The principle of stainless steel anti-rust property

All metal contact oxygen and react with it, to form oxide film on metal surface. Unfortunately, ferric oxide on common carbon steel surface keeps going on oxidizing and enlarge the area of rust, finally the rusted hole come out. Paint and metal film with anti-corrosion property can be used to protect carbon steel surface, such as Zinc, Nickel, Chromium. This kind of film is very thin, and steel will get rusted again if it is damaged.

The stainless steel anti-rust property is determined by Chromium component. The protect method is various in different metal.

When the Chromium component is 10.5%, the anti-corrosion to air increase obviously. But if Chromium percentage increase, the property will be a little better but not obvious. For when use Chromium to proceed alloying for steel, the oxide film change into the one on pure Chromium. This kind of oxide film is attached very closely on metal surface and rich of Chromium. The film is very thin, the natural silver can be seen through it and make stainless steel with unique surface. And even if the oxide film is damaged, the exposed stainless steel surface can react with air and repair itself. Passive film can be formed again to protect surface.

Above all, all stainless steel have one same characteristic, which is Chromium component is above 10.5%.