Effect of Quenching Temperature on Microstructure and Mechanical Properties of 12Cr14Ni2 Stainless Structural Steel

Effect of quenching temperature on microstructure and mechanical properties of a 12Cr14Ni2 sorbite stainless steel was investigated by optical microscopy, scanning electron microscopy, electron probe and transmission electron microscopy, respectively. The results show that the fine and uniform tempered sorbite structures can be obtained in the hot-rolled steel plate after quenching at 900~1 050℃ for 0.5 h and tempering at 710℃ for 2 h. There are a large number of Cr-riched M23C6 precipitates at the grain boundaries of tempered sorbite with a diameter of 100~200 nm. As the quenching temperature increases from 900℃ to 1050℃, the austenitic grain size gradually increases after quenching, resulting in the coarsening of the tempered sorbite structure after heat treatments. The strength of the experimental steel first decreases and then increases, and both the elongation and impact energy increase first and then decrease. The excellent mechanical properties can be obtained at an optimal quenching temperature of 950℃, corresponding to the tensile strength of 767 MPa, the yield strength of 588 MPa, the elongation after fracture of 22%, and the impact energy of 107 J at 20℃. © 2021, Editorial Department of Journal of Northeastern University. All right reserved.