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Technical Paper

Development of Heat Exchangers with Non-Chromate High Corrosion Resistance Treatment

2000-03-06
2000-01-0572
Aluminum alloy heat exchangers use chromium (VI) compound for their surface treatment to prevent white rust. The use of chromium (VI) compound is restricted and will be banned worldwide in view of environmental concerns. Therefore, we need a timely change to the non-chromate type treatment. Considering this trend, we have developed and released non-chromate type heat exchangers. In addition to high corrosion resistance, these heat exchangers feature a good hydrophilic ability, antibacterial activity, and smell preventing property. With simultaneous development activities at the development and design divisions, as well as making good use of the quality function deployment (QFD) method into the total process from design work to production we have completed the project in a short time.
Technical Paper

Springback of Sheet Metal Subjected to Multiple Bending-Unbending Cycles

2000-03-06
2000-01-1112
A Draw Bead Simulator (DBS), with modified draw beads, was employed in this study to understand the springback behavior of sheet metal subjected to multiple bending-unbending cycles. The investigations were carried out in both the rolling and the transverse rolling directions on four types of materials: Electro-Galvanized DQ steel, light and heavy gauge Hot-Dip Galvanealed High Strength Steels, and Aluminum alloy AL6111. The sheet geometries, thickness strains, pulling forces and clamping forces were measured and analyzed for the purpose of establishing a benchmark database for numerical predictions of springback. The results indicate that the springback curvature changes dramatically with the die holding force. The conditions at which the springback is minimized was observed and found to depend on the material properties and the sheet thickness. Analysis with an implicit FEM showed that the predicted and the experimental results are in very good agreement.
Technical Paper

Development of Lightweight Oil Pans Made of a Heat-Resistant Magnesium Alloy for Hybrid Engines

2000-03-06
2000-01-1117
A new heat-resistant magnesium alloy (hereafter referred to as “ACM522”) for die-casting based on the Mg-Al-Ca-RE system has been developed by Honda R&D Co. In the 150°C temperature range, the ACM522 alloy yields high creep resistant characteristics which are superior to the conventional AE42 heat-resistant magnesium alloy, and it also exhibits an excellent resistance to both heat and corrosion which can be favorably compared with the A384 general-purpose aluminum alloy. The use of magnesium for oil pans has raised a number of issues such as reduced axial force in the bolted areas and, until now, oil pans made of magnesium had not reached the stage of commercial viability for mass-produced automobiles. The authors applied the ACM522 alloy to develop light-weight oil pans which are 35% lighter than conventional aluminum oil pans.
Technical Paper

Automotive Applications Using Advanced Aluminum Die Casting Processes

2000-03-06
2000-01-0678
This paper provides a description of commercially available die casting processes including conventional die casting process (high pressure, high velocity), squeeze casting (high pressure, controlled cavity fill rate), semi-solid metal casting, and Vacural™ (a variation of the conventional die casting process). The various automotive products made using these processes are also reported in the study. In this study, the mechanical (tensile, impact, fatigue strength and fracture toughness) and wear properties are compared among the above processes. Results indicate that mechanical and wear properties of aluminum alloys made using the “high integrity” casting processes (squeeze, semi-solid metal casting and Vacural™) are superior to those of conventional die castings.
Technical Paper

Springback Analysis with a Modified Hardening Model

2000-03-06
2000-01-0768
Previously-reported draw-bend tests showed large discrepancies in springback angles from those predicted by two-dimensional finite element modeling (FEM). In some cases, the predicted angle was several times the measured angle. With more careful 3-D simulation taking into account anticlastic curvature, a significant discrepancy persisted. In order to evaluate the role of the Bauschinger Effect in springback, a transient hardening model was constructed based on novel tension-compression tests for for three sheet materials: drawing-quality steel (baseline material), high-strength low-alloy steel, and 6022-T4 aluminum alloy. This model reproduces the main features of hardening following a strain reversal: low yield stress, rapid strain hardening, and, optionally, permanent softening or hardening relative to the monotonic hardening law. The hardening law was implemented and 3-D FEM was carried out for comparison with the draw-bend springback results.
Technical Paper

