Distortion and residual stresses in thick plate weld joint of austenitic stainless steel: Experiments and analysis

Abstract

Abstract The present work aims to evaluate distortion and residual stresses in thick plate weld joints of austenitic stainless steel. Quantification of residual stresses in thick austenitic stainless steel weld joint is important because it is not desirable to carry out stress relieving after welding owing to the susceptibility to sensitization in the heat-affected zone. Therefore, systematic studies were carried out to predict and measure distortion and residual stresses in the austenitic stainless steel plate weld joint. Variables influencing the generation of residual stresses such as heat input, welding speed, constraints during welding were considered. 20 mm thick plate weld joint of austenitic stainless steel material was prepared using gas tungsten arc welding (GTAW) in unclamped condition and distortions were measured during welding after each pass. Sub-surface and through-thickness residual stresses were measured using blind hole drilling (BHD) and deep hole drilling (DHD) techniques respectively. Thereafter, the weld joint was modeled using the finite element method and analyzed for residual stresses and distortions. Thermal analysis was carried out using actual welding parameters and temperature-dependent material properties to generate temperature profile and compare it with the measured values. The temperature profile along with necessary boundary conditions was used for structural analysis to obtain distortion and residual stresses. Experimental and finite element analysis results for distortion and residual stresses compare well. Details of the experimental and numerical analysis results of distortion and residual stresses for thick section plate weld joints have been discussed in this paper. Also, the effects of differences in yield strengths of weld and base metals on distortion and residual stress results have been brought out.