高速切削30CrNi3MoV淬硬钢切屑形成机理的试验研究

EXPERIMENTAL RESEARCH OF CHIP FORMATION MECHANISM DURING HIGH SPEED MACHINING HARDENED STEEL

通过30CrNi3MoV淬硬钢的高速切削试验,观察和测量不同切削条件下切屑形态的演变过程、锯齿状切屑形成的临界切削条件、切削力。结果表明,切削速度和刀具前角是影响切屑形态和切削力的主要因素,随着切削速度的提高,在某一临界切削速度下,切屑形态由带状屑转变为锯齿状切屑,随着刀具前角由正前角逐渐变为负前角,临界切削速度明显减小,当锯齿状切屑形成时,切削力大幅度降低。使用金属切削过程中绝热剪切临界切削条件判据对锯齿状切屑形成临界切削速度预测的结果表明,锯齿状切屑形成的根本原因是主剪切区内发生周期性的绝热剪切断裂。

The development of chip morphology, critical cutting conditions of serrated chip formation and cutting forces were observed and measured by high speed machining experiment of 30CrNi3MoV hardened steel. Results show that the cutting velocity and rake angle are leading factors influencing chip morphology and cutting forces, at a certain critical cutting velocity the ribbon chip transforms into serrated chip with increase of cutting velocity, as the negative rake angle is changed to positive rake angle the critical cutting velocity significantly decreases, the cutting forces abruptly reduces when the serrated chips form. The results from predicting critical cutting velocity using the critical cutting condition criterion of adiabatic shear in metal cutting process show that the leading reason of serrated chip formation is that the adiabatic shear fracture repeatly occurs within the primary shear zones.