Sinter hardening is a cost effective process to manufacture P/M parts exhibiting high strength and apparent hardness at lower cost than conventional heat treatment. This process is particularly attractive for parts that are difficult to quench due to their size and shape. Indeed, during the sinter hardening process, the transformation to martensite takes place during the cooling phase of the sintering cycle, thus reducing thermal stresses as compared to oil quenching. Many powder grades have been developed for sinter hardening applications. Depending on their alloy formulation, these grades offer a wide range of compressibility and response to hardening. The objective of this paper is to discuss the effect of alloy composition on compaction behavior and response to hardening of different powder grades in order to facilitate the selection of materials, mix formulations and processing conditions to optimize the properties of sinter hardened P/M parts.
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