The influence of microstructures on the corrosion resistance of Cr-Mo-Sn low alloy steel in a tropical marine atmospheric

Through dry/wet cycle corrosion experiment and corrosion big data monitoring technology, the effects of different microstructures on the corrosion resistance of Cr-Mo-Sn low alloy steel in tropical marine atmospheric environments were studied. The research results indicate that the fine grain zone in the heat-affected zone has the best corrosion resistance, mainly due to the formation of Cr2O3, NiFe2O4, SnO2 and MoO2 corrosion resistant products, which promotes the densification of the rust layer. Conversely, the coarse grain zone displays the lowest corrosion resistance due to a significant presence of dislocation entanglements within the grains, elevated local strain, and a higher prevalence of high-angle grain boundaries, all contributing to a reduction in corrosion resistance.