1. Uncoiling and welding
Disassemble the aluminum-zinc plate coil to show the strip that needs continuous operation, and weld the tail of the previous strip and the head of the next strip to ensure continuous production of the unit.
2. Degreasing and cleaning
The cleaning part is to clean the surface of the strip to remove rolling oil and zinc powder to obtain good coating adhesion and surface quality. It usually includes spraying, brushing, electrolytic cleaning, brushing, spraying, extrusion and hot air drying. The dry waiting cleaning section is more important for hot-dip galvanized steel sheets, and is the main process to obtain good strip steel process performance.
3. Annealing
Recrystallize and anneal the aluminum-zinc sheet to obtain excellent product mechanical properties. According to the atmosphere in the furnace, in order to obtain good strip steel coating performance, the annealing furnace usually includes preheating, heating, soaking and cooling. A segment composition.
4. Air knife zinc layer control
The coating thickness on the surface of the strip is controlled by spraying liquid, usually air or pure nitrogen, on the surface of the strip steel after the galvalume is plated.
5. Fine grain strengthening treatment
The fine-grain strengthening treatment is also a process of heating the strip steel after the tinplate to obtain the aluminum-zinc sheet alloy coating.
6. Flatten and stretch
Small rolling is carried out on the strip steel, the compromise platform of high carbon steel is removed, the strip properties are improved, the required strip roughness is obtained, the strip steel rigidity is improved, and the excellent flatness is obtained. Perform tension correction after straightening, that is, for strip straightening, the most important thing is to obtain an excellent plate shape.
7. Post-processing
Passivation or other chemical surface treatments are applied to galvalume steel sheet to obtain corrosion resistance, lubricity or other requirements expected by customers, usually spray extrusion or drum drying.
8. Chamfer
Trim the strips as needed to obtain the proper width accuracy.
9. Oiling
Oil the galvalume steel sheet to obtain certain anti-rust and lubricating properties.
