Reasons for the rust of hardware shrapnel
When brown rust spots appear on the surface of the hardware shrapnel, many people will feel surprised that: stainless steel does not rust, and the rust is not stainless steel. It may be that there is a problem with the steel. Originally stainless steel will rust under certain conditions.
The raw material of shrapnel metal stamping parts has the strength to resist atmospheric oxidation, which is called stainless. It also has the ability to corrode in media containing acid, alkali, and salt—that is, corrosion resistance. However, the strength of corrosion resistance varies with its own steel chemical composition, processing form, application conditions and environmental media types. For example, 304, in a dry and clean atmosphere, the anti-corrosion strength is very good, if it is moved to the seaside area, it will quickly rust in the sea fog with a lot of salt; while 316 is excellent . Therefore, it is not any kind of stainless steel, which can resist corrosion and rust in any environment.
Shrapnel metal stamping parts are made of a very thin, firm and thorough and stable chromium-rich oxide film (protective film) created on the surface of the raw material to prevent oxygen atoms from continuing to penetrate and continue to oxidize, thereby achieving the function of anti-corrosion. Once this protective film is constantly attacked by a certain substance, oxygen atoms in the air or liquid will continuously penetrate or iron atoms in the metal will continuously separate out, resulting in loose iron oxide, and the metal surface will also be continuously affected. Rust. There are many modes of damage to the surface film, such as dust, metal particles, and organic liquid adhesion.