Some precautions for repairing welding titanium pipes and titanium alloy pipes!
In order to obtain high-quality titanium pipe castings and titanium alloy seamless pipes for repair welding, the following points should be noted during the repair welding process:
(1) The surface of the repaired castings must be cleaned and dried, and the castings are not allowed to be directly touched by hand before being loaded into the welding box.
(2) During the process of repairing titanium pipes, strict precautions should be taken to prevent short circuits between the tungsten electrode and the repaired welding parts, which may cause the tungsten electrode to break and cause tungsten inclusions in the welding points.
(3) When the area and depth of the repair welding area are relatively large, multiple far layer welding should be carried out, and the next layer of welding can only be carried out after the previous layer of welding has completely cooled down. Single welding is not allowed to prevent deformation of the casting.
(4) At the end of repair welding, the current should be gradually reduced to narrow the melting zone. Therefore, it is recommended to use pulse current to prevent sharp arc breaking, which may lead to cracks.
(5) After the repair welding is completed, the casting should be allowed to cool in the box for a period of time before being opened and taken out to prevent cracks or deformation in the welding area of the casting caused by rapid cooling; The length of cooling time depends on the wall thickness of the casting, usually between 15-30mm.
(6) After repairing welding of titanium pipe castings, they should be annealed or hot isostatic pressed in a timely manner, and should not be left for too long, usually not exceeding 5 days.
(7) The frequency of repair welding shall not exceed the provisions of relevant technical documents.
The titanium pipe manufacturer is required to repair welding titanium pipes in an environment where there is no flowing air, and other aspects are the same as repairing welding in the welding box. But special attention should be paid to:
(1) The area for repair welding should not be too large, and the nitrogen flow rate during the repair welding process should be higher, with no gas stopping in the middle;
(2) After the repair welding is completed, nitrogen protection should continue to be applied until the area cools down;
(3) For some special castings, such as complex thin-walled castings, in order to prevent oxidation on the back of the repair welding area, argon gas can be blown on the back until the casting cools down;
(4) Require repair welding operators to have a high level of technical proficiency.
