1. Composition of chemical elements
Strictly speaking, 201 stainless steel Vibration Finish Stainless Steel Sheet should be called stainless iron. Its chemical element composition is very different from 301, 304 and other stainless steels, and its chromium content is much lower. The reason why stainless steel is not rusted depends on the formation of a very thin, firm and dense chromium-rich oxide film on the surface. Obviously, this film of 201 stainless steel Vibration Finish Stainless Steel Sheet is not as good as 301 or 304. If there is some factor that damages this layer of film, the damaged part will contact with the outside, react to form iron oxide, and continue to rust.
2. Rinsing process
201 stainless steel Vibration Finish Stainless Steel Sheet did not rust after cleaning, but gradually rusted after a period of time. In many cases, it appeared in the rinsing process of cleaning. Many hardware manufacturers are more subjective in the process of cleaning products. They only pay attention to whether the oil stains are cleaned up, and only roughly one or two rinses are carried out in the rinsing process. If there is no residue on the naked eye, it is considered that the cleaning is completed. Actually this is incorrect. General stainless steel cleaning agents are alkaline. If the rinsing is not thorough, the alkaline components in the cleaning agent will remain on the surface of the workpiece in the form of micro-particles. There will be no rust when the cleaning is completed, and the naked eye observation is quite perfect. However, after 3-10 days of storage, these alkaline components completely destroy the protective film layer of 201, and rust spots appear.
3. Acidity and alkalinity of cleaning agent
If the cleaning agent contains acidic components, the entire 201 protective film layer will be damaged or become uneven and intermittently cracked. Therefore, oxidation and rusting occur after cleaning, and rust occurs in the form of whole flakes, partial rust, or after short-term storage.
4. Rinse residue
Why does it still rust even if the cleaning agent is neutral? I believe this will only happen after a period of storage. This is also a problem with rinse residue. The water-based cleaning agent is mainly based on organic matter, and the residual organic matter is adsorbed on the workpiece. After that, the organic attachment can condense the moisture in the air together, and then also adsorb the sulfide, carbide, nitride, etc. in the air. A galvanic battery environment is formed, and the protective film will be damaged, resulting in electrochemical corrosion and rust.