Effect of Inclusions Modified by Y-Based Rare Earth on the Corrosion Behavior of EH36 Shipbuilding Steel

摘要

High-strength steels are widely used with marine resource exploitation. However, the marine environment is harsh, especially in special marine environment with high salt spray, high humidity, or alternating wet and dry environment. Thus, corrosion behavior of high-strength steel in harsh marine environment has become a highly significant topic. The effect of Y-based rare earth (RE) on the inclusion modification and corrosion behavior of EH36 shipbuilding steels has been investigated. The results demonstrate that the elongated MnS inclusions in EH36 steel, noticeable in the absence of RE, were replaced by spherical RE complex inclusions upon addition of 0.029 wt% RE, leading to the formation of the EH36RE steel. Furthermore, the addition of Y-based RE effectively improves the corrosion resistance. Y-based RE addition inhibits the precipitation of MnS, restrains the initiation of corrosion. The electrochemical test exhibits a decrease passive current as well as a higher resistance of the EH36RE steel.