What Would Cause Stainless Steel To Rust?

What Would Cause Stainless Steel To Rust?

 When brown rust spots (spots) appear on the surface of stainless steel pipes, people are surprised: “Stainless steel does not rust, and rust is not stainless steel. It may be that there is a problem with the steel.” In fact, this is a one-sided misconception about the lack of understanding of stainless steel. Stainless steel can also rust under certain conditions. Stainless steel can resist atmospheric oxidation-that is, non-rust, and it also can resist corrosion in media containing acid, alkali, and salt-that is corrosion resistance. However, the size of its corrosion resistance varies with the chemical composition of the steel itself, the state of addiction, the conditions of use, and the type of environmental media. For example, 304 steel pipe has excellent anti-corrosion ability in a dry and clean atmosphere. However, if it is moved to a coastal area, it will quickly rust in sea fog containing a lot of salt; while 316 steel pipe has performance. good. Therefore, not any kind of stainless steel can resist corrosion and rust in any environment.


Stainless steel relies on a very thin, strong, dense, and stable chromium-rich oxide film (protective film) formed on its surface to prevent oxygen atoms from continuing to penetrate and continue to oxidize, thereby obtaining the ability to resist rust. Once this film is continuously destroyed for some reason, oxygen atoms in the air or liquid will continue to infiltrate or iron atoms in the metal will continue to separate, forming loose iron oxide, and the metal surface will continue to be rusted.

Keep reading: A complete guide to AISI 303 Stainless Steel  

AISI 304; AISI  301; AISI 316;AISI 316L…