SUS410L (Fe-12 wt%Cr) and graphite mixed powder compacts are sintered at 1473 K to 1598 K, followed by heat treatment for controlling the matrix microstructure to martensite. The effects of carbon content on the sintering behavior and tensile properties are discussed, in order to develop the high strength P/M martensitic stainless steels. The results are summarized as follows:
The amount of δ-ferrite at sintering temperature decreases and that of austenite increases with increase in carbon content and decrease in temperature. Specimens containing much amount of δ-ferrite undergo densification and pore-rounding during sintering, because of high self-diffusibility of δ-ferrite.
0.1 wt% of carbon is necessary at least in order to control the matrix microstructure to martensite through optimum solution treatment.
Tensile strength of low temperature tempered specimens increases with increasing carbon content as well as advance in densification. The latter method might be better for strengthening the specimens in view of corrosion resistance.