Powder metallurgy steels for highly loaded precision parts

Ferrous powder metallurgy precision components are increasingly being used for highly loaded applications. This requires consistent improvement in materials properties without sacrificing geometrical precision. Here, the various approaches for obtaining this goal are discussed. The relationships between density/porosity and properties, especially fatigue, are described, as is the effect of higher sintering temperatures. The resulting requirements towards equipment are discussed, and the consequences of sintering Cr and Mn containing steels for the sintering atmosphere are shown. Secondary operations performed in PM parts production are described and typical examples for high performance PM parts are shown, and the dominating trends are identified.