Corrosion and stress corrosion cracking behavior of 316L austenitic stainless steel in high H_2S-CO_2-Cl~- environment

摘要

In oil and gas production environments, H_2S and Cl~- can coordinate to cause pitting or stress corrosion cracking (SCC) of stainless steels. There has been limited work conducted on corrosion and SCC of autenitic stainless steels in high H_2S-CO_2-Cl~- environments. In this paper, by four-point bending test method and scanning electron microscopy analysis, SCC of 316L steel was investigated under high H_2S-CO_2 pressures with 150,000 ppm Cl~- at 60 C. The effect of high H_2S-CO_2 pressure was discussed. The results indicated that the higher H_2S-CO_2 pressure can accelerate anodic dissolution process, deteriorate passive films, and aggravate SCC sensitivity. Using cyclic potentiodynamic polarization measurements, the corrosion behavior of 316L steel was studied in high H_2S-CO _2-Cl~- environments. The effect of pH on pitting corrosion was discussed. Lower pH can promote both cathodic and anodic actions on 316L steel and facilitate passive film breakdown.