Numerical investigation on weld residual stresses in tube to tube sheet joint of a heat exchanger

Crack development in weld of the tube to tube sheet region of heat exchanger is a common problem. The residual stresses associated with welding can play a major role in this situation. In this paper, the Finite Element Method (FEM) is used to predict the residual stresses in a tube to tube sheet weld. The effect of heat input, preheating temperature, and gap between tube and tube hole on residual stresses was also investigated by numerical simulation. The peak Mises residual stress occurs in the base metal near the interface between surface welding layer and base metal. The heat input has little effect on the residual stresses. The maximum residual stress is determined by the yield strength rather than heat input. With the preheating temperature increasing, the peak hoop stresses are decreased. With the gap between tube and tube hole increasing, the residual stresses are increased.

► Discontinuous stress is generated between surface welding and base metal.
► The peak residual stress is determined by the yield strength rather than heat input.
► With the gap increasing, the peak residual stresses are increased.
► With the preheating temperature increasing, the peak residual stresses are decreased.