To successfully weld titanium alloys without cracking, a series of protective measures and correct welding techniques need to be taken:

1. Welding protection: Titanium alloys are very sensitive to harmful gases in the air, so argon or other inert gases should be used for protection during the welding process. A nozzle can be used to spray argon gas to protect the area under the arc, and a protective drag cover can be added to the welding gun to protect the already welded seam, as well as to keep the weld seam cooled to an Ar atmosphere below 200 degrees Celsius.

2. Strengthening heat dissipation: Due to the low thermal conductivity of titanium alloys, the accumulation of heat during the welding process may lead to coarse grain size in the weld seam and heat affected zone (HAZ). To reduce this situation, effective methods can be adopted, such as adding thermal conductive copper pressure plates on both sides of the weld or passing cooling water on the copper pressure plates to help dissipate heat.

3. Choose appropriate welding methods and materials: When welding titanium alloys, welding wires with the same composition as the base material should be used, and consideration should be given to reducing the strength requirements of the welded joints to meet toughness requirements. The choice of welding method is also important, for example, tungsten inert gas arc welding is suitable for thicker titanium alloy plates, while plasma arc welding requires the use of a mixture of argon and hydrogen gas in the shielding gas to avoid the risk of hydrogen compounds formed by 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, it is necessary to adjust the air pressure of the welding equipment to ensure sufficient gas supply. The selection of welding materials should also be determined based on specific welding methods and technical requirements.

In summary, successful titanium alloy welding requires comprehensive consideration of welding protection, heat dissipation measures, appropriate welding materials and methods, as well as sufficient attention to the preparation work before welding.