LASER NARROW GAP WELDING OF THICK CARBON STEELS USING HIGH BRIGHTNESS LASER WITH BEAM OSCILLATION

摘要

Laser narrow gap welding with beam oscillation wasrndeveloped to prevent lack of fusion and hot cracking inrnthe welding of thick steel plates. The weld qualities ofrncarbon steel joints with a thickness of 60 and 150mmrnwere examined in this work. The results show thatrnbeam oscillation condition, especially oscillationrnamplitude affects soundness of the weld, and must bernadjusted by considering the change in groove width tornavoid lack of fusion on the side wall of the groove. Inrnaddition, geometry control of each weld bead in builduprnwelding is required to avoid solidification crackingrnof weld metal. Mechanical properties of the joints suchrnas tensile strength, ductility, hardness distribution andrntoughness were also evaluated, and confirmed to meetrnproduct requirements. Beam oscillation in narrow gaprnwelding with high power laser has a great potential tornimprove weld qualities of large scale weld structure.