【摘要】 在锯切花岗石过程中,用三明治薄膜热电偶监测接触界面的温度响应,研究了节块式金刚石工具与花岗石接触界面的温度特征,通过将试验结果与解析结果拟合得到热量传入节块的比例,并在此基础上求解出金刚石磨粒的表面温度.结果表明,在干摩擦下的花岗石锯切过程中,工具与工件接触弧区内90%以上的热量传入金刚石节块,节块表面部分金刚石磨粒的表面温度超过1000℃,金刚石的3种典型失效方式均受到锯切热的直接影响.在金刚石表面镀覆Ti-Cr合金可以有效抑制锯切热引起的磨粒脱落.更多还原

【Abstract】 The temperature responses at the toolworkpiece interface during circular sawing of a typical gray natural granite with diamond segmented blades were measured by using a foil thermocouple consisting of two thin foils sandwiched in a split workpiece specimen. The sawing experiments were conducted in a down cutting mode on a bridgetype experimental sawing machine. Scanning electron microscope and optical microscope were employed to observe the morphologies of diamond grits and their bonding with the metal matrix.The measured results, taking into account the net sawing power,were fitted with the theoretical counterparts so as to estimate the heat partition transferred to the granite and the segments,using a temperature matching technique. Based on the heat partition value obtained from the experiments, the diamond tip temperature was calculated. As the results, more than 90% of the heat generated at the cutting zone was conducted to the diamond segments during the dry sawing. The tip temperatures at a part of the diamond grits on the segment surfaces were possibly above 1000℃. The three typical wear modes of the diamond grits, namely, mechanical wear, fracture, and pullout, were closely related to the heat generated during the sawing process. When the diamond grits were coated with TiCr alloy before sintering, strong metallurgical bonding was observed between the diamond grits and the metal matrix. Thus TiCr coating was effective in restraining the heat induced pullout of the diamond grits.更多还原