Prepainted Grey Wood Grain Steel

To determine whether a color-coated sheet meets quality standards, the primary method is to verify it against national standard requirements: Visual Inspection (Can be performed using only the naked eye and touch) A compliant color-coated sheet must satisfy the following criteria: The sheet surface must be flat and smooth, free from defects such as bulges, pits, wavy distortions, uncoated spots, or scratches; The texture and color must be uniform and consistent; any printed patterns must be clear—without breaks or smudging—and exhibit no significant color variation; The cut edges must be neat and free of burrs, and the coating layer must show no signs of delamination, blistering, or peeling. Verification of Substrate Quality Substrate Type Verification: For outdoor applications, the substrate must be aluminum-zinc alloy coated or hot-dip galvanized steel; cold-rolled steel lacking a protective anti-corrosion coating is unacceptable. This distinction can be made by examining the cut edges: galvanized or aluminum-zinc coated edges appear silver-gray, whereas cold-rolled edges reveal the pure steel color; Thickness Tolerance Verification: Use a micrometer with a precision of 0.01 mm to measure the thickness at 3 to 5 different points. If the deviation exceeds ±0.02 mm, the sheet is deemed non-compliant. Specifically, the substrate thickness for roofing panels is required to be no less than 0.6 mm, and for wall panels, no less than 0.5 mm.