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利用强激光模拟实验 ,对硬质合金刀具在端铣过程中的温度变化规律进行了模拟。扫描电镜分析结果显示 ,热源的热冲击会产生以热源为中心的径向裂纹。实验中发现 ,裂纹萌生寿命、每一次冲击所引起的裂纹长度的增加量 ,以及裂纹总数量的增加都具有相当大的随机性。刀具中原有缺陷的随机性和不同区域微观性能的随机性是引起热裂纹萌生和扩展随机性的主要原因。有限元法分析的结果表明 ,在最高温度为 1 0 0 0℃时 ,最大热拉应力小于材料的抗拉强度 ,而最大热剪应力较大 ,因此 ,最大剪应力理论可作为刀具热裂的判据
Using strong laser simulation experiment, the temperature variation of carbide cutting tool in end milling was simulated. Scanning electron microscopy analysis showed that the thermal shock of the heat source will produce a radial crack centered on the heat source. It is found in experiments that there is considerable randomness in the crack initiation life, the increase of the crack length caused by each impact and the increase of the total crack number. The randomness of the original defects in the tool and the randomness of microscopic properties in different regions are the main causes of the randomness of hot crack initiation and propagation. The results of finite element analysis show that the maximum hot tensile stress is less than the tensile strength of the material and the maximum thermal shear stress is maximum at the maximum temperature of 100 ° C. Therefore, the maximum shear stress theory can be used as the tool thermal cracking Criteria