156. Development of a High Performance Nickel-Free PM Steel   A developmental nickel-free P/M steel containing Cr, Mn, Si and Mo is being evaluated as a new high performance material. Bonded premixes with varying carbon contents were made with the AncorMax^® D system and pressed to densities of 7.2 g/cm³. Sintering studies were performed at 1177°C and 1260°C. Higher strengths were achieved in the CrMnSiMo steel as compared to a Ni containing steel with a higher total alloy content. Ultimate tensile strengths over 1200 MPa and hardnesses of 70 HRA can be achieved in the sinter + temper condition. The effect of sintering temperature, cooling profile and carbon content on mechanical properties and microstructure will be discussed.

154. A Review of Current Sinter-Hardening Technology Sinter-hardening has developed into a highly cost effective production method for the production of through hardened P/M parts without the need for additional heat-treatments. Over the last several years advances have been made in sinter-hardening material systems and furnace technology. This paper reviews these advances as well as some key processing parameters required to produce high quality sinter-hardened components. Specific topics included are proper alloy selection, mechanical and fatigue properties, microstructural development, optimization of furnace cooling rates, and proper tempering practices.