用热扭转法测定了M_2高速钢热塑性曲线,并对其变化机理进行了研究,发现:升温时是相变超塑性效应造成了850℃的高塑性区,降温时无此效应出现,但在特殊条件下,该效应能够出现。 The thermomechanical curve of M_2 high speed steel was determined by the hot twisting method. The mechanism of the change was also studied. It is found that the phase transition superplastic effect caused the high plasticity zone of 850 ℃ during heating and no such effect occurred during the cooling. However, Under the conditions, the effect can appear.