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利用有限元分析软件SYSWELD建立了三维有限元模型,对不同预热温度下激光熔覆铁基涂层的过程进行了数值模拟,分析了不同预热温度下温度场和组织转变的变化规律,研究了冷却速度和组织转变对残余应力场的影响。结果表明,预热温度越高,熔覆层中心的峰值温度越高,同时能有效降低熔覆层冷却速度。预热温度在20~300℃范围内时,随着预热温度的增加,熔覆层贝氏体含量逐渐增加,铁素体和马氏体含量逐渐减少,使得熔覆层残余应力增大;预热温度高于300℃以后,随预热温度增加冷却速度显著降低,组织中铁素体含量逐渐增加,贝氏体含量逐渐减少,残余应力随之减小。
The three-dimensional finite element model was established by finite element analysis software SYSWELD. The process of laser cladding iron-based coating under different preheating temperatures was numerically simulated. The variation of temperature field and microstructure transition under different preheating temperatures were analyzed. Effect of cooling rate and microstructure transformation on residual stress field. The results show that the higher the preheating temperature, the higher the peak temperature of the cladding center and the lower the cooling rate of the cladding layer. When the preheating temperature is in the range of 20 ~ 300 ℃, the content of bainite in the coating increases with the preheating temperature increasing, and the content of ferrite and martensite gradually decreases, which leads to the increase of the residual stress in the cladding. After the preheating temperature is higher than 300 ℃, the cooling rate decreases obviously with the increase of preheating temperature. The content of ferrite in the microstructure increases gradually, the content of bainite decreases and the residual stress decreases.