For 316 stainless steel, it is not that it will never rust during use. This applies to stainless steel pipes of any material. Nowadays, the two most commonly used stainless steel pipes are 304 stainless steel and 316 stainless steel, and 316 stainless steel has better corrosion resistance.
But in a concentrated sulfuric acid environment, 316 stainless steel will also rust. 316 stainless steel is formed by a very thin and dense chromium-rich oxide film (protective film) formed on its surface to prevent oxygen atoms from continuously entering and continuing to oxidize, and to obtain anti-corrosion ability. Once there is a certain reason, this kind of film is continuously damaged, the oxygen atoms in the air or liquid will continuously separate out, forming loose iron oxide, and the metal surface will be continuously rusted.
