Study on corrosion tendency of stainless steel vessel in oil and gas field environment

The intergranular corrosion cracking tendency of stainless steel cladding materials (304L, 316L) after monolithic post-welding heat treatment was studied by electrochemical method in oil and gas field environment. The results show that in the simulated environment, the open circuit potential of the material is more positive than the self-corrosion potential, and there is a possibility of corrosion in the absence of applied potential. The sensitivity value of 304L intergranular corrosion in standard solution measured by double-loop electrochemical potentiodynamic method is 0.0360, there is possibility of intergranular corrosion, 316L is 0.00002, there is no sensitivity. In order to determine the sensitivity of the materials under actual working conditions, the same method was used to measure in the simulated environment, and it was found that the two materials were always in the activated state and no intergranular corrosion characteristic curve appeared. It was verified by optical microscope that the material was mainly damaged by point corrosion, and there was no sensitivity to intergranular corrosion cracking, and intergranular corrosion cracking did not need to be considered in the periodic inspection of containers and RBI inspection.