Deformation and residual stress of T-shaped joints fabricated by laser-arc hybrid welding for steel bridge members

A series of experiments and analyses were performed for applying laser-arc hybrid welding to fabricating steel bridge components. Two-pass fully penetrated T-shaped joints using high-performance steel (SBHS400) having a 15-mm thickness were produced using hybrid welding. T-shaped joints having identical dimensions were manufactured using conventional arc welding. Without considering the inter-pass cooling time, the duration of hybrid welding was reduced by roughly 83% in comparison to that for GMAW. The average out-of-plane deformation caused by hybrid welding was decreased by 67% compared to arc welding. The fully coupled thermal elastic–plastic analyses were performed to replicate the distribution of residual stress in as-welded T-shaped joints. The analytical results indicated that the tensile residual stress range in hybrid-welded T-shaped joints was approximately one third (1/3) of that in arc-welded T-shaped joints. The weld joints produced by hybrid welding may have advantages over those produced by arc welding in terms of reducing welding deformation, decreasing welding residual stresses, and shortening welding time when manufacturing large steel bridge components.