Finite Element Analysis of Residual Stress and Distortion in Laser Welded Stainless Plate

摘要

Laser welding is used extensively in industry to join metals of different thickness and lengths. Localized heating during welding, followed by rapid cooling, generates residual stress and distortion in the weld and base metal. Selection of the appropriate combination of input variables is one of the main criteria for achieving the required weld qualities without residual stress and distortion. In the last few decades various research efforts have been directed towards the control of welding process parameters aiming at reducing the residual stress and distortion. In the present work Finite Element Analysis (FEA) has been carried out on a single pass butt-welding model to illustrate the temperature distribution, distortion and residual stress field developed in the weldment. Thermo elasto-plastic analysis has been used to find the residual stress and distortion. It is found that with increase in laser power, residual stresses and distortion increase. In contrary as the speed increases distortion and residual stress decrease. As the thickness of the job increases there is a reduction of residual stress and distortion. Similarly, as the length of the job increases there is a reduction of residual stress and distortion. It is found that the geometric distortion and residual stress induced during welding can be minimized by selecting appropriate process parameters. It is therefore demonstrated that FEA can be used effectively for better understanding of the root cause of residual stress and distortion in laser welding and hence be a useful tool for further development.