What is GI (galvanized iron) sheet?
GI sheet is low-carbon cold-rolled steel — DX51D to EN 10346, 0.30–4.00 mm — that has been passed through a bath of molten zinc at about 450 °C so that both faces carry a zinc layer of 100–275 g/m² (Z100–Z275, 7–20 µm per side). The zinc protects the steel twice: as a barrier and, where the sheet is cut or scratched, sacrificially. The result is the standard material for roofing, cladding, HVAC ducting, purlins, cable trays, appliance panels and the skins of sandwich panels.
"GI" (galvanized iron) is the Gulf and South Asian trade name; Europe says hot-dip galvanized (HDG) or DX51D+Z, the US says G60/G90, Japan SGCC. They are the same product family — the table in section 3 lines them up.
Galvanized grades — one page each
Every EN 10346 grade has its own page with chemistry, mechanical values, coating table, weight per m² and price band. Forming grades: DX51D (bending, the stock grade), DX52D (drawing), DX53D (deep drawing), DX54D (extra-deep drawing). Structural grades: S220GD, S250GD (roofing and light profiles, stock), S280GD (purlins, stock), S320GD, S350GD (decking, solar, long spans, stock).
Coil, cut sheet, slit strip or corrugated — which form to order
Coil is cheapest per ton and loads best (three 7–8 t coils fill a 20' container). Cut sheet suits distributors and fabricators without a decoiler; slit strip feeds tube mills, roll-formers and purlin lines; corrugated and trapezoidal sheet is roll-formed here and ships as roofing.
| Form | Range | Typical buyer | Packing | Container |
|---|---|---|---|---|
| Coil | 0.30–4.00 mm × 1 000–1 500 mm, ID 508/610, 5–25 t | Service centres, panel makers, tube mills | Eye-to-sky on cradle, VCI paper, steel strapping | 20' ≈ 21 t · 40' HC ≈ 24–25 t |
| Cut-to-length sheet | 0.30–4.00 mm × 1 000/1 250/1 500 × 2 000/2 500/3 000 mm | Stockists, HVAC, fabricators | Packs 2–3 t on skids, wrapped | 40' HC ≈ 24 t |
| Slit strip | 20–600 mm wide, 0.30–3.00 mm | Tube mills, purlin and profile lines | Eye-to-wall on pallets or eye-to-sky | 20' ≈ 20 t |
| Corrugated / trapezoidal | 0.30–0.70 mm, profiles 18/76, 27/150, 38/151 | Roofing distributors, contractors | Packs to 3 t, 6–12 m | See trapezoidal sheet page |
Grades and international equivalents
DX51D+Z is the general-purpose bending grade and covers 80% of orders. DX52D–DX54D are drawing grades for deeper forming (ducting fittings, appliance panels); S250GD–S350GD+Z are structural grades with guaranteed yield for purlins, decking and light-gauge framing. Full chemistry, mechanical limits and the DX51D data sheet are on our reference site (links below).
| EN 10346 | ASTM A653 | JIS G3302 | GOST 14918 | Use |
|---|---|---|---|---|
| DX51D+Z | CS Type B | SGCC | 08пс ХП | Bending, roofing, ducting, general |
| DX52D+Z | FS Type B | SGCD | 08пс ПК | Forming, fittings |
| DX53D+Z | DDS | SGCD | 08Ю ПК | Deep drawing |
| DX54D+Z | EDDS | SGCE | 08Ю ПК | Extra-deep drawing |
| S250GD+Z | SS Grade 37 | SGC340 | 250 | Purlins, decking |
| S280GD+Z | SS Grade 40 | SGC340 | 280 | Purlins, framing |
| S350GD+Z | SS Grade 50 | SGC400 | 350 | Structural profiles, guardrail |
Zinc coating classes Z100–Z275
The Z number is the total zinc mass on both faces in g/m² (triple-spot test). Z140 is the export default for roofing and general work; Z200–Z275 for coastal, industrial and Gulf humid sites; Z100 for indoor ducting and painted parts. ASTM G90 corresponds to about Z275.
| Class (EN 10346) | Zinc g/m² both sides | µm per side | ASTM A653 | Typical life to first rust* |
|---|---|---|---|---|
| Z100 | 100 | 7 | G30–G40 | Indoor: 20+ yr · rural: 10–15 yr |
| Z140 | 140 | 10 | G50 | Rural: 15–25 yr · urban: 8–15 yr |
| Z200 | 200 | 14 | G60–G70 | Urban: 12–20 yr · coastal: 6–10 yr |
| Z275 | 275 | 20 | G90 | Coastal/industrial: 10–15 yr · rural: 30+ yr |
* ISO 9223 corrosivity categories C2–C4, unpainted. Painted (PPGI) or aluzinc for longer coastal life.
Thickness, gauge and weight table
Weight per m² = thickness × 7.85 kg + zinc (0.14 kg/m² for Z140, 0.275 for Z275). A 0.50 mm Z140 sheet weighs 4.07 kg/m²; a 1 250 × 2 500 mm sheet 12.7 kg, so about 79 sheets make a ton. Gulf buyers order by gauge — the table maps the galvanized gauge series to millimetres.
| Gauge | mm | kg/m² (Z140) | kg per 1 250 × 2 500 sheet | Sheets per ton |
|---|---|---|---|---|
| 30 | 0.30 | 2.50 | 7.8 | 128 |
| 28 | 0.40 | 3.28 | 10.3 | 97 |
| 26 | 0.50 | 4.07 | 12.7 | 79 |
| 25 | 0.60 | 4.85 | 15.2 | 66 |
| 24 | 0.70 | 5.64 | 17.6 | 57 |
| 22 | 0.80 | 6.42 | 20.1 | 50 |
| 21 | 0.90 | 7.21 | 22.5 | 44 |
| 20 | 1.00 | 7.99 | 25.0 | 40 |
| 18 | 1.20 | 9.56 | 29.9 | 33 |
| 16 | 1.50 | 11.92 | 37.2 | 27 |
| 14 | 2.00 | 15.84 | 49.5 | 20 |
| 12 | 2.50 | 19.77 | 61.8 | 16 |
| 11 | 3.00 | 23.69 | 74.0 | 14 |
| 8 | 4.00 | 31.54 | 98.6 | 10 |
Gauge figures follow the common galvanized-sheet gauge series used in the Gulf and India; order in mm to avoid ambiguity.
