Effect of Bead Deposition by Repair Welding on Residual Stress in Pipe Welds

Residual stress by repair welds in a pipe weld is computed using the thermal elastic-plastic analysis. Weld bond and heat-affected zone of a butt-welded joint is gouged and then deposited by weld metal in repair process. Heat source is synchronously moved with the deposition of the finite-element as the weld deposition. The effects of initial stress, heat input, and weld length on residual stress distribution are studied from the organic results of numerical analysis. Initial residual stress before repair weld has no influence on the residual stress after repair treatment near weld metal, because the initial stress near weld metal releases due to high temperature of repair weld and then stress by repair weld regenerates. Heat input has an effect for residual stress distribution, for not its magnitude but distribution zone. Weld length should be considered for reducing the magnitude of residual stress in the edge of weld bead; short bead induces high tensile residual stress.