Skip to content 
Galvanized Steel coil
Galvanized Steel coil
Zhaojian Steel is a galvanized steel coil manufacturer China construction, automotive, and appliance buyers rely on for consistent zinc coating quality and reliable export shipments. As a direct GI coil supplier with four hot-dip galvanizing lines and an annual galvanized product capacity of 1.2 million tons, we produce hot-dipped galvanized steel coil, electro galvanized steel coil, and galvannealed coil across a wide range of thicknesses, widths, coating weights, and surface treatments.
Our galvanized steel coils offer strong corrosion resistance through a zinc layer that acts as both a physical barrier and a sacrificial anode, protecting the base steel even at cut edges and scratches. Every coil is traceable from raw material to finished product, with a Mill Test Certificate supplied with every shipment.
Hot-Dipped and Electro Galvanized Coil
We produce galvanized steel coils in two main types. The right choice depends on your coating thickness requirement, surface finish expectation, and end application.
Hot-Dipped Galvanized Steel Coil
Hot dipped galvanized steel coil is made by passing steel strip through a bath of molten zinc at approximately 450°C. The metallurgical bond formed between the steel substrate and zinc creates a durable, adherent coating that provides long-term protection in outdoor and industrial environments.
Key advantages:
- Excellent corrosion resistance from thick zinc layer
- Long service life, typically 20 to 50 years depending on environment
- Strong zinc adhesion that resists peeling and chipping
- Cost-effective corrosion protection for structural applications
- Suitable for roofing, cladding, fencing, HVAC, and construction
Electro Galvanized Steel Coil
Electro galvanized coil is produced by electrically depositing zinc onto the steel surface in an electrolytic bath. This process creates a thinner, more uniform coating with a smoother, brighter surface.
Key advantages:
- Smooth and uniform surface finish
- Better dimensional accuracy
- Excellent paintability and coating adhesion
- Preferred for appliances, automotive panels, and decorative parts
- Suitable for precision manufacturing where appearance matters
GI Coil Specifications
| Item | Specification |
|---|---|
| Thickness | 0.3mm – 3.0mm (customizable) |
| Width | 600mm – 1500mm (common: 1000mm / 1220mm / 1250mm) |
| Coil Weight | 3 – 25 MT per coil |
| Zinc Coating Weight | G30/G60/G90 (ASTM) or Z100 – Z275 (EN 10346) |
| Zinc Coating Type | Hot-Dip Galvanized / Electro-Galvanized |
| Steel Grade | SGCC, DX51D+Z, ASTM A653, S350GD, etc. |
| Surface Finish | Skin Pass / Chromated / Oiled / Dry / Anti-Fingerprint |
| Surface Appearance | Regular Spangle / Minimized Spangle / Zero Spangle |
| Coil Inner Diameter | 508mm or 610mm |
| Coil Outer Diameter | Typically up to 1500mm (varies with thickness and weight) |
| Packing | Waterproof paper + plastic film + steel straps |
| Standards | ASTM A653, EN 10346, JIS G3302, GB/T 2518 |
Coil Dimension Quick Reference
| Parameter | Standard Options |
|---|---|
| Coil Inner Diameter (ID) | 508mm / 610mm |
| Coil Outer Diameter (OD) | Up to 1500mm (varies by thickness and weight) |
| Coil Weight | 3 MT – 25 MT |
| Slit Width Tolerance | ±1mm |
| Thickness Tolerance | ±0.02mm to ±0.05mm depending on gauge |
Coating Weight and Spangle
Zinc coating weight determines how long a galvanized steel coil resists corrosion. Spangle type affects surface appearance and downstream processing suitability. Select both based on your end use and environment.
Coating Weight Options
| Coating | EN 10346 | ASTM A653 | Total Zinc (g/m²) | Best For |
|---|---|---|---|---|
| Z60 | Z60 | G20 | 60 | Indoor, light industrial |
| Z80 | Z80 | G25 | 80 | General fabrication |
| Z120 | Z120 | G40 | 120 | Construction, ducting |
| Z180 | Z180 | G60 | 180 | Outdoor structures, roofing |
| Z275 | Z275 | G90 | 275 | Coastal, severe environments |
Z275 galvanized coil is the most commonly requested heavy-coating spec for roofing and structural applications in high-humidity or coastal regions. Heavier coatings mean slower zinc consumption and a longer service life.
Spangle Types
Regular Spangle: The traditional galvanized appearance with visible zinc crystal patterns formed naturally during solidification. Suitable for industrial applications, roofing, and structural use where appearance is secondary.
Minimized Spangle: Produced by adding elements like aluminum or antimony to the zinc bath to reduce crystal size. Provides a smoother, more uniform appearance while maintaining corrosion protection. Good for painted or coated applications.
Zero Spangle: Achieved through rapid quenching after galvanizing. Produces a nearly flat, uniform surface ideal for high-quality painting, prepainted processing, and decorative applications requiring a clean base.
Quality Certification
Surface Finish Options
After galvanizing, each coil can be supplied with specific surface treatments to improve corrosion resistance, handling performance, or downstream processability.
Chromated Surface A chromate conversion coating applied after galvanizing to reduce white rust formation during storage and transportation. Suitable for export shipments with extended transit times or outdoor storage exposure.
Non-Chromated Surface Produced for markets where chromate treatments are restricted under environmental or regulatory standards such as RoHS and REACH. A reliable alternative with good processing characteristics and compliance with green building requirements.
Oiled Surface A thin rust-inhibiting oil is applied to protect the fresh zinc surface during storage and transit. Commonly selected when additional temporary corrosion protection is needed before fabrication begins.
