In order to obtain the titanium pipe casting with good supplementary welding quality, the following points should be noted during the supplementary welding process:

(1) The surface of the supplementary welded casting must be cleaned and dried, and the casting is not allowed to be directly touched by hand before loading into the welding box.

(2) In the process of rewelding titanium pipe, strictly prevent the short circuit between the tungsten electrode and the rewelding part, resulting in the breaking of the tungsten electrode, resulting in the tungsten inclusion of the solder joint.

(3) When the area and depth of the supplementary welding area are relatively large, it should be divided into multiple far layer welding, and the next layer can only be carried out after the previous welding layer is completely cooled. Secondary welding is absolutely not allowed to prevent the deformation of the casting.

(4) At the end of the repair welding, the current should be gradually reduced to reduce the melting area. Therefore, it is recommended to use a pulse current to prevent a sharp arc break and lead to cracks.

(5) After the replacement welding, the casting should be cooled for a period of time before removing the casting to prevent crack or deformation in the welding area of the casting; the cooling time depends on the wall thickness of the casting, usually 15-30mm.

(6) After supplementary welding of titanium pipe casting, annealing or thermal isostatic pressure should be used in time, and should not be shelved for too long, usually not more than 5 days.

(7) The number of supplementary welding shall not exceed the provisions of the relevant technical documents.

It is required that the environment of titanium pipe manufacturer can not have flowing air, other aspects and the repair welding in the welding box. Special attention should however, be paid to:

(1) The welding area should not be too large, the flow of nitrogen in the welding process should be too large, and the gas should not be stopped in the middle;

(2) After the replacement welding, the nitrogen gas protection shall be continued until the area is cooled;

(3) For some special castings, such as complex thin-wall castings, to prevent the oxidation of the back of the supplementary welding area, argon can be blown on the back until the casting is cooled;

(4) Repair welding operators are required to have a high technical level.