Cause of Cracking on 304 Austenitic Stainless Steel Pipe Welded Joint

304 austenitic stainless steel pipe cracked near the welded joint during use. The causes of cracking on 304 austenitic stainless steel pipe welded joint were analyzed by means of macro and micro observation, chemical composition analysis, energy spectrum analysis and metallographic examination. The results show that the cracking form of stainless steel pipe welded joint is intergranular cracking caused by intergranular corrosion. The main reason was that the composition of stainless steel pipe on one side does not meet the standard, the carbon content of stainless steel pipe was high and the chromium content was low. During the welding heating process, the welding sensitization phenomenon occured, which reduced the corrosion resistance of welded joint and led to corrosion cracks in the heat affected zone of welded joint. In addition, there were more chloride ions in tap water transported by steel pipe, which provided a corrosive environment and further promoted the crack propagation.