GI Steel Strips in Coil

Hot-Dip Galvanized Steel Strips in Coil for Tube Making and Roll Forming

Continuous hot-dip galvanized (GI) steel strips manufactured to EN 10346, ASTM A653, and JIS G3302 standards. Supplied in precise slit widths with zero, minimum, or regular spangle finishes, our GI strip coils provide uniform zinc coating adhesion, controlled camber, and tight thickness tolerances for pre-galvanized pipe welding, light gauge steel framing, cable tray forming, and electrical metallic tubing (EMT).

Galvanized Iron Coil
Name: Galvanized Iron Coil . Material Grade: DX51D, SGCC, ASTM A653 . Available Thickness: 0.30-3.00mm . Standard Width: 600-1500mm . Zinc Layer: Z40-Z275 . Coil Inner Diameter: 508/610mm . Coil

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Coil Coated Galvanized Steel
Name: Coil Coated Galvanized Steel . Steel Thickness: 0.12-1.5mm . Coil Width: 600-1500mm . Zinc Coating: 30-275g/m² . Coating Type: PE, SMP, HDP, PVDF . Coil Weight: 1-10 Tons . Tensile Strength:

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Galvanized Wire Coil
Name: Galvanized Wire Coil . Wire Diameter: 0.15-6.0mm . Zinc Coating: 30-300g/m² . Coil Weight: 0.5-100kg . Tensile Strength: 350-550MPa . Delivery Time: 7-30 days .

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Corten Steel Tube
Name: Corten Steel Tube. Grade: Corten A / Corten B. Diameter: 20-200mm. Wall Thickness: 0.25-5.5mm. MOQ: 1mt.

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Galvanized Steel Strip
Name: Galvanized Steel Strip. Thickness: 0.1-3.0mm. Zinc coating: Zn20-Zn275. Coil weight: 0.5-10mt. MOQ: 1mt.

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Gi Coil Galvanized Steel
Name: Gi Coil Galvanized Steel. Thickness: 0.1-3.0mm. Zinc coating: Zn20-Zn275. Coil weight: 0.5-10mt.

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Hot Dip Gi Strip
Name: Hot Dip Gi Strip. Thickness: 0.1-3.0mm. Zinc coating: Zn30-Zn275. Coil weight: 0.5-10mt. Delivery Time: 5-25 days.

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Hot Dip Gi Strip Coil
Name: Galvanized steel coils. Thickness: 0.35-6.0mm. Zinc coating: Zn20-Zn275. Coil weight: 3-10mt. MOQ: 1 mt.

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Gi Sheet Coil
Name: Gi Sheet Coil. Thickness: 0.35-6.0mm. Zinc coating: Zn20-Zn275. Coil weight: 3-10mt. MOQ: 1 mt.

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Product Categories

Zero Spangle GI Strips:

Smooth surface finish ideal for precision roll-forming, painted tubing, and applications requiring high surface uniformity without spangle pattern show-through.

Regular / Regular-Minimized Spangle GI Strips:

Standard metallic zinc crystal finish offering economical atmospheric corrosion resistance for structural framing, cable trays, and agricultural profiles.

Chromated and Passivated GI Strips:

Chemical conversion coating applied post-galvanizing to prevent white rust (wet storage stain) during humid transit and storage.

Oiled / Anti-Fingerprint (AFP) GI Strips:

Light oiling or transparent organic resin coating to facilitate deep stamping and reduce smudge marks during handling.

