Argon arc welding of tungsten plate is the most widely used in the production of titanium and titanium alloy welding, and vacuum argon filling welding is also.Under the protection and cooling of argon gas flow, the arc heat is concentrated, the current density is high, the heat affected zone is small, and the welding quality is high.

   welding titanium and titanium alloys, when the temperature is higher than 500 700 C, it is easy to absorb air, hydrogen and nitrogen, which seriously affects the welding quality.Therefore, titanium and titanium alloys are welded, the weld zone of the weld pool and the high temperature part (400 ~650 ~above) must be strictly protected. For this reason, special protective measures must be taken when titanium and titanium alloys are welded, spraying larger welding moment to expand the area of gas protection zone. When the nozzle is insufficient to protect the high temperature metal in the weld and near seam area, argon protective tow cover should be attached.The color of weld seam and near area is the flag wing with protection effect. Silver white means the best protection, yellow is slightly oxidized, generally allowed.

   Considering the practicability and high efficiency of the project, we first prepared a simple tow hood. Argon enters the distribution pipe from the intake port and enters the protection zone directly through the distribution pipe hole. With this towing cover, the welding protection effect is not very good, and the weld bead is dark blue. According to the analysis, the air flow directly enters the reserve from the distribution pipe. The air flow is not uniform and smooth, which makes the high temperature weld bead not well protected by oxidation.

  Therefore, we further improved the structure of the drag hood, argon from the intake hole into the distribution pipe and back down through the top of the drag hood; through the porous plate, the porous plate mainly plays the role of gas sieve and distribution, making the argon flow more stable, the welding protection effect is better, and the weld bead is silver or River yellow. The material of the tow cover is brass with a length of L ranging from 40 mm to 100 mm.In TI and Ti alloy TIG arc welding, attention should also be paid to the protection of the northern side of the weld bead. Considering the welding deformation, we adopt the method of slotting and fixing the copper pad for argon filling protection. In order to make the back of the weld bead fully protected, we add a porous copper pipe in the pool to make the argon enter the protection area evenly through the copper pipe holes. The protection effect is good, and the back of the weld bead is silver white.