Investigation on Residual Stress Distribution in An Austenitic Stainless Steel Pipe Narrow-gap Girth Weld and Effect of Radius-to-wall Thickness Ratio

The residual stress distribution in narrow gap multipass girth weld of an austenitic stainless steel pipe of ϕ273 mm×28 mm was investigated with the experiment by contour method and finite element numerical simulation method. The effect of radius-to-wall thickness ratio (R/t)on the residual stress distribution in the girth weld was also investigated using the finite element method.The results show that the distributions of hoop stress in the girth weld obtained by the contour method and finite element method are similar. The hoop and axial stresses in the weld zone demonstrate a bending-type distribution, which means that the stress of the inner surface in the weld and its adjacent region is compressive and that of the outer surface is tensile. Under the same wall thickness, the region of hoop tensile stress increases a little with the value of R/t increasing, while the region of hoop compressive stress decreases.With the value of R/t increasing, the axial compressive stress value of the inner surface and its adjacent region decreases, and that of the outer surface and its adjacent region decreases too, and the axial stress in thickness direction changes to self-equilibrating stress type.