高速铣削淬硬模具钢的切屑变形

使用TiAlN涂层整体圆柱立铣刀，以200～942m/min的铣削速度，对淬硬P20钢进行了高速铣削试验，研究了各种切削速度下的切屑变形。对于淬火硬度为41HRC的P20钢，切削速度为754～942m/min时，形成了带有绝热剪切带的锯齿形切屑;对于淬火硬度为32HRC的P20钢，锯齿形切屑形成的切削速度是848～942m/min;切削速度和工件硬度对切屑变形有着重要的影响。基于切屑纵截面尺寸的微观测量，建立了高速铣削淬硬钢时锯齿形切屑变形的计算模型。结果显示：应变、应变率和锯齿频率随切削速度增大而快速增大，在切削速度为942m/min时，它们分别高达23、107s－1和244kHz。

Chip Formation in High Speed Milling of Hardened Mold Steel

Using solid carbide straight end mills with TiAlN coating, P20 steel was machined in the cutting speed range of 200 to 942m/min. The chip formations at various speeds were investigated. The saw-tooth chips with adiabatic shear bands are observed at 754 to 942m/min with P20 steel of 41HRC, but for P20 steel of 32HRC, they are formed at 848 to 942m/min. Cutting speed and workpiece hardness are found to have significant influences on chip formation. Based on micro-measurement of the chips, a calculation model for saw-tooth chip formation during high speed end milling of hardened steel was proposed. The results show that the average shear strain and shear strain rate are within the shear bands, and the saw-tooth frequency increases rapidly by increasing cutting speed, and their maximums at 942m/min exceed 23, 107s－1 and 244kHz respectively.