Preparation of titanium alloy pipe fittings by continuous driven friction welding

Ti6246 titanium alloy, TA2 pure titanium pipe and TC4 titanium alloy blind-hole pipe were prepared by continuous driven friction welding. The influence of welding parameters on the macro-appearance of welded joints, especially on the microstructure and mechanical properties of welded joints under the condition of heat treatment, was analyzed. The results showed that welding parameters had little influence on performance of welded joints within the range of welding parameters in the study. Welding coefficients of Ti6246 and TA2 pipes could reach0. 99. Friction welding could break microstructure of weld zone, which made microstructure of weld zone obviously fine than that of the base material. After friction welding, microstructure of weld zone in TC4 blind-hole pipe changed from widmanstatten to basket microstructure. The tensile strength was reduced by about 60 MPa, but the welding coefficient was still 0. 94, and the plasticity and toughness were better than that of the base metal.