FAQ About Color-Coated Steel

MOQ: 10 metric tons. If you have questions about the minimum order quantity, please see → Why Don’t Steel Mills Accept Small-Volume Orders?

Common thicknesses range from 0.15 to 1.8 mm. A thickness of 0.12 mm is also available, but the material is prone to breaking during production or processing.

600 mm, 625 mm, 1,000 mm, 1,212 mm, 1,200 mm, etc.

Back coat + coating + substrate + coating + primer + topcoat.

Primer: Bonds firmly to the substrate and provides rust protection;
Topcoat: Provides the final color, gloss, and weather resistance, and enhances corrosion resistance;
Backcoat: Primarily provides basic corrosion protection.

Important note→The primer is the foundation, and the topcoat is the surface. Even if PVDF is used for the topcoat, the entire system will still fail prematurely if the primer is substandard.

It is measured in gloss units (GU) and classified as high gloss (≥70 GU), medium gloss (30–70 GU), and low gloss (≤30 GU). The gloss range for matte color-coated steel sheets is 25°–45°.

Gloss level is controlled by the amount of matting agent added and is not necessarily related to the type of coating (PE/PVDF). Both PE and PVDF paint coatings can achieve high-gloss or matte finishes.

No. “Printed” refers to the “printing” process, while “embossed” refers to the “roll-embossing” process. Industry standards classify them as “Printed Sheets (YI)” and “Embossed Sheets (YA),” respectively, and they belong to different categories. The two products differ in their forming methods, as well as in price and visual appearance.

Thickness selection requires a balance between “safety” and “budget.” We recommend appropriate thicknesses based on the customer’s intended use to avoid increasing costs and creating safety hazards. The following are Changjiang’s recommendations.

We should neither oversell thicker sheets and increase the customer’s costs nor compromise safety by using thinner sheets solely for lower prices.
① Less than 0.4 mm: Temporary fencing, interior ceilings—lightweight and low-cost;
② 0.4–0.5 mm: Walls of industrial plants/warehouses—the mainstream choice, economical and sufficient;
③ 0.5–0.6 mm: Roofs with wide purlin spacing, areas with strong winds or heavy snowfall—resistance to deformation;
④ 0.7–1.0 mm: Heavy-duty industrial plants, long-span structures, and walkable roofs—high load-bearing capacity, but higher cost.

The cross-cut test is used!!! The procedure involves cutting a cross-hatch pattern on the coated surface and observing any peeling to determine the adhesion grade. Grade 1 allows for slight peeling at the cut edges and intersections, covering an area of ≤5%. The cross-cut must reach the substrate surface; otherwise, the test is invalid.

The T-bend test. High-quality color-coated steel sheets should be bent at a radius equal to twice the substrate thickness; the coating should show no cracking or peeling, demonstrating good flexibility.

Yes. Paint film thickness directly affects light reflection and absorption; when thickness varies, the color saturation and brightness perceived by the human eye will differ. During production, we strictly control the uniformity of the paint film thickness. We recommend using products from the same production batch for a single project whenever possible, or purchasing VCM steel coil products—these laminated metal sheet products exhibit no color variation.

Coating type (e.g., PVDF vs. PE), operating environment (e.g., coastal vs. inland), and maintenance practices (e.g., regular cleaning) are the three key factors.

Self-cleaning color-coated steel sheets achieve easy-to-clean functionality through a special topcoat design. They are suitable for panels on kitchen and bathroom appliances such as refrigerators, freezers, dishwashers, range hoods, microwaves, and water heaters, as well as for hospital ventilation systems. Note that self-cleaning ≠ antimicrobial; choose self-cleaning for “reduced dust adhesion/easy cleaning,” and choose antimicrobial for “bacteria killing and inhibition.”

Oil-resistant color-coated steel sheets are not laminated but are painted; they use a special coating formulation to reduce dust adhesion and improve cleanability.

Refrigerator door panels typically use oil-resistant or antimicrobial coatings (requiring a hardness of HRB 40 or higher) and are not self-cleaning. Outdoor air conditioner panels commonly use oil-resistant or self-cleaning coatings and require good stamping and forming performance.

① Thin coils thinner than 0.3 mm require an inner tube to prevent the coil from collapsing;
② Due to high coil tension, embossed and 3D wood-grain patterns require an inner tube even for thick coils.

These four coatings have different characteristics and advantages, and choosing the right coating can effectively extend the service life of color-coated steel. See the table below for details.

Production typically begins after receiving a 30% deposit from the customer. The production lead time varies depending on the order quantity and ranges from 7 to 30 days.

EXE, FOB, CIF, etc.

This generally depends on the product specifications, coil weight, destination port, and shipping line requirements.

As a general rule, depending on the steel product, a 20GP container typically holds around 25 metric tons, while a 40GP container generally holds up to 28 metric tons. Longer steel products (12 meters) are typically loaded into 40GP containers.

For example, for a 5-metric-ton steel coil, a 20GP container can hold approximately 4–5 coils, with a total weight of about 20–25 metric tons. For an 8-metric-ton steel coil, a 20GP container can hold approximately 3 coils, with a total weight of about 24 metric tons.

We conduct rigorous inspections after production. If you require a third-party inspection, we fully support this and can assist with the arrangements; customers may also send their own inspectors to our factory. SGS is the third-party inspection agency most commonly used by our customers, and all our products have passed their inspections. Please refer to our SGS reports for details.