Why is stainless steel stainless and corrosion resistant?
Time:
Nov 13,2023
Stainless steel has the ability to resist atmospheric oxidation, that is, rust resistance, and it also has the ability to resist corrosion in media containing acids,
Stainless steel has the ability to resist atmospheric oxidation, that is, rust resistance, and it also has the ability to resist corrosion in media containing acids, alkalis, and salts, that is, corrosion resistance.The corrosion resistance of stainless steel depends on the content of chromium. When the amount of chromium added reaches 12.5%, its resistance to atmospheric corrosion increases significantly. In oxidizing media, chromium can quickly form a layer of chromium-rich oxide film on the surface of steel that the corrosive medium cannot pass through and does not dissolve. This layer of oxide film is very dense.And it is very firmly combined with the metal body. This tightly attached chromium-rich oxide can protect the surface and prevent further oxidation. If the surface layer is damaged, the exposed steel surface will react with the atmosphere to repair itself, re-forming this “passivation film” and continuing to play a protective role.This oxide layer is extremely thin, and the natural luster of the steel surface can be seen through it, giving stainless steel a unique surface.Moreover, chromium can effectively increase the electrode potential of steel.When the chromium content is not less than 12,5%, the electrode potential of the steel can be mutated, from the negative potential to the positive electrode potential, which can significantly improve the corrosion resistance of the steel.The higher the chromium content, the better the corrosion resistance of steel.When the chromium content reaches 25%, 37,5%, the second and third mutations will occur, making the steel have higher corrosion resistance.
Key words:
Finishing of aluminum forgings
2023-07-25
Application of aluminum alloy forgings in electric power industry
2023-07-25
How to distinguish between stainless steel screws, galvanized and nickel-plated screws?
2023-11-13