Research on laser welding of BT20 titanium alloy

Abstract

By using of CO2 laser beam and YAG laser beam, the butt welding of BT20 titanium alloy sheet with 2.5mm thickness was carried on. It was found that the joint geometry of welded joint was different because of different laser beam models. The stable welding process and good welding quality were guaranteed by using suitable welding parameters. On the condition of butt welding without welding wire, the welded defect such as undercut on the weld face was generated because of the heat physics properties of BT20 titanium alloy and the high energy density laser beam, which affected the mechanical properties of welded joint seriously, especially the fatigue strength and the fracture toughness. Use of the active fluxes in the welding procedure, or making use of laser welding technique with filler wire and revolving scanning beam could be a good method to solve undercut and improve the mechanical properties of laser welded joint.By using of CO2 laser beam and YAG laser beam, the butt welding of BT20 titanium alloy sheet with 2.5mm thickness was carried on. It was found that the joint geometry of welded joint was different because of different laser beam models. The stable welding process and good welding quality were guaranteed by using suitable welding parameters. On the condition of butt welding without welding wire, the welded defect such as undercut on the weld face was generated because of the heat physics properties of BT20 titanium alloy and the high energy density laser beam, which affected the mechanical properties of welded joint seriously, especially the fatigue strength and the fracture toughness. Use of the active fluxes in the welding procedure, or making use of laser welding technique with filler wire and revolving scanning beam could be a good method to solve undercut and improve the mechanical properties of laser welded joint.