采用TIG+MIG+MAG焊接工艺对TA1/ X65爆炸冶金复合板(复层Ti厚2 mm, 基层X65管线钢厚14 mm)试件进行了以V/Cu作为过渡填充金属的板-板对接焊实验. 利用OM, XRD, EDS面扫描, 显微硬度测试和拉伸实验, 研究了焊缝区组织特征、界面元素分布、主要物相、显微硬度分布及焊缝力学性能. 结果表明, 圆弧状“U”型坡口设计有利于过渡层Cu的MIG焊接, 在Cu-钢界面不会引起应力集中而萌生裂纹. 熔敷金属Ti, V, Cu和Fe有明显分区, 扩散互融现象不明显, 各区域间由固溶体相过渡连接, Ti/V过渡界面组织结构为钛基固溶体, V/Cu过渡界面组织结构为钒基固溶体, Cu/Fe过渡界面组织结构为铜基固溶体. 焊缝硬度较高区域出现在Ti/V过渡界面和V/Cu过渡界面处, 硬度达326和336 HV₁₀, 对过渡界面层塑韧性有一定影响. 焊缝抗拉强度可达546 MPa, 主要由碳钢层贡献.

Titanium/steel clad material with excellent mechanical properties and corrosion resistance has important application in storage and transportation equipment of oil and gas. Due to the metallurgical incompatibility of titanium and steel, the mechanical properties of weld joint would completely lose when the brittle intermetallic phase Ti_xFe_y and TiC appeared in the fusion welding process. Therefore, the gas tungsten arced welding (TIG), metal inert-gas welding (MIG) and metal active-gas welding (MAG) with V/Cu composite filler metals for butt joint in this study was carried out on TA1/X65 pipeline steel clad plates with thickness 16 mm ( titanium cladding with thickness 2 mm, X65 pipeline steel with thickness 14 mm). The microstructure, interface element distribution, main phase, microhardness distribution on cross section and mechanical properties of butt welds were investigated by using OM, XRD, EDS element mapping, microhardness and tensile test. The results indicate that the design of “U-type” circular groove advantageous to the MIG of Cu transition-metals, because of the “U-type” circular groove does not cause stress concentration and crack initiation. The deposited metal of Ti, V, Cu and Fe have obvious zoning, interdiffusion melting phenomenon is not severe, and by using solid solution phases to transit zonings of deposited metal. The microstructure of Ti and V transition interface was composed of Ti-based solid solution, the microstructure of V and Cu transition interface was composed of V-based solid solution, and the microstructure of Cu and Fe transition interface was composed of Cu-based solid solution. The high hardness region of butt weld cross section appeared in the Ti/V transition-interface and V/Cu transition-interface, the hardness value was respectively 326 HV₁₀ and 336 HV₁₀, and weakened the ductility of transition interfacial layer. A joint with a tensile strength of 546 MPa, mainly of that of the carbon steel was obtained.