钛合金光纤激光焊接接头特征分析

Characteristics of Titanium Alloy by Fibre Laser Welding

采用对接焊方法,对比研究了TC4钛合金薄板光纤激光焊接和YAG激光焊接接头的宏观形状特征,分析了两种焊接热源在焊缝背宽比相同时的接头拉伸性能差异,并获得了焊接热输入对光纤激光焊接接头宏观形状与拉伸性能的影响规律。试验结果表明:光纤激光焊缝背宽比常常大于YAG激光焊缝,焊接接头的强度和塑性均高于YAG激光焊接接头。在稳定光纤激光全熔透深熔焊接条件下,焊缝背宽比和焊接接头的拉伸性能随焊接热输入的增加呈现先上升再下降的趋势,当焊接热输入为40J/mm,焊缝背宽比约0.8时,光纤激光焊接接头具有最好的拉伸性能,抗拉强度为1133.72MPa,断后伸长率为14.32%。

The fibre laser welding and YAG laser welding experiments of TC4 titanium alloy sheet are carried out by butt welding method. The macrography characteristics of the welded joints are studied. The tensile properties of the joints are also studied with the differ- ent heat resources, when the back width to surface width ratio （Rw） of the fibre laser welding seam is same as that of the YAG laser welding seam. Meanwhile, the effects of the heat input on macrography and tensile properties of fibre laser welding joints are analyzed. The results show that the weld R~ of the fibre laser welding is often lager than that of the YAG laser welding, and the strength and plasticity of the former joints are higher than that of the lat- ter joints. With the heat input of the stable full-penetration fibre laser welding increasing, the change tendencies of the weld Rw and the joint tensile properties are firstly increased and later decreased. When the heat input is 40J/ram and the weld Rw is about 0.8, the joint of the fibre laser weld- ing has the best tensile properties, including l133.72MPa of the tensile strength and 14.32% of the elongation after fracture.