Tribocorrosion Behavior of FH36 Steel in Simulated Seawater with Different Salinity

Using the UMT-2 multifunctional friction and wear tester to test the reciprocating friction behavior of FH36 marine low-temperature steel plates under open circuit potential and cathodic protection potential with different salinities seawater. Combined with electrochemical workstation to explore the friction corrosion of FH36 steel samples and the change of electrochemical parameters during this process. White light interferometer and scanning electron microscope were used to characterize the microstructure morphology and wear scar morphology of the steel samples. The results showed that with the increase of Cl^- concentration, the friction coefficient decreased, but the profile of wear scar and wear amount increase gradually, the open corrosion potential shifted negatively, and the corrosion tendency of the steel sample increased correspondingly. Among them, the amount of wear decreased from 86.2% of the material loss to 78.2%. When the steel sample was at the open circuit potential, the wear mechanism in the low-salinity simulated seawater was abrasive wear, and the wear mechanism in the high-salinity simulated seawater was corrosion wear and fatigue wear; when the steel sample was at the cathodic protection potential, the wear process at various Cl⁻ concentrations (0~1.2 mol/L) was mainly abrasive wear. Through the quantitative analysis of the friction corrosion coupling, it was confirmed that the abrasive wear and corrosion wear promoted each other during the tribocorrosion tests of FH36 low alloy carbon steel. The coupling effect had the greatest influence when the Cl⁻ concentration reached 0.6 mol/L and the material loss was mainly dominated by abrasive wear followed by corrosion wear at this critical point.