Welding Process of Corrosion-Resistant Alloy Clad Plate for Inner Wall of Sulfur-Containing Crude Oil Storage Tank

The welding of corrosion-resistant alloy clad plate for the inner wall of sulfur-containing crude oil storage tanks requires a layered welding process: the base layer (16MnR) is primed with E5015 welding rod using shielded metal arc welding, preheated to 150°C; the transition layer (E309-16 welding rod) controls heat input ≤ 1.5kJ/cm and interpass temperature ≤ 250°C; the cladding layer (0Cr18Ni9) uses ER308L welding wire for gas tungsten arc welding, the current is reduced by 20%, and the dilution rate is strictly limited to ＜8%.

Key process points include: 1) The groove is designed as a 60° single V-groove, with a 1mm machining allowance reserved on the cladding side; 2) The transition layer adopts multi-pass thin-layer welding (each layer thickness ≤ 2mm) to avoid cracks in the dissimilar metal fusion zone; 3) After welding, the cladding weld is subjected to HNO3+HF pickling passivation, and the base layer weld is subjected to 590°C local annealing. After a 100,000 m³ storage tank adopted this process, no defects were detected in the weld PT test, and there were no signs of sulfide corrosion after 3 years of service.

Quality control needs to be implemented: 1) The deviation of Cr/Ni content in the cladding weld spectral analysis is ≤ 5%; 2) The RT detection of the base layer weld meets the Level II standard; 3) There are no defects larger than 3mm in the side bending test of the transition layer. It is recommended to use a digital welding parameter monitoring system to real-time adjust heat input and interpass temperature.