Do you know how to choose color-coated steel coils?

Do you know how to choose color-coated steel coils?
The selection of color-coated steel coils mainly refers to the selection of mechanical properties, substrate type and coating weight, and the performance of the front and back coatings. Application, environmental corrosion, service life, durability, processing method and degree of deformation are important factors to be considered when selecting materials.
1. Selection of mechanical properties, substrate type and coating weight
Mechanical properties are mainly selected based on factors such as application, processing method and degree of deformation. For example, the roof panels of buildings are usually not load-bearing, and the deformation is not complicated during processing, so TDC51D is usually selected. For parts with a relatively large degree of deformation, materials with good formability such as TDC52D and TDC53D should be selected. For components with heavy requirements, appropriate structural steel should be selected according to design requirements, such as TS280GD, TS350GD, etc. The commonly used processing methods for color-coated plates are shearing, bending, rolling, etc. When ordering, you should choose according to the characteristics of each processing method. In addition, since the mechanical properties of the substrate are usually used to replace the mechanical properties of the color-coated sheet in actual production, and the color-coating process may cause the mechanical properties of the substrate to change, this should be noted. The type of substrate (type of coating) and the weight of the coating are mainly selected based on the purpose, environmental corrosion, service life and durability. Anti-corrosion is one of the main functions of color-coated sheets, and the type of coating and the weight of the coating are the main factors affecting the corrosion resistance of color-coated sheets. Since color-coated sheets for construction are usually directly exposed to the atmospheric environment, substrates such as hot-dip galvanized sheets and hot-dip aluminum-zinc sheets with good corrosion resistance and thick coating are usually selected. In addition, the corrosion resistance of different types of coatings is also different. For example, under the same coating thickness, the corrosion resistance of hot-dip aluminum-zinc coating is higher than that of hot-dip galvanized coating. In addition, corrosion resistance usually increases with the increase of coating weight, so the corrosion resistance of color-coated sheets can be improved by using a substrate with high corrosion resistance and/or increasing the coating weight. There are differences in the corrosion resistance of the cut edges of steel plates with different coating types, which should also be noted. In addition, service life and durability are also important factors that cannot be ignored when selecting materials. If long service life and high durability are required, a substrate with good corrosion resistance or heavy coating weight should be selected. Since the coating of galvanized materials contains about 55% aluminum (Al), aluminum is a bipolar metal that can react with both acid and alkali. After cement and water are mixed into concrete sand, it is highly alkaline. In such an alkalinity environment, aluminum (Al) will undergo a chemical reaction, which will eventually cause the coating to dissolve and lose its anti-corrosion protection ability. Therefore, galvanized plain sheets, including color-coated sheets on galvanized substrates, are not suitable for direct contact with wet cement.
2. Selection of front coating performance
The selection of front coating performance mainly refers to the type of coating, coating thickness, coating color difference, coating gloss, coating hardness, coating flexibility/adhesion, coating durability, and other performance selections.
Types of coatings 1. Topcoat
Common topcoats include polyester, silicon-modified polyester, high-durability polyester,,r and polyvinylidene fluoride. There are certain differences in hardness, flexibility/adhesion, corrosion resistance,e and other aspects of different topcoats. Polyester is the most widely used coating at present, with general durability, good hardness and flexibility of the coating, and moderate price. The durability, gloss, and color retention of silicon-modified polyester are improved, but the flexibility of the coating is slightly reduced. High-durability polyester has the advantages of polyester and has been improved in durability, with high-cost performance. Polyvinylidene fluoride has excellent durability and good flexibility of the coating, but the hardness is relatively low, the colors available are few, and the price is expensive. For detailed performance indicators of various topcoats, please refer to relevant materials or consult experts. Topcoats are mainly determined according to factors such as use, environmental corrosion, service life, durability, processing method and degree of deformation.
2. Primer
Common primers include epoxy, polyester and polyurethane. There are certain differences in adhesion, flexibility, corrosion resistance and other aspects of different primers. Epoxy has good bonding with the substrate and high corrosion resistance, but its flexibility is not as good as other primers. Polyester has good bonding with the substrate and excellent flexibility, but its corrosion resistance is not as good as epoxy. Polyurethane is a primer with relatively good comprehensive performance. Detailed performance indicators of various primers can be referred to relevant materials or consulted with experts. Primers are usually determined by manufacturers based on production processes, uses, environmental corrosiveness, and matching relationships with topcoats.
3. Coating thickness
The corrosion resistance of color-coated plates is closely related to the coating thickness. Usually, corrosion resistance increases with the increase of coating thickness. The appropriate coating thickness should be determined based on environmental corrosiveness, service life, and durability.
4. Coating color difference
Color-coated plates may have color differences during production and use. Since color differences are affected by multiple factors such as production batches, color depth, use time, use environment, and use, they are usually negotiated by both supply and demand parties when ordering.
5. Coating gloss
The coating gloss is mainly selected based on the purpose and usage habits. For example, domestic color-coated plates for construction usually choose medium and low gloss, and color-coated plates for home appliances usually choose high gloss.
6. Coating hardness
Coating hardness is the ability of the coating to resist mechanical effects such as scratches, friction, collision, and depression. It is closely related to the scratch resistance, wear resistance, and indentation resistance of the color-coated plate. It is mainly selected based on the purpose, processing method, storage and transportation conditions, etc.
7. Coating flexibility/adhesion
Coating flexibility/adhesion is closely related to the processability of the color-coated plate. It is mainly selected based on the processing method, deformation degree, etc. When the deformation speed is fast and the deformation degree is large, color-coated plates with high impact energy value and small T bend value should be selected.
8. Coating durability
Coating durability is the performance of color-coated plates during use, which is usually measured by the length of service life. Coating durability is mainly affected by factors such as coating type, coating thickness, and environmental corrosion. The true durability of the coating can be determined by atmospheric exposure tests. Durability can also be evaluated through artificial aging tests. The neutral salt spray resistance test is one of the simplest and most commonly used artificial aging test methods, and the ultraviolet light accelerated aging test is also a relatively common artificial aging test. In addition, color-coated panels may be used in special environments such as acid rain and humidity. At this time, the corresponding artificial aging test should also be selected for evaluation. It should be noted that artificial aging tests usually cannot fully simulate the actual use environment.