Corrosion Properties of 16MnR Steel Used to Fabricate LPG Spherical Tanks in H₂S-Containing Environment

The corrosion properties of 16MnR steel used to fabricate LPG spherical tanks in H2S-containing solution were investigated by potentiodynamic polarization measurement and electrochemical impedance spectroscopy (EIS). The results show that H2S content and pH value considerably influenced the corrosion of the 16MnR steel, and its corrosion rate increased with increasing the H2S content and decreasing the pH value. In solution with lower pH value, the capacitive loop radius decreased with the prolongation of immersion time and the steel was in the process of dissolving state. With the increase of pH value and the prolongation of immersion time, the capacitive loop radius increased. With the increase of temperature, the corrosion rate increased. The adherence of the sulfide film to the steel was poor, and thus the steel could not effectively be protected from further corrosion.