Damage Characterization and Damage Percolation Modelling in Aluminum Alloy Sheet

2000-03-06
2000-01-0773
Tessellation methods have been applied to characterize second phase particle fields and the degree of clustering present in AA 5754 and 5182 automotive sheet alloys. A model of damage development within these materials has been developed using a damage percolation approach based on measured particle distributions. The model accepts tessellated particle fields in order to capture the spatial distributions of particles, as well as nearest neighbour and cluster parameter data. The model demonstrates how damage initiates and percolates within particle clusters in a stable fashion for the majority of the deformation history. Macro-cracking leading to final failure occurs as a chain reaction with catastrophic void linkage triggered once linkage beyond three or more clusters of voids takes place.
Technical Paper

Sheet Metal Forming Simulation for Aluminum Alloy Sheets

2000-03-06
2000-01-0774
This work describes a sheet forming process simulation, cup drawing and redrawing, using a new plane stress anisotropic yield function that describes the anisotropic behavior of aluminum alloy sheets well. The anisotropy of the function was introduced in the formulation using only linear transformations on the Cauchy stress tensor or deviator. The implementation of this constitutive equation in finite element codes was briefly explained. Simulation results were presented and compared with experimental data.
Technical Paper

Aluminum Alloys for Automotive Knuckle Castings

2000-03-06
2000-01-1291
Knuckle castings for the automotive industry have traditionally been made from ductile iron, but engineers are now looking to aluminum castings as a lightweight alternative. Amcast Automotive has been involved in the development and manufacture of A206 aluminum knuckle castings since 1989 when it first supplied Aluminum castings for Ford Motor Co. (MN-12 platform). Recently, several new high volume automotive knuckle castings have been introduced using A356 aluminum alloy with T-6 temper. This paper presents mechanical property information on both A206 and A356 aluminum alloys to assist engineers in the design of knuckle castings in aluminum. In addition to microstructural evaluation, mechanical properties will be obtained from test bars cut from actual heat-treated knuckle castings.
Technical Paper

Wear Properties of In-Situ Reacted Al-AlN Composite Sintered Material and Application for Automatic Transmission Parts

1999-03-01
1999-01-1048
In-situ formed Al-AlN sintered composite materials have been developed by the direct nitriding process based on the reaction of the aluminum matrix to nitrogen gas during sintering. A traditional press-sinter(P/S) method, hot extrusion(H/E) and powder forging (P/F) processes are available to consolidate the composite aluminum alloys. Fine AlN particles less than 1 μm in diameter dispersed as hard particles in the material have a significantly strong bonding to the matrix. They have an important role to improve wear resistance equivalent to the hard anodizing or Ni-P plating. The aluminum alloy also shows a low friction coefficient (less than 0.01) under oil lubricating conditions because fine AlN particles make it possible to form oil film at the interface between the counterpart material.
Technical Paper

Development of a Wear Resistant Aluminum Alloy for Automotive Components

1999-03-01
1999-01-0350
Hypereutectic Al-Si alloy 390, containing large amounts of hard silicon particles, has mainly been used for wear-resistant alloy applications. In the case of hypereutectic Al-Si alloys, the primary silicon particle size and distribution must be controlled to obtain stable wear resistance. The service life of furnaces and molds is shortened by the high melting and casting temperatures required for controlling primary silicon. Furthermore, machinability is degraded by large primary silicon particles. To overcome these problems, a new wear-resistant Al-Si alloy has been developed which provides good castability and machinability. This alloy also has wear resistance and mechanical properties similar to those of the 390 alloy. Specifically, the problems regarding castability and machinability were solved by decreasing the silicon content of the 390 alloy, but that also reduced wear resistance.
Technical Paper

