30 mm TA2双激光同步对称焊接接头组织及力学性能研究

为提高钛合金焊接效率和焊接精度,采用TA2钛合金双激光同步对称焊接技术,对30 mm厚板TA2钛合金试板开展双激光同步对称焊接工艺,并对焊后试板进行接头成形质量、焊接变形、接头金相组织形貌、力学性能和工艺性能研究。结果表明:30 mm厚板TA2试板焊接接头表面成形良好,呈银白色,焊接变形较小;焊缝低倍金相组织呈块状分布,内部无明显缺陷,无贯穿整个焊缝的树枝状柱状晶,焊缝和热影响区微观金相组织均为锯齿状α相,母材为细小的等轴α相,接头心部焊缝晶粒比近表面焊缝粗大;焊接接头整体平均抗拉强度略低于近表面和心部接头抗拉强度,而近表面和心部焊缝屈服强度高于母材的,塑性低于母材的;焊接接头在近表面和心部区域冲击性能差距较大;弯曲试样均合格,焊接接头工艺性能良好。这表明厚板钛合金双激光同步对称焊接技术在高效高精度焊接方面具有良好的工程化应用前景。

Study on Microstructure and Mechanical Properties of Dual Laser Symmetrical Synchronous Welded Joint of 30 mm Thick TA2

In order to improve the welding efficiency and welding precision of titanium alloy, the double laser synchronous symmetric welding is carry out on the double laser synchronous symmetric welding on the 30 mm thick TA2 titanium alloy test plate, and the joint forming quality, welding deformation, microstructure, mechanical properties and process performance of the welded joint are studied. It is found out that the welded joint of the 30 mm thick TA2 plate is good and silver-white, and that the welding deformation is small. The macrostructure of the joint is of blocks, and has no obvious defects. No columnar crystals lie through the weld. The microstructures of the weld line and heat-affected zone are of the jagged α phase, and the microstructures of the base material is of the fine equiaxial α phase. The grains in the heart of the weld line are coarser than those in the near-surface of the weld line. The overall hardness of the welded joint is lower than those of the near-surface and heart of the weld line. The yield strength of the near-surface and heart of the weld line is higher than that of the base material, and the plasticity lower than that of the base material. The near-surface zone and the heart zone have a big difference in impact properties. The bending specimens are qualified, and the welded joints have good process performance. This shows that the dual laser synchronous symmetric welding technology for the thick titanium alloy plate has high-precision and good engineering application prospects.