1.What basic parameters need to be verified?
Identify the material type
Colored steel plates are mainly divided into single-layer colored steel plates and sandwich colored steel plates, and different types have different quality standards:
Single-layer plates: focus on the thickness of the substrate and the quality of the coating.
Sandwich plates: In addition to the substrate and coating, the density and adhesion of the core material need to be checked.
Check product qualifications
Ask the manufacturer to provide quality inspection report, production license, and warranty.
Pay attention to whether the report is issued by an authoritative organization and whether the inspection date is within the validity period.
2.How to inspect substrates and coatings?
Substrate thickness: measured with a caliper, the common thickness of single-layer board substrate is 0.3-0.8mm, and the thickness of sandwich board substrate is 0.35-1.0mm. The thickness error of high-quality board is ≤0.02mm, and low-quality board often cuts corners.
Coating uniformity: The surface coating should be smooth and flat, without missing coating, bulging, and color difference. The coating can be scratched lightly with a hard object. High-quality coating is not easy to fall off, while low-quality coating is easy to peel off and expose the bottom.
Edge flatness: Observe whether the edge of the board is straight, without obvious warping and burrs. Uneven edges will cause the joints to be too large after installation, which is easy to leak water and air in.
3.How to test impact resistance?
Use a 5cm diameter steel ball to fall freely from a height of 1 meter to impact the surface of the color steel plate:
High-quality plate: only slight marks are left, the coating does not fall off, and the substrate does not deform.
Poor-quality plate: The coating falls off over a large area, and the substrate has obvious pits or deformation.
4.How to judge fire resistance?
Rock wool and glass wool core materials: Class A non-combustible materials. The core materials can be burned continuously with a lighter, and should not burn or smoke.
Polyurethane and polystyrene core materials: It is necessary to confirm whether they are flame retardant (B1 grade). After ignition, they should extinguish themselves without dripping (non-flame retardant types will continue to burn and release toxic gases).
5.How to judge the process details?
Coating process: High-quality color steel plates are roller coated, while low-quality plates are mostly spray coated. It can be judged by the surface gloss: roller coated plates have uniform gloss, while spray coated plates may have local color difference or graininess. Sandwich panel bonding process ◦ High-quality sandwich panels use a fully automatic composite production line, and the core material and the substrate are bonded without bubbles or debonding, and the edges are completely sealed.
Low-quality panels may be manually bonded, and gaps are prone to appear on the edges. The core material will mold and swell after being exposed to moisture. Cutting edge
Observe the cutting surface of the board: High-quality board: The substrate cuts neatly and has no burrs; the core material of the sandwich board fits tightly with the substrate without looseness. Low-quality board: The substrate cuts are deformed, and the sandwich board may have core material shedding and voids.
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