中文摘要：

采用单道次热压缩实验在Gleeble．1500热力模拟机上研究了不同变形速率和变形温度下Hi-B钢的软化行为。结果表明，试验钢在较低应变速率下，主要以动态回复作为软化机制，在较高应变速率下，主要以动态再结晶作为软化机制。采用回归法计算出动态回复的变形激活能和应变指数分别为287．12kJ／mol和4．88，由此建立了试验钢在低应变速率下的动态回复模型。

英文摘要：

The deformation temperatures softening behavior of Hi-B steel under different deformation rates and ere investigated by a single-pass hot compression experiments in Gleeble- 1500 thermal simulation machine. The results showed that for the investigated steel, its softening was mainly attributed to dynamic recovery at low strain rate, and to dynamic recrystallization at higher strain rate. Regression method was used to calculate the dynamic response of activation energy and the strain index, which were 287.12 kJ/mol and 4.88 respectively, thereby establishing the dynamic recrystallization model of the investigated steel at low strain rate.