With the gradual increase in the use of color-coated steel sheets in the construction industry, people’s attention to color-coated steel sheets continues to rise.
According to incomplete statistics: In 2016, China’s domestic use of pre-painted steel plates was about 5.8 million tons.So, how exactly is pre-painted steel plate produced?
Color-coated steel plates (also known as organic coated steel plates and pre-coated steel plates) are named after the base steel plates (referred to as substrates) coated with various colors.
Color-coated steel sheet is a product with a relatively long production cycle. From hot rolling to cold rolling, it has a specific thickness, width and pattern, and then undergoes annealing, galvanizing and color coating to form a colorful color-coated sheet.The main production processes of the color coating unit include:Pretreatment process, coating process, baking process
1、Pretreatment process
It is mainly the process of removing impurities and oils attached to the surface after the substrate is cleaned; and undergoing composite oxidation and passivation treatments to form a pretreatment film. The pretreatment film is an effective means to improve the bonding force between the substrate and the coating.
2、Coating process
At present, the most commonly used coating process for color coating units in major steel plants is roller coating. Roll coating is to bring the paint in the paint pan to the coating roller through a belt roller, and a certain thickness of wet film is formed on the coating roller. , And then transfer this layer of wet film to the coating method of the substrate surface.By adjusting the roller gap, pressure and roller speed, the coating thickness can be increased or decreased within a certain range;It can be painted on one side or on both sides at the same time. This method is fast and has high production efficiency.
3、Baking process
The baking process mainly deals with the curing of the coating on the surface of the steel plate, which means that the coating undergoes chemical polycondensation, polyaddition, crosslinking and other reactions under a certain temperature and other conditions through the main film-forming material, auxiliary film-forming material and curing agent. The process of changing from liquid to solid.The coating curing and baking process generally includes primary coating baking, fine coating baking and the corresponding waste gas incineration system.
4、Subsequent processing of pre-painted steel sheet
Including embossing, printing, laminating and other treatment methods, waxing or protective film can also be added, which not only increases the anti-corrosion effect of the color-coated plate, but also protects the color-coated plate from scratches during handling or processing.