10:35 〜 10:55
[16F-T12-11] Tempering Effect on Cr Containing Low Alloy Steel after Sintering
キーワード：Tempering, Sintered Steel, Microstructure
Cr containing steels have good hardenability among commercially available low-alloy steel powders. Martensitic structure can be obtained on sintered compact made from Fe-3%Cr-0.5%Mo (CrM) powder by a conventional belt furnace by adjusting copper and carbon content. If martensitic microstructure is obtained by quenching, tempering is commonly applied. It is considered that the tempering is also necessary if the martensite occurs during sintering. In this study, the effect of tempering temperature on the microstructure and the mechanical properties for CrM was investigated. CrM is oxidized at high temperature in air, the influence of tempering atmosphere was also checked. The CrM+2%Cu+0.7%C showed around 1200MPa of tensile strength and 25J of impact energy at 250C tempering both in H2 and air. On the other hand, more than 573K the effect of tempering temperature in air differed from that effect in H2.