As we all know, the corrosion damage of metal has a considerable impact on the life, reliability and service life of the valve. The effect of mechanical and corrosive factors on metals greatly increases the total wear on the contact surface. The total amount of wear on the friction surface of the valve during operation. During the operation of the valve, the frictional surface is worn and damaged due to the simultaneous mechanical action and the chemical or electrochemical interaction between the metal and the environment. For valves, the climatic conditions of their pipelines are complicated; the presence of hydrogen sulfide, carbon dioxide and certain organic acids in media such as oil, natural gas, and oil layer water increases the destructive power of the metal surface, thereby quickly losing its ability to work.
Corrosion of the valve is usually understood as the damage to the metal material of the valve under the action of a chemical or electrochemical environment. As the corrosion phenomenon occurs in the spontaneous interaction between the metal and the surrounding environment, how to isolate the metal from the surrounding environment or use more non-metallic synthetic materials has become a common concern.
Because the chemical corrosion of metals depends on the temperature, the mechanical load of the friction parts, the sulfide contained in the lubricating material and the stability of its acid resistance, the duration of contact with the medium, and the catalytic effect of the metal on the nitriding process, corrosion and erosion The conversion speed of the molecules of the substance to the metal, etc. Therefore, the anti-corrosion methods (or measures) of metal valves and the application of synthetic material valves have become one of the themes of current research in the valve industry.
The anti-corrosion of metal valves can be understood as coating the metal valve with a protective layer (such as paint, pigment, lubricating material, etc.) that protects it from corrosion, so that the valve can be manufactured, stored, transported or used. No corrosion during the whole process. The anti-corrosion method of metal valves depends on the required protection period, transportation and storage conditions, valve structure characteristics and materials. Of course, it is suitable to consider the economic effect of removing anti-corrosion.
There are four main methods for preventing corrosion of metal valves and their parts:
1. Put the volatile corrosion inhibitor into the steam atmosphere (wrap it with barrier paper, blow to inhibit air from passing through the product chamber, etc.).
2. Use blocked water and alcohol solution.
3. Apply a thin layer of anti-corrosion (protective) material to the surface of the valve and its parts.
4. Coat the blocked film or polymer thin layer on the surface of the valve and its parts.