12.10.2008 Pressing & Sintering

Influence of Sintering Temperature and Component Density on the Properties of Prealloyed PM Steel Grades Containing Cr, Mo and Mn

Chromium, molybdenum and manganese are effective alloying elements suitable for low-alloyed structural steel components. Efficient use of these alloying elements in PM steels will make the PM technology more competitive in high performance applications. This study demonstrates mechanical properties obtained with prealloyed powder grades containing Cr, Mo and Mn after application of different press-sinter process routes. Astaloy CrL (Fe-1.5%Cr-0.2%Mo) with 0.7%C obtains tensile strength values of 714/880 MPa combined with elongations of 1.2/1.8% at density levels 7.0/7.2 g/cm3 after conventional sintering at 1120°C. Corresponding tensile strength and elongation values for two development grades with more ductile property profiles are 632/736 MPa combined with 2.2/3.0% for Fe-1.8%Cr, and 586/662 MPa combined with 3.3/4.0% for Fe-0.8%Cr-0.4%Mn, both with 0.7%C after sintering. Application of higher sintering temperature is beneficial for the mechanical performance of the studied materials. Sintering at 1250°C leads to increased tensile strength values by 15-25% compared to the properties obtained after sintering at 1120°C.