Why is the corrosion resistance of 05cupcni weathering steel strong?

The main purpose of adding Cu and P to 05cupcni weathering steel is to improve corrosion resistance and strengthen ferrite by solution.

1. Cu is the main and widely used alloy element to improve atmospheric corrosion resistance. The addition of Cu to 05cupcni weathering steel can form a dense copper oxide thin layer between the corrosion layer of steel and the copper accumulation layer, so as to slow down and inhibit the corrosion of medium to the steel plate.

2. When the content of Cu is more than 0.15%, the atmospheric corrosion resistance is improved slowly. P is an effective element to improve atmospheric corrosion resistance of alloy elements, and is an anode depolarizer. In electrolyte solution, it can accelerate the uniform dissolution and iron oxidation rate of 05cupcni weathering steel, which helps to form a uniform corrosion layer on the surface of 05cupcni weathering steel and has a clear boundary with the inner rust layer, thus improving the corrosion performance of 05cupcni weathering steel.

3.05 cupni weathering steel can meet the requirements of atmospheric corrosion resistance if Cu content is controlled within 0.25% - 0.35% and P is controlled within 0.07% - 0.10% according to the lower limit. Cr is also one of the alloying elements to improve the atmospheric corrosion resistance of 05cupcni weathering steel, but the effect is obvious only when Cu element is combined.

4. In the process of atmospheric corrosion, the content of Cr is controlled at 0.30% - 0.45%, and Ni is also one of the effective alloy elements for atmospheric corrosion resistance. When Ni content is 51% and Cu is contained in 05cupcni weathering steel, the effect of improving corrosion resistance is not obvious.