Effects of Cl~- concentration on corrosion behavior of carbon steel and super13cr steel in simulated oilfield environments

摘要

In order to understand the changing tendency of the corrosion behavior of carbon steel and stainless steel with different chloride ion concentration, Electrochemical method and high temperature and high pressure immersion method combined with scanning electron microscopy were used in this paper. The results show that the corrosion potential of carbon steel is almost the same at 60°C. While for super13Cr martensitic stainless steel, its critical pitting potential sharply decreases from -48 mV to -213 mV (vs Ag/AgCl). However, with the increase of Cl~- content at 90°C, the corrosion potential of carbon steel is gradually reduced. While for the superl3Cr, the corrosion potential reduces sharply, and when the Cl~- concentration is greater than or equal to 40g/L, the corrosion potential basically remained constant, the critical pitting potential also is not obviously changed. Carbon steel corrosion is mainly controlled by the diffusion effect. Super13Cr martensitic stainless steel displays the single capacitive reactance arc.