10F, Building B, Erqi Center, Erqi District,
Zhengzhou City, Henan Province, China
Color coated steel has excellent weather resistance, corrosion resistance and good processing performance. It is widely used in construction, home appliances, transportation, automobile industry, steel mills, power plants, electrical industry, medical uses, advertising, furniture industry, and so on. Also, pre-painted steel is available in different base metals, paintings, coating thicknesses, coating methods, surface treatment methods, etc. Wanzhi Steel is specialized in the customization of high-end color-coated steel according to the use, use environment, designed service life, and special needs of customers. Below let’s review how to choose prepainted steel for different uses.
Pre-painted steel is getting popular in public buildings, such as stadiums, railway stations, exhibition halls, theaters, etc. In terms of public buildings, beauty and durability are the primary considerations for color-coated steel. It has higher requirements for color retention, chalking resistance, and surface quality. Therefore, we usually adopt an AZ150 galvalume sheet, Z275 galvanized sheet, or aluminum-manganese-magnesium alloy sheet as the base metal. The top coating is commonly PVDF coating or HDP coating, 25μm in thickness and mostly in a light color. And the paint is applied by double coating and double baking.
Color coated steel is often used as roofing or wall panel for residential buildings, including civil residences, villas, guard boxes, interior decorations, army barracks, and other fields. These buildings are mainly in the living area. When selecting color coated steel, it should be beautiful, natural, interesting, and personalized. That’s why custom pattern printed steel, such as wood grain, brick grain, marble grain, etc., has been more and more applied to interior and exterior decoration of civil buildings.
The prefab house is mainly used in construction sites as temporary offices, dormitories, and storage rooms. When choosing color coated sheets, practicality and cost will be more important while ensuring safety. As a temporary building, it is recommended to use ordinary color coated steel, with a galvanized sheet as substrate (common zinc layer thickness). Using PE coating as top paint, with a thickness of 15-20μm, will be a cost-effective option.
The use environment of general industrial plants and warehouses is not corrosive. When choosing color coated steel, it requires more practicability and cost-effectiveness, rather than higher corrosion resistance and aging resistance. Therefore, PE color coated steel is the most widely used in general industrial plants and warehouses. It adopts galvanized sheet as substrate with a double-sided zinc layer of 80 g/㎡, and the top paint thickness is 20μm. Of course, you can also lower or improve the quality requirements of the pre-painted steel according to your budgets and specific industries.
Unlike general industrial plants, chemical plants, chemical tanks, and other chemical projects are highly corrosive. Chemical products are prone to produce highly corrosive volatile substances, such as acid or alkali. It is easy to form acid or alkaline dewdrops on the surface of the color plate when exposed to water. Then the acid or alkaline dewdrops will corrode the painting, and further corrode the zinc layer and even the base metal. It is recommended to use PVDF or HDP coated steel sheets, and the ideal thickness of the top painting is 20-25 μm, with Z275 galvanized sheet or AZ150 galvalume sheet as substrate.
Non-ferrous metal smelting factories, steel mills, power plants, etc., are also highly corrosive. Because coal combustion produces a large amount of corrosive media, such as sulfur dioxide and nitric acid, which is easy to corrode steel plates. So the color coated steel used in these industries requires high corrosion resistance. It is generally recommended to use PVDF or HDP coated color steel. Besides, the zinc layer on double sides of the substrate is no less than 120 g/㎡, and the paint thickness (top/back) is no less than 25 μm/15 μm.
Color-coated sheets for iron ore, coal, and other mining industries also have high requirements for corrosion resistance. The heavy sand, dust, and metal dust are mixed and precipitated on the surface of the color-coated steel and then form rust when exposed to water. Thus, for mining sites, it is recommended to choose the SMP (silicon modified polyester) coated color steel, with 20+ μm top paint, which has excellent anti-corrosion, anti-scratch, and wear resistance. The substrate adopts galvanized sheets with a double-sided zinc layer of not less than 120 g/㎡. Due to its high coating hardness, great wear resistance, no chalking, and durability, it is also suitable for areas with severe wind and sand.
