Corrosion Behavior of Super 13Cr Stainless Steel in Cl^-/CO₂ Medium at Different Temperatures

The resistant to uniform corrosion and pitting corrosion of super 13Cr stainless steel at different temperatures was studied in simulated oil field corrosion environment with Cl- and CO2. The surfaces of specimens were analyzed by metallography, scanning electron microscopy (SEM), energy disperse spectroscopy(EDS) and X-ray diffraction (XRD). The results showed that the uniform corrosion rate increased with the increase of temperature, and slight uniform corrosion turned moderate at 150 ℃. In Cl-/CO2 corrosive environment, pitting corrosion of super 13Cr stainless steel occurred very easily, pitting corrosion rate increased firstly and then decreased when temperature raised, pitting corrosion was the most serious when temperature was 120 ℃. X-ray diffraction showed that there was no CO2 corrosion product at all the tested temperatures, indicating that the CO2 corrosion resistance of super 13Cr stainless depends on the passive film formed on the material surface.