Simplified Dissimilar Metal Weld Through-Wall Weld Residual Stress Models for Single V Groove Welds in Cylindrical Components

Abstract

Two simplified models are developed and benchmarked for predicting through-wall axial and hoop weld residual stress (WRS) distributions in single V groove dissimilar metal welds (DMWs) joining cylindrical components such as piping or nozzles. The models can be used to predict WRS distributions for different pipe mean radius to wall thickness ratios (Rm/t) without an inside surface repair and WRS distributions at a single Rm/t for various inside surface weld repair depth to pipe thickness ratios (x/t). The models are developed by approximating the through-wall WRS distribution using a finite Fourier series where the coefficient of each term in the Fourier series is determined using a linear equation in which the Rm/t or x/t is the independent parameter. The model for the unrepaired condition has been benchmarked against two plant specific finite element WRS analyses of BWR nozzle to safe end welds as well as experimental and FEA WRS data from the PWR pressurizer safety/relief nozzle to safe end weld documented in MRP-317. The weld repair model has been benchmarked against the pressurizer surge nozzle experimental data presented in MRP-316. The models have been used to perform numerous plant specific DMW residual life calculations and can save significant time and money when performing weld specific fracture mechanics analyses.