Pneumatic stainless steel butterfly valve under certain conditions will rust
The pneumatic stainless steel butterfly valve has the characteristics of resistance to atmospheric oxidation, wear resistance and corrosion resistance because of the stainless steel material. Through a thin and solid stable chromium-rich oxide film ( protective film ) formed on its surface, the ability to resist corrosion is obtained by preventing the infiltration of oxygen atoms from causing oxidation hardening. These characteristics can fully reflect the advantages of stainless steel, but in some special environmental media, rust may still occur.
The corrosion resistance of stainless steel varies with the chemical composition of the steel itself, the state of addition, the conditions of use and the type of environmental media. Such as 304 steel pipe, in the dry and clean atmosphere, has excellent corrosion resistance ; but in the coastal area, 316 steel pipe performs better. Therefore, once the film is constantly destroyed, the oxygen atoms in the air or liquid will continue to penetrate or the iron atoms in the metal will continue to separate out, forming a loose iron oxide, so the stainless steel material on the surface of the pneumatic butterfly valve will be continuously corroded. As a result, the valve body structure is deformed, the sealing performance is reduced, and the pneumatic butterfly valve cannot operate normally.
Stainless steel material in different cases, the surface film is damaged in many forms : such as electrochemical corrosion, chemical corrosion, in the presence of water and oxygen, constitute organic acids, stainless steel surface adhesion contains acid, alkali, salt substances and so on. In order to ensure that the metal surface is bright for a long time and not rusted, it is necessary to effectively prevent the oxidation of the stainless steel surface. The surface of stainless steel must be cleaned and scrubbed regularly to remove attachments and eliminate external factors that cause modification. It is also necessary to pay attention to whether the chemical composition of stainless steel tubes meets the corresponding national standards, and to consider the working environment and use.
