Numerical simulation on the effect of welding parameters on welding residual stresses in T92/S30432 dissimilar welded pipe

• The peak residual stress is located at HAZ of T92 steel side.
• By changing welding parameter to reduce residual stress on dissimilar welds.
• Small groove angle greatly reduces peak residual stress in HAZ of T92 steel side.
• More layer number reduces peak tensile residual stress on welds and S30432 steel.
• Small heat input reduces peak tensile residual stress on welds and S30432 steel.

Dissimilar welded joints are commonly used in fossil power plants to connect martensitic steel components and austenitic stainless steel piping systems. The integrity for such welded structures is depended on residual stresses induced by manufacturing process. In this paper, the characteristics of residual stresses on the dissimilar welded pipe between T92 steel and S30432 steel were investigated using finite element method. Moreover, the effects of heat input, groove shape and layer number on the residual stress distribution were studied to find the approach to reduce the residual stress. The numerical results revealed that the hoop and axial stress in heat affected zone (HAZ) of T92 steel side of the dissimilar welded joint had sharp gradients. By decreasing the groove angle, the peak values of the hoop and axial stress on T92 steel side were reduced greatly while the peak values in welded metal and HAZ of S30432 steel side differed little. Furthermore, more layer number and less heat input decreased the peak value of the tensile residual stress on welded metal and S30432 steel side, but had little effect on the residual stress in T92 steel side.