Abstract: Butt welding of TC4 titanium alloy sheet with thickness of 1 mm is realized by pulsed YAG laser induced tungsten inert gas(TIG) arc hybrid welding technology. The influences of parameters on the hybrid welding shape are studied, which are including the energy cooperation between laser and arc, butt joint gap and heat source angle. The results of experiments show that the energy cooperation between laser and arc would make obviously effect on the weld appearance in laser induced TIG arc hybrid welding process. In comparison to variation of arc power, the weld appearance is more susceptible to variation of laser power. As heat source angle decreases, thermal conductivity of hybrid source grows. Since high welding speed, little thermal input and small deformation, the laser induced TIG hybrid welding process can obtain the perfect weld appearance at the butt joint gap among 0-0.5 mm. In order to get the ideal joint, the back of the specimen should be protected by the Ar gas. When the protective gas flow is 5-8 L/min, the favorable performance can be obtained.

Key words: buttjoint gap, heat source angle, power cooperation, shielding gas flow, titanium alloy sheet