How to deal with valve corrosion

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This post was last edited by yuchenchf on 2017-8-5 at 15:58. With the advancement of technology, the products in the valve industry are constantly evolving to meet the growing demands of industry. In the industrial sector, fluid media are increasingly exposed to conditions such as high temperatures, high pressures, extreme cold, severe corrosion, and flammability. This makes the corrosion problem of valves increasingly severe, making corrosion protection for valves all the more important. 　　The corrosion of valves is generally understood as the degradation of the valve’s metal materials under chemical or electrochemical conditions. 　　The corrosion of valve bodies takes two forms: chemical corrosion and electrochemical corrosion. Its corrosion rate is determined by the temperature, pressure, and chemical properties of the medium, as well as the corrosion resistance of the valve body material. Corrosion grades can be divided into six categories: 1. Completely corrosion-resistant: corrosion rate is below 0.001 millimeters per year ； 　　2. Extremely corrosion-resistant: corrosion rate of 0.001 to 0.01 millimeters per year ； 　　3. Corrosion resistance: Corrosion rate of 0.01 to 0.1 millimeters per year ； 　　4. Good corrosion resistance: corrosion rate of 0.1 to 1.0 millimeters per year ； 　　5. Poor corrosion resistance: corrosion rate of 1.0 to 10 millimeters per year ； 　　6. Poor corrosion resistance: corrosion rate greater than 10 mm/year. 　　The corrosion protection of valves needs to be determined by taking various factors into consideration; it cannot be based on just one factor alone. So, what are the methods to prevent valve body corrosion? 　　I. Choose the right materials. The difficulty in selecting valve body materials lies in the fact that one cannot consider only corrosion issues; factors such as pressure and temperature resistance, economic viability, and ease of procurement must also be taken into account. 　　Second, lining measures can be adopted, such as lining with lead, aluminum, engineering plastics, natural rubber, and various synthetic rubbers. If the medium conditions permit, it is indeed a cost-saving method. 　　III. Under conditions of low pressure and temperature, using non-metals as the material for the valve body can often effectively prevent corrosion. 　　IV. The outer surface of the valve body is also subject to atmospheric corrosion; generally, steel materials are protected by painting. 　　 If anyone has other opinions on preventing valve corrosion, feel free to discuss them.