Many powder metallurgy (P/M) parts must undergo a secondary heat treating operation (after sintering) to develop a tempered martensitic microstructure either in a surface layer or throughout the part. The need for a secondary operation may beavoided by the process of sinter-hardening. Accelerated cooling techniques for sintering furnaces have been developed which permit larger parts, or materials with lower hardenability in smaller cross-sections, to be sinter-hardened. This article, from apresentation at the PM{sup}2TEC '98 International Conference on Powder Metallurgy & Particulate Materials, sponsored by the Metal Powder Industries Federation, describes how the alloying process for ferrous P/M materials influences hardenability. Examples of sinter-hardenable materials will be provided, and the benefits and disadvantages of the sinter-hardening process will be discussed.
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