Influence of alloying elements on atmospheric corrosion resistance of S235J2W steel plate

Carbon element is unfavorable to atmospheric corrosion resistance of S235J2W steel plate.
Reduce the carbon content of S235J2W steel plate to reduce the precipitation of carbides, which can prevent the formation of galvanic cells.
Generally, the carbon content of S235J2W steel plate is controlled below 0.12%.

When adding copper content of 0.2% ~ 0.4% in S235J2W steel plate, it can improve the corrosion resistance of S235J2W steel plate.

Phosphorus is one of the most effective elements to improve the corrosion resistance of S235J2W steel plate.
Phosphorus can be uniformly dissolved in S235J2W steel plate, which helps to form a dense protective film.
Generally, S235J2W steel plate has the best corrosion resistance when the phosphorus content is 0.08% ~ 0.15%.

Chromium can form a dense oxide film on the surface of S235J2W steel plate, improve the passivation ability of S235J2W steel plate, slow down the growth rate of rust layer.
Generally, the chromium content of S235J2W steel plate is 0.4% ~ 1.0%.

Nickel is a relatively stable element. The addition of nickel can make the self-corrosion potential of S235J2W steel plate change in the positive direction, increasing the stability of S235J2W steel plate.

Rare earth elements (RE) can refine grain, change the state of inclusions in S235J2W steel plate, reduce the number of harmful inclusions and reduce the corrosion source point, so as to improve the atmospheric corrosion resistance of S235J2W steel plate.