17Cr2Ni2MoVNb和20Cr2Ni4A齿轮钢的动态再结晶行为及热加工图

利用Gleeble-3800热模拟试验机得到17Cr2Ni2MoVNb和20Cr2Ni4A齿轮钢在1000~1150 ℃、0.01~10 s^-1的流变应力曲线,构建了两种钢的动态再结晶Avrami动力学模型和热加工图。结果表明,两种钢在高变形温度、低应变速率下易发生动态再结晶。17Cr2Ni2MoVNb钢中较高的Nb和Mo含量对动态再结晶的抑制作用大于20Cr2Ni4A钢中的高Ni含量的影响,导致在相同的热变形条件下17Cr2Ni2MoVNb钢的动态再结晶体积分数小于20Cr2Ni4A钢。17Cr2Ni2MoVNb钢的最佳热加工工艺参数为:温度为1050~1150 ℃、应变速率为0.1~0.6 s^-1;20Cr2Ni4A钢的最佳加工参数为:温度为1100~1150 ℃、应变速率为3.3~5.5 s^-1。

Dynamic recrystallization behavior and processing map of 17Cr2Ni2MoVNb and 20Cr2Ni4A gear steels

The flow stress curves of 17Cr2Ni2MoVNb and 20Cr2Ni4A gear steels at 1000-1150 ℃ and 0.01-10 s^-1 were obtained by means of thermal simulation Gleeble-3800, and the dynamic recrystallization Avrami dynamics model and the processing map of the two steels were constructed. The results show that both steels are susceptible to dynamic recrystallization at high deformation temperatures and low strain rates. The higher Nb and Mo content in 17Cr2Ni2MoVNb steel has a greater inhibitory effect on dynamic recrystallisation than the high Ni content in 20Cr2Ni4A steel, which results in a smaller dynamic recrystallisation volume fraction in 17Cr2Ni2MoVNb steel than in 20Cr2Ni4A steel under the same heat deformation conditions. The optimal hot processing parameters of 17Cr2Ni2MoVNb steel are in the processing temperature range of 1050-1150 ℃ and at the strain rate of 0.1-0.6 s^-1, while those of 20Cr2Ni4A steel are in the processing temperature range of 1100-1150 ℃ and at the strain rate of 3.3-5.5 s^-1.