Abstract: 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 900~1050℃ for 0.5h and tempering at 710℃ for 2h. There are a large number of Cr-riched M₂₃C₆ precipitates at the grain boundaries of tempered sorbite with a diameter of 100~200nm. 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 767MPa， the yield strength of 588MPa， the elongation after fracture of 22%， and the impact energy of 107J at 20℃.

Key words: 12Cr14Ni2 sorbite stainless structural steel; quenching temperature; heat treatment; microstructure; mechanical property