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There are many opportunities for lightweighting with ductile iron castings. Current research shows ductile iron castings free of massive carbides can be achieved at under 2 mm (0.080”) through alloying or process changes which means that significant weight reductions are possible. In fact, for aluminum components over 4 mm thick, ductile iron may provide lightweighting opportunities at a cost savings. However, the conventional guidelines for casting design are inadequate when using ductile iron at dimensions less than the typical machine stock. This paper will discuss the current research on thin walled ductile iron, when it is superior to aluminum, design considerations, and current DOE SBIR funded research efforts to address these inadequacies. Research results on efforts to quantify and improve surface roughness in expanded polystyrene for lost foam casting are also discussed.

Typical sand-casting techniques have been shown to be inappropriate in pouring particulate reinforced aluminum metal matrix composite (Al-MMC) castings. New gating/risering configurations were necessary to produce castings of acceptable soundness. Several automotive components, including brake rotors, cylinder liners and camshaft thrust plates, were prepared using special techniques. Initial durability test results of several Al-MMC prototype components are presented.

Chrysler Corporation has developed an 8.0-liter engine for light truck applications. Numerous features combine to produce the highest power and torque ratings of any gasoline-fueled light truck engine currently available while also providing commensurate durability. These features include: a deep-skirt ten-cylinder 90° “V” block, a Helmholtz resonator intake manifold that enhances both low and mid-range torque, light die cast all-aluminum pistons for low vibration, a unique firing order for smooth operation, a “Y” block configuration for strength and durability, a heavy duty truck-type thermostat to control warm up, and a direct ignition system.

THE Junkers 211B engine follows the usual German practice of very large displacements and conservative mean effective pressures and rotative speeds. However, the relative light weight per unit of displacement results in a net weight per horsepower that is not far above its competitors. Fully automatic devices which control propeller speed, manifold pressure, mixture ratio, spark advance, and supercharger gear ratio follow the German policy of removing all possible distractions from the pilot. This is one of three large liquid-cooled engines known to be produced in quantity in Germany; it powers an impressive percentage of the Luftwaffe. While of external appearance and displacement that resemble the Daimler-Benz DB-601 engine, the fundamental construction, detail design practice, and metallurgy of the Junkers 211B are surprisingly different.

A new three-speed automatic transmission has been designed, developed and is being produced in the U.S. by the Chrysler Corporation for its new family of front wheel drive vehicles. The transmission was designed around the Chrysler-proven TorqueFlite concept. The features of the new transmission include a “folded” construction for installation in a transverse power train. The case is a one-piece aluminum die cast housing and contains the final drive and differential unit. This paper describes the design and development of this new automatic transmission.

Aluminum alloy castings are attractive when a light weight, inexpensive, near net shape component is desired. Unfortunately, the presence of internal porosity within these materials can have a significant detrimental effect upon the mechanical properties, appearance, and function of these parts. Hot isostatic pressing (HIP) and Densal® (a proprietary hot isostatic densification process) have been employed to reduce or eliminate porosity in cast metals. This paper compares the fatigue strength and microstructures of end chill sand cast A356 and high pressure, die cast 380 and 383 aluminum alloys which have undergone either HIP or Densal® processing with identical components in the as-cast condition. The castings which underwent isostatic processing show decreased porosity and improved fatigue strength and functionality. Additionally, the economics and suitability for high volume production of these two post-cast processes are reviewed.