Performance of the API L80 steel front the corrosion of Co₂ in environment similar to pre - salt

In this work evaluated the corrosion of API L80 type 1 steel in similar environment to pre -salt in high pressures (15 and 30 MPa) and high temperature (50 °C), for 7 and 30 days, using brine saturated with CO₂. The corrosion rates were determined by weight loss and the properties of the corrosion products were evaluated by scanning electron microscope and electrochemical measures of the polarization potentiodynamic and electrochemical impedance. The lower corrosion rate was obtained for corrosive condition of 15 MPa, 50 °C and 30 days. However, the corrosion product film that provided best passivation of the steel surface, according as electrochemical measurements performed, was the scale formed at 15 MPa, 50°C and 7 days, exhibiting polarization resistance of 6.6x10³ Ω.cm², indicating that this film tends to act as barrier for steel corrosion in this corrosive environment. (author)