In industry, the stability and durability of valves, a key component in controlling the flow of fluids, is of paramount importance. Corrosion, a natural phenomenon, but often becomes one of the main causes of valve damage. In order to protect the long-term stable operation of the valve, petroleum, petrochemical and other large enterprises attach great importance to the valve corrosion protection measures. So, how exactly does valve corrosion occur? How to valve corrosion? Selection of corrosion-resistant valves and what is the basis? Let us explore.
Valve corrosion form
Valve corrosion is mainly divided into chemical corrosion and electrochemical corrosion in two forms. Chemical corrosion is the medium does not produce current conditions, direct chemical reaction with the metal, resulting in metal damage. Electrochemical corrosion is the metal and electrolyte contact, resulting in the flow of electrons, so that the metal suffered damage under the electrochemical effect. Common acid and alkali salt solution corrosion, atmospheric corrosion, soil corrosion, seawater corrosion, etc., are electrochemical corrosion.
Valve corrosion rate classification
According to the corrosion rate, we can categorize the corrosion resistance of valves into six grades, ranging from fully corrosion resistant to non-corrosion resistant. Understanding these classes helps us to better assess the corrosion resistance of the valve and take appropriate anti-corrosion measures.
Nine valve anti-corrosion measures
Selection of corrosion-resistant materials according to the corrosive medium: different media have different corrosive properties of the valve, so you need to select the appropriate corrosion-resistant materials according to the nature of the medium, concentration, temperature and pressure and other factors.
The use of non-metallic materials: non-metallic materials have excellent corrosion resistance, suitable for making the valve body, valve cover, lining and other components.
Metal surface treatment: through galvanizing, chromium plating, oxidation and other surface treatment processes to improve the corrosion resistance of the valve connections and sealing surfaces.
Thermal Spraying: Utilizing high energy density heat source to heat and melt metallic or non-metallic materials and spray them onto the valve surface to form a corrosion-resistant coating.
Spray paint: paint is a widely used means of corrosion protection, can isolate the medium and the atmosphere on the valve corrosion.
Add corrosion inhibitors: corrosion inhibitors can promote the polarization of the battery, slowing down the corrosion of the medium on the equipment and valves.
Electrochemical protection: through anodic protection or cathodic protection and other electrochemical methods to prevent the valve from suffering corrosion.
Control of corrosive environment: by controlling the environment and media conditions at the valve installation, slowing down the corrosion rate of the valve.
Improve the processing technology and valve structure: reasonable design and structural improvements to help improve the corrosion resistance of the valve.
For different valve components of the corrosion prevention considerations
Stem corrosion and protection: stem corrosion is mainly caused by the filler, so you need to pay attention to the selection and processing of filler. The use of non-corrosive impurities filler, surface treatment of the valve stem, improve processing finish and other measures can effectively prevent stem corrosion.
Shut-off parts corrosion and protection: shut-off parts are often subject to fluid flushing, easy to accelerate corrosion. Therefore, the need to try to use corrosion-resistant materials, improve the structure of the closure parts, to avoid generating oxygen concentration cells and other measures to prevent corrosion of the closure parts.
In summary, valve corrosion is to ensure the stable operation of industrial equipment is the key. By understanding the form and speed of valve corrosion, taking appropriate anti-corrosion measures and paying attention to the anti-corrosion requirements of different parts, we can effectively extend the service life of the valve and improve the overall performance of industrial equipment.
Valve anti-corrosion: the key to ensure stable operation of industrial equipment
