What is stainless steel? In many people’s understanding, “stainless steel” is steel that will not rust, but many customers produce rust spots when brown rust spots (spots) appear on the surface of stainless steel valves. What is the reason? Stainless steel valves have the ability to resist atmospheric oxidation-that is, stainless, but also have the ability to corrode in the medium containing acid, alkali, salt-that is, corrosion resistance. However, the size of its anti-corrosion ability changes with the chemical composition of the steel itself, the mutual state, the use conditions and the type of environmental medium. Such as 304 steel pipe, in the dry and clean atmosphere, it has absolutely excellent anti-corrosion ability, but when it is moved to the seaside area, it will soon rust in the sea fog containing a lot of salt; and 316 steel pipe shows good. Therefore, it is not any kind of stainless steel, which is resistant to corrosion and rust in any environment.
The stainless steel valve is based on an extremely thin, strong, dense and stable chromium-rich oxide film (protective film) formed on its surface to prevent the infiltration and oxidation of oxygen atoms from continuing to obtain the ability to resist rust. Once for some reason, this film is continuously destroyed, oxygen atoms in the air or liquid will continue to infiltrate or the iron atoms in the metal will continue to separate out, forming loose iron oxide, and the metal surface will be continuously rusted. There are many forms of damage to this surface film,
There are several types of stainless steel valves that are common in daily life:
1. The surface of the stainless steel valve accumulates dust or other metal particles containing other metal elements. In humid air, the condensate between the attachment and the stainless steel connects the two into a micro battery, which initiates electrochemistry Reaction, the protective film is damaged, called electrochemical corrosion.
2. Organic matter juice (such as melon and vegetable, noodle soup, sputum, etc.) adheres to the surface of the stainless steel valve. In the presence of water and oxygen, it forms an organic acid, and the organic acid will corrode the metal surface for a long time.
3. The surface of the stainless steel valve contains acid, alkali and salt substances (such as alkali water and stone water splashing on the wall decoration), causing local corrosion.
4. In contaminated air (such as an atmosphere containing a large amount of sulfides, carbon oxides, and nitrogen oxides), condensed water will form sulfuric acid, nitric acid, and acetic acid liquid spots, causing chemical corrosion. The above conditions can cause the damage of the stainless steel surface protective film and cause rust.
Therefore, in order to ensure that the metal surface is permanently bright and not rusted, we recommend:
1. The surface of the decorative stainless steel valve must be cleaned and scrubbed frequently to remove attachments and eliminate external factors that cause modification.
2. The 316 stainless steel valve should be used in the seaside area. The 316 material can resist seawater corrosion.
3. The chemical composition of some stainless steel pipes on the market can not meet the corresponding national standards, and can not meet the requirements of 304 materials. Therefore, it will also cause rust, which requires users to carefully select products from reputable manufacturers. Construction and construction points of attention In order to prevent scratches and adhesion of pollutants during construction, stainless steel valves are constructed in the state of film. However, with the extension of time, the residue of the paste solution is in accordance with the use period of the film. After removing the film after construction, the surface should be washed, and special stainless steel tools should be used. When cleaning common tools with general steel, it should be cleaned in order to prevent the adhesion of iron filings. . Care should be taken not to allow the highly corrosive magnetism and stone luxury cleaning drugs to contact the stainless steel surface. If they are in contact, they should be washed immediately. After the construction is completed, use neutral detergent and water to wash the cement, fly ash, etc. attached to the surface.
In summary, stainless steel valves will not be completely rust-proof, and will still rust under certain conditions. We must install, maintain, and repair stainless steel valves in strict accordance with the requirements, and try to control the rust phenomenon of stainless steel valves under certain conditions.
Post time: May-02-2020