-06
Technical Paper
2000-01-0760
Robert Wolfe, Rob Bailey
Proper alloy and process selection is critical to the commercial production and application of any high-integrity casting. These activities must be focused directly on critical part performance criteria. This paper presents examples of how a casting supplier, with a sound foundation in a broad range of the high-integrity casting techniques, can select and optimize critical criteria in the areas of product design, alloy design, casting process design and heat treatment to achieve a commercial manufacturing success which satisfies the casting customers' functional needs. Three case studies are described which show how proper process selection aided the casting customer in choosing the correct casting process. Case Study 1 Optimization of a 357 semi-solid metal casting (SSMC) alloy with T-5 heat treatment for a swaging application. Case Study 2 Optimization of a 365 alloy and T-5 heat treatment for Johnson Apparent Elastic Limit (JAEL).
2000-03-06
Technical Paper
2000-01-0754
Jiten V. Shah
In today's global competitive environment, the OEMs (original equipment manufacturers) are forced to introduce new products in a relatively short turnaround time and the products are required to be custom designs and developed in a concurrent engineering environment. Concurrent Product and Process Development (CPPD) using Casting Process Simulation brings agility to new product and process design and development. The current computer aided technologies have enabled metal casters to understand and apply physics behind mold filling, solidification, and microstructure evolution. The commercially available tools allow to simulate most of the conventional casting processes such as sand, plaster molded, investment, permanent mold and die casting. Using this technology, castings are virtually made on computer before any hard tooling is made. Case study on cast component product development is presented.
1999-09-28
Technical Paper
1999-01-3155
Michael Ziegler
In this paper the effects of pulsating blankholder forces in deep draw processes for sheet metal parts are discussed. Areas with and without tangential compressive stresses in the flanges, which are located between the binders, are discussed separately. Areas without tangential compressive stresses can be simulated by a special friction strip-draw test using a pulsating normal force ( representing the blankholder force ). Investigations using this equipment show that by pulsating blankholder forces it is possible to avoid galling and to reduce the friction force. Areas with tangential compressive stresses can be simulated by deep drawing axissymmetric cups using a pulsating blankholder force. Investigations with this equipment show that without increasing the danger of wrinkling the friction forces can be reduced by pulsating blankholder forces, when a certain frequency limit is reached.
2000-03-06
Technical Paper
2000-01-0312
Gardner Haynes, Michael Haynes, Bijendra Jha
Clad metals are metallurgical materials systems comprised of two or more metals or alloys which are metallurgically bonded to form a single material. This results in specific and unique properties of the clad metal system which are not available in a monolithic metal or alloy. Historically, they have been used for many decades by the automotive industry but the cladding process as well as the ability to design specific properties into a clad system are not well understood. This paper describes the cold roll bonding process for fabrication of clad metals. The mechanism of bond formation and limitations of the process are discussed. Rules for calculating a number of properties of clad metals are presented. Methods for designing clad metals to obtain unique properties for specific applications are described. The history of the use of clad metals on automobiles is also reviewed.
2000-03-06
Technical Paper
2000-01-0067
Wayne Perrard, Alan Gibson
Copper clad aluminum wire and copper clad steel wire are commercial products widely used in the telecommunications and electric utility industries, but they are not currently used to a great extent by the automotive industry. Copper clad aluminum is most often chosen as a lighter, lower cost substitute for copper. It is especially efficient for high frequency applications where its impedance is often no greater than solid copper. Copper clad steel is usually applied where strength is important and lower conductivity can be accepted. In addition to wire applications in other industries, bimetallic wire has unique properties that make it attractive for automotive applications. Two new areas of application are suggested: The use of copper clad aluminum to reduce the weight and conductor cost of power cables. The use of smaller diameter copper clad steel for wiring leads that are now sized based on strength rather than conductivity.
2000-03-06
Technical Paper
2000-01-0066
M. Ridha Baccouche, David A. Wagner, Mahmoud Y. Ghannam
The crush resistance of roof structures is critical to minimizing injuries and enhancing occupant survival during rollover crashes. Federal Motor Vehicle Safety Standard FMVSS 216 requires the roof structure to resist a load equal to one and one half (1&1/2) the unloaded weight of the vehicle during the first 127 millimeters (five inches) of deformation. This paper discusses the analytical methodologies applied and challenges encountered developing a hybrid Aluminum-Random Chop Material (RCM) roof structure. The roof structure materials are extruded 6260T6 aluminum and RCM. This hybrid roof structure has to satisfy not only the FMVSS 216 roof crush resistance, but also packaging, torsional stiffness and head impact requirements. Due to packaging constraints, the structure has to be developed without the roof bow at the B-pillar level.
