At present, it is generally customary to use the number of times of coating or baking and curing in the production process of prepainted galvalume steel sheet to represent the production process of prepainted galvalume steel sheet, such as one coating and one baking, two coatings, and two baking, three coating and three baking, and four coating and four baking. At present, the majority of the double-coating and double-baking production processes are used. This section mainly introduces the production process of double-coating and double-baking.
When using cold rolled steel sheet as the substrate, the production process flow is:
Unwinding – shearing – burr pressing – stitching – pre-cleaning – tension roller – inlet looper – brushing – degreasing – cleaning – phosphating – cleaning – chroming – drying – coating – baking and curing – air cooling – water cooling – blow drying – secondary coating – secondary baking curing – air cooling – water cooling – blow drying – tension roller – outlet looper – tension roller – wax coating – coiling.
When galvalume substrates are used, the surface treatment is different, that is, surface activation and tempering treatment are carried out after degreasing treatment and water cleaning, and other processes before and after are generally different.
The three-coating and three-baking process are used in the production of high-end products:
Unwinding – shearing – burr pressing – sewing – pre-cleaning – tension roller – inlet looper – brushing – degreasing treatment – cleaning – phosphating treatment – cleaning – chroming treatment – drying – coating application – baking curing – air cooling – water cooling – drying – secondary coating – secondary baking curing – air cooling – water cooling – drying – three coating – three baking – air cooling – water cooling – drying – tension roller – outlet looper – tension Roller – Wax – Coil.