Welding-induced residual stresses and distortions of butt-welded corroded and intact plates

The welding-induced residual stresses and distortions of butt-welds between non-corroded and corroded steel plates are studied experimentally and numerically, simulating a repair in an aged structure. Butt welds are made between plates with different corrosion levels and intact ones, and temperature distributions and distortions have been measured. Finite element analyses of the butt-welded corroded and non-corroded plates are performed to estimate the welding-induced distortions and residual stresses for different levels of corrosion degradation. The environmental conditions during the welding repair process are also accounted for. Experimentally evaluated mechanical properties of corroded steel plates as a function of the temperature during the welding process are employed in non-linear finite element analyses. The importance of the material properties as a function of the severity of the steel plates' corrosion degradation on the welding-induced distortions and residual stresses is also quantified. This study shows the importance of considering the ageing of steel in the repair process. The developed methodology allows critical operational decisions to be made with greater ease and confidence in analysing the welding-induced distortions and residual stresses when ageing structures are repaired to extend their service life. Furthermore, different welding sequence scenarios may be analysed to identify the most appropriate repair solution in minimising the repair cost.