Residual Stresses and Distortion in Boiler Tube Panels With Welded Overlay Cladding

Abstract

In this study, finite element models are developed to analyze and predict the transient temperature profiles, residual stresses, and distortion incurred during deposition of protective overlay cladding on boiler tube waterwall panels. Plane strain models are used to simulate the evolution of residual stresses on the cross-section of a typical boiler tube panel during deposition of filler metal in sequential weld passes. The results demonstrate how residual stresses from previous weld passes are affected by an adjacent weld bead during the cladding process. Determination of the increment in panel warpage during each weld pass, for a sufficent number of passes, provides the necessary information to estimate of the total panel warpage after cladding coverage on a very large panel surface. It is noted that the total welding induced distortion can be adequately estimated from a relatively small number of weld passes over the typical waterwall cross-section.