Cause Analysis of Girth Weld and Joint Crack of the Fourth Effect Evaporator C534 Upper and Lower Head in EOEG Unit
During the overhaul inspections in 2021,internal surface cracks were found around the girth welds of the upper and lower heads of the fourth effect evaporator C534 In the EOEG unit of a petrochemical company.Cracking causes for upper and lower head of metastable austenitic stainless steel was analyzed by means of penetration testing,hardness testing,ferrite detection,and metallographic analysis.The results showed that,as the straight sections of the upper and lower heads were made of austenitic stainless steel,during the cold working process,some of the microstructure transformed into deformed martensite.It is recommended that in the manufacturing process of pressure vessels,appropriate processing techniques should be determined based on different materials,specifications,and environmental conditions.