22.6.2005 Pressing & Sintering

Chromium Pre-Alloyed PM Steels Suitable for High Performance Applications

Steel powders pre-alloyed with chromium are successfully used in PM components for high performance applications. Good mechanical properties are obtained after conventional sintering and the properties can be further improved by the use of high temperature sintering and/or sinter-hardening. Case hardening operations may also be applied for applications where the PM component surfaces are highly loaded. This paper presents dynamic as well as static mechanical properties obtained for different Cr-Mo pre-alloyed powder grades after various process routes. Compaction pressure, sintering temperature and cooling rate have been varied and case hardening has been applied. Correlations between microstructures and mechanical properties are described for the different materials. The benefits of using case hardening are highlighted, which is demonstrated by the excellent fatigue properties obtained.