Numerical modelling on the influence of repair welding during manufacturing on residual stresses and distortions of T-joints

Abstract

Related to weld quality, level of imperfections is limited which can result in the need of grinding and repair welding. It results in material removal and additional heat cycles causing superimposed distortions and altering the distribution of residual stresses. The current paper investigates the influence of repair welding using welding simulation. Small-scale T-joint is analysed and used for validating the numerical model based on macrographs and distortion measurements. Furthermore, a parametric numerical analysis is conducted to evaluate the influence of repair welding sequence, heat input, and weld size. The research highlights the significance of welding technology and the importance of avoiding repair welding. Plastic strain increment of approx. 33 % occurred in the analysed T-joint, while von Mises residual stress peak increased approx. 26 % at the weld toe due to rewelding. Rewelding sequence had the most significant impact on final distortions; angular distortions could be tripled or nearly zeroed out. On the other hand, a quasi-linear relationship was evaluated between maximum transverse distortion and rewelding heat input. In addition, maximum von Mises stress peak was approximately 500 MPa on the rewelded side, regardless of the fillet size.