利用MMS-200型热力模拟试验机研究了10B06冷镦钢连铸坯在750~1 100 ℃、应变速率为0.01~20 s-1条件下的热压缩流变行为, 并且通过线性回归确定了该钢的应变硬化指数以及热激活能, 获得了其在变形条件下的流变应力本构方程。结果表明: 该钢在热压缩变形时的流变软化行为是动态再结晶、动态回复与加工硬化联合作用的结果; 当变形温度较低、应变速率较小时, 软化效应以动态再结晶为主; 而当变形温度较高、应变速率较大时, 软化效应是动态再结晶和动态回复共同作用的结果; 该钢的流变应力可采用Zener-Hollomon 参数的函数来描述, 其热激活能为220.132 3 kJ·mol-1。

The flow stress behavior of 10B06 cold heading steel continuous casting billet during hot compression deformation was studied by an MMS-200 thermal simulation test machine at deformation temperatures ranged from 750 ℃ to 1 100 ℃ and strain rates ranged from 0.01 s-1 to 20 s-1. The strain hardening index and thermal activation energy of the steel were determined by linear regression analysis, and the flow stress constitutive equation of this steel was also obtained. The results show that the flow softening behavior of the steel during hot compress deformation was the result of combined effects of dynamic recrystallization, dynamic recovery and work hardening. Soften effect was dominated by dynamic recrystallization at lower deformation temperatures and smaller strain rates, and by dynamic recrystallization and recovery at higher deformation temperatures and larger strain rates. A function of Zener-Hollomon parameter was used to describe the flow stress of the steel, and the thermal activation energy was 220.132 3 kJ·mol-1.