Understand the reasons for the cracking of ∮89*2 sanitary stainless steel elbows in the short term

Understand the reasons for the cracking of the ∮89*2 sanitary stainless steel elbow in the short term. According to the reason for the cracking of the sanitary stainless steel elbow made of 304 stainless steel in the short term, the analysis and research are carried out. The cracks and fracture morphologies of the failed parts were characterized by metallographic microscope and scanning electron microscope, and the chemical composition of base metal, weld, heat-affected zone, and corrosion products were analyzed by electronic energy spectroscopy. The results show that the leakage of the pipeline is due to the sensitization treatment during welding, and the chloride.... According to the short-term cracking of the stainless steel head made of 304 stainless steel, the analysis and research are carried out. The crack and fracture morphology of the failed parts were characterized by metallographic microscope and scanning electron microscope, and the chemical composition of base metal, weld, heat-affected zone, and corrosion products were analyzed by electronic energy spectroscopy. The results show that the leakage of the pipeline is caused by the sensitization treatment during welding and the rapid occurrence of intergranular stress corrosion cracking under the dual action of chloride and sulfide solutions. Corresponding protective measures are proposed. 304 stainless steel is a versatile stainless steel material with stronger rust resistance than 200 series stainless steel materials. It also has good corrosion resistance to alkaline solutions and most organic and inorganic acids. High temperature resistance is also better, and the general use temperature limit is less than 650°C. 304 stainless steel has excellent corrosion resistance and good resistance to intergranular corrosion. For oxidizing acids, it is found in experiments that 304 stainless steel has strong corrosion resistance in nitric acid with a concentration ≤ 65% below the boiling temperature.