PVD Film Method for Measuring Grinding Temperature

应用新近发展起来的PVD薄膜法测量了平面磨削中工件近表面的温度分布。在该技术中，工件在平行于磨削方向的方向上被分成尺寸相同的两个部分。然后将两个零件的内表面研磨并研磨至镜面。将两个部件紧固在一起，并在内表面上气相沉积具有一定熔点的材料后进行研磨。当在磨削试验后用显微镜观察界面时，由磨削热引起的熔融膜区域和界面上的未熔融膜区域之间的边界被明确地识别。可以预期边界上的工件的温度与沉积的膜材料的熔点一致。采用不同熔点的PVD膜重复进行相同的实验，可以准确地估计出工件近表面沿深度方向的温度分布，并在常规平面磨削条件下，研究了磨削条件、工件材料和砂轮材料对温度分布的影响。得到的结论如下。(1)It实验表明，近地表温度梯度与基于Jaeger移动热源理论的Takazawa近似值符合得很好。它仅取决于工件的热扩散率、工件速度和砂轮与工件的接触长度。（2）根据磨削条件、工件材料和砂轮材料的不同，用外推的表面最高温升计算的能量分配系数在0.5 ~ 0.9之间变化。（3）本文提出的温度测量技术在磨削研究领域是一种很有前途的方法。

The near-surface temperature distribution in the workpiece in surface grinding was measured by applying the PVD film method developed recently. In this technique, the workpiece is parted into the two parts same in size in the direction parallel to the grinding direction. Then the inner surfaces of the both parts are ground and lapped to mirror surface. The two parts are fastened together and ground after the material with a definite melting point is vapor-deposited on the inner surfaces. When the interface is observed by a microscope after the grinding test, the boundary between the melted film zone caused by grinding heat and the unmelted film zone on the interface is positively identified. The temperature of the workpiece on the boundary can be expected to agree with the melting point of the deposited film material. If the same experiment is repeated by using various PVD films of different melting points, the temperature distribution of the near-surface of the workpiece in the depthwise direction can be estimated accurately.The influence of the grinding condition, the work material and the grinding wheel material on the temperature distribution was investigated under a conventional surface grinding. The conclusions obtained are as follows.(1)It was shown experimentally that the temperature gradient at the near-surface is in good agreement with Takazawa's approximation based on Jaeger's moving heat source theory. It depends on only the thermal diffusivity of the work' the wotk speed and the wheel-work contact length.(2)Energy partition coefficient, calculated with the extrapolated maximum temperature rise at the surface, changed from 0.5 to 0.9, depending on the grinding conditions, the work material and the wheel material.(3)The temperature measuring technique outlined in this paper seems to be a promising method in the field of grinding research.