Why Do Small Stainless Steel Screws Rust?

The small stainless steel screws of the M1-M3 are generally used for fastening on precision instruments. Some people think that the small screws are made of stainless steel and you don’t have to worry about rust. SHI SHI TONG screw manufacturers tell you that this idea is wrong. No screw manufacturer can guarantee that the small screws produced by stainless steel can never rust.

So why do small stainless steel screws rust? Stainless steel does not necessarily rust, but it is much less corrosive than other steels in the same environment, and sometimes even negligible. Stainless steel screws made of 304 have absolutely excellent rust resistance in a dry and clean atmosphere, but if they are moved to coastal areas, they may rust in sea fog containing a lot of salt. It can also cause rust when the surface film of stainless steel screws is damaged:

★The surface of stainless steel contains dust or other metal particles attached to other metal elements. In humid air, the condensate between the deposit and the stainless steel connects the two into a microbattery, triggering an electrochemical reaction. The protective film is destroyed, which is called electrochemical corrosion.

★The surface of the stainless steel adheres to the organic juice (face soup, melon, etc.) and forms an organic acid in the presence of water and oxygen. The organic acid corrodes the metal surface for a long time.

★ Condensed water is encountered in the polluted air, causing chemical corrosion caused by the formation of sulfuric acid, nitric acid and acetic acid.

★Mechanical abrasives are things that will scratch the metal surface. For example: steel rub, metal wire brush, metal fragments, etc.

★ Corrosive liquid (bleach, etc.) is attached to the surface of small stainless steel screws.

These five kinds are common cases that cause the small stainless steel screws to rust. If you want to know more about screws, please contact us: sst@szsst88.com