What is the rust principle of weathering steel?

Weathering steel is a kind of low alloy steel between ordinary carbon steel and stainless steel. The content of alloy elements in weathering steel is not high, but its performance is very good. Weathering steel is widely used in railway, landscape, bridge and other places.

At the initial stage of corrosion, rust layer will be formed on the surface of weathering steel, and the corrosion cracks and holes of weathering steel are relatively less. There is no difference in local delamination and corrosion products between carbon steel and weathering steel. The main difference between them is the effect of alloy elements in rust layer. Cu and Cr alloy elements precipitate in the rust layer of weathering steel. The precipitated elements can gather at the crack of weathering steel and resist the invasion of water vapor and harmful ions in the atmosphere to prevent further corrosion of weathering steel.

After the surface of weathering steel is rusted, some methods should be used to stabilize the corrosion. It is necessary to suppress the rust from the initial stage of steel to stabilize the weathering steel. It is similar to the general coating in appearance, but the general coating is to block the external air and the outside of the steel to inhibit rust, and the rust stabilization is to promote the stabilization of rust. There is a big difference in function.

Because after the implementation of coating, if the coating deteriorates, it will cause the phenomenon of coating peeling off, thus rust, in order to maintain the beauty, we have to repaint. However, the rust stabilization treatment is to dissolve the skin film slowly, so that the rust produced gradually expands to all, covering the steel surface with a layer of film, and no maintenance is needed.