实现零件磨削淬硬的热源优化及淬硬层预测

Heat Source Optimization and the Hardening Layer Prediction for Realization of Grinding-Hardening Parts

磨削淬硬是利用磨削加工过程中产生的热、机械复合作用直接对钢质零件进行表面硬化的加工新技术。由于零件淬硬层深度对零件性能具有显著影响,因此对零件淬硬层深度进行预测具有工程实际意义。根据热源强度变化特点,将零件沿长度方向划分为切入区、中间区以及切出区并对热源强度模型进行优化。基于有限元方法,对磨削过程中的各区域温度场分布及瞬时温度变化进行仿真分析,并对零件的切入区、中间区及切出区的淬硬层深度进行预测。结果表明,由于加工过程中热源强度的变化,磨削加工后的零件两端均有未淬硬部分,中间区淬硬层深度最大且均匀。最后将零件淬硬层深度预测与实验结果进行对比,验证了热源优化模型的合理性和预测方法的有效性。

Grinding hardening is a new technology for steel parts surface enhancing which uses thermal and mechanical composite effects on the parts in the grinding process. Since component properties are influenced greatly by hardened depth of parts,prediction of hardened layer depth is significant to the practical engineering. First,the part is divided into cutting-in zone,middle zone and cutting-out zone along length direction according to the characters of heat source strength changes.Then the heat source strength model of each zone is optimized respectively. Moreover,the finite element method is applied to simulate and analyze the distribution of temperature field and the change of instantaneous temperature in each zone of the grinding process. And the hardened depth in each zone is predicted accordingly. Test result shows that heat intensity changes during the grinding process makes the parts unhardened at both ends after grinding. Specifically,hardened depth is gradually increase in the cutting-in zone,and then reaches its maximum value in the middle zone,and finally decrease in the cuttingout zone. For the last part,the comparison between predictive value and experiment result shows that the heat optimization model is reasonable and the predictive method is effective as well.