Effect of Deoxygen on Pitting Propogation of Carbon and Manganese Steels

For five kinds of deoxygenized carbon manganese steels,the microstructure and inclusions was studied with metallurgy analysis,the corrosion rate of pitting was detected with immersion tests,and the mechanism of pitting was investigated with OCC testing and microstructure analysis.The results show that deoxygen methods had much important effect on the microstructure and inclusions of the manganese steels.The deoxygen of boiling steels is poor and the inclusions is I type potato like sulfide.The deoxygen of killed steel is well and the inclusions were eutectic Ⅱ type sulfide which was bar-slice like after rolling.The inclusions of half-killed steel are short bar like or long cigar like.With the decline of deoxygenization degree,the OCC current density dropped.The immersion test results show that the corrosion resistance of half-killed steels is better than that of the killed manganese steels.The corrosion rate of pitting in immersion test is the same with OCC test in the laborotary.