Color coated aluminum before winding processing work

The production process of color coated aluminum coil is relatively strict. Only color coated aluminum coil needs a lot of treatment before it is rolled, which is a new kind of aluminum material often used in construction. Before aluminum coil is rolled, some pretreatment sections are needed to ensure that the surface of aluminum coil is clean. Lest there is residual grease and smooth agent on the surface, affect the coating and application. Before forming aluminum coil, it should be pretreated in the following aspects.
1, hot water cleaning. Color coated aluminum coil hot water cleaning is mainly to clean the residual degreaser on the surface of the substrate, to ensure that these residues can be dissolved in them, in order to prevent these degreaser caused secondary pollution to the substrate. The way of use is mostly immersion and spray scrub. The hardness of the water used should not be too high, otherwise, the minerals in the water will generate ore spots on the surface of the substrate.
2, hot alkali degreasing: hot alkali degreasing due to the precoated line speed, so the degreasing agent used is generally higher concentration, typical degreasing agent contains sodium hydroxide (NaOH), sodium carbonate (Na2Co3), sodium silicate (Na2SiO3), phosphate and other components. The hot alkali degreasing process is generally divided into two steps to ensure that the surface of the aluminum coil substrate is cleaned, and the way of spray brushing is often used.
3, passivation treatment. Color coated aluminum coil passivation treatment is through pressure spray, dip coating or roll coating, passivation agent on the surface of the substrate to form a conversion film. The general use of pressurized spray, passivation liquid in the process of use in the mud will often plug the spray hole, thus affecting the spray effect. Dip coating solves this problem, but the consumption of passivation liquid is larger.
The above two ways in the essential operation need water cleaning excess passivation liquid, will occur waste water recovery and purification problems, roll coating is a good passivation construction method, with average coating, economic application, do not need to wash and other characteristics. Do these jobs well before color coated aluminum rolls, and then ensure the orderly progress of other processes, you can ensure the quality of aluminum rolls to a certain extent.