高速切削过程中绝热剪切临界条件的研究

Study on Adiabatic Shearing Critical Condition in High-speed Cutting

对高速切削过程中绝热剪切带的特征进行了分析,获得了绝热剪切临界切削条件:绝热剪切发生的临界条件由剪应变、剪应变率和变形温度三者组成。在临界状态下,当变形温度一定时,临界剪应变与临界剪应变率成反比。变形温度越高,绝热剪切所需临界剪应变或临界剪应变率越大。当切削速度提高到一定程度时,锯齿形基体屑片间连续面积随着剪切带开裂而减小,直至完全分裂分离。

The characteristics of adiabatic sheafing band in high-speed cutting were analyzed. The critical cutting condition of adiabatic shearing was gained which contains three parts： shear strain, shear strain rate and distortion temperature. Under the crit- ical condition, when distortion temperature was given, critical shear strain was inversely proportional to critical shear strain rate. When distortion temperature getting higher, the critical strain or strain rate must be bigger to take place adiabatic shearing. When cutting speed increased to some extent, the continuous area of the base of sawtoothed chip was minishing and absolutely separated with the cracking of shear band at last.