Precautions for operating techniques during TIG welding of titanium alloy pipes

1. Before welding, conduct a period of gas replacement for a certain duration. You can use the open flame detection method to inspect the weld joint and confirm that the gas inside the pipe is completely argon. Then, proceed with the welding. Use short arc welding and do not swing the welding gun or welding wire. When covering the surface, only a slight and slow swing is allowed. The end of the welding wire must not leave the protection range during the welding process; otherwise, the end of the welding wire will be oxidized. If you find that the end of the welding wire has been oxidized, you must cut off the oxidized part before using it. After stopping the welding, delay the gas supply until the temperature in the welding area drops below 300°C. During welding, the starting and ending points of the arc must be inside the breach and not on the base material.

2. When feeding the wire, do not rapidly fill the wire in and out. Slowly and evenly feed the welding wire into the molten pool. Otherwise, it will cause gas disorder and affect the protection effect. The distance between the nozzle and the pipe opening should be as low as possible without affecting the line of sight. The angle is about 75°, but it must not cause the tungsten electrode to touch the base material and cause tungsten inclusion. The angle between the welding wire and the pipe opening is about 12°. During the welding process, strictly control the interlayer temperature. The next layer must wait until the temperature drops to room temperature before continuing to weld the next layer. There should be a 0.5-1mm gap between the rubber sealing plate and the inner diameter of the pipe. During welding, it can play the role of pre-replacing the internal air of the pipe, releasing excess argon during the welding process, and cooling. During welding, always observe the color of the weld surface. The best color is silver white, followed by golden yellow, purple, blue, gray, and gray-white.

3. The welding environment is very important. The welding site must be kept dry and clean. The environmental temperature during welding should be controlled above 18°C. There should be no crosswind in the welding area. Water, steam, or other gases must not penetrate the welding pool and the heat affected zone. Otherwise, there must be shielding measures to avoid the weld seam from being contaminated and affecting the welding quality. In summary, to weld titanium and its alloy pipes well, from selecting the welding material, opening the groove, grinding, cleaning and drying, environmental measures, gas protection, process parameters, welding operation, etc., every link is very important. Treat it seriously and only then can you weld a qualified welding joint.