Search for filler metal for welding of ferrous alloys to titanium

The use of a filler metal to facilitate the gas tungsten are (GTA) welding of ferrous alloys to titanium alloys has heen investigated. Semi-empirical rules have been applied to identify alloying elements that would resolve th e important problems of brittle intermetallic formation and weld cracking. Vanadium was found appropriate. The GTA welds between a low carbon steel an d Ti-15V-30-3Sn-3Al made with a vanadium filler wire resisted cracking bett er than comparable autogenous welds. However, the presence of a hard, britt le eutectic microconstituent along the ferrous side of the fusion boundary drastically limited the gain in weldability. As anticipated, analysis of GT A welds produced with vanadium filler wire suggested the presence of a tern ary (Fe, Ti, V) single phase. Although cracking was reduced with i,vanadium , the practical benefit of a vanadium filler wire for GTA welding is small because the, weld metals remain hard and brittle.