The Effect Of Zr On Weathering Corrosion Resistance Of Carbon Steel

In recent years ,weathering steel has developed greatly.Carbon steel by adding alloyelements can inhance the weathering collision resistance performance of it.Someresearches in and outside have shown that the steels with Zr addition can improve themechanism performance, transforming the inclusions of steels.But there are few reports onwether Zr can improve the weathering corrosion resistance performance of carbon steel.Zrhas perfect corrosion resistance performance and also plays different roles in manysteels.Therefore,in this paper,some researches were done on weathering corrosionresistance of carbon steel with Zr addition.Four experimental steels were trial-produced and Zr content is 1^#(0.018 %Zr),2^#(0.023%Zr),3^#(0.059 %Zr),4^#(0.049 %Zr).Also in 4^#-experimental steel,the content of P is0.11%,higher than that of the other three steels.The experimental steel was forged androlled to 3.5mm thickness steel slabs,then processed to experimental corrosionpieces.Choose SS400 carbon steel as contrast steel.The corrosion test was tesed bylaboratory accelerate corrosion test.The microstructure and rust layer were analyzed bygolden-paragraph microscope,SEM and XRD.The corrosion resistant of experimental steelwas also estimated by electrical chemistry test.Meanwhile,the mechanism performance wastested.The results showed that :1)The inclusions in experimental steel were smaller,and mostof them were president as ball-oxides.ZrO inclusions made the rust layer much morestable,prevented the corrosion ions from destroying the rust layer;2)Under the industryatmosphere environment,the weathering corrosion resistant performance of carbon steelwith Zr addition was improved. The corrosion resistance of carbon steel with Zr additionsimplely was 1.14-1.25 times of that of carbon steel.The corrosion resistance of carbonsteel with Zr(0.049 %) and P(0.11 %) was 1.175-1.40 times of that of carbon steel;3) Underthe ocean climate environment,the corrosion resistance performance of the fourexperimental steels were all higher than that of carbon steel; 4)With Zr addition ,the phaseconstitution of rust layer was easily transformed fromγ-Fe₂O₃/γ-FeOOH intoα-FeOOH.,itis easy for the protected rust layer to form and also make the rust layer more compact;5) The rust layer which was made by cyclic immersion for 72 h,144 h was investigatedthrough electrochemistry polarization curve and electrochemical impedance spectroscopytest.The result showed that: the potential of four experimental steels all moved towardspositive position for different extent,the resistance was enhanced.From the above,in the condition of this paper,the corrosion resistance of carbon steelwith Zr addition simply was improved.Under the industry atmosphere environment,theweathering corrosion risitance of carbon steel with 0.049 %Zr and 0.11%P was enhancedaround 20%,under the ocean climate environment was enhanced 11.8 %.The mechanismperformance of carbon steel with Zr addition was not affected basically.