Technical Specifications

Parameter	Capability / Standard Range	ASTM Benchmark	EN Benchmark
Thickness Range	0.30 mm - 4.50 mm (+/-0.02 mm to +/-0.05 mm tolerance)	ASTM A653	EN 10143
Width Range	20 mm - 685 mm (Slit width tolerance +/-0.15 mm)	ASTM A568	EN 10143
Zinc Coating Mass	Z40 to Z275 g/sqm (G10 to G90 double-sided)	ASTM A653	EN 10346
Coil Inner Diameter (ID)	508 mm (20 in) / 610 mm (24 in)	Standard Industry ID	Standard Industry ID
Coil Outer Diameter (OD)	900 mm - 1500 mm	Customer spec	Customer spec
Coil Weight	0.5 MT - 6.0 MT per coil (customizable)	Customer spec	Customer spec
Camber (Sickle Bend)	le 2.0 mm per 2000 mm length	ASTM A568	EN 10143
Surface Treatment	Chromated (C), Oiled (O), Anti-Fingerprint (AFP), Dry	ASTM A653	EN 10346

Steel Grades and Mechanical Properties

Commercial and Bending Grades
• EN 10346: DX51D+Z, DX52D+Z (Lock-forming and general bending quality)
• ASTM A653: CS Type A, CS Type B, CS Type C (Commercial steel substrates)
• JIS G3302: SGCC, SGCD1 (Commercial and lock-forming applications)

Structural and High-Strength Grades
• EN 10346: S250GD+Z, S280GD+Z, S350GD+Z, S550GD+Z (Structural steel for cold-formed profiles)
• ASTM A653 SS: Grade 33 (230 MPa), Grade 40 (275 MPa), Grade 50 (340 MPa), Grade 80 (550 MPa)
• GB/T Standards: Q195, Q235, Q355 galvanized steel substrates

Manufacturing and Processing Capabilities

Continuous Hot-Dip Galvanizing Line:

Substrate steel passes through an inline annealing furnace before entering the molten zinc bath, ensuring tight metallic bond interlayer formation without zinc flaking during tight-radius bending.

Automated Air-Knife Control:

Closed-loop X-ray gauge monitoring adjusts nitrogen/air pressure continuously across the strip width, maintaining zinc coating thickness uniformity within +/-5 g/sqm target variance.

Tension Leveling and Skin-Pass Mill:

Eliminates coil break, improves strip flatness (wave height le 3 mm/m), and produces a fine matte surface finish for uniform paint application.

Precision Slitting Arbor Shafts:

Rotary carbide cutters accommodate strip widths down to 20 mm, keeping edge burrs below 6% of sheet thickness to extend downstream forming die service life.

Quality Control and Compliance Standards

Every production heat and coil master undergoes physical, metallurgical, and corrosion testing. Mill Test Certificates (MTC) matching EN 10204 3.1 accompany every shipment.

Zinc Coating Mass Testing:

Triple-spot weigh-strip-weigh chemical test according to ISO 1460 / ASTM A90 to confirm g/sqm compliance on top and bottom faces.

Adhesion Testing:

180-degree bend test and impact test (ISO 7438) verifying zero flaking or peeling along the bend radius.

Salt Spray Corrosion Testing:

Neutral salt spray (NSS) testing according to ISO 9227 / ASTM B117 confirming chromate passivation resistance up to 72+ hours against white rust formation.

Dimensional and Camber Inspection:

Continuous laser tracking for thickness profile, slit width accuracy, and lateral camber within 2.0 mm per 2-meter gauge length.

Target Applications

Pre-Galvanized Tube and Pipe:

Round, square, and rectangular tubing, EMT conduits, scaffolding, and greenhouse frame pipes.

Drywall Framing and Construction:

C-studs, U-tracks, ceiling furring channels, corner beads, and cable trays.

Electrical and Infrastructure:

Cable armoring steel tape, junction boxes, switchgear enclosures, and solar mounting structure accessories.

Automotive and Hardware:

HVAC duct flanges, door frame reinforcements, stamped mounting brackets, and drawer slides.

MOQ and Lead Time

Minimum Order Quantity (MOQ):
Standard Grades and Gauges (e.g., DX51D+Z / SGCC, 0.5mm - 2.0mm thickness, Z80-Z120 coating): 25 Metric Tons (1x20ft Container).
Custom High Structural Grades or Heavy Zinc Mass (e.g., S350GD+Z, Z275): 50 Metric Tons.

