What kind of paint is generally used for gate valves?
Corrosion is one of the main causes of gate valve damage. Industrial valve anti-corrosion coating can play a good role in protecting the substrate. Damage to parts caused by rust has virtually become a huge cost. Paint anti-corrosion protection is currently more effective one of the measures.
The protective effect of the surface paint coating on the gate valve is based on the following three aspects:
1. Shielding effect
After coating the surface of the gate valve, relatively speaking, the metal surface is separated from the environment. This protective effect can be called a shielding effect. But a thin layer of paint cannot provide absolute shielding. Because polymers have a certain degree of air permeability, they can pass freely when the coating is very thin. It can be seen that for many coatings, the value is greater than the surface of the gate valve without coating. In order to improve the impermeability of the coating, the anti-corrosion coating should use film-forming substances with low air permeability and solid fillers with large shielding properties. At the same time, the number of coating layers should be increased to make the coating reach a certain thickness and be dense and non-porous.
2. Corrosion inhibition
The internal components of the paint react with the metal of the gate valve internals to passivate the metal surface or generate protective substances to improve the protective effect of the coating. Pay attention to the paint composition to avoid serious adverse effects.
3. Electrochemical protection
When the dielectric penetration coating contacts the metal surface, electrochemical corrosion under the film will be formed. Use metals with higher activity than iron as fillers in coatings, such as zinc. It will play the role of sacrificial anode protection, and the corrosion products of zinc are basic zinc chloride and zinc carbonate, which will fill the gaps of the film, make the film tight, and greatly reduce the corrosion, and extend the service life of the gate valve.
The casting surface of the gate valve is suitable for most paints, but special attention should be paid to the use of paint on the cutting surface. The cutting surface is very smooth, and the adhesion of many paints cannot achieve the desired effect. It is prone to peeling and paint peeling problems, which cannot provide good The anti-corrosion protection effect.
Epoxy primer is an anti-corrosive paint product with excellent adhesion. It is especially suitable for coating the cutting surface of gate valves. It can ensure excellent adhesion. The paint film is firmly bonded to the substrate, and the adhesion is very strong. In terms of adhesion Compared with ordinary paint, it has great advantages.
Epoxy primer not only has excellent adhesion performance, but also does not require sandblasting or sanding on the surface of the gate valve. You can use a solvent to wipe to remove oily grease, which saves time and effort; the paint film has very good salt spray resistance and has a significant anti-corrosion effect; It can be matched with various topcoats, such as fluorocarbon topcoat, acrylic polyurethane topcoat, epoxy topcoat, etc.