When sourcing a PPGI coil for roofing sheet factory operations, manufacturers demand consistent color, durable coating, and reliable supply chains. As a leading prepainted galvanized steel coil producer, ChinaCNU Steel delivers high-performance color coated steel coil that meets the rigorous standards of roofing sheet production. With our Qingdao factory operating for over 15 years, we provide ISO-certified PPGI coil for roofing sheet factory clients worldwide, ensuring every coil meets strict thickness, adhesion, and corrosion resistance requirements. Our FOB pricing and MOQ of 25 tons make us a trusted partner for large-scale roofing projects across 80+ countries.
Why Choose Prepainted Galvanized Steel Coil for Roofing Sheets?
Prepainted galvanized steel coil, commonly known as PPGI, is the backbone of modern roofing sheet manufacturing. The combination of a hot dip galvanized steel substrate with a durable paint system provides exceptional weather resistance, UV stability, and aesthetic flexibility. For any PPGI supplier China, the key lies in controlling the zinc coating weight, paint thickness, and curing process. At ChinaCNU Steel, we use continuous galvanizing lines (CGL) to ensure uniform zinc adhesion before applying polyester, PVDF, or SMP coatings. This results in color coated steel coil that withstands harsh climates, from tropical heat to coastal salt spray. Roofing sheet factories benefit from reduced waste, faster production cycles, and superior end-product longevity when using our PPGI coil for roofing sheet factory applications.
PPGI Coil For Roofing Sheet Factory Price Trend (USD/Ton) – Last 12 Months
Data: ChinaCNU Steel Market Research | FOB Tianjin Reference Price
Key Properties of PPGI Coil for Roofing
- Zinc coating: 80–275 g/m² (Z80–Z275) for corrosion protection
- Paint system: Polyester (PE), Silicon Modified Polyester (SMP), or PVDF
- Thickness range: 0.12–1.5 mm for various roofing profiles
- Width: 600–1250 mm, customized per customer needs
- Color options: Full RAL color PPGI palette, including RAL 3005, RAL 9002, RAL 8017
Comparing PPGI Coil for Roofing Sheet Factory – Grades & Specifications
Roofing sheet factories often require specific mechanical properties to ensure the final product can withstand wind uplift, snow loads, and thermal expansion. The table below compares common PPGI grades used in roofing applications, helping buyers select the right prepainted galvanized steel coil for their production line.
| Grade | Yield Strength (MPa) | Tensile Strength (MPa) | Zinc Coating (g/m²) | Typical Use |
|---|---|---|---|---|
| DX51D+Z | 140–300 | 270–500 | 80–275 | General roofing, corrugated sheets |
| DX52D+Z | 140–300 | 270–500 | 100–275 | Roll-formed roofing profiles |
| DX53D+Z | 140–260 | 270–420 | 100–275 | Deep drawing roofing accessories |
| S250GD+Z | 250–350 | 330–470 | 100–275 | Structural roofing panels |
| S350GD+Z | 350–450 | 420–540 | 140–275 | High-strength roofing for industrial buildings |
Selecting the correct grade of hot dip galvanized steel is critical for the final roofing sheet’s performance. For example, S350GD+Z offers higher strength for long-span roofing, while DX51D+Z is cost-effective for standard profiles. Our RAL color PPGI range includes over 200 standard shades, and we can match custom colors for large orders. As a PPGI supplier China with 15+ years of export experience, we provide mill test certificates and third-party inspection reports for every shipment.
Production Process of Color Coated Steel Coil at ChinaCNU Steel
Understanding the manufacturing process helps roofing sheet factories evaluate the quality of their prepainted galvanized steel coil supplier. At our Qingdao factory, we follow a strict sequence:
- Hot dip galvanizing: Steel substrate passes through molten zinc bath for corrosion protection
- Chemical treatment: Surface is cleaned and treated with conversion coating for paint adhesion
- Primer application: A thin layer of primer is applied to enhance corrosion resistance and paint bonding
- Topcoat application: Polyester, SMP, or PVDF paint is applied via reverse roll coating
- Baking and curing: Coil passes through ovens at controlled temperatures to cross-link the paint film
- Cooling and inspection: Final coil is cooled, inspected for color consistency, film thickness, and adhesion
- Packaging: Coils are wrapped with waterproof paper, steel strapping, and edge protectors for export
This process ensures that every color coated steel coil we ship meets ISO 9001:2015 and SGS standards. Our PPGI coil for roofing sheet factory clients consistently reports zero delamination or color fading issues, even after years of exposure.
Quality Control Measures
- T-bend test (≤ 3T for standard PE coating)
- Impact resistance test (≥ 9 J)
- Salt spray test (≥ 500 hours for standard coating)
- Color difference measurement via spectrophotometer (ΔE ≤ 1.0)
- Film thickness uniformity (20–25 μm for topcoat)
FOB Pricing & MOQ for PPGI Coil for Roofing Sheet Factory
We understand that cost predictability is essential for roofing sheet factory procurement. Our FOB Tianjin pricing is calculated based on substrate thickness, zinc coating weight, paint type, and order volume. With an MOQ of 25 tons, we serve both medium and large-scale manufacturers. Typical lead time is 15–25 days after deposit, and we offer flexibility on payment terms (T/T, L/C at sight). For bulk orders exceeding 100 tons, we provide volume discounts and priority production slots. As an ISO certified PPGI supplier China, we guarantee that every coil meets the agreed specification or we replace it at our cost.
Frequently Asked Questions (FAQ)
1. What is the difference between PPGI and PPGL for roofing sheets?
PPGI uses a hot dip galvanized steel substrate (zinc coating), while PPGL uses Galvalume (aluminum-zinc alloy coating). PPGI offers better cut-edge corrosion protection, making it ideal for roofing sheets in humid or coastal environments. PPGL provides higher heat reflectivity but may require edge sealing. For most roofing sheet factory applications, PPGI is the preferred choice due to its balance of cost and performance.
2. How do I choose the right RAL color for my roofing project?
Select RAL colors based on local building codes, climate, and aesthetic preferences. Lighter colors (e.g., RAL 9002, RAL 9016) reflect more solar heat, reducing cooling costs. Darker colors (e.g., RAL 3005, RAL 8017) absorb heat but may require thicker paint film to prevent fading. We provide color cards and digital samples for all RAL color PPGI options before production.
3. What is the minimum order quantity for custom colors?
Our standard MOQ is 25 tons per color. For custom RAL colors not in our standard inventory, we require a minimum of 50 tons to justify the paint changeover. We recommend ordering standard colors (RAL 3005, RAL 9002, RAL 8017, RAL 5010) for faster delivery and lower cost.
4. Can I get a sample coil before placing a bulk order?
Yes, we offer sample coils (1–3 tons) at FOB pricing with a lead time of 10–15 days. Samples are cut from actual production runs to ensure color and quality match bulk production. Sample cost is deductible from the final order.
5. How does ChinaCNU Steel ensure on-time delivery for roofing sheet factories?
Related Products from ChinaCNU Steel
We maintain a buffer stock of 5,000 tons of hot dip galvanized steel substrate at our Qingdao factory. Our production planning team monitors raw material availability and shipping schedules weekly. Over 95% of our orders ship within the agreed lead time. We also offer expedited production for urgent orders (additional 5% surcharge).