采用热力模拟试验研究了新型抗热损伤车轮钢20CrSiMnMo在温度为850~1 250 ℃、应变速率为0.1~1 s-1条件下的热变形行为.结果表明:车轮钢在高温低应变速率下具有动态再结晶型流变曲线,低温高应变速率下其应力-应变曲线呈现硬化型;动力学分析得到该钢的热变形激活能Q=352.272 5 kJ/mol,应力指数n=5.56;组织观察和加工图表明,温度和应变速率参数选择在1 000~1 100 ℃,0.1~0.5 s-1或1 250 ℃,1~0.25 s-1范围内变形,将获得细小的动态再结晶晶粒和转变组织.

Hot deformation behavior of the new hot-damage-resistant wheel steel 20CrSiMnMo was investigated by thermo-mechanical modeling tests in 850-1 250 ℃ and strain rate range 0.1-1 s-1.The results indicate that the flow curves at higher temperature and lower strain rate are characterized by dynamic recrystallization,and strain-hardening curves are obtained at lower temperature and higher strain rate.Kinetic analysis is carried out to determine the stress exponent n=5.56 and the activation energy Q=352.272 5 kJ/mol.Microstructure observation and processing map indicate that finer dynamic recrystallization grains and transformed structure will be obtained deforming in temperature and strain rate ranges of 1 000-1 100 ℃,0.1-05 s-1 or 1 250℃,1-0.25 s -1.