Research on hybrid technology involving laser penetration and narrow gap laser filler welding for thick bimetallic composite plates

A hybrid welding technology including laser penetration root welding and narrow gap laser filling welding is proposed to realize the layered welded joint for DSS2205/X65 bimetallic thick plate. This hybrid technology is an effective way to produce an overall bidirectional gradient layered weld distinguished by the microstructural and elemental distribution. Especially, the laser penetration thin bimetallic composite plate with an appropriate parameters combination of laser penetration direction, power and welding speed can effectively inhibit solute mixing and diffusion between the upper base and lower cladding layers, resulting in a layered root weld with a metallurgically and mechanically bonded interlayer. Finally, the formation of bidirectional gradient microstructure, and its residual stress and mechanical properties are extensively discussed.