SPA-H Steel weathering refers to the chemical composition of these steels, allowing them to exhibit increased resistance to atmospheric corrosion compared to other steels. This is because the steel forms a protective layer on its surface under the influence of the weather.
The corrosion retarding effect of the protective layer is produced by the particular distribution and concentration of alloying elements in it. As a result, the layer protecting the surface develops and regenerates continuously when subjected to the influence of the weather. In other words, the steel rusts to form the protective coating.

SPA-H steel material can be produced as SPA-H steel plate, SPA-H steel sheet, SPA-H steel bar, SSPA-H section steel, SPA-H structural shapes. SPA-A steel all made of carbon steel and copper, nickel, phosphorus and other chemical elements.

 JIS G3125 SPA-H Corten Steel Weathering Plate. It is a high phosphorous structural weathering steel with a minimum yield strength of 350MPa.

The content of these chemical elements, only a few percent. Because different alloying elements, weather resisting steel has better mechanical properties, as well as greater corrosion resistance. Thus, SPA-A steel used for marine containers, container, bridges, and train tracks.