Effect of Cooling MethodsonMicrostructure and Tensile Propertyof Tempered1Cr13Ni Steel

To investigate the effects of different cooling methods on the tempered microstructure and tensile properties of 1Cr13Ni steel, four cooling processes—water quenching + tempering, oil quenching + tempering, air cooling + tempering, and furnace cooling + tempering—were applied. The results show that the as-quenched microstructure mainly consists of martensite and retained austenite, while the tempered microstructure is primarily composed of sorbite and ferrite. Faster cooling rates led to a higher proportion of martensite. Subsequent tempering of the rapidly cooled samples revealed polygonal and fine ferrite grains, along with partial dissolution of cementite. Both the as-quenched and tempered hardness increased significantly. Among the processes, water quenching + tempering yielded the best tensile properties, with a strength of 1191 MPa and an elongation of 24.24%. This indicates that the martensite content directly influences the mechanical properties of 1Cr13Ni steel. Furthermore, a slower tempering rate resulted in reduced grain boundary density and dissolution of carbides, which contributed to improved material plasticity.