GI Coil (Galvanized Iron Coil)
GI coil is cold rolled steel coil coated with zinc by the continuous hot dip process. The zinc layer is what stops the steel rusting, and how much of it you specify is the single most important decision on a GI coil enquiry. Seen Steel supplies GI coil across all seven emirates, slit to width and delivered to your yard.
Zinc coating classes
Coating is quoted as a Z number under EN 10346, or a G number under ASTM A653. The figure is the total zinc mass across both faces in grams per square metre, so Z275 means 275 g/m² shared over the two sides. More zinc means longer life and a higher price.
| EN 10346 | Total both sides | Approx. per side | Typical use |
|---|---|---|---|
| Z100 | 100 g/m² | 7 microns | Indoor use, painted parts, ducting |
| Z140 | 140 g/m² | 10 microns | Indoor, light humidity |
| Z180 | 180 g/m² | 13 microns | Sheltered outdoor, appliances |
| Z200 | 200 g/m² | 14 microns | General outdoor, cladding |
| Z275 | 275 g/m² | 19 microns | Roofing, outdoor UAE standard |
| Z350 | 350 g/m² | 25 microns | Coastal and high humidity |
| Z450 | 450 g/m² | 32 microns | Marine, aggressive exposure |
| Z600 | 600 g/m² | 42 microns | Severe industrial and marine |
For most UAE outdoor work Z275 is the sensible default. Within a few kilometres of the coast, or on anything washed down regularly, Z350 and above is worth the extra.
Sheet weight by thickness
Steel weight only, calculated at 7.85 g/cm³. The zinc adds a further 0.1 to 0.6 kg/m² depending on the coating class.
| Thickness | Weight | Thickness | Weight |
|---|---|---|---|
| 0.15 mm | 1.18 kg/m² | 0.80 mm | 6.28 kg/m² |
| 0.20 mm | 1.57 kg/m² | 1.00 mm | 7.85 kg/m² |
| 0.30 mm | 2.35 kg/m² | 1.20 mm | 9.42 kg/m² |
| 0.40 mm | 3.14 kg/m² | 1.50 mm | 11.77 kg/m² |
| 0.50 mm | 3.92 kg/m² | 2.00 mm | 15.70 kg/m² |
| 0.60 mm | 4.71 kg/m² | 3.00 mm | 23.55 kg/m² |
Working out coil weight
To estimate the weight of a coil: length in metres multiplied by width in metres multiplied by thickness in millimetres multiplied by 7.85. A 1250 mm wide coil at 0.5 mm running 1000 m works out at roughly 4,906 kg before zinc.
Standard sizes we supply
- Thickness 0.15 mm to 3.0 mm
- Width 600 mm to 1500 mm, slit to narrower widths on request
- Coil inner diameter normally 508 mm
- Standard and full coils, plus slit mother coils
Surface finish and treatment
Regular spangle, minimised spangle or zero spangle. Zero spangle is the usual choice where the sheet will be painted or where a uniform appearance matters. Chromate passivation resists white rust in storage and transit, and oiling is available. Say at enquiry stage if the material is to be painted or powder coated, because passivation and oiling both affect paint adhesion.
Grades
Supplied to ASTM A653 or EN 10346. Commercial steel for general forming, structural grades where a defined yield is needed, and deep drawing grades where the part is heavily formed. Tell us what the coil is being formed into and we will match the grade.
Common applications
- Roofing sheets, purlins and wall cladding
- HVAC ducting and ventilation systems
- Cable trays, trunking and electrical enclosures
- Home appliance and automotive panels
- General fabrication and light structural sections
What to send for a quote
- Thickness and width, and whether you need it slit
- Zinc coating class, or the exposure if you would rather we advise
- Grade or the end use
- Spangle and whether it will be painted
- Tonnage required
- Delivery location
Frequently asked questions
What is the difference between GI and GL coil?
GI is zinc coated. GL, or galvalume, is coated with an aluminium zinc alloy and lasts longer in some environments but is harder to weld and paint. For most UAE roofing and ducting work GI is the standard.
What coating should I use near the coast?
Z350 or higher. Z275 is fine inland but salt spray eats a thin coating quickly on an exposed roof.
Can you slit coil to width?
Yes. Send the widths you need and the tonnage and we will confirm.
Do you supply mill test certificates?
Yes, MTCs are issued with the material, showing coating mass and grade.
Which emirates do you deliver to?
All seven. Dubai, Abu Dhabi, Sharjah, Ajman, Umm Al Quwain, Ras Al Khaimah and Fujairah, delivered to your yard.
Send your coil requirement on WhatsApp at +971 56 227 5722 or email seensteelfze@gmail.com and we will come back with a rate.