Corrosion resistance of stainless steel

Hongzhe, a stainless steel precision casting manufacturer, tells us that all metals react with oxygen in the atmosphere to form an oxide film on the surface of the metal. Unfortunately, the iron oxide formed on ordinary carbon steel continues to oxidize, causing the corrosion to expand and eventually forming voids.Paint or oxidation-resistant metals (such as zinc, nickel, and chromium) can be used for electroplating to ensure the surface of carbon steel, but as known, this protection is only a thin film. Once the protective layer is destroyed, the steel underneath will rust.

Stainless steel precision castingThe corrosion resistance of chromium is determined by chromium, but because chromium is one of the components of steel, its protection methods are also different.

When the amount of chromium added reachesAt 10.5%, the atmospheric corrosion resistance of steel is significantly improved, and when the chromium content is higher, the corrosion resistance is improved but not obvious. This is because when the steel is alloyed, the type of surface oxide will change, forming a metal surface oxide similar to that of pure chromium. The clinging chromium oxides protect the surface and prevent further oxidation. This is a very thin oxide layer, through which you can see the natural luster of steel, which makes stainless steel precision casting have a unique surface. In addition, if the surface layer is damaged, the exposed steel surface will repair itself and react with the atmosphere to re-form an oxide "passivation film" to continue to protect the metal.

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