Aluminum Alloys for Automotive Disc Brake Calipers

1999-03-01
1999-01-0346
Disc brake calipers for the automotive industry have traditionally been made from ductile iron, but more of the calipers are currently being converted to aluminum, with weight savings of nearly 40 percent. Amcast Automotive has been involved in the development and manufacture of aluminum caliper castings since 1984 when it first supplied service production aluminum caliper castings for the four-wheel disc brake Pontiac Fiero. Presently, Amcast is introducing several new high volume automotive calipers using heat-treated aluminum 354 and 357 alloys. The paper presents alloy optimization and mechanical property information of aluminum 354 and 357 alloys to aid brake engineers in the design of calipers. In addition to microstructure evaluation, mechanical properties obtained from test bars cut from actual heat-treated caliper castings are presented.
Technical Paper

Squeeze Cast Automotive Applications and Squeeze Cast Aluminum Alloy Properties

1999-03-01
1999-01-0343
The emergence of squeeze casting process for aluminum alloys has given material and design engineers a new alternative to conventional casting techniques: gravity permanent mold (GPM) and conventional (high velocity, high pressure) die casting. In recent years, the squeeze casting process has been applied to near net shape products requiring high impact strength, high fatigue strength, pressure tightness, or high wear resistance. This paper provides both a description of the HVSC squeeze casting process and examples of select components manufactured at CONTECH. In this study, the mechanical (tensile, impact, fracture toughness, fatigue strength) and wear properties of various aluminum alloy squeeze castings are also compared with those of gravity permanent mold and conventional die-castings. Results indicate that mechanical and wear properties of aluminum squeeze castings are superior to those of gravity permanent mold and conventional die-castings.
Technical Paper

Consideration of Fluid Velocity Effects in the Design and Development of Aluminum Cooling System Components for Heavy Duty Diesel Engines

1999-03-01
1999-01-0128
In the design of aluminum (Al) cooling system components for heavy duty diesel engines, coolant flow velocities are critical to the durability of the parts. The geometries of the individual component parts used in the system must be designed to minimize turbulence which will affect the rate and type of corrosion. In addition, flow passages must be “sized” to maintain coolant velocities below a critical value. In high velocity flow, a combination of the mechanical damage produced by the impingement of a liquid on a metal surface and the inherent corrodibility of the metal may result in erosion-corrosion and impingement attack. Aluminum alloys are very prone to this type of corrosion damage because of the low inherent hardness of the material as compared to other alloy systems. The development of aluminum cooling system parts for a new 15 liter diesel engine was undertaken to lower weight and make a more compact design for the engine profile.
Technical Paper

Development of Spraying Technology for Improving the Wear Resistance of Engine Cylinder Bores

2003-09-15
2003-32-0066
In response to design requirements for lower weight and higher output, the motorcycle engine cylinder block has evolved from a cast cylinder block to an aluminum alloy cylinder block whose bore walls are surface-treated for wear-resistance. Hard-chromium plating, nickel-compound plating, and the like are in wide use as the wear-resistance surface treatment method, but spray technology has recently been attracting attention because of less impact on the environment, superior initial running-in performance and good oil retention. We have been applying a unique spraying method called wire explosion spraying to those models with a special need for wear-resistance surface. In this report we describe our wire explosion spray technology. With the aim of improving the bond strength of the sprayed coat, we studied the effects of the collided particles' form on bond strength in the wire explosion spraying conditions.
Technical Paper

Energy Absorption Capacity for HPDC Components

2004-03-08
2004-01-0128
The long-term objective of this work is to develop design and modeling tools that allow the structural behavior of thin-walled cast components to be predicted when subjected to static and dynamic loads such as in crash situations. Here, the energy absorption potential of High Pressure Die Cast components made of magnesium alloys AM20, AM50, AM60, AZ91 and the aluminum alloy AlSi7Mg is investigated using a shear-bolt principle. For the AM60 alloy, single plates cast with different thickness have been tested in order to investigate the effect of plate thickness on the shear-bolt mechanism. It is found that this deformation principle gives an approximately constant mean force during the deformation process. The behavior seems to be very robust, especially for the magnesium alloys. A simple empirical model for prediction of the mean shearing force as a function of plate thickness and bolt diameter is proposed.
Technical Paper

