Galvanized Iron (GI) coils remain one of the most versatile and cost-effective steel products in 2025, widely used in construction, automotive, appliances, and renewable energy projects. With advancements in coating technologies, sustainability, and smart manufacturing, GI coils are evolving to meet modern industry demands.

This guide covers: 

✔ What is a GI Coil? (Definition & Manufacturing Process)

✔ Types of GI Coils in 2025 (Regular, AZ Coated, High-Strength)

✔ Key Applications (Construction, Automotive, Solar Panels)

✔ 2025 Market Trends (Prices, Demand, China’s Export Policies)

✔ How to Choose the Best GI Coil Supplier

By the end, you’ll understand why GI coils dominate the steel industry and how to source them cost-effectively in 2025.

1. What is a GI Coil?

 1.1 Definition & Composition 

A GI (Galvanized Iron) coil is a cold-rolled steel coil coated with a layer of zinc through a hot-dip galvanizing process. This coating protects the steel from rust and corrosion, extending its lifespan by 20-50 years.

 1.2 How GI Coils Are Made (2025 Process) 

1. Cold Rolling: Base steel is rolled into thin sheets (0.2mm–3mm).
2. Cleaning: Acid pickling removes impurities.
3. Galvanizing: Dipped in molten zinc (450°C) for coating.
4. Passivation: Anti-corrosion treatment (chromate-free in 2025).
5. Coiling: Cut into rolls (typical widths: 600mm–1,500mm).

2025 Innovation: Some mills now use hydrogen annealing to reduce CO₂ emissions.

2. Types of GI Coils in 2025

 2.1 Regular GI Coils (Zinc Coated) 

– Coating Thickness: 50–150 g/m²

– Best For: Roofing, ductwork, general fabrication

– Price (2025): $1,100–$1,400/ton (China FOB)

 2.2 AZ Coated (Aluminum-Zinc Alloy, 55% Al) 

– Advantages:

– 3X longer lifespan vs. regular GI

– Heat-resistant (up to 315°C)

– Applications: Solar panel frames, industrial chimneys

– Price: $1,500–$1,800/ton

 2.3 High-Strength GI Coils (HSGI) 

– Grades: HSLA 350, DP 600

– Key Feature: Stronger yet lighter (used in EVs, warehouses)

– Price: $1,600–$2,000/ton

 2.4 Electro-Galvanized (EG) Coils 

– How It Differs: Thinner, smoother coating (5–20µm)

– Used In: Automotive panels, electronics

– Price: $1,300–$1,600/ton

3. Top Applications of GI Coils in 2025

 3.1 Construction & Architecture 

– Roofing & Wall Cladding:

– Why GI? Low cost, weather-resistant

– 2025 Trend: Color-coated PPGI replacing traditional GI

– HVAC Ducts:

– GI’s Advantage: Mold-resistant, easy to fabricate

 3.2 Automotive Industry 

– EV Battery Trays: HSGI coils reduce weight vs. carbon steel.

– Chassis Parts: AZ-coated coils resist road salt corrosion.

 3.3 Renewable Energy 

– Solar Mounting Structures: AZ-coated GI lasts 30+ years outdoors.

– Wind Turbine Towers: High-strength GI handles coastal corrosion.

 3.4 Appliances & Furniture 

– Washing Machines, Refrigerators: EG coils for smooth finishes.

– Office Partitions: Pre-painted GI for aesthetics + durability.

4. 2025 GI Coil Market Trends

 4.1 Price Forecast (China FOB)   

Why Prices Are Rising: 

– Zinc costs up 18% (2024–2025)

– China’s export taxes (+5% on GI coils)

 4.2 Demand Growth Sectors 

– EV Manufacturing: +22% YoY demand for HSGI

– Solar Energy: +15% demand for AZ-coated coils

 4.3 Sustainability Shifts 

– Green Galvanizing: 12% of EU mills now use hydrogen-powered lines.

– Recycling: GI coils are 100% recyclable (LEED-certified projects prefer them).

5. How to Choose a GI Coil Supplier in 2025

 5.1 Key Selection Criteria 

✔ Mill Certifications: ISO 9001, ASTM A653

✔ Coating Consistency: Ask for third-party thickness tests

✔ Stock Availability: Avoid 60-day waits—choose suppliers with ready stock

✔ Sustainability: Prefer low-carbon galvanizing for EU/US buyers

 5.2 Red Flags to Avoid 

❌ No zinc coating weight warranty

❌ No batch testing reports

❌ Unrealistically low prices (may indicate poor zinc adhesion)

 5.3 Why Buy from China? 

– Cost Savings: 20–30% cheaper than EU/US mills

– Scale: Top 5 Chinese mills produce 45% of global GI coils

– Tech Advancements: AI-driven quality control in leading mills

6. Future of GI Coils (2025–2030)

– 2026: Self-healing zinc coatings enter mass production

– 2027: 90% of GI coils will use recycled zinc

– 2030: Carbon-neutral galvanizing becomes industry standard

 Is GI Still the Best Choice in 2025? 

Yes—if you need:

✅ Low-cost corrosion protection

✅ Lightweight strength (for EVs/solar)

✅ Easy fabrication & recycling

For Best Results:

1. Choose AZ-coated GI for outdoor projects
2. Buy in bulk (5% discount on 100+ tons)
3. Partner with a certified supplier (like GL Steels)

📞 Contact us for 2025 GI coil quotes!

🌐 Website: www.zhimajituanst.com
📧 Email: Info@zhimajituanst.com
📍 Based in: China | Exporting Globally
🚢 Delivery To: UAE, Saudi Arabia, Oman, South Africa, and beyond.