Why not easy to corrode stainless steel pipe?
All metal and atmospheric oxygen in the reaction, formed in the surface oxide film. Unfortunately, in the ordinary carbon steel pipe on the formation of the oxidation iron oxide continue, kept expanding rust, eventually forming holes. Can use paint or resistant to oxidation of the metal (for example, zinc, chromium and nickel) on plating to ensure that the carbon steel pipe surface, however, as we know, the protection is only a thin film. If the cover was damaged, the following steel began to rust.
Corrosion resistance of stainless steel pipe depends on chrome, but because of the chromium is one part of the steel, so the protection method is not the same.
In the chromium content reaches 10.5%, atmospheric corrosion resistance of steel increased significantly, but the chromium content is higher, although still can raise corrosion resistance, but not obvious. Reason is that with chromium alloying of steel pipe processing, change the type of surface oxide became similar to that of pure chromium oxide is formed on the metal surface. This tight adhesion of the surface of the rich chromium oxide protection, to prevent further oxidation. This kind of extremely thin oxide layer, you can see on the surface of the steel pipe through natural luster, make the surface of the stainless steel pipe has a unique. And, if damaged surface, the exposed surface of the steel pipe and atmospheric response to repair itself, to form the oxide “passivation membrane, ” continued protection.
Therefore, all stainless steel pipe elements have a common characteristic, namely the chromium content in more than 10.5%.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)