Residual Stress Analysis of TIG Welding Process of Thin-Walled Stainless Steel and Red Copper

Abstract

The connecting pipe in solar hot water system is made by TIG welding of thin-walled stainless steel and copper. As the welding of stainless steel and copper belongs to dissimilar metal welding and their physical properties are very different, thus the welding process is difficult and it is likely to cause a variety of defects in the welding process. In this paper, ANSYS software is used to simulate the welding process of stainless steel and copper, and the residual stress distributions in the welding process are obtained. The results show that: at the end of the welding cooling, large residual stress (253MPa) is remained in the junction area of the starting and ending position of welding, which is close to the yield strength of material at the same temperature. Therefore, there will be greater deformation in the junction area and more cracks inside. Meanwhile, the stress distributions of stainless steel and copper tubes in the welding process are greatly different. Different volume changes emerge in two tubes, which are harmful to the welding seam and also leads to the unfitness of dimensional tolerance of welding parts, resulting in the scrapping of welding parts. The results provide references and theoretical basis for the welding technology of dissimilar materials.