Galvalume Color Coated Steel Coils

Coil Geometry Precision
Pre-painted coil dimensional accuracy is maintained through closed-loop gauge control systems achieving thickness tolerances of ±0.003mm across 1,250mm widths. Laser profilometers map crown (center bulge) and edge drop with 0.1µm resolution, feeding real-time data to hydraulic shape rolls that apply 1,200-tonne corrective forces. Coil camber (longitudinal curvature) is constrained to <0.5mm/m via tension leveling at 15% yield strength, while width tolerances meet ASTM A924 Class B (±1.0mm). Post-coating, thermal expansion differentials are compensated by predictive algorithms adjusting coiling tension to 12-18 MPa, preventing telescoping and ensuring I-units <0.3% (coil deviation from perfect cylinder). Surface flatness standards exceed EN 10131:2006 FC class with wave heights <0.5mm/300mm.

This geometric perfection enables high-speed downstream processing:

• Slitting: Tolerance ±0.1mm at 800m/min speeds using pneumatic side guides and carbide knives

• Blank Cutting: CNC servo-presses achieve ±0.05mm dimensional accuracy

• Roll Forming: Profile consistency with springback compensation <0.25°

• Stamping: Reduced scrap rates from material instability (<0.3%)
  Automated optical inspection verifies edge condition (burr height <3µm), eliminating lamination failures in appliance manufacturing. The tight tolerances prevent oil-canning in architectural panels - flatness deviations are constrained to <0.2mm/mm² per EN 10162. Coil set (residual curvature) is minimized to <0.5° per meter through stress equalization annealing at 340°C for 90 seconds, critical for automotive exterior panels requiring Class A surfaces.