Analysis of the cause of rusting of stainless steel special screws

Update:29 Jun 2019
Summary:

Many customers say why stainless steel special screws w […]

Many customers say why stainless steel special screws will rust, stainless steel is not omnipotent. For special reasons, it will also rust the screw factory. The reasons are as follows:
A: The surface of the stainless steel contains dust or other metal particles attached to other metal elements. In humid air, the condensed water between the attached material and the stainless steel connects the two into a micro battery, triggering an electrochemical reaction. The protective film is destroyed, which is called electrochemical corrosion.
Second: the surface of the stainless steel adheres to the organic juice (such as melon, noodle soup, glutinous rice, etc.), in the case of water and oxygen, constitutes an organic acid, and the organic acid corrodes the metal surface for a long time.
Three: The surface of the stainless steel adheres to acid, alkali and salt substances (such as alkali water and stone water splashing on the wall), causing local corrosion.
4. In the polluted air (such as the atmosphere containing a large amount of sulfide, carbon oxide, nitrogen oxide), in the case of condensed water, sulfuric acid, nitric acid, acetic acid liquid point is formed, causing chemical corrosion.
Five: There is also a trace element of nickel, such as nickel, which is also a component of stainless steel itself. For example, 304 will definitely have no 316 anti-rust performance. 304 is better than 201's rust resistance.