Evaluation of stress corrosion of duplex stainless steel overlay

In order to prevent stress corrosion in petrochemical facilities,2205 duplex stainless steel was deposited on the surface contacted with the corrosive media in projects. In order to explore the application scope and feasibility of the solution, two welding processes (automatic welding and manual welding),three kinds of common corrosion environment (saturated hydrogen sulfide,magnesium chloride,calcium chloride) were used to evaluate its stress corrosion comprehensively at the constant tensile load based on the microanalysis of fracture,and the mathematical model of stress-life was established based on the experimental results. The results indicate that the constant tensile load threshold is 0.45 R_eL for automatic welding and 0.4 R_eL for manual welding in saturated H₂S environment,and there is an error of 17% between them. All the samples are good after 96 hours in 0.9 R_eL stress test with the calcium chloride environment, which shows the excellent resistance to chloride stress corrosion. But the coating cannot be used in boiling magnesium chloride environment.