Production Lead Time:
• Standard mill inventory coils for slitting: 7-12 days.
• Custom galvanizing runs and specialized width slitting: 15-22 days from deposit or L/C confirmation.

Export Packaging and Transport Safety

Galvanized steel strips are susceptible to wet storage stain (white rust) when exposed to trapped moisture in marine environments. We utilize heavy-duty export moisture barrier wrapping tailored for eye-to-sky or eye-to-side shipping:

Passivation and Oiling:

Chromate passivated surface with optional light rust-inhibitive oil film.

Inner Seal:

VCI (Vapor Corrosion Inhibitor) paper and waterproof plastic film wrapping around each coil package.

Protective Armor:

Galvanized steel inner and outer edge protectors, steel side covers, and outer corrugated steel wrapping sheets.

Strapping:

Minimum 3 radial steel straps through the eye and 3 circumferential steel straps around the OD.

Container Lashing:

Coils secured on wooden pallets or cradles using high-tensile steel banding, anti-slip rubber pads, and timber bracing inside 20ft heavy-tested containers (max load 27-28 MT per container).

FAQ

Q: How do you prevent white rust on galvanized steel strips during long ocean transit?

A: We apply trivalent chromate passivation (or environmental anti-fingerprint coating) followed by light rust-inhibitive oiling. Coils are wrapped in VCI anti-corrosion paper and sealed in waterproof plastic before outer galvanized steel armor is strapped on.

Q: What is the minimum slit width you can produce, and how is edge burr controlled?

A: We slit widths as narrow as 20 mm with width tolerances within +/-0.15 mm. Precision rotary carbide cutters maintain edge burr heights below 6% of material thickness, preventing mill roll damage during high-speed tube forming.

Q: Can your GI steel strip withstand tight 180-degree bending without zinc peeling?

A: Yes. Inline annealing prior to the zinc pot controls the iron-zinc alloy layer thickness, providing superior coating adhesion. DX51D+Z and DX52D+Z grades pass 180-degree bend tests without zinc flaking or cracking on the outer bend radius.

Q: What zinc coating weight is recommended for outdoor structural vs indoor drywall framing?

A: Indoor drywall framing typically uses Z40 to Z100 (G30 to G40). Outdoor structural applications, greenhouse frames, and cable trays exposed to atmospheric conditions generally specify Z140 to Z275 (G60 to G90) for extended corrosion protection.

Q: Do you provide EN 10204 3.1 Mill Test Certificates (MTC) with each shipment?

A: Every shipment includes an original 3.1 MTC specifying the exact heat number, substrate chemical composition, yield strength, tensile strength, elongation, measured zinc coating mass per side, and passivation status.

Q: What coil inner diameter (ID) and weight options fit standard automated decoilers?

A: Standard inner diameters are 508 mm (20 in) and 610 mm (24 in). Coil weights can be tailored from 0.5 MT up to 6.0 MT to match your uncoiler mandrel weight capacity and crane limitations.

Request a Technical Quote and Material Sample

Send us your required substrate grade, thickness, strip width, zinc coating mass (g/sqm), surface finish, and target tonnage. Our metallurgical engineering team will evaluate mill limits and deliver a detailed price quotation within 12 hours.
Email: info@tjrsr.com
WhatsApp / Direct Line: +86 15900235505
Factory Location: Tianjin Steel Industrial Zone, China
Required Quote Details: Grade (e.g., DX51D+Z / SGCC) | Dimensions (Thickness x Width) | Zinc Mass (e.g., Z100 / Z275) | Surface Finish (Zero/Regular Spangle, Chromated) | Quantity (MT) | Destination Port

As one of the most professional gi steel strips in coil manufacturers and suppliers in China, we also support customized service. Please feel free to wholesale cheap gi steel strips in coil in stock here from our factory. For price consultation, contact us.

Gi Sheet Coil, Hot Dip Gi Strip, Galvanized Steel Strip