Opportunities for conversion of powertrain components from malleable/ductile cast irons to powder metallurgy

摘要

Malleable and ductile cast irons are used extensively in gearing and high- strength applications within automotive power train applications. Advantages of malleable and ductile cast irons are low material cost with mechanical properties that meet or exceed the requirements of the intended application(s). One disadvantage of the malleable cast iron is the extensive heat treating required to obtain the proper microstructure and mechanical properties. Both malleable and ductile iron components require extensive machining to produce the finished component. The combination of heat treating and extensive machining often results in a component that is costly to manufacture. Recent advances in the Powder Metallurgy (P/M) process including high-strength material systems and high density processing have achieved mechanical properties that meet or exceed the level achieved with the current malleable and ductile cast iron materials. This paper will present an evaluation and comparison of the mechanical properties of malleable cast iron with selected P/M material systems and processing parameters. This property discussion will demonstrate the suitability of the P/M process in replacing these cast and machined components. Examples of specific parts will be cited and discussed.