Precautions in the Processing and Forming of Architectural Color-Coated Steel Sheets

During the processing and forming of color-coated steel sheets, if relevant precautions are not observed, it may lead to a decline in product quality and even impact the safety and service life of construction projects. Therefore, understanding and mastering the precautions during the processing and forming of architectural color-coated steel sheets is of great significance for improving processing quality and engineering quality. The following points should be noted during processing:
1. Handling Scratches Handling scratches typically appear as scratch marks or backside paint particles adhering to the surface of the color-coated steel sheet. These defects arise from poor handling operations, insufficiently cured paint, and irregularities on the steel sheet’s surface.
The degree of paint curing, hardness, and lubricity affect the occurrence of scratches. Good roller lubrication and suitable backside paint can help reduce scratch defects. Sometimes, applying a transparent, peelable film on the surface of the steel sheet can prevent handling scratches. Lifting within the bundling factory can also cause scratches; to avoid scratches caused by bending, lifting equipment for long bundles should support most of the bundle’s length. Bundles must be fixed both longitudinally and transversely. During transportation by truck, ensure that bundles do not come into direct contact with other objects, such as structural components. When using forklifts for handling, careful loading and unloading are necessary to prevent excessive bending or scratching of the steel sheets.
2. Surface Cleaning Metal filings, drill shavings, cutting chips, and other metal objects like rivets and fasteners must never remain on the surface of the color-coated steel sheet. Metal residues, once eroded, can cause rust stains. Any detected residues must be immediately swept off the roof or at least cleaned daily after work. In strictly required situations, inspections should be conducted within two weeks of installation to remove potentially rusted residues. Removing these residues helps maintain the roof’s appearance for a longer period.
3. Protective Film Some color-coated steel sheets have a specially designed transparent organic film applied to their surfaces. This organic film protects the coating from scratches during storage and transportation but must be removed immediately after installation. Sunlight exposure enhances the adhesion between the organic film and the steel sheet surface, so it is essential to cover the sheets when placing them on-site to avoid direct sunlight.
4. Cutting Edge-cutting plates should be used as much as possible to avoid on-site cutting. If cutting is necessary, tools such as straight shears, curved shears, sawing machines, and hand shears can be used. All on-site cutting must not damage the steel sheet’s coating or galvanized layer and should maintain good cut edges. Cutting blades must be sharp to minimize burrs. When cutting, the steel sheet should be placed face-up so that any burrs form on the backside. Cutting should not be performed on the surface of other color-coated steel sheets. If power cutting or drilling is required, tape or cloth should cover the areas around the drill holes and cuts to prevent hot chips from burning the coating. Avoid using tools like grinding wheels, hacksaws, or flame cutters, which can damage the galvanized layer and coating.
5. Metallic Colors Metallic colors like silver have flake-like pigments (as opposed to spherical pigments in regular colors), significantly influencing the optical properties of the coating. This means that the same light will produce different reflective effects when viewed from different angles. For the same formula, this flake-like structure results in varying brightness at different angles. Therefore, if there are differences in pressing angles or installation directions, optical light and dark color differences may occur. During use, attention should be paid to:
1. Maintain the press equipment in its most stable state during pressing to ensure each steel sheet is consistently oriented during pressing and installation, avoiding color differences due to directional changes.
2. Pressed panels on the same wall of a building must lie in the same plane without angular deviations.
3. It is recommended to check and compare the color differences between different steel coils before installation. Caution should be exercised when using products from different contracts in the same project.
6. Galvanized Aluminum-Zinc Coating Galvanized aluminum-zinc and high-aluminum zinc aluminum-magnesium materials contain aluminum (AI) elements. Aluminum is an amphoteric metal that reacts with both acids and alkalis. Cement mixed with water forms concrete mortar, which is highly alkaline. In such an alkaline environment, aluminum (AI) undergoes chemical reactions, eventually leading to the dissolution of the coating and loss of corrosion protection. Therefore, galvanized aluminum-zinc and high-aluminum zinc aluminum-magnesium sheets, including corresponding color-coated sheets, should not come into direct contact with wet cement.
7. Other Considerations To avoid reduced performance of coatings during low-temperature processing, steel sheets and strips should be formed at room temperature. The processing performance of coatings decreases over time, so users are advised to process and use the material within one year of manufacturing. When producing sandwich panels, consider compatibility with adhesives and production processes, and conduct small-scale trials first. Pay attention to preventing condensation. For products with PVDF coatings, which have special coating characteristics, it is recommended to apply plastic film during processing to reduce the risk of coating detachment.
To ensure product quality and fully leverage the advantages of color-coated steel sheets, providing aesthetically pleasing, durable, and reliable materials for the construction industry, it is crucial to strictly adhere to all precautions. This not only affects the quality and performance of color-coated steel sheets but also directly impacts the overall quality and safety of construction projects.