Effect of Ce Element on the Microstructure and Corrosion Resistance of DH36 Ship Plate Steel

Currently， there are fewer studies on the effect of rare earths on the corrosion resistance of DH36 ship plate steel.Herein， the effect of the addition of rare earth Ce on the microstructure and corrosion resistance of DH36 ship plate steel was studied by metallographic microscope， scanning electron microscope， electrochemical workstation and X-ray diffractometer.Results showed that Ce had a significant refining effect on the grain size of the test steel； The addition of Ce modified the Al2O3， MnS and Al2O3＋MnS inclusions in the steel to CeAlO3＋MnS，Ce2O3 inclusions，and the stress around rare earth inclusions significantly decreased，reducing the active zone where corrosion occurred.Moreover， the addition of Ce increased the self-corrosion potential of the test steel and reduced the self-corrosion current density.After immersed in 3.5%NaCl solution for 5 d， the corrosion current density of the test steel decreased from 8.431×10-5 A/cm2 without the addition of rare earth Ce to 2.384×10-5 A/cm2 with the Ce content of 0.009 2%； The addition of Ce declined the content of γ-FeOOH in the corrosion products，while increased the content of α-FeOOH and Fe3O4.All of test results indicated that the increase of Ce content would improve the corrosion resistance of the test steel.