Mitigation of corrosion of carbon steel in a marine atmospheric via weak deoxidation

A low-carbon, low-cost, and high-efficient method was reported for remarkably improving corrosion resistance of C–Mn structural steel by weak deoxidation. The results showed that, with the total oxygen content (w_OT) increasing in the tested steel from 41 × 10⁻⁶ to 195 × 10⁻⁶, both the degree of element segregation and the level of banded microstructure weakened, presenting the lower potential difference between pearlite (P) and ferrite (F), and then smaller galvanic corrosion driving force, and thus effectively improving general corrosion properties. In addition, with w_OT growing up, the number and size of inclusions increased, and the shape also changed from long chain or small particle to large particle ball with typical mosaic structure, which could effectively inhibit the preferential dissolution of local component due to multiple complex interfaces, and correspondingly suppress the pitting susceptibility. However, the impact toughness at low temperature of the tested steel reduced with w_OT increasing, and then, taking the mechanical properties and corrosion resistance all into account, 160 × 10⁻⁶ was the optimal oxygen content within the present scope.