Research On Corrosion Resistance And Corrosion Behavior Of Wet Smooth Cold Rolled Strip Steel

In recent years,with the upgrading of the domestic steel rolling field,the traditional dry leveling technology has gradually been transformed and upgraded to the wet leveling technology.The biggest feature of the wet leveling technology is the use of wet leveling liquid during the steel rolling leveling process,which will form a surface on the surface of the steel plate.A layer of wet leveling liquid film will provide corrosion protection for the wet leveled steel plate.If it can be demonstrated that this layer of wet leveling liquid film can replace the current dry leveling oil-coated plate for transportation,then the electrostatic oiling process can be omitted for the manufacturer.It saves a lot of cost,and will be beneficial to the promotion of wet leveling technology,driving the further upgrade of the domestic cold-rolled strip steel field.After observing the surface morphology of the wet-flattened steel plate and the dry-flattened steel plate,it is found that the surface of the wet-flattened steel plate has a rolling pattern,the real surface area is large,and the kurtosis is small.At the same time,it is found that the surface element composition of the two steel plates is roughly the same.The study found that the N element was found below40nm on the surface of the wet-leveled steel plate,indicating that the wet-leveling fluid has been pressed into the steel plate below 40nm.At this time,the organic amine component in the wet-leveling fluid as a rust inhibitor will provide certain corrosion resistance to the wet-leveled steel plate.Through electrochemical tests,it is found that the bc of wet-flattened steel plate is 3.759,and the bc of dry-flattened steel plate is 3.217.The wet-flattened liquid film will hinder the oxygen transfer in the cathode process,thereby improving the corrosion resistance of the steel plate.At the same time,the salt spray test has small and dense corrosion pits on the surface of the wet flat steel plate,while the corrosion pits on the surface of the dry flat steel plate are large and sparse,which shows that the corrosion resistance of the wet flat steel plate is better.Through the contact angle test,it is found that the contact angle values of the wet leveling fluid residue and DOS oil have increased compared with the degreasing plate,and the increase values are close,indicating that the wet leveling fluid and DOS oil can effectively hinder the mass transfer on the surface of the steel plate.To improve corrosion resistance,wet leveling liquid steel strip has the possibility of replacing dry leveling oil-coated plates.Through the lamination test,it is found that the corrosion pattern of the wet flat steel plate is denser and the corrosion resistance is better.Cyclic anode polarization curve found that the hysteresis ring area of dry flat steel plate is4.81×10^-8,while the hysteresis ring area of wet flat steel plate is 1.51×10^-10,which is much smaller than that of dry flat steel plate,indicating that its crevice corrosion resistance is better.Through time domain spectrum analysis,frequency domain analysis,cluster analysis and wavelet analysis of the corrosion current,the data characteristics of different corrosion periods are summarized,and it can be found that the crevice corrosion process of dry flat steel plate and wet flat steel plate can be divided into three The two stages are the slow incubation period,the severe corrosion period and the stable period.The surface state of the steel plate can only affect the length of the slow incubation period,but it cannot change the state of the final stable period.