In the process of welding titanium pipes, the following operation points should be strictly implemented:
(1) Before welding, argon gas should be opened for some time before replacement. Open flame detection method can be used to check the welding joint and confirm that the gas in the pipeline is argon as a whole before welding.
(2) the extension length of the tungsten pole should be short, so as not to prevent the weld pool from being seen; Argon flow should be moderate, too large flow is not easy to form a stable flow layer, but will form turbulent flow in the protected area, so that harmful gas into the molten pool, in addition, too large flow will speed up the cooling of the molten pool, weld surface is easy to crack; Too small air flow makes the protection incomplete and cannot reach the protection effect. When the weld bottom welding, the argon gas flow on the back should not be too large, otherwise it will affect the efficiency of the front protection.
(3) In the welding process, not only should there be argon gas protection in the welding gun, but also need to add an argon-protected trailing cover behind the welding gun. At the same time, the titanium pipe should be filled with argon protection. During welding, the distance between the drag cover and the nozzle should be kept in the range of 20~25mm. At the end of welding, the protection of the drag cover cannot be immediately ended, and the air can only be stopped when the temperature of the weld drops below 200℃.
(4) In the welding process, the temperature between the layers must be strictly controlled. After each welding, the temperature should be reduced to room temperature before the welding of the lower layer can be continued.
(5) When welding, the arc starting and ending point must be in the groove, can not be on the base metal above the arc starting and ending. When the wire is sent, the welding wire can not be sent and pumped fast, and the welding wire should be filled into the molten pool slowly and evenly, otherwise it will cause gas disorder and affect the protection effect.
(6) The welding construction site shall be kept dry and clean, and the ambient temperature during welding shall be controlled above 10℃. There is no draft in the welding area.
(7) Short arc welding, quick welding, straight welding rod and filling wire should be adopted for welding titanium pipes. Swinging welding rod and wire should not be allowed. When the surface is covered, even if it is to swing, it can only swing slightly slowly.
(8) The head of the welding wire can not be separated from the range of protection in the welding, otherwise the end of the wire will be oxidized, if found that the end of the wire has been oxidized, the oxidation part must be cleaned up, and then can be used.