Machined surface temperature in hard turning
Machined surface temperature in hard turning
复制标题
DOI：
10.1016/j.ijmachtools.2017.03.003
复制
发表时间：
2017-10
影响因子：
14
通讯作者：
Lei Chen;Bruce L. Tai;R. Chaudhari;Xiaozhong Song;A. Shih
中科院分区：
文献类型：
--
作者：
Lei Chen;Bruce L. Tai;R. Chaudhari;Xiaozhong Song;A. Shih
加工表面温度在淬硬钢的车削中是关键的，因为高表面温度可导致白色层的形成，这可对钢的疲劳寿命具有负面影响。本文介绍了两种硬态车削加工表面温度的实验测量方法。第一种方法，基于工具箔热电偶，使用嵌入在工件中的金属箔来测量工具尖端温度来估计加工表面温度。第二种方法使用嵌入在刀具中的热电偶，其尖端在硬车削过程中在切削刃后面的加工表面上连续滑动。建立了三维热模型，并采用逆传热法求解切削刃附近的加工表面温度。为了验证，硬车削试验进行了切削力，工具箔电压和嵌入式热电偶电压同时测量在三个水平的进给速度。加工表面温度峰值沿着切削刃与加工表面相交处出现。其大小主要由剪切面热源决定，后刀面摩擦热源使其进一步增大。测量结果表明，两种方法的预测结果相当，在500-800 °C范围内的平均偏差为30 °C。这两种方法虽然基于非常不同的方法，但都被证明是测量硬车削加工表面温度的可行方法。
Machined surface temperature is critical in turning of hardened steels because high surface temperature can lead to the formation of the white layer, which may have negative impacts on the steel fatigue life. This paper presents two experimental methods to measure machined surface temperatures in hard turning. The first method, based on a tool-foil thermocouple, estimates the machined surface temperature using a metal foil embedded in the workpiece to measure the tool tip temperature. The second method uses a thermocouple embedded in the tool with its tip continuously sliding on the machined surface behind the cutting edge during hard turning. A three-dimensional thermal model is developed and the inverse heat transfer method is applied to find the machined surface temperature near the cutting edge. For validation, hard turning tests were conducted and the cutting forces, tool-foil voltages and embedded thermocouple voltages were measured simultaneously at three levels of feed rates. The peak machined surface temperature occurred along the intersection of cutting edge and the machined surface. Its magnitude was mainly determined by the shear plane heat source and further increased due to flank face frictional heat source. Measurement results showed comparable predictions between the two developed methods with an average deviation of 30 °C over the 500–800 °C range. These two methods, although based on very different approaches, have both proven feasible for the measurement of hard turning machined surface temperatures.