BT20钛合金激光焊技术研究

针对2.5 mm厚BT20钛合金进行了CO2激光焊和YAG激光焊研究,结果表明由于激光特性不同,形成的焊缝几何特征不同,当焊接工艺适当,可保证焊接过程的稳定性和焊接接头的质量.在激光自熔焊时主要的焊缝缺陷是咬边,这是由于钛合金物理性能和激光高能束流焊特性所致.这种咬边缺陷不利于焊接接头性能,尤其是接头的疲劳性能和断裂韧性.采用活性剂和填丝焊,以及激光旋扫焊可以改善焊缝咬边缺陷,提高钛合金激光焊接头的力学性能.

Research on Laser Fabrication Weldability of BT20 Titanium Alloy

By using CO2 laser beam and YAG laser beam, the butt welding of BT20 titanium alloy sheet with 2.5 mm thickness is carried out. It is found that the geometry of welded joint is different because of different laser beam models. The stable welding process and welding quality are 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 is generated because of the heat physics properties of BT20 titanium alloy and the high energy density laser beam, which affects the mechanical properties of welded joint seriously, especially the fatigue strength and the fracture toughness. Using the active fluxes in the welding procedure, or making use of laser welding technique with filler wire, revolving scanning beam could be a good method to solve undercut and improve the mechanical properties of laser welded joint.