Correlation between active/inactive (Ca, Mg, Al)-Ox-Sy inclusions and localised marine corrosion of EH36 steels

The correlation between (Ca, Mg, Al)-O-x-S-y inclusions and localised marine corrosion of EH36 steels was investigated. According to their ability to induce localised corrosion, the inclusions were categorised as 'active' or 'inactive', and the main difference between them was the ratio of CaO/Al2O3. The residual stress at the active inclusion/matrix interface was higher than the yield strength of the steel; therefore, a local plastic deformation region was preferentially formed, triggering localised corrosion initiation. Moreover, the occluded cell accelerated the localised corrosion propagation, and finally the dissolution of the inclusions and the matrix resulted in a stable pit. (C) 2021 The Author(s). Published by Elsevier B.V.

Automated summary

The study investigated the correlation between (Ca, Mg, Al)-O-x-S-y inclusions and localised marine corrosion of EH36 steels. The inclusions were categorized as 'active' or 'inactive' based on their ability to induce corrosion, with the ratio of CaO/Al2O3 being the main difference between them. Residual stress at the active inclusion/matrix interface was higher than the steel's yield strength, leading to the formation of a local plastic deformation zone and initiation of localized corrosion. Additionally, the occluded cell accelerated the propagation of corrosion, ultimately resulting in the dissolution of inclusions and the matrix forming a stable pit.