Optimized welding process of residual stress control of P91 steel considering martensitic transformation

Abstract

Abstract P91 steel belongs to martensitic heat-resistant steel. Solid phase transformation during welding will affect temperature field and stress field. In this paper, a method for calculating welding residual stress of P91 steel considering martensitic transformation is proposed by using finite element software ABAQUS and self-compiled user subroutines. The methods of reducing residual stress are analyzed through the preheating, changing the starting temperature of martensitic transformation and controlling the interlayer temperature. It is found that the Mises stress decreases and the low stress area at the weld bead enlarges after preheating. Within a certain range, the Mises stress value can be reduced by decreasing the starting temperature of martensitic transformation. The starting temperature of martensitic transformation is suggested to be 325\u202f°C. Within a certain range, increasing interlayer temperature can enlarge the low Mises stress area, increase the longitudinal compressive residual stress and reduce the transverse residual tensile stress. The highest interlayer temperature should not exceed 315\u202f°C.