应变速率对不同钢压缩真应力-应变曲线的影响

Effect of Strain Rate on Compressive True Stress-strain Curves of Steels

摘要: 用Gleeble 1500型热/力学模拟实验机对20Cr、40Cr和45钢进行了变形温度为1 050 ℃,应变速率为1,5,10 s-1,变形量为0.7～0.9的热模拟单向压缩试验,分析了钢热变形过程中的真应力-应变曲线.结果表明:试验钢在应变速率为1,5 s-1的变形过程中,均发生了动态再结晶;动态再结晶阶段具有反复动态再结晶→变形→动态再结晶即交变出现软化→硬化→软化的现象;应变速率为10 s-1时,45钢发生了动态再结晶,动态再结晶阶段也具有交变软化→硬化→软化的现象,而20Cr和40Cr钢处于动态回复阶段.

Abstract: The Gleeble-1500 heat/mechanics moulding experimental setup was used to make hot compressive tests of 20Cr,40Cr and 45 steels.The true stress-true strain curves at 1 050 ℃ in a strain rate range of 1-10 s-1 were studied.Periodic dynamic recrystallization takes place in the steels in a strain rate range of 1-5 s-1 and dynamic recovery takes place in 20Cr,40Cr steels in a strain rate of 10 s-1.