2000-03-06
Technical Paper
2000-01-0060
C. J. Buynacek, W. L. Winterbottom
This paper addresses the design and development of a Semi-Solid Metal (SSM) aluminum master cylinder for vehicle applications. This light weight, near-net-shape, fully dense aluminum master cylinder manufactured by semi-solid forming (SSF) methods is being supplied by Delphi for automotive and truck brake systems. Several million master cylinders have been put into service over the past three years with an outstanding field service record. The application illustrates the benefits of a supplier/customer joint development in the design and manufacture of lightweight, high quality, critical application parts at a cost competitive with other less reliable casting methods. One of the advantages of using an aluminum SSM forging in place of the traditional permanent mold casting is the improved dimensional control capability which makes possible a reduction in mass and final machining.
2000-03-06
Technical Paper
2000-01-0059
Tim Basner
The most popular aluminum alloys for semi-solid automotive components are A356 and A357. The density of rheocast semi-solid A357 is higher than die cast A357 and allows for both T5 and T6 heat treatment. The mechanical properties of rheocast semi-solid A357 was found to be more dependent upon the heat treat schedule and casting soundness than by the solid content of the semi-solid slurry or the globule shape.
2005-04-11
Technical Paper
2005-01-1387
Rick Borns, Don Whitacre
Many vehicle chassis and suspension components are constructed of aluminum alloys, due to the metals relatively high strength-to-weight ratio and inherent corrosion resistance. A high percentage of these components' were converted from other materials. This has resulted in design geometries developed for materials and product forms that do not take advantage of aluminum's best attributes. In an effort to create the most efficient designs, Alcoa has developed an integrated approach to design of suspension components, combining precise process refinement, development of strength-optimized alloys, and intelligent use of advanced structural optimization tools.
2005-04-11
Technical Paper
2005-01-1389
Takuya Sakaguchi, Shin Takeuchi, Yasuo Kogo, Naohiro Igata, Katsuhiro Nishiyama
We have tried to improve damping capacity of an aluminum alloy by means of dispersing ceramic particles (low damping SiC and high damping NdNbO4) of different sizes and volume fractions in the aluminum alloy by powder metallurgy. It is shown that the damping capacity is increased in every case accompanying an increase of Young's modulus. It is also shown that the intrinsic damping capacity of dispersed particles does not play a role in improving the damping capacity. The increase of the damping capacity seems to be attributed to dislocations breakaway, interaction of fine particles and dislocations, and relaxation of interface between ceramic particles and aluminum matrix.
2005-04-11
Technical Paper
2005-01-1391
C. L. Xie, M. Hailat, Z. Abedin, X. Wu, G. Newaz, M. Taya, B. Raju
A composite of an aluminum matrix reinforced by short TiNi shape memory alloy (SMA) fibers was fabricated. The processing and thermomechanical behaviors of the composite TiNi/Al6061 were investigated experimentally and analytically. Optimal hot-pressing conditions of TiNi/Al6061 processing were identified. The shape memory effect (SME) was activated by prestraining the composite at the temperature between Ms and As, followed by heating up to Af. SME on mechanical properties, such as microhardness, yield stresses of the composite, were investigated. A computational model for the strengthening mechanism of the short fiber metal matrix composite was utilized to analyze SME on yield stress of the composite. Yield stress of the composite as a function of prestrain was predicted numerically and verified experimentally.
2005-04-11
Technical Paper
2005-01-1390
Yuji Hisatomi, Yoshifusa Shoji, Taketoshi Toyama, Yoshiharu Hasegawa
Through the years, aluminum automotive heat exchangers have been developed in order to have a high performance and a light weight. Therefore, the thickness of the aluminum sheets for the application has been reduced. As the brazeability declines with the reduction in thickness, fins having a thickness under 80μm may be difficult to secure a good brazeability. Therefore, we studied the brazeability to determine the limit of thickness using clad fins from 40 to 80μm. The fillet volume formed at the joints of the fin and tube decreased with the decreasing fin thickness and the Si content in both the filler metals and the core alloys. The suitable range of Si content in the filler metals and the core alloys to obtain a good brazeability decreased with the decreasing fin thickness. When the fins were thinner than the critical values, it was impossible to have a good brazeability.
2005-04-11
Technical Paper
2005-01-0615
Yancy W. Riddle, C. Edward McComas
New electroless nickel (EN) surface engineering and tribological coating solutions have been providing automotive, industrial, and military engineers more options for base alloy, lubrication selections, and improved performance properties. Recent advancements have been made in electroless nickel (Ni) coatings through the introduction of boron (B) to yield hard materials with inherently high lubricity and significantly better wear resistance. Unlike previous generation of Ni-B coatings that contained low levels of B these new Ni-B coatings contain 5-6wt% B with the balance being Ni. The higher level of B in the coating is responsible for the major improvement in properties. In addition, the plating process for these new coatings is environmentally-friendly and safe to work with providing a viable option for the replacement of hard chrome coatings and the dangers associated with hexavalent chrome.
2005-04-11
Technical Paper
2005-01-0723
Matthew Abate, Mike Willman
The seat frame can play an important part in improving the overall craftsmanship and safety of the seat. This paper discusses the design and research done to a cast magnesium seat back frame to affect seat craftsmanship and safety.
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