Weathering steel is different from ordinary steel

Weathering steel is suitable for outdoor building structures, landscapes, sculptures, curtain walls, and modeling. It does not require any coating, and can be used outdoors for a long time with its own performance. Its corrosion resistance is 5-8 times that of ordinary carbon steel, and the price less than 1/3 higher. The corrosion resistance of weathering steel and the need for no coating are combined with the concept of green environmental protection and saving. It is deeply loved by designers and engineers, and many steels in corrosive environments are gradually replaced by weathering steels, keeping pace with the times.

Weathering steel is different from ordinary steel, in the beginning, it will rust on the surface like ordinary steel. This process is even faster than normal steel due to its higher degree of alloying. However, due to the more complex lattice inside the weathering steel, a dark black dense rust layer will grow under the loose rust on the surface. This rust layer consists of nanoparticles of α-FeOOH. In this dense rust layer, nickel atoms replace some of the positions of iron atoms, which makes the rust layer have cation selectivity and inhibits the permeation of corrosive anions.

It is this dense rust layer that makes the weathering steel rust on the surface, but the interior will not continue to be rusted. In fact, as long as you distinguish carefully, you can see that the surface of weathering steel is not the same as ordinary rust: the rust of weathering steel is uniform and dense, and it is close to the surface of the steel to protect the steel; while the rust is mottled, loose and porous, It will fall off when touched.