Why Do Stainless Steel Bolts Rust?

 Has anyone ever encountered such a situation, when decorating, the stainless steel bolts that were specially used for aesthetics and anti-rust were originally thought of once and for all, but they still did not escape the claws of rust, which is really annoying. When I think about the guarantee that the owner of the hardware store swore when I bought it, it adds fuel to the fire, and I can't wait to come to the door to discuss it immediately!

wait, let me explain

In fact, stainless steel bolts are not rust-free, but they are not easy to rust. Under certain conditions, stainless steel bolts can also get rusty.

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The surface of stainless steel bolts has a very thin, firm, dense and stable chromium-rich oxide film, which is also one of the characteristics of stainless steel. The reason why stainless steel bolts are rust-resistant is that this layer of oxide film prevents oxygen atoms from penetrating into oxidation reactions that lead to rust. rust. When the oxide film is damaged, it is easy to rust.

You need to pay attention to the following situations:

1) The environment where stainless steel bolts are located is humid. In the presence of water and oxygen, organic acids are formed to corrode and damage the surface of stainless steel bolts.

2) The stainless steel bolts are mechanically damaged by the installation tool during installation and damage the surface protective film. For example, when stainless steel bolts are installed in an outdoor curtain wall project, the wrench will cause mechanical damage to the place where the bolt head contacts. After washing by rain, the stainless steel bolt head will appear slight floating rust.

3) There are dust impurities or metal particles on the surface of stainless steel bolts, which are prone to electrochemical reactions with stainless steel in humid air and accelerate the corrosion of stainless steel.

4) The surface of stainless steel bolts is easily corroded by chemical reactions when exposed to acids, alkalis, salts and other substances. For example, 316 stainless steel products (more corrosion-resistant than 304 stainless steel) are generally selected for curtain wall connection fasteners in coastal cities, because the high salt content in the air in coastal cities easily corrodes stainless steel.

Therefore, in order to keep the stainless steel bolts bright and not corroded, it is necessary to choose the stainless steel bolts of the correct material. The second is to clean and maintain the stainless steel bolts to remove surface impurities to avoid reaction and corrosion.