Effect Of Si On Corrosion Resistance Of Cabon Steel In Atmospheric Conditions

In the field of weathering steel studying, Silicon is always considered as a beneficial element for enhancing corrosion resistance of steel;however the role and the effect mechanism are not very clear. There are many factors influence the ability of the corrosion resistance of steel, it had not been deep and systemic researched that the variety of corrosion resistance when silicon addition to carbon steel in the industrial environments of domestic. In this paper, based on the carbon steel which utilizing some residual elements Cu and P of the scrap steel, the effect and mechanism of corrosion resistance variety has been studied through change the Silicon content.Four content of Silicon addition to carbon steel has been studied such as 0.026% , 0.51 % , 0.98 % , 1.44 % , and compared their corrosion resistance with SS400 by laboratory-accelerated test and electrochemistry test method. The morphology of rust layer, its compact and densification properties and its composition and phase constitution had been analyzed by SEM, XRD, EDAX and Raman spectrum after laboratory-accelerated test, and the mechanical properties of the steel had been studied too.From the experimental result and analysis, the results can summarize as follows: 1) in simulated industrial environments, element Si have no beneficial effects on corrosion resistance, to some extent, have a detrimental effect on corrosion. The corrosion rates of steel contains 0.026%Si and 1.44%Si were 2.6~ 2.8 and 1.4—1.6 times to that of SS400 respectively. 2) The good effect on corrosion resistance of Cu, P has been affirmed, the corrosion resistance of steel have some residual elements Cu and P was better than SS400 obviously. 3) In simulated industrial environment, a-FeOOH is most stable phase, a better protective ability of rust has relations to not only the content of a-FeOOH, but also to the microstructure of the rust layers and its adhesive, compact properties and so on.