Influence of Heat Treatment Temperature on Microstructure and Property of 00Crl3Ni5Mo2 Supermartensitic Stainless Steel

The microstructural evolution and mechanical property of 00Crl3Ni5Mo2 supermartcnsitic stainless steel (SMSS) subjected to different heat treatments were investigated. Room tensile tests, hardness tests, scanning electron microscopy, transmission electron microscopy and X-ray diffraction were conducted on the heat-treated steels. It is found that the microstructure of the heat-treated steel is composed of tempered lath martensite, retained austenite and δ-ferrite. The austenitizing temperature and tempering temperature have a significant effect on the microstructural changes, which leads to the complex variations of mechanical properties. The fine tempered lath martensite and more dispersed reversed austenite in the microstructure facilitate improving the comprehensive mechanical properties of the studied steel. The optimal heat treatment process of 00Crl3Ni5Mo2 SMSS is obtained by austenitizing at 1000 °C for 0.5 h + hair cooling followed by tempering at 630 °C for 2 h + hair cooling, where the excellent combination of tensile strength, elongation and hardness can be achieved.