Color Coated GI Steel Coils

Coil Coating Line (CCL) Integration
Modern pre-painted steel production occurs on integrated coil coating lines (CCLs) combining 12 continuous processes: decoiling, stitching, cleaning, pretreatment, drying, primer coating, curing, topcoat application, final curing, quenching, inspection, and recoiling – operating at 30-200 m/min. Line tensions are maintained at 5-15% of yield strength via digital PID loop control across 30 drive sections. Automated defect detection systems (3D laser profilometers + 200MP cameras) scan surfaces at 2m²/sec, identifying 10µm defects with AI classification (oil spots, craters, inclusions). Centralized DCS systems synchronize 500+ I/O points, enabling coil-to-coil changeovers in <8 minutes. The integrated design minimizes handling, reducing surface abrasion to Sa0.5 (Rz<0.8µm).

This vertical integration ensures quality consistency impossible with offline painting. Real-time thickness gauges (X-ray fluorescence for metallic coatings; beta backscatter for paint) provide closed-loop control to ±0.5g/m². In-line spectroscopy verifies chemical pretreatment conversion coating weights within ±2mg/m². Curing ovens employ multi-zone PMT control with ±1°C accuracy across 2m wide coils. The continuous process achieves: DFT uniformity CV<3%, color difference ΔE<0.3 coil-to-coil, and mechanical property variation <5%. Production efficiency exceeds 98% with scrap rates <0.2%. Environmental controls capture 99% VOCs via regenerative thermal oxidizers (RTOs), reducing emissions to <15g VOC/m² coated surface. CCL integration allows customized orders (100m min length) with full traceability via coil ID laser marking.