Will Stainless Steel Pipe Rust (Part One)?

We will firstly talk about why stainless steel pipe fittings is not easy to rust, then explaining why stainless steel will rust.

Stainless steel is not easy to rust, which is closely related to its composition. Besides iron, stainless steel also contains chromium, nickel, aluminum, silicon and so on. Chromium content in general stainless steel is generally not less than 12%, and even as high as 18%. After adding chromium and other elements into steel, the properties of steel can be changed. For example, the molecular structure of steel is more uniform, and it is easier to form a dense oxide protective film on the surface of steel, thus greatly improving the corrosion resistance of stainless steel. Therefore, stainless steel can resist the corrosion of fire, water, acid, alkali and various solutions without rusting. Scientists have found that the more uniform the internal structure of steel is, the closer the various components are connected, and the more difficult it is for corrosive to invade. In addition, a layer of oxide protective film is attached to the surface, just like putting armor on steel, so it is naturally not easy to rust.

Why does stainless steel rust? When brown rust spots appear on the surface of stainless steel pipes, people are greatly surprised, because they think that "stainless steel does not rust. If rust, it is not the right type, and there may be a problem with steel material". In fact, this is a one-sided wrong view of the lack of understanding of stainless steel. Atcutally, stainless steel will rust under certain conditions.

Stainless steel has the ability to resist atmospheric oxidation—that is, stainless property, which has the ability to resist corrosion in the medium containing acid, alkali and salt, namely, corrosion resistance. However, its anti-corrosion ability varies with the chemical composition of steel, the state of mutual addition, service conditions and the type of environmental medium. For example, 304 steel pipe has absolutely excellent corrosion resistance in dry and clean atmosphere, but when it is moved to coastal areas, it will soon rust in sea fog containing a lot of salt; while 316 steel pipe has a good performance. Therefore, not any kind of stainless steel can resist corrosion or rust in any environment.