Comparative Study on Microstructure and Properties of High Strength Steel Thick Plate by Adjustable Dot-ring Laser Ultra-narrow Gap Welding and Arc Welding
In order to eliminate sidewall fusion defects commonly associated with laser ultra-narrow gap welding,a dot-ring laser filling welding process was developed.The welding wire was heated using a central spot laser,while the narrow gap bevel was heated using a ring laser.Welding was successfully performed on a 30 mm thick 10CrNi3MoV high strength steel,and a comparative analysis of the microstructure and properties with a traditional arc-welded joint was conducted.The results indicate that the weld zone of the laser ultra-narrow gap filling welded joint consists of acicular ferrite,granular bainite and a small amount of martensite,while the arc-welded joint is composed of acicular ferrite and granular bainite.The rapid cooling characteristic of laser welding results in a finer microstructure compared to arc welding.The heat-affected zone of the laser-welded joint is characterized by a higher proportion of ferrite and granular bainite,and a lower proportion of M-A constituents,contributing to improved joint performance.The tensile strength of the laser ultra-narrow gap filling welded joint is approximately equivalent to that of the arc-welded joint,but the former exhibits superior impact toughness.
laser ultra-narrow gap weldingarc weldinglow-alloy high-strength steelthick plate
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