Color coated steel coils mainly adopt the continuous roll coating process, with the mainstream being the 2-coat 2-bake process (the 3-coat 3-bake process is optional for high-demand scenarios). The complete process consists of 4 steps:
1. Substrate pretreatment: Degreasing → pickling/alkaline washing → phosphating → passivation → drying, which improves coating adhesion and prevents rust reoccurrence.
2. Primer roll coating + high-temperature curing (200-250℃), serving as the bottom layer for corrosion protection.
3. Topcoat roll coating (PE/PVDF/HDP, etc.) + secondary high-temperature curing, enabling customization of colors and weather resistance.
4. Post-treatment + full inspection: Cooling → application of PE protective film, followed by tests for coating thickness, adhesion, color difference, etc. The coils are wound up only after passing the inspection.
What is the coating process for color coated steel coils?
- March 14, 2025