Effect of Annealing Temperature on Microstructure and Mechanical Property of Hot-rolled M390

Hot-rolled M390 high-carbon and high-chromium martensitic stainless steel was annealed at 650℃, 750℃ and 850℃. Therefore, the changes of microstructure and mechanical properties of M390 under different initial rolling temperatures and different annealing temperatures after hot rolling were studied by thermal expansion machine, Vickers hardness tester, X-ray diffractometer and scanning electron microscope (SEM). The results show that the strength of M390 deteriorates but the plasticity increases significantly with the increase of annealing temperature after hot rolling, while the carbide size becomes larger and the number of carbides decreases. After initial rolling at a high temperature of 1 200℃ and then annealing at a high temperature of 850℃, M390's ferrite matrix uniformly distributed with fine spherical carbide. At this time, the best comprehensive mechanical properties with tensile strength of 920 MPa and elongation of 0.83% are obtained, which was facilitates to the subsequent processing and heat treatment of the material.