How can titanium alloy be welded without cracking?

To successfully weld titanium alloys without cracking, a series of protective measures and correct welding techniques are required:

1.Welding protection: Titanium alloy is very sensitive to harmful gases in the air, so argon or other inert gases should be used in the welding process for protection. Argon gas can be sprayed from the nozzle to protect the area under the arc, while a protective drag cover is added to the torch to protect the already welded seam, as well as to keep the weld cool to at least 200 degrees below the Ar atmosphere.

2.Strengthen heat dissipation: due to the small thermal conductivity of titanium alloy, the weld and heat affected zone (HAZ) grain may be coarse due to heat accumulation during the welding process. In order to reduce this situation, effective methods can be used such as adding thermal conductive copper plates on both sides of the weld or passing cooling water on the copper plates to help heat dissipation.

3.Choose the appropriate welding method and material: titanium alloy welding should use the same composition as the base metal wire, and consider reducing the strength of the welded joint to meet the toughness needs. The choice of welding method is also very important, for example, argon tungsten arc welding is suitable for larger thickness of titanium alloy plates, while plasma arc welding requires the use of a mixture of argon and hydrogen in the shielding gas to avoid the risk of forming hydrides between titanium and hydrogen.

4.Preparation before welding: the welding area should be thoroughly cleaned before welding to remove oxide film, grease, moisture and dust. In addition, the air pressure of the welding equipment needs to be adjusted to ensure adequate gas supply. The selection of welding materials should also be determined according to the specific welding method and technical requirements.

To sum up, successful welding of titanium alloys requires comprehensive consideration of welding protection, heat dissipation measures, appropriate welding materials and methods, and sufficient attention to the preparation work before welding.