Some Precautions for Welding Titanium and Titanium Alloy Tubes

To ensure high-quality welds on titanium tube castings, the following points should be noted during the welding process:
1. The surface of the casting to be welded must be thoroughly cleaned and dried. It is not allowed to touch the casting directly with hands before it is placed in the welding box.
2. During the welding of titanium tubes, it is essential to prevent the tungsten electrode from short-circuiting with the casting to avoid electrode breakage and tungsten inclusions in the weld.
3. When the area and depth of the welding zone are large, multiple layers of welding should be carried out, and the next layer should only be welded after the previous layer has completely cooled to prevent casting deformation. It is strictly forbidden to weld in one go.
4. As the welding nears completion, the current should be gradually reduced and the molten zone narrowed. It is recommended to use pulsed current to prevent sudden arc interruption and the formation of cracks.
5. After the welding is completed, the casting should be left to cool in the box for a period of time before being removed. Rapid cooling can cause cracks or deformation in the weld area. The cooling time depends on the wall thickness of the casting, usually ranging from 15 to 30 minutes.
6. After the titanium tube casting is welded, it should be annealed or subjected to hot isostatic pressing promptly and not left for too long, typically no more than five days.
7. The number of welding operations should not exceed the requirements specified in relevant technical documents.

When titanium tube manufacturers perform welding outside the welding box, the environment should be free of flowing air. Other aspects are the same as welding in the box. However, special attention should be paid to the following:

1. The welding area should not be too large, and the flow rate of nitrogen should be increased during the welding process without interruption.
2. After welding, nitrogen protection should continue until the area has cooled completely.
3. For some special castings, such as complex thin-walled castings, argon gas should be blown onto the backside of the weld area to prevent oxidation until the casting has cooled. 4. The welding operators should have a high level of technical proficiency.