Large diameter of industrial pure titanium pipe back double arc welding welding method, belonging to the pipe welding technology, suitable for various industries of large diameter (600 mm) Φ acuity titanium pipe, equipment and other non-ferrous metal root welding.Clean the oil and oxide on the surface of the welding wire and welding parts;Groove processing of pipes;In the pipeline group, the interval is 1 ~ 2mm;Titanium pipe inside and outside the two torch assignments to welding of titanium pipes, together with belt protection cover of the tungsten electrode argon arc welding gun, welding in the welding direction and welding gun nozzle in former protection cover, the torch nozzle argon flow 25 ~ 30 l l/min, welding torch nozzle argon flow within 15 ~ 20 l l/min, the welding torch the argon gas flow drag cover 25 ~ 35 l l/min, the welding torch the argon gas flow drag cover 25 ~ 30 l l/min, the torch outside the current 140 ~ 160 a.It is easy to control the weld molding quality and fast welding speed, which is 3 ~ 5 times of welding speed of single arc welding.Saving energy and raw materials.