What is corrosion of butterfly valves?
Corrosion of butterfly valves is usually understood as the damage of the metal material of the valve under the action of chemical or electrochemical environment. Since the phenomenon of “corrosion” occurs in the spontaneous interaction between metal and the surrounding environment, how to isolate the metal from the surrounding environment or use more non-metallic synthetic materials is the focus of corrosion prevention. The body of the butterfly valve (including the valve cover) occupies most of the weight of the valve and is in frequent contact with the medium, so the butterfly valve is often selected from the body material.
There are only two forms of valve body corrosion of butterfly valves, namely chemical corrosion and electrochemical corrosion. Its corrosion rate is determined by the temperature, pressure, chemical properties of the medium, and the corrosion resistance of the valve body material. The corrosion rate can be divided into six levels:
1. Complete corrosion resistance: the corrosion rate is less than 0.001 mm/year;
2. Extremely corrosion resistance: corrosion rate 0.001-0.01 mm/year;
3. Corrosion resistance: corrosion rate 0.01-0.1 mm/year;
4. High corrosion resistance: corrosion rate 0.1-1.0 mm/year;
5. Poor corrosion resistance: corrosion rate 1.0-10 mm/year;
6. Non-corrosion resistance: the corrosion rate is greater than 10 mm/year.
How to prevent corrosion of butterfly valves?
The anti-corrosion of the valve body of the butterfly valve is mainly due to the correct selection of materials. Although the information on anti-corrosion is very rich, it is not easy to choose the right one, because the problem of corrosion is very complex, for example, sulfuric acid is very corrosive to steel when the concentration is low, and when the concentration is high, it makes the steel produce a passivation film, which can prevent corrosion; Hydrogen is only shown to be very corrosive to steel at high temperature and pressure, and the corrosion performance of chlorine gas is not large when it is dry, but the corrosion performance is very strong when there is a certain humidity, and many materials cannot be used. The difficulty of choosing valve body materials is that we cannot only consider corrosion problems, but also consider factors such as pressure and temperature resistance, whether it is economically reasonable, and whether it is easy to purchase. So you have to be attentive.
1. The second is to take lining measures, such as lead, aluminum, engineering plastics, natural rubber and various synthetic rubber. If the medium conditions permit, this is a saving method.
2. Thirdly, when the pressure and temperature are not high, the main material of the fluorine-lined butterfly valve can often be very effective in preventing corrosion.
3. In addition, the outer surface of the valve body is also corroded by the atmosphere, and the ductile iron material is generally protected by nickel plating.
TWS will soon launch a new anti-corrosion product line, covering a full range of valve solutions such as butterfly valves, gate valves, check valves and ball valves, etc. This series of products adopts advanced corrosion resistance technology and special material treatment processes to maintain excellent sealing performance and operational stability under extreme working conditions. We are committed to providing customers with durable industrial valve products, significantly extending the service life of equipment, reducing maintenance costs throughout the lifespan cycle, and helping customers achieve higher value purchasing decisions.
Post time: Aug-04-2025
