回填式搅拌摩擦点焊过程温度场的数值模拟

Numerical Simulation of Temperature Field During Refill Friction Stir Spot Welding

根据回填式搅拌摩擦点焊的连接机理,合理的温度场是获得高性能接头的基础;根据回填式搅拌摩擦点焊过程的特点,利用有限元分析软件MSC.Marc建立了焊接过程的有限元模型;在利用测温试验验证有限元模型正确性的基础上,利用数值模拟的方法对7075–T6铝合金焊接过程中的温度场进行研究。结果表明:在预热阶段,温度峰值随摩擦时间的增加呈现先快速后缓慢上升的趋势,在8s左右趋向稳定;在焊接阶段,温度峰值始终位于套筒端面的中心附近,且最大值出现在套筒回抽1s时,同时提高搅拌工具的旋转速度可增加焊接过程的温度最大值。

According to the joining mechanism of refill friction stir spot welding,reasonable temperature field is the basis of obtaining joints with high quality.Based on the characteristics of refill friction stir spot welding process,a finite element model was established by the finite element analysis software MSC.Marc.The rightness of this model was verified by the temperature measurement experiments,and then the temperature field of 7075-T6 aluminum alloy during welding was investigated by numerical simulation.The results show that at the pre-heating stage,the peak temperature increases rapidly and then slowly with the increase of friction time,and the value reaches a stable one at about 8s.At the welding stage,the peak temperature is located at the center of bottom surface of the sleeve,and the maximum value is obtained when the sleeve is retracted for 1s.Increasing the rotating speed of stirring tool can increase the peak temperature during welding.