Dry Surface Supplied without oil. Preferred when painting, coating, or immediate fabrication is planned and a clean surface is needed from the outset.
Fingerprint-Resistant (Anti-Fingerprint) Surface A special treatment applied to reduce visible handling marks on the surface. Widely used in home appliances, electronics, and visible panel applications where surface appearance must be maintained through handling and installation.
Production Line and Quality Assurance
Zhaojian Steel operates four hot-dip galvanizing lines at its Bazhou, Hebei facility, producing 1.2 million tons of galvanized products annually. Our galvanizing lines use the Sendzimir process with multi-stage waste heat recovery, providing tight coating thickness control across full coil width.
In-process monitoring covers coating weight (magnetic induction measurement), surface uniformity, dimensional accuracy, and mechanical properties at every production stage. Post-production inspection includes:
- Coating weight verification against customer specification and applicable standard
- Surface visual inspection for pinholes, bare spots, spangle consistency, and roughness
- Tensile and bend tests to confirm mechanical properties meet specified grade
- Dimensional check on thickness, width, and coil ID/OD
Results are documented in a Mill Test Certificate (MTC) issued per EN 10204 3.1, supplied with every shipment. Third-party inspection by SGS, BV, or TUV can be arranged on request.
ISO 9001 certified. IQNet recognized. Philippine PS mark certified. Korean KS mark certified.
Galvanized Steel Coil Uses
Galvanized steel coil is used widely in construction, manufacturing, and consumer products.
Roofing and wall cladding for homes, commercial buildings, and industrial facilities.
Cable trays, HVAC ducts, and ventilation parts that require corrosion resistance.
Automotive parts, including inner panels, brackets, and support frames.
Home appliances such as refrigerators, washing machines, and air conditioner shells.
Electrical cabinets and enclosures needing protection and a clean finish.
Steel framing systems, roll-formed profiles, and lightweight trusses used in modern construction.
More Details About Zhaojian Steel Products
GI Coil Key Features
High Flatness
High-precision rolling ensures smooth, wrinkle-free coils for easy processing.
Premium Packaging
Steel straps with buckles and protective corners provide export-grade protection for safe transport.
Large-Scale Capacity
Our factory supports bulk orders with fast turnaround, maintaining consistent quality across every coil and sheet.
Manufacturing Process
We also produce electro-galvanized steel coil for applications requiring finer surface finish
- 1. Cleaning: The steel coil is degreased and acid-pickled to remove rust and scale.
- 2. Galvanizing: Hot-dip: The steel coil passes through molten zinc (~450 °C) for strong protection. Electro-galvanized: Zinc is electrically deposited on the steel coil surface for a smoother finish.
- 3. Post-treatment: Includes skin pass, passivation, oiling, or anti-fingerprint coating to enhance surface quality and corrosion resistance.
- 4. Inspection: Coating thickness, adhesion, and surface appearance are tested before applying export packaging.
Coil Packaging
All galvanized steel coils are packed to export sea-worthy standard for ocean freight container shipment. Packaging is designed to prevent rust, surface damage, and coil deformation during loading, transit, and port handling.
- Waterproof paper and plastic film wrapping to prevent moisture ingress and white rust during shipping
- Inner and outer steel ring protection at coil edges to prevent deformation
- Edge guards at both faces of the coil to protect the wound strip from damage
- High-strength steel strapping with buckles to secure the coil and prevent unwinding
- Wooden pallets or iron saddles depending on coil weight and customer requirements
- Container loading follows strict blocking and bracing procedures to prevent coil movement
Each package is labeled with grade, coating weight, heat number, dimensions, and order number for easy customs clearance and warehouse identification.
FAQ
Contact us to get more info about our stock of galvanized steel coils for sale, ready for export. Global shipping to Southeast Asia, Europe, Middle East, South Africa,etc
Hot-dip coils have thicker zinc for better corrosion resistance (outdoor use). Electro-galvanized coils have a thinner, smoother coating (indoor use, paintable).
Typically over 20 years, up to 50 years depending on the environment and coating thickness.
Yes. Thickness from 0.3mm to 3.0mm, width from 600mm to 1500mm, and coating weight from Z30 to Z275 can all be customized. Surface treatment, spangle type, and coil weight can also be specified.
All coils are packed with waterproof paper, inner and outer steel rings, edge protectors, and wooden pallets or iron saddles. Packaging follows export sea-worthy standards to prevent rust, damage, or deformation during shipping.
Standard lead time is 15–25 days after deposit and order confirmation.
For stocked sizes or urgent orders, faster delivery may be possible.
Yes. We provide MTC (Mill Test Certificate) with every shipment.
If required, we can also arrange SGS, BV, TUV, or third-party inspection before loadin
We offer Z30 through Z275 under EN 10346, equivalent to G30 through G90 under ASTM A653. Common stock specifications are Z60, Z120, Z180, and Z275. Higher coating weights can be produced on order.
MOQ varies by specification. As a general guide, one container (approximately 25 metric tons) is the standard minimum. Please contact our sales team with your required grade, coating weight, width, and thickness for an exact MOQ confirmation.
Standard coil inner diameters are 508mm and 610mm. Outer diameter varies depending on coil weight and thickness.
We export to customers across Southeast Asia, the Middle East, Africa, Europe, South America, and other international markets. Our logistics team manages full export documentation including commercial invoice, packing list, bill of lading, certificate of origin, and MTC.
Yes. Samples are available for standard stock specifications. Courier freight is typically charged to the buyer’s account. Custom specification samples are quoted on a case-by-case basis.
