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考虑材料热物性参数和对流换热系数的非线性,以空气、纯水和2#分级油为介质环境,采用连续气流保护熔池,建立基体浸没式激光动态热加工过程的三维数值模型,对不同自然冷却介质中基体热响应温度场及残余应力场进行对比研究。结果表明,三种环境中的温度场规律基本一致,空气中基体温度最高。表面高温区域油冷效果明显,低温区水冷效果明显;油冷环境可有效控制重熔区和热影响区深度,而水冷环境材料表面可获得更大的温度梯度和冷却速度。不同介质环境对残余应力分布影响显著:空冷基体内部应力过大,且在两端应力有集中,整体以拉应力为主,而水、油环境中的热应力得到了及时释放,其中水冷环境对降低残余应力更为有效。
Considering the thermophysical parameters of the material and the nonlinearity of the convective heat transfer coefficient, a three-dimensional numerical model of dynamic immersion laser heat treatment process was established by using continuous flow of gas flow to protect the weld pool with air, pure water and 2 # fractionated oil. Comparison of temperature field and residual stress field of substrate in different natural cooling media. The results show that the law of the temperature field in the three environments is basically the same, and the temperature of the substrate in air is the highest. The effect of oil cooling in the high temperature region is obvious, and the water cooling effect in the low temperature region is obvious. The oil cooling environment can effectively control the depth of the remelting zone and the HAZ, while the larger temperature gradient and cooling rate can be obtained on the surface of the water cooling environment material. The influence of different media environment on the residual stress is significant: the internal stress of the air-cooled matrix is too large, and the stress is concentrated at both ends, the whole is mainly tensile stress, while the thermal stress in the water and oil environment is released in time. Reduce the residual stress more effective.