Mechanical Properties of Case-Hardened Low Cr Sintered Steel

Abstract

A newly developed Ni-free pre-alloyed steel powder, Fe-0.5 %Cr-0.2 %Mn-0.2 %Mo (JIP^® 5CRA) shows a rotating bending fatigue limit of 510 MPa after compacting, sintering and case-hardening process. This is approximately 40 % higher than that of a case-hardened sintered steel based on a conventional diffusion bonded steel powder, Fe-4 %Ni-1.5 %Cu-0.5 %Mo (4Ni). This is attributed to the higher compressive residual stress of the 5CRA based material. In spite of the higher fatigue limit, its tensile strength is lower than that of the 4Ni based material. The difference in the microstructural transformation behavior is a possible cause of this reverse phenomenon.