Fatigue design for plug/ring type gas welded joints of sts301l including welding residual stresses

Abstract

This paper presents a fatigue design method for plug and ring type gas welded joints, which incorporates welding residual stress effects. A non-linear finite element analysis (FEA) was first performed to simulate the gas welding process. The numerically predicted residual stresses of the gas welds were then compared to experimental results measured using a hole drilling method. In order to evaluate the fatigue strength of the plug and ring type gas welded joints, a stress amplitude (σa)R taling the welding residual stress of the gas weld into account was introduced and is based on a modified Goodman equation incorporating the effect of the residual stress. Using the stress amplitude (σa)R, the ΔP-Nf relations obtained from fatigue tests for plug and ring type gas welded joints having various dimensions and shapes were systematically rearranged into (σa)R-Nf relations. It was found that the proposed stress amplitude (σa)R could provide a systematic and reasonable fatigue design criterion for the plug and ring type gas welded joints.