The fixed tube-plate heat exchanger is a heat transfer energy-saving device widely used in the petrochemical industry at present, which has a simple structure and low manufacturing cost. The tube side and shell side of the heat exchanger are formed by welding. Welding will inevitably produce residual stress. Under the joint action of residual stress and corrosive medium, stress corrosion cracking and leakage will occur at the weld of the tube sheet.
A welded joint of a tube sheet after a welded tube sheet heat exchanger of a refinery had a serious leak. The analysis shows that a large residual stress is generated in the weld and heat affected zone. The ring stress is the largest, the radial stress is the second, the axial stress is the smallest, and the maximum residual stress is generated at the junction of the weld and the base metal.Compared with L-shaped and V-shaped repair welding grooves, the residual stress of U-shaped groove welded joints is smaller.Compared with the L-shaped groove, the maximum residual stress of the U-shaped groove is reduced by 21.1%.Compared with the single U-shaped groove, the bilateral U-shaped groove can reduce the welding residual stress, and the maximum residual stress is reduced by 15.3%. The bilateral U-shaped groove is helpful to reduce the sensitivity of stress corrosion cracking.