All metals react with oxygen in the atmosphere to form an oxide film on the surface. Unfortunately, the iron oxide formed on ordinary carbon steel continues to oxidize, causing the corrosion to continue to expand, eventually forming holes. The surface of carbon steel can be guaranteed by electroplating paint or oxidation-resistant metals (such as zinc, nickel, chromium), but as people know, this kind of protection is just a thin film. If the protective layer is damaged, the steel underneath will begin to rust.

The corrosion resistance of Guangdong stainless steel casting depends on chromium, but because chromium is a part of steel, the protection method is different.

When the chromium content reaches 10.5%, the atmospheric corrosion resistance of the steel is significantly improved, but when the chromium content is higher, the corrosion resistance can still be improved, but it is not obvious. The reason is that when steel is alloyed with chromium, the type of surface oxide becomes similar to that formed by pure chromium metal. This closely adhered chromium-rich oxide protects the surface and prevents further oxidation. This kind of oxide layer is very thin, you can see the natural luster of the steel surface, so that Guangdong stainless steel casting has a unique surface. In addition, if the surface is damaged, the exposed steel surface will react with the atmosphere to repair itself, re-form the oxide "passivation film", and continue to play a protective role.

Therefore, all Guangdong stainless steel casting elements have a common feature, that is, the chromium content is above 10.5%.