NUMERICAL SIMULATION OF WELDING RESIDUAL STRESSES IN A MULTI-PASS BUTT-WELDED JOINT OF AUSTENITIC STAINLESS STEEL USING VARIABLE LENGTH HEAT SOURCE

Recent discoveries of stress corrosion cracking at welded joints in pressurized water reactors and boiling water reactors have raised wide concerns about the safety and integrity of plant components It has been recognized that residual stress and applied stress on their surfaces largely increase the expanding risk of initial stress corrosion cracking Therefore it is very important to investigate the welding residual stress in welded joint's It is very expensive and time-consuming to measure the residual stress and sometime is impossible As an alternative approach a computational procedure on the basis of finite element method is effective in solving non-linear problems such as thermal and mechanical nonlinearity in a welding process Accurately simulating welding residual stress not only needs generally a long computational time but also strongly depends on the analyst's experience and know-how which is a main hindrance for the welding process simulation Therefore it is an urgent task to develop a time-effective numerical simulation procedure to calculate welding temperature held and residual stress distribution in this study a new method on the basis of the variable length heat source was developed to simulate the welding residual stress lit a multi-pass butt welded joint of austenitic stainless steel Meanwhile the experiment was carried out to obtain the welding residual stress in the butt-welded joint Comparing the simulated with experimental results it was found that this method could not only save a large amount of computational time but also provide a highly accurate numerical result for the residual stress in multi-pass butt-welded joints.