薄板钛合金光纤激光-钨极惰性气体保护焊电弧复合焊接工艺研究

Study on Fiber Laser-Tungsten Inert Gas Hybrid Welding of Titanium Sheet

针对1mm厚TC4钛合金薄板进行光纤激光-钨极惰性气体保护焊(TIG)电弧复合焊接试验,研究了激光功率、电弧电流、热源间距、保护气成分等工艺参数对焊缝成形的影响,同时分析了焊接接头的显微组织及力学性能。研究结果表明:随着电弧电流增加、主保护气中He气比例升高,焊缝的熔化量逐渐增加;随着激光功率和两热源间距的增加,焊缝熔化量呈波动性变化。焊缝咬边程度和复合热源的热输入有关,输入的能量越大越集中,焊缝咬边深度越小。焊接保护效果主要由电弧输入的热量决定,输入的热量越大,保护效果越差。在优化的工艺参数下,复合焊接的接头抗拉强度高于母材,延伸率低于母材,这与焊缝中马氏体组织的分布有关,拉伸断裂位于母材。

Fiber laser-tungsten inert gas （TIG） hybrid welding is applied to TC4 sheet with the thickness of 1 ram. The influences of welding parameters such as laser power, arc current, the distance of heat sources and the shielding gas on weld bead formation are studied. The metallographic structure and mechanical properties are also analyzed. The results indicates that with the increasing of arc current and the ratio of He in main shielding gas, the welding fusion area gradually increases. With the increasing of laser power and the distance of heat sources, the welding fusion area changes in fluctuation. The tendency of undercut is related to the heat input of hybrid heat sources. With the rising of concentration and input of the energy, the undercut depth on the back side of the welding seam decreases. The efficiency of shielding is mainly determined by the heat input of arc. The more input heat is, the poorer protective effect is. The tensile strength of hybrid welding joint under optimum welding conditions is larger than the base metal, and the elongation is smaller than the base metal. This is related to the distribution of martensite in the welding seam. The fracture takes place in the base metal.