Discussion on Welding and Heat Treatment of Petrochemical Pressure Vessels
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This post was last edited by Wang Wei2 on 2025-1-27 at 10:39. 1. For steel welding of pressure vessel products, weld procedure qualification shall be carried out in accordance with JB4708-2000 \"Welding Procedure Qualification for Steel Pressure Vessels\" for the butt welds between pressure-bearing components, as well as for the T-joint welds that require full penetration; for the T-joint or fillet welds that ensure full penetration between pressure-bearing components and non-pressure-bearing components that bear loads; and also for the corrosion-resistant cladding layers on pressure-bearing components. And a corresponding welding process is developed, with welding carried out by certified welders. 2 Post-weld heat treatment: The purpose of post-weld heat treatment for steel is to eliminate residual stresses resulting from deformation and welding processes, improve the properties of the welded joint, and reduce its hardness. For the circumstances under which post-weld heat treatment should be carried out, refer to GB150-1998 \"Steel Pressure Vessels\" and the \"Regulations on Pressure Vessels\". The temperature and holding time for post-weld heat treatment are specified in JB/T4709-2000 \"Welding Procedures for Steel Pressure Vessels\". 3 Non-destructive testing of welds: For the welded joints of pressure-bearing components in pressure vessels, during welding, due to factors such as the chemical composition of the material, welding materials, welding procedures, and the type of weld joint, defects such as pores, inclusions, and cracks are inevitably generated in the welds. To ensure the long-term safe operation of pressure vessels in installations, it is necessary to conduct appropriate non-destructive testing on the welds based on the operating conditions of the vessels and the materials used, and to meet the requirements of relevant standards. For specific testing requirements, refer to GB150-1998 \"Steel Pressure Vessels\" and the \"Regulations on Pressure Vessels\". The testing methods shall comply with the provisions of JB4730-94 \"Non-destructive Testing of Pressure Vessels\".
The welding and heat treatment of petrochemical pressure vessels are key aspects in ensuring their safety and reliability. Before welding, it is necessary to conduct process evaluations on various weld joints in accordance with the JB4708-2000 standard, and establish appropriate welding procedures to be carried out by certified welders. After welding, post-weld heat treatment is required to eliminate residual stresses and improve the performance of the weld joint. The specific conditions for post-weld heat treatment can be found in relevant standards such as GB150-1998 and JB/T4709-2000. Non-destructive testing of welds is also an important step. During welding, defects such as pores, inclusions, and cracks may occur in the weld due to various factors; therefore, non-destructive testing of the weld is necessary depending on the operating conditions and materials, in order to ensure the long-term safe operation of pressure vessels. The specific testing requirements and methods shall comply with relevant standards such as GB150-1998 and JB4730-94. .