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利用Gleeble-1500D热模拟试验机,在应变速率为0.01~10 s-1,变形温度为1000~1150℃条件下对铸态27Si Mn钢进行等温恒应变速率压缩试验。通过真应力-真应变曲线,分析了应变速率和变形温度对流变应力的影响规律,建立了铸态27Si Mn钢热变形时的本构方程和热加工图。结果表明,铸态27Si Mn钢高温变形时的峰值应力随应变速率的增大和变形温度的降低而升高;变形激活能为Q=369.0 k J/mol;热变形失稳区域集中在变形温度1000~1060℃、应变速率为1~10 s-1的区域内;最优热加工条件为变形温度1130~1150℃,应变速率4~10 s-1的区域,此时表现为典型的动态再结晶,对应的峰值效率达到35%。
The isothermal constant strain rate compression test of as-cast 27Si Mn steel was carried out with Gleeble-1500D thermal simulator at a strain rate of 0.01-10 s-1 and a deformation temperature of 1000-1150 ℃. The effect of strain rate and deformation temperature on the flow stress was analyzed by means of true stress-true strain curve. The constitutive equation and the hot working diagram of as-cast 27Si Mn steel during thermal deformation were established. The results show that the peak stress of as-cast 27Si Mn steel increases with the increase of strain rate and deformation temperature. The deformation activation energy is Q = 369.0 kJ / mol. The thermal deformation instability zone concentrates at deformation temperature 1000 ~ 1060 ℃ and strain rate of 1 ~ 10 s-1. The optimum thermal processing conditions are the region of deformation temperature 1130 ~ 1150 ℃ and strain rate 4 ~ 10 s-1, and the typical dynamic recrystallization , Corresponding to the peak efficiency of 35%.