Test and Analysis of Residual Stress in Welding with Inconel 690 and 321 Stainless Steel Based on XRD

Following more than 100 welding process for the dissimilar metal girth welded joint, there appeared stress accumulation, large deformation and other issues in the weld joint, which should have unfavorable influence on the resistance capacities of the joint against fatigue and stress corrosion. X-ray diffraction method is employed to measure the surface residual stress, obtaining the radial and circumferential residual stress distribution rule. The results show that the radial and circumferential residual stresses are almost tensile ones, and being high in the middle and low on the both sides, like parabolic shape. Because the fusion line of austenite stainless steel base metal side is typical dissimilar metal welded zone, the residual stress gradient of the zone is larger. Additionally, there exists the columnar crystal in the weld, so larger residual stress gradient appears in the weld center.