Treatment of valve body rust
With the advancement of technology, more and more high-parameter chaotic working conditions, such as high temperature, high pressure, deep cooling, high vacuum, strong corrosion, radioactivity, flammability and explosion, are produced in industry. Then, more and more stringent demands are put forward on safety, durability and service life of valves in Chongqing.
"Corrosion" occurs in the spontaneous interaction between metal and its surroundings. How to isolate metal from the surroundings or use more non-metallic synthetic materials is the focus of corrosion protection. Corrosion of valves is generally understood as damage to the valve metal material under chemical or electrochemical conditions.
Corrosion of Chongqing valve body can take two forms, 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. Corrosion rates can be divided into six categories:
- Complete corrosion resistance: corrosion rate is less than 0.001 mm/year;
- Corrosion resistance: corrosion rate 0.001 to 0.01 mm/year;
- Corrosion resistance: corrosion rate 0.01 to 0.1 mm/year;
- Corrosion resistance: corrosion rate 0.1 to 1.0 mm/year;
- Poor corrosion resistance: corrosion rate 1.0 to 10 mm/year;
- No corrosion resistance: the corrosion rate is more than 10 mm/year.
Secondly, lining measures are taken, such as lead lining, aluminium lining, engineering plastic lining, natural rubber lining and various synthetic rubber lining. This is a cost-effective method, if media conditions permit.
Third, under the condition of low pressure and temperature, non-metal is often used as the main material to prevent corrosion effectively.
In addition, the valve body surface is subject to atmospheric corrosion, and generally steel materials are painted to protect it.
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