Static is dangerous in industries such as clothing, textiles, electronics, instruments, medical facilities, etc., which may lead to safety accidents. Therefore, the color coated steel used in these workshops should be anti-static. The painting of antistatic color steel is with special conductive pigments. The anti-static steel is able to prevent dust from adhering and it is easy to clean. In terms of substrate, it is recommended to use galvanized steel with a zinc layer not less than 80 g/㎡, and the top coating thickness is not less than 20 μm.
The food and medical workshops, hospitals, and other fields have strict antibacterial requirements. The steel sheets used in these industries are covered with a special antibacterial coating, which has nontoxicity, semi-permanent antibacterial effects, and far-infrared radiation effects. The antibacterial rate against Escherichia coli and Staphylococcus aureus can reach more than 99%. Besides, there is a new material, such as nano coated steel, which is very easy to clean because of the good hydrophilic properties of the coating. It is also an ideal option for wall panels and ceiling decorations in hospitals, food, and medical industries. This color coated steel uses galvanized steel as base metal, with a zinc layer not less than 80 g/㎡, and the top coating thickness is not less than 20 μm. This kind of antibacterial color steel is also widely used in air conditioning ventilation ducts.
Arched roofing sheets are mainly used in stadiums, trading markets, exhibition halls, warehousing, and other fields. Due to the arched roofing with no beams, and no purlins, but a large space span, it requires high-strength color coated panels. According to the span of the arch roof, it is recommended to use a base metal with a yield strength of 280-550 Mpa. The recommended code includes S280GD+Z – S550GD+Z. And the zinc layer thickness is not less than 120 g/㎡. The coating structure is generally double-coating and double-baking. The face painting thickness is not less than 20 μm. While the painting can be PVDF or HDP or PE according to your budget and the use environment.
Color steel sheets in the boiler industry are mainly used as outer casing, shells, etc. Usually, the boiler works at a high temperature, with a big temperature difference. Therefore, it is recommended to use PVDF or HDP color steel, which has great resistance to high temperatures and big temperature differences. While PE coated steel is widely used in the boiler industry due to its affordable cost. The popular color is silver gray and white. The base metal adopts galvanized sheet, with a zinc layer of 80 g/㎡, and the top coating thickness is not less than 20 μm. This kind of material is also versatile in thermal insulation and anti-corrosion engineering of pipelines for heat, oil, natural gas, and chemical products.
Coastal areas are of high humidity and salt spray climate. So when choosing color-coated sheets, please put the corrosion resistance in the first place. The chloride ion in seawater has a strong penetration ability, which can directly corrode the zinc coating through a thin or non-dense paint layer. Therefore, it is recommended to use PVDF or HDP color steel plates. The substrate shall be AZ150 GL sheet or Z275 GI sheet, and the thickness of the top paint shall not be less than 25 μm.
Curtain wall mainly plays the role of sound insulation, heat insulation, anti-frost, moisture-proof, and wind pressure resistance. It requires color-coated sheets with high-strength and less maintenance, or good self-cleaning ability. It is recommended to use high-strength color coated sheets with a yield strength of 350-550MPa. As for top paints, PVDF and HDP coating with thickness not less than 20 microns are recommended.
When choosing color coated steel, there are some parameters to consider, including the base metal (strength, grade, material, coating layer), thickness, painting types, painting thickness, coating methods, surface treatment, color or pattern, etc. So how do you make the right decisions? You need to take some factors into account, such as the use purposes, use environment, life expectancy, your budgets, and your other requirements. Wanzhi Steel has a wide range of color coated steel in different specifications, paintings, and substrates, to choose from. Also, we have more than 10 years of experience in this industry to offer you a customizable solution. Welcome to contact us for more details.