基于非对称热源的异种钢深熔TIG焊接数值模拟

Numerical Simulation of Keyhole TIG Welding of Dissimilar Steels Based on Asymmetric Heat Source

针对深熔钨极氩弧焊接方法,研究其在8 mm厚316L不锈钢与Q345低合金钢连接上的应用,并采用ANSYS有限元软件模拟焊接过程,对焊接过程的稳定性进行评估。结果表明,一定焊接参数下,深熔TIG焊接8 mm厚度异种钢能达到单面焊双面成形,得到成形良好的焊缝。同时基于异种钢焊接试验结果提出一种非对称的热源模式,由上部分双椭球热源与下部分圆柱热源组合形成,热源各部分独立调节。非对称热源在模拟中的应用,得到与实际焊缝吻合度更高的结果,平均误差不超过8%;模拟结果显示,316L不锈钢侧温度较低,其窄的背面焊道宽度和高表面张力,弥补Q345侧的不足,使得小孔平衡,维持焊接过程的稳定进行。

A research of the welding process of the 8 mm thickness 316 L stainless steel and Q345 low alloy steel is conducted using key-hole tungsten inert-gas welding.ANSYS finite element software is used to simulate the welding process and evaluate the stability of the welding process.The results show that under certain welding parameters,a well formed weld with sided welding double-sided forming can achieved by keyhole TIG welding of dissimilar steel.At the same time,an asymmetric heat source model is proposed based on the results of dissimilar steel welding.The upper part of the double ellipsoid heat source is combined with the lower part of the cylindrical heat source,and the heat source is adjusted independently.The application of asymmetric heat source results in a high degree of coincidence with the experimental weld,with an average error of no more than 8%.The simulation results show that,temperature in the 316 L stainless steel side is lower,and the narrow root weld bead width and high surface tension in 316 L stainless steel side make up for the defect of Q345 side,causing the keyhole balanced and maintaining the stability of the welding process.