基于温度场评估的激光熔覆顺序决策方法研究

为了在激光熔覆再制造过程中得到更优的激光熔覆顺序选择决策方法，采用有限元法对平面基材多道激光熔覆传热学模型的温度场瞬态解进行了理论分析，并利用基于热电偶的测温系统验证了整个数值模拟过程的可靠性。提出了一种评估选择法，即利用数值模拟来分析和评估基体瞬态温度场，根据评估准则选择熔覆过程激光扫描顺序的轨迹优化方法。结果表明，取得单向逐次和评估选择样件的实验硬度数据分别为625.38HV，620.58HV，623.34HV，680.09HV，673.58HV和683.01HV，变形均值为0.9722mm和0.6458mm；评估选择法有最均匀的温度场，熔池周围有最大的温度梯度，其能产生较大的熔覆层硬度及较小的组织尺度，同时测量变形较小。该方法为激光熔覆的顺序选择提供了重要的参考价值。

Research of decision method of laser cladding sequence selection based on temperature field evaluation

In order to obtain a better decision method of laser cladding sequence selection in laser cladding remanufacturing process, finite element method was used to analyze transient solution of temperature field of multichannel laser cladding heat transfer model of flat substrate. The reliability of whole numerical simulation process was verified by temperature measurement system based on thermocouple. An evaluation selection method was proposed. Numerical simulation was used to analyze and evaluate the transient temperature field of the matrix, and select laser scanning sequence during the cladding process according to evaluation criteria. It was the trajectory optimization method. The results show that experimental hardness data are 625.38HV, 620.58HV, 623.34HV, 680.09HV, 673.58HV and 683.01HV of one way successive method and evaluation selection method respectively. The average deformation values are 0.9722mm and 0.6458mm respectively. Evaluation selection method has the most uniform temperature field and the maximum temperature gradient around the pool, which can produce larger cladding layer hardness, smaller microstructure scale and smaller measurement deformation. This method provides an important reference value for sequential selection of laser cladding.