Comparative Evaluation of Automotive Oil Pans Fabricated by Creep Resistant Magnesium Alloy and Aluminum Alloy

2004-03-08
2004-01-0658
A series of comparative tests were conducted on two geometrically-identical automotive oil pans, one produced from A380 aluminum - pulled directly from its high-volume production line - and a second produced in a casting trial using DSM's MRI 153M creep-resistant magnesium alloy. While the theoretical differences in mechanical behavior of cast aluminum parts versus cast magnesium parts are relatively simple to determine, very few quantified, experimental comparisons exist. Where these comparisons do exist, they are often performed on simple shapes. Therefore, the objective of this project was to compare the stiffness, modal behavior, natural frequencies, and damping ratios of the two materials in a complex, functional geometry. Stiffness, natural frequencies, and flexural modes were determined using holographic laser interferometry and finite element analysis. Natural frequencies, modal behavior, and damping ratios were determined via hammer-impact excitations.
Technical Paper

Evaluation of High Temperature, Cast Magnesium Alloy, Front Engine Covers

2004-03-08
2004-01-0657
A variety of new magnesium casting alloys specifically designed for high temperature applications are currently available. However, there is little published data from component tests or from test specimens sectioned from component castings. In this study, the mechanical properties (tensile, bracket thread integrity, bracket distortion and fastener/attachment point acceptability) of front engine covers made from three magnesium alloys (AZ91D, AJ62x and MRI-153M) and from aluminum alloy 380 are presented.
Technical Paper

Study of Thermal and Heat Transfer Phenomenon in Friction Stir Welding of Aluminum Alloy 6061-T6 Thick Plates

2004-03-08
2004-01-1328
In the friction stir welding (FSW) process, heat is generated by friction between the interfaces between the tool and the workpiece. The amount of heat conducted into the workpiece determines the quality of the weld. In this paper, 37.6 mm (1.48 inch) thick plates made of aluminum alloy 6061-T6 were welded using the FSW process. We report (a) welding parameters such as tool RPM, welding speeds, (b) power and heat input to the welding process, (c) a complete temperature history from 27 thermocouples. Data are reported for one weld with a full-length pin and two welds with a short pin. In conjunction with the measurement, finite element analyses were also performed to study (1) the heat inputs from the tool shoulder as well as from the probe pin, and (2) temperature distribution and history in the workpiece. The analysis results are also compared with the measured data.
Technical Paper

Aluminium Crash Management Systems

2004-03-08
2004-01-1612
The specific characteristics of aluminum alloys offer the possibility to design cost-effective lightweight structures with high stiffness and excellent crash energy absorption potential. As a consequence, aluminum is the preferred material to ensure the safety of the vehicle and its occupants fulfilling also related requirements such as pedestrian protection, low repair costs, etc. Applications range from aluminum side impact beams, bumper beams and crash boxes to complete structural modules. Crashworthy aluminum structures are the result of a total systems approach taking into account the benefits achieved by specifically developed alloy qualities, design concepts and appropriate fabrication methods. Cost-efficient aluminum component production processes include in particular the extrusion technology.
Technical Paper

Development of an Innovative Concept of Light Semi-Trailer By Means of FEM and Testing

2004-03-08
2004-01-1517
A new light semi-trailer concept has been developed using numerical and experimental methods. In order to achieve this objective different types of light materials, such as high strength steels, aluminum alloys and sandwich compound materials, have been studied. The different semi-trailer models have been studied by means of a numerical model simulation based on F.E.M. (Finite Element Method) and subjected to whole loads and various boundary conditions. In testing whole strain values from critical points located in the semi-trailer have been obtained in order to correlate the numerical and the experimental results. Finally, some of the initial semi-trailer parts and areas were optimized by means of numerical methods. Results obtained in the numerical simulations were applied to the analyzed structure in order to design a second generation of semi-trailer structure in which weight is decreased.
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