Fine grain titanium alloy is used extensively in aerospace and ailrraft because of its excellent comprehenslve properties and outstanding machinability. Fine grain Ti-6Al-4V alloy and common grain Ti-6Al-4V alloy were welded by tungsten iner-gas arc welding(GTAW)respectively. Welding parameters and appearance of two Ti-6Al-4V alloys welded were investigated. The results indicate that the heat conductivity impediment of grain boundary strengthened because of fine grain Ti-6Al-4V alloy grains refinement and g...