GI coil, galvanized steel coil, a cost-effective, versatile corrosion-resistant metal material, is typically sold in various forms such as hot-dip galvanized steel coils and electrogalvanized steel coils. Currently, Wanzhi Group supplies multiple types of galvanized steel coils—including large zinc flake, small zinc flake, standard zinc spangle, coated, embossed, and painted varieties—to sectors including construction, home appliances, and industry.

GI Coil – Surface
Surface treatment of GI coils not only meets diverse aesthetic requirements but also effectively extends the corrosion resistance lifespan of galvanized steel, preventing rust caused by transportation or storage conditions.
Surface Treatments
- Chromate Passivation: Standard treatment providing basic rust prevention.
- Chromate-Free Passivation: Eco-friendly treatment compliant with RoHS directives.
- Oil Coating: Enhances short-term rust resistance, facilitating storage and transportation.
Zinc spangle Pattern
- Regular Spangle GI Steel: Distinct zinc spangle crystals naturally formed on the steel surface during zinc layer solidification.
- Small Zinc Spangle GI Steel: Achieved through controlled processes for a finer, more uniform galvanized surface.
- Free Zinc Spangle GI Steel: Features a smooth, flat surface, making it the preferred substrate for subsequent coating applications.
GI Coil – Value-Added Processing
Wanzhi Group is a professional coated steel factory supplier. We not only provide GI coil raw materials but also offer one-stop value-added processing services.

GI Coil – Film Coating

GI Coil – Embossing

GI Coil – Slitting

GI Coil – Leveling

GI Coil – Painting

GI Coil – Punching/Shearing

GI Coil – Light Steel Stud Forming

GI Coil – Roll Forming

GI Coil Factory
Wanzhi GI Coil Factory is certified under ISO9001, ISO14001, and other standards. Our galvanized products comply with international standards including GB/T2518, GB/T25052, EN10346, JIS G3302, and ASTM A653. We offer a diverse product range and provide OEM/ODM services.

Production Line
Our galvanized steel production line is located in Boxing County, Binzhou City, Shandong Province, China, with an annual capacity of 600,000 tons. Our production scope includes galvanized, aluzinc, and zinc-aluminum-magnesium materials, as well as value-added processing such as painting, bending, slitting, leveling, and corrugating. Standard galvanized steel coil models are available from stock with delivery times ranging from 5 to 45 working days.
Packaging
We employ precision export-grade packaging, including vertical/horizontal coil wrapping options. Each coil is wrapped in plastic film, moisture-proof paper, galvanized iron sheet, stretch film, and steel strapping to ensure product integrity during long-distance transport and harsh conditions. (Standard coil weights range from 3-8 tons. Wooden or steel pallets can be used upon request, with customizable packaging weights or Wanzhi LOGO.)
Services
Technical Consultation: Assisting you in selecting the most suitable specifications, grades, and coatings.
Flexible Ordering: Free samples provided, supporting small trial orders and large-scale procurement.
Rapid Delivery: Stocked standard specifications with short production cycles.
Quality Assurance: Third-party quality inspection support available (e.g., SGS, BV, TUV).
Case
Our GI coils are exported to over 100 countries and regions worldwide for applications including building structures, electrical manufacturing, cable trays, and agricultural greenhouses. We continuously receive feedback from customers across diverse industries.
GI Coil – Buying Guide
| Application Scenario | Recommended Zinc Coating (g/m²) | Recommended Substrate Thickness | Surface Treatment Recommendation |
| Indoor Dry / Home Appliance Interior | Z40 – Z90 | 0.3 – 1.2mm | Oil coating or Chromate passivation |
| General Building Roofs/Walls | Z90 – Z150 | 0.4 – 1.5mm | Chromate passivation |
| Industrial Environment/Structural Components | Z150 – Z275 | 1.0 – 3.0mm | Chromate passivation |
| Coastal / High Corrosion Areas | Z200 – Z275+ | ≥1.2mm | Non-chromate passivation |
| Subsequent Coating (Pre-coated Substrates) | Z90 – Z180 | Varies by application | No zinc flowers + non-chromate passivation |
GI Coil and GL Coil
| Characteristic | GI Coil (Galvanized Steel Coil) | GL Coil (Galvalume Steel Coil) |
| Coating Composition | 99% Zinc | 55% Aluminum, 43.4% Zinc, 1.6% Silicon |
| Corrosion Resistance | Excellent | Outstanding, 2-6 times better than GI |
| Heat Resistance | Poor, continuous use temperature ≤160℃ | Excellent, can withstand continuous temperatures ≤315℃ |
| Thermal Reflectivity | Average | High, helps with building insulation and energy savings |
| Appearance | Silver-gray, with zinc flowers | Bright silver-white, with fish-scale pattern |
| Protection Mechanism | Sacrificial protection | Barrier protection + sacrificial protection |
| Workability | Excellent | Good |
| Cost | Economical | Relatively higher |















