When it comes to stainless steel valves, everyone's most direct intuition is that stainless steel valves will never rust, and they think that if we buy a stainless steel valve with rust, it must be stainless steel. In actual fact, stainless steel will also rust under certain conditions. Stainless steel has the ability to resist atmospheric oxidation, ie, stainless, but also has the ability to resist corrosion in media containing acids, alkalis, and salts, ie, corrosion resistance. However, the corrosion resistance of stainless steel varies with the chemical composition of the steel itself, the environmental conditions, and the type of media used. Such as stainless steel 304 valve, in the dry and clean atmosphere, there is absolutely excellent resistance to corrosion, but moved it to the sea area, in the sea fog with a lot of salt, will quickly rust, 316 valve It is good. Therefore, not any kind of stainless steel can resist corrosion and rust in any environment. Why do stainless steel valves rust? Next, let us analyze the reasons. The surface of the stainless steel valve is a thin, strong, and stable chromium-rich oxide film that prevents oxygen atoms from continuing to infiltrate and oxidize to obtain the ability to resist rust. Once this kind of film is destroyed by certain factors, the oxygen atoms in the air or liquid will continuously infiltrate or the iron atoms in the metal will continue to separate out, and then the loose iron oxide will be formed, and the metal surface will be continuously rusted. Therefore, stainless steel will also rust.

What is the reason for the destruction of the film on the surface of stainless steel? Here we give an example:

1, electrochemical corrosion. The surface of the stainless steel valve contains deposits of dust or other metal particles containing other metal elements. In humid air, the condensate between the attachment and stainless steel connects the two into a microbattery, which triggers an electrochemical reaction. The protective film is damaged.

2. The surface of the stainless steel valve adheres to the organic matter sap. In the case of water and oxygen, organic acids are formed, and organic acids attack the metal surface for a long time.

3, stainless steel valve surface adhesion contains acid, alkali, salt, will cause local corrosion.

4. In contaminated air (such as an atmosphere containing a large amount of sulfides, carbon oxides, and nitrogen oxides), condensed water is formed and sulfuric acid, nitric acid, and acetic acid liquids are formed, causing chemical corrosion.

The above conditions can cause the destruction of the stainless steel surface protective film to cause rust.

To avoid stainless steel rusting, please note the following:

1. The surface of stainless steel valves should be cleaned and scrubbed regularly to remove attachments and eliminate external factors that cause corrosion.

2, the use of 316,316L stainless steel material in the waterfront, 316,316L material can resist seawater corrosion.

3. The chemical composition of some stainless steel valves in the market can not meet the corresponding national standards and reach the material requirements of 304, so it will also cause rust, which requires the user to seriously choose products with reputable manufacturers.