| Because of grade B ship plate’s high ratio of performance and cost, it had been widely used in the shipbuilding industry, but the low corrosion resistance greatly affected its service life and service safety. In this paper, through immersion test and in-situ corrosion test, the effects of A1 element and inclusions-modified on the corrosion resistance of the grade B ship plate in artificial seawater were systematically studied, with metallographic, electrochemical, SEM,XRD and other analytical methods. The results showed that the thickness and impedance of the rust layer had increased, with the increase of Al content in the B grade plate. Compared with low A1 steel, the corrosion resistance of medium and high Al steel in 168 h was improved by more than 14%, and that in 720h was improved by more than 28%. However, when the content of Al in the grade B ship plate increased from 0.49% to 1.08%, the grain size was significantly increased. After the inclusion-modified, the number of inclusions was reduced, the pitting susceptibility decreased and the pitting corrosion resistance was improved in the grade B ship plate. Rare earth or Ca could promote the transition of γ-FeOOH to a-FeOOH in the rust layer after inclusions-modified, so that the stability of the rust layer was improved, and it little increased in resistance to 720 h immersing corrosion. |
PDF Full Text Request