Predicting multi-pass welding distortion using the strain as directed boundary method considering interpass

In this study, we propose a method for predicting welding distortion caused by multi-pass welding using the strain as directed boundary (SDB) method considering the interpass temperature. This method is divided into two scenarios—one where the weld is cooled to room temperature and the other where the weld is cooled to an intermediate temperature (700 °C). Temperature boundary conditions were calculated by overlapping the values derived for each pass, and the thermal expansion coefficient was calculated for intermediate temperatures. Subsequently, the calculated coefficients were applied to the simulation model and used for quantitative and qualitative analyses. Consequently, a maximum error of 56.2 % was generated using the existing method; however, using the proposed method, the error reduced to 6.11 %. In addition, the welding deformation decreased as the temperature of the interpass welding increased. Thus, the proposed method provides an analytical approach to multilayered welding distortions.