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This paper investigated two kinds of corrosion resistant low alloy steels depending on the environment of the North China see(Steel S)and South China sea(Steel N),respectively.The mechanical and corrosion properties of the two steels were analyzed in this paper.Tin was added into both steels to improve the corrosion resistance.Structure and mechanical properties of the two steels were detected,and the results revealed that the microstructures of both steels were ferrite and little divorced pearlite.The yield strength and impact toughness at-40℃ of the steel S are 423MPa and 98 J,respectively.The yield strength and impact toughness at-40℃ of the steel N are 437 MPa and 70 J,respectively.The properties mentioned above met or even exceeded the requirement(yield strength 355 MPa,toughness 34 J)in these areas.The corrosion resistant properties of the two steels were also investigated via the means of immersion test and electrochemical experiment.The immersion test indicated that the corrosion rate of steel S and steel N was 0.00938 mg/h·cm2 and 0.00838 mg/h·cm2,respectively,when completely immersed for 168 hours,and the corrosion rate was much lower than that of E36.The Electrochemical experiments showed that the corrosion potential(Ecorr)of both steels was higher in contrast to E36,which indicated a lower corrosion trend.