Color Coated Galvanized Steel Coil has Better Protection and Usability

The color coating on the steel gives it a protective organic coating that gives the steel long-term protection even in corrosive conditions. This coating does not add to the strength of the steel but gives it the necessary protection so that its integrity and strength are maintained.

The process of manufacturing color coated galvanized steel coil is one that is highly automated. This coating is also called a duplex coating. This organic coating is applied to the coil in a continuous process that includes its cleaning, chemical pre-treatment, and the application of primers and paints. The paints are then cured or can be laminated with permanent films of plastic.

Color Coated Galvanized Steel Coil Process

Europe pioneered industrial coating lines in the 1940s and the advantages that it had made it increasingly popular, like higher productivity, energy saving, consistent properties of the sheets, and lesser wastage of the coating material. The pre-painting of sheets in controlled conditions gives these coatings an advantage over the same galvanized sheet being painted after it is installed in any application. Finishes are smooth and can have a high gloss, matt, or textured finish. The thickness of coatings varies from 15 to 40 microns. Standard galvanized colored sheets have thicknesses that vary from 0.2 mm to 1.6 mm and widths vary from 600 mm to 1600 mm. Lengths can vary depending on the customer's requirements.

The color coating can be applied to any form of steel, whether it is cold-rolled, galvanized, or galvalume steel. Galvanizing the steel is a separate process, where zinc or a combination of zinc and aluminum is applied to the steel by hot dipping it in these metallic solutions. So a color-coated galvanized steel coil will have this coating of zinc over the base metal which is then further protected by the color coating. This coating will have a pre-treatment chromate coating, a primer coat, and then the topcoats of paint. It can also be given a guard film.

Green Color Coated Steel Coil

A color coating line will coat both cold-rolled steel and steel that has received any other metallic coating. In this process, the coil is uncoiled and its head mechanically joined to the previous coil that has already been coated. Before any paint or primer is applied to the steel coil, it needs to be pre-treated so that there is better adhesion of the paint. This is done by applying a chemical treatment that helps the surface of the steel to bind with any coating. The strip may need to be washed and dried before any chemical is applied that will give the pre-treatment chromate coating.

RAL3020 Pre-painted Steel Coil

Once the pre-treatment is completed the coil will then receive a coat of the chosen primer. These primers also contain corrosion inhibitors and can be of different types depending on the paints that are to form the color coating. The color coating line is equipped to apply the primer or paint on both sides simultaneously, of the strip being coated. After all the coats are applied, the strip then passes into a convection oven, where the coatings are cured by hot air.

This completes the process of color coating in the galvanized steel coil.