Interfacial evolution of titanium/steel clad plates during pulsed tungsten inert gas welding

Joining titanium alloy with steel has important applications in the shipbuilding and aerospace industries. Successful titanium/steel joints fabricated by explosive welding have been reported recently. However, explosive welding is not ideal for welded structures with complex geometry. Here, pulsed tungsten inert gas (TIG) welding is introduced to promote the application of explosively welded transition joints. In this work, pulsed TIG of commercially pure titanium to mild steel with an explosively welded titanium/steel transition joint was carried out. The results showed that at peak current (I-p) <= 260 A, the TiC layer hampered the generation of FeTi and Fe2Ti. However, at I-p = 300 A, the TiC layer broke up, which resulted in the thickness of FeTi and Fe2Ti increasing sharply to 0.8 mu m.