To guarantee the cleanness of aluminum trim coil floor, some pre-remedy steps are vital to take away remains grease and lubricants at the coil surface. Usually speaking, the pre-treatment entails three steps.
First, wash the raw 3003 aluminum coil stock in hot water. The main motive of warm water cleaning is to cast off the degreaser residue at the surface by having them dissolved in water therein, which further prevents secondary decontamination of the substrate by way of the degreaser. Not unusual techniques are soaking and spray scrubbing. The hardness of water have to no longer be too high. In any other case, minerals in the water will shape mineral spots at the surface of the substrate.
Secondly, due to the high line pace of the pre-lined line, the degreasers used are typically excessive in awareness. Normal degreasers consist of sodium hydroxide (NaOH), sodium carbonate (Na2CO3), sodium silicate (Na2SiO3), phosphates, and other components. The new alkaline degreasing technique is generally achieved in two steps to easy the floor of the aluminum trim coil substrate and frequently employs a spray wash.
Thirdly, the aluminum trim coil receives passivated. The passivation treatment is to shape a conversion movie at the surface of the substrate with the aid of stress spraying, dipping or roll coating of aluminum coil coating. Pressure spraying is typically used. The sludge generated at some stage in using the passivation solution frequently blocks the orifice and affects the orifice. Despite the fact that the impregnation technique solves this problem, the passivation solution is fed on in a huge amount. The above techniques require water to scrub an excessive amount of passivation solution in real operation, with a view to cause troubles of waste water healing and purification. Roll coating is a superb passivation creation method, which has the advantages of uniform coating, economical use, and no want for cleaning. Aluminum trim coil rolls are usually treated with a chromate or chromic oxide kind of additive comprising chromate, chromic acid, phosphoric acid and extender fluoride and molybdate. One of these remedy agent desires to be brought with phosphoric acid, otherwise it cannot be used for the remedy of aluminum coil rolls for ingredients and beverages.