刀具导热特性对淬硬钢车削性能的影响

Effect of Tool Thermal Characteristics on Hardened Steel Turning Performance

针对高速硬切削淬硬钢表面白层的问题,使用不同的热传导特性刀具对SCM415淬硬钢进行了高速硬切削试验和表面白层测试。使用二色温度计和光学显微镜(Axio Scope A1)对切削温度和白层厚度进行测量。研究了刀具热传导特性与高速硬切削热的关系,分析了后刀面温度对白层特征的影响规律。分析结果表明,后刀面温度随着刀具热传导率的增加而降低,采用热传导率大的刀具切削可以降低切削温度,从而减少白层厚度。刀具热传导率越大,温升率越小,在v=100m/min时,CBN1刀具随着后刀面磨损由0~0.1mm的温升率为7.6%,而CBN4刀具温升率仅为2.6%;在一定切削速度和切削热范围内,白层厚度随着切削速度和切削温度的增加而增加,超过临界切削速度值和切削温度值后,白层厚度随着切削速度和切削温度的增加而减少;少量的的后刀面磨损(VB=0.05mm)有利于降低白层厚度从而提高表面质量。

In order to study the issue about the formation of white layer and concluding the relationship be- tween the characteristics of white layer, tool flank temperature and the thermal conductivity. SCM415 （car- burizing and quenching） is used to carry out a series of high-speed dry cutting tests with different thermal conductivity tools and observing the white layer by optical microscope Axio Scope A1 in this paper. The cut- ting temperature is measured by two color thermometer. By analyzed these results we found that the temper- ature of tools is lower when the thermal conductivity of tool is higher. Cutting temperature can be reduced by the tool with high thermal conductivity, thus reducing the thickness of the white layer. The greater the ther- mal conductivity of the tool, the lower the rate of the rising temperature. The temperature rise rate of CBN1 is 7.6% when the flank wear increased from 0 to 0. lmm inv = 100m/min. But the temperature rise rate of CBN4 tool is only 2.6%. When the flank temperature and the cutting speed increased, the thickness of white layer increased. However, the white layer thickness is reduced, when the cutting speed and the flank temperature are more than a critical value. A small amount of flank wear （ VB = 0.05mm） can reduce the thickness of white layer and improve the surface quality.