The non-metal protective layer of the spring is dip-coated or sprayed on the surface of the spring with a layer of organic substances, such as paint, asphalt, plastic, etc., to protect the spring from corrosion. The non-metal protective layer has a thicker film and good chemical stability. It has good mechanical anti-corrosion effect, but the hardness is low, it is easy to be scratched and damaged, and the film layer is aging.
The paint used for the spring paint layer usually has the following types:
A. Asphalt paint Asphalt paint has good water resistance, moisture resistance and corrosion resistance, especially excellent acid resistance and good alkali resistance. However, adhesion, mechanical strength, and decoration are poor.
b. Phenolic paint Phenolic paint is divided into two types: primer and top coat. Phenolic primer has strong adhesion and good anti-rust performance, but the mechanical strength and gloss of the paint film are poor. Phenolic top paint has a hard film, good gloss, but resistance The climate is poor, and the paint film is easy to turn yellow.
c. Alkyd paint The alkyd paint film is tough, strong adhesion, good mechanical properties, excellent gloss, good durability and certain oil resistance and insulation properties. The disadvantage is that the surface dries quickly and the hand sticks for a long time , Easy to wrinkle, intolerant to water and alkali.
d. Epoxy paint Epoxy paint has strong adhesion, high hardness, good toughness, flex resistance, impact resistance, hard but not brittle, and has excellent resistance to water, acids, alkalis and many organic solvents. Especially alkali resistance is more prominent. Its disadvantage is that the surface chalks fast and the solvent selectivity is large. Water-soluble epoxy paint is used for electrophoretic coating.
Under normal circumstances, the paint layer can be used alone or as a colorant after phosphating. Sometimes, some springs are also sprayed with different colors to distinguish them in order to be classified according to the load. Which type and brand to choose The paint should be determined according to the working environment. If necessary, it should be indicated in the spring pattern.