Features

As the pretreatment process before painting works, which is the facility for increasing corrosion proof and durability of products by removing oil stain, dust, impurities, etc.

​In the field of metal coating, because oil, fat and contaminant have bad influence to the adhesiveness or dry of paint, they are the cause of swelling up, abrading, crack, etc, so it needs to carry enough pretreatment for the metal. As this facility is a way of chemical washing, when the products pass the pretreatment line, the spray nozzle impacts regularly on the products.

* Process of pretreatment

1. Hot water rinsing : To steep dirty oil and remove contaminant on the surface of metal(Average temperature : Abt 60℃~65℃)

2. Degreasing : To remove organic materials, such as rust-preventing oil, rolling oil, and cutting oil greased on the surface of metal and inorganic materials, such as iron powder, abrasives, and dust on the surface of steel plate. Alkaline cleaning is a pre step of chemical conversion treatment painting(Average temperature : Abt50℃~55℃)

3. Rinsing : To remove the residue in the prosess of degreasing by the first and second step rinsing

4. Surface activation : Steel surface by alkaline degreasing agent becomes wild and sloppy surface by corrosive action and phosphate coating crystal grains are bigger. Surface activation should be used in order to prevent that. And this prevents and suppresses the oxidation of steel surface after degreasing and uniformizes the properties of steel surface.

5. Chemical conversion coating : To produce corrosion product layer(phosphate coating) on the metal surface by chemical and electrochemical reaction. The main function is to improve the chemical property, such as antirust, corrosion resistance, thermal resistance, and oxidization, and also increase hardness and anti-abrasion.

6. Rinsing : To remove the residue of chemical conversion coating process by the third and forth rinsing.

7. Air blower : The last process for removing moisture on the surface of metal. When the material is approched, it is dehydrated automatically from the air and can be dehydrated by manual depending on material

8. Dry-Off-Oven : Indirect heating system fueled by gas burner, which is the process for drying remaining moisture after pretreatment. Dry-Off-Oven is tunnel type and air curtain installed in the entrance minimize the thermal losses.