Corrosion evolution and residual tensile performance of laser surface remelted low-alloy butt welds in marine structures

Laser surface remelting (LSR) technology offers a viable solution to enhance the corrosion resistance for the welding in coastal and offshore steel structures. This paper studies the effects of LSR on the corrosion evolution and residual tensile performance of low-alloy steel butt welds (LASBWs) used in marine infrastructures. A total of two specimen groups (A and B) were fabricated and exposed to neutral salt-spray environments for 0, 15, 30 and 60 days. Subsequently, the corroded specimens underwent a series of characterization procedures including mass-loss measurement, confocal laser scanning microscopy, and tensile testing. The results indicated that LSR reduced the mass loss rate, average thickness loss, and surface roughness of LASBWs after corrosion, thereby confirming its protective effectiveness. In addition, the surface height profiles of Group A coupons followed a Gaussian distribution, suggesting that LSR marginally affected the corrosion damage patterns of LASBWs. Moreover, LSR increased the residual strength, but reduced the residual ductility of LASBWs. Finally, a modified nonlinear hardening constitutive model and corresponding prediction equations were developed for corroded LSR-treated LASBWs. Validation against test data indicated that the proposed model reasonably predicted the mechanical response of LSR-treated LASBWs after corrosion.