GI Coils

Bobines d'acier galvanisé

Galvanized steel coil (referred to as GI) is a steel product manufactured by applying a zinc coating to the surface of a cold-rolled or hot-rolled steel coil through a continuous hot-dip galvanizing process. The zinc layer provides protection through both a sacrificial anode mechanism and a physical barrier, effectively preventing the underlying steel from rusting. This is one of the most well-established and widely used methods for the anti-corrosion treatment of steel.

Indicative price Please contact us for more details Final price depends on quantity, tolerance and destination port.

Specifications
Thickness	0.20 mm – 6.0 mm
Width	600 mm – 1500 mm
Coating	Z30 – Z275
Coil inner diameter	508 mm / 610 mm
Coil weight	3-8 tons
Spangle	regular,mini, zero

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EN 10204 3.1 mill test certificate with every shipment
SGS / BV pre-shipment inspection on request
FOB / CFR / CIF — tell us your discharge port

Product overview

Galvanized steel coil (referred to as GI) is a steel product manufactured by applying a zinc coating to the surface of a cold-rolled or hot-rolled steel coil through a continuous hot-dip galvanizing process. The zinc layer provides protection through both a sacrificial anode mechanism and a physical barrier, effectively preventing the underlying steel from rusting. This is one of the most well-established and widely used methods for the anti-corrosion treatment of steel.

For our clients, galvanized coils serve as an economical substrate for manufacturing profiled roofing panels, perimeter fencing panels, and general decorative panels. They offer a stable supply and ease of processing, making them well-suited for both indoor and outdoor applications where both cost-effectiveness and corrosion resistance are required.

Key Performance Advantages

Reliable corrosion resistance. The zinc layer forms a dense oxide film when exposed to air, providing a physical barrier. If the coating is scratched, the zinc acts as a sacrificial anode—corroding preferentially to protect the exposed steel substrate at the site of the damage. This is the core value that distinguishes galvanized coils from cold-rolled coils.

Excellent formability. These coils can undergo standard processing—such as shearing, bending, and roll forming—and are well-suited for continuous roll-forming operations (e.g., in tile-pressing machines). The zinc layer maintains strong adhesion throughout the forming process.

Surface characteristics and coating compatibility. The surface features a characteristic "spangle" pattern, making it suitable for applications where high-end aesthetics are not a primary requirement. Alternatively, it can serve as a substrate for color-coating, resulting in pre-painted galvanized iron (PPGI) coils, which offer enhanced color and decorative appeal.

Cost-effectiveness. Compared to Galvalume (Al-Zn alloy coated) or pre-painted coils, galvanized coils represent one of the most economical options among coated steel products, making them ideal for large-scale projects with standard weather-resistance requirements.

Common Specification Range

Item	Parameter
Thickness	0.20 mm – 6.0 mm (commonly 0.3–1.5 mm)
Width	600 mm – 1500 mm (commonly 1000/1200/1250 mm)
Coating Weight	Z30 – Z275
Coil Inner Diameter	508 mm / 610 mm
Coil Weight	3–8 tons (customizable)
Surface Treatment	Chromate passivation, Oiling, Anti-fingerprint (AFP), etc.
Spangle	Regular spangle, minimized spangle, zero spangle (customizable)

Common Grades and Standards

European Standard System: DX51D+Z (general bending and forming grade), DX52D+Z, DX53D+Z, S250GD+Z, S350GD+Z, S550GD+Z
Applicable Standards: EN 10346, ASTM A653, JIS G3302, GB/T 2518

Typical Applications (Based on Use Cases of Our Clients)

Roofing/Cladding Panels: Galvanized coils are roll-formed into silver-white profiled roofing panels, which can be used directly for industrial facilities, warehouses, temporary structures, and other applications where specific color requirements do not apply. They can also serve as a substrate for color-coating, resulting in pre-painted roofing panels.
Construction Site Fencing/Enclosures: These materials are processed into site hoardings or temporary partitions. The corrosion resistance provided by the galvanized layer is sufficient for typical outdoor service lifecycles; given their cost-effectiveness, they are a common choice for fencing projects. If specific colors are required for the appearance of the fencing, pre-painted galvanized coils can be used instead.
Decorative Purposes: The zinc-spangle texture on the surface offers a distinct metallic aesthetic, making these panels suitable for decorative applications, partitions, or backing panels where high-end visual finishes are not strictly required. For projects demanding color, the material can be further processed via color-coating.

Comparison of Spangle

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Selection Reference: Comparison with Galvalume (GL) Coils

Comparison Item	Galvanized (GI) Coils	Galvalume (GL) Coils
Coating Composition	Pure zinc	55% aluminum + 43.4% zinc + 1.6% silicon
Corrosion Resistance	Good	Superior (approx. 3+ times that of GI)
Heat Resistance	Moderate	Better (up to approx. 300°C)
Surface	Zinc spangles	Al-Zn spangles; bright, silvery-white appearance
Cost Positioning	Economical	Mid-to-high end
Typical Applications	General construction, fencing, substrates for color-coated steel	Highly weather-resistant roofing, fencing, decorative substrates

Quality and Supply

Original manufacturer’s warranty certificates and coating weight test reports are available.
We provide recommendations on suitable steel grades and coating weights based on the intended application (e.g., Z120/Z180 for perimeter fencing; Z180/Z275 for roofing panels, depending on the environment).
Services such as slitting and cut-to-length processing are available upon request.
Export packaging can be customized to meet specific requirements, ensuring compliance with international maritime shipping standards.

Application

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