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The importance of welding work: Pressure vessels pose a risk of explosion, and an explosion would have catastrophic consequences. It has been found that most leaks and explosions in pressure vessels stem from the failure of weld joints. Therefore, welding quality is key to ensuring the safety and reliability of pressure vessels. Welding requirements: The welding requirements for stainless steel pressure vessels are as follows: 1. The groove surfaces of the weld joints must be prepared by mechanical methods. 2. Welding materials must be dehydrogenated and thoroughly cleaned. 3. The personnel responsible for aligning the welded joints must wear clean gloves; they must not touch the groove or the areas surrounding it, and it is strictly prohibited to strike the surface of the titanium plate or the groove with metal tools. 4. Welding should be carried out immediately after the welding joint has been aligned and cleaned. 5. The purity of argon and helium used for welding must be at least 99.99%, with a dew point not higher than minus 50°C. 6. Before welding titanium materials, the groove and the area within 25 mm on both sides must be thoroughly mechanically cleaned and degreased. Measures should be taken during welding to prevent groove contamination. 7. Effective measures should be taken to prevent interdiffusion between steel and titanium during welding. When required by the pattern, an iron contamination test should be conducted. 8. During the welding process, after each weld is completed, it is necessary to check the color of the weld surface; the surface color of the weld and the heat-affected zone should be silver-white or golden-yellow. Those with unacceptable surface color should be completely removed and then rewelded. The inspection of surface color shall be carried out in accordance with the provisions of relevant standards. 9. Inert gas shielded arc welding or plasma welding must be used for double-sided protection. The connection between titanium tubes and tube sheets should preferably be made using strength welding or welding after expansion. 10. The weld surface after welding must be free of defects such as undercut, pores, crater, and cracks.