Standard sizes and coil data
Widths 1 000, 1 200, 1 250 and 1 500 mm (1 000 and 1 250 from stock in every thickness); sheet lengths 2 000, 2 500 and 3 000 mm, or cut to any length up to 6 000 mm. Coil inner diameter 508 or 610 mm, outer diameter up to 1 800 mm, coil weight 5–25 t (export coils are usually held to 7–8 t so three fit a 20' container). Thickness tolerance per EN 10143 normal or restricted class; width +5/−0 mm; flatness class.
Surface: spangle, passivation and oiling
Regular spangle is standard and cheapest; minimized or zero spangle gives a smooth surface for painting and visible parts (ducting, appliances). Surface treatments: chromate or chromate-free passivation (Cr-free is required for EU and many Gulf projects), light oiling for storage in humid climates, or dry for immediate painting. Skin-passed (SP) surface on request for a uniform finish.
GI sheet for HVAC ducting
Ducting shops use 0.50–1.20 mm Z140–Z275 DX51D in cut sheets 1 250 × 2 500 mm, minimized spangle, lightly oiled. SMACNA and DW/144 duct gauges map to 0.6 mm (26 g), 0.8 mm (24 g), 1.0 mm (22 g) and 1.2 mm (20 g). We pack duct sheet in 2 t skids, 20–24 t per 40' HC, with the mill certificate and a SASO/QCC-ready packing list.
GI for roofing, purlins and framing
Roofing sheet is roll-formed here from 0.30–0.70 mm Z140–Z275 coil into corrugated, trapezoidal and tile profiles; purlins from 1.5–3.0 mm S250GD–S350GD+Z. If your order is roofing rather than flat material, the trapezoidal & corrugated sheet and C and Z purlin pages carry the profile tables; the coil grade and coating are the same as here.
GI vs aluzinc vs PPGI vs electro-galvanized
Hot-dip GI stays the default because it is the cheapest coating per year of service in most climates; move to aluzinc or PPGI for roofs within 5 km of the sea, and to zinc-magnesium for unpainted outdoor structures that must last 25+ years.
| Product | Coating | Life outdoors | Price vs GI Z140 | Choose when |
|---|---|---|---|---|
| GI (hot-dip) | Zinc 100–275 g/m² | Good; sacrificial at cut edges | 1.00 | General, roofing, ducting, purlins |
| Aluzinc AZ150 | 55% Al-Zn 150 g/m² | 2–4× GI in humid/coastal air | 1.05–1.15 | Roofing in Gulf, West Africa; heat reflection |
| PPGI (pre-painted) | GI + PE/PVDF paint | Longest; colour | 1.25–1.45 | Visible roofing and cladding, panels |
| Electro-galvanized | Zinc 2.5–10 µm | Indoor only | 1.05–1.10 | Appliances, painted parts |
| Zinc-magnesium ZM | Zn-Mg-Al 90–310 g/m² | 3–5× GI | 1.10–1.25 | Solar mounting, agricultural, outdoor frames |
Tolerances (EN 10143)
Tolerances are stated on the offer and the certificate; ordering to the restricted class costs 1–2% more and matters for ducting seams and appliance panels.
| Nominal thickness | Tolerance ± |
|---|---|
| 0.30–0.40 mm | 0.05 |
| 0.40–0.60 mm | 0.06 |
| 0.60–0.80 mm | 0.07 |
| 0.80–1.00 mm | 0.08 |
| 1.00–1.20 mm | 0.09 |
| 1.20–1.60 mm | 0.11 |
| 1.60–2.00 mm | 0.13 |
| 2.00–2.50 mm | 0.15 |
| 2.50–3.00 mm | 0.17 |
| 3.00–4.00 mm | 0.19 |
Restricted class (S) at half these values on request.
Galvanized coil price per ton and per kg
Indicative FOB Istanbul bands from our weekly export list, DX51D+Z140, full-container quantities. Thin gauges (0.30–0.50 mm) cost more per ton because of the extra rolling passes; Z200 and Z275 carry a zinc surcharge that moves with the LME zinc price. Per kilogram, divide the band by 1 000: a 0.50 mm GI sheet at 880–1 050 USD/MT is 0.88–1.05 USD/kg FOB before freight.
Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.
Export and packing
Coils are loaded eye-to-sky on timber cradles, lashed with steel strapping and wrapped in VCI paper and PE film for voyages over 14 days. HS code 7210.49 (plain galvanized, non-alloy, ≥600 mm wide), 7210.41 (corrugated), 7212.30 (slit strip <600 mm).
| Term | Detail |
|---|---|
| MOQ | 1 × 20' container (3 coils, ~21 t) or 1 truck (22–24 t); mixed thicknesses allowed |
| Incoterms | FOB Istanbul (Ambarlı / Gemlik) · CIF / CFR Gulf, Red Sea, West and East Africa · DAP by truck to EU, Balkans, Iraq, Caucasus · DAP Aktau / Almaty via Baku ferry |
| Lead time | Stock: 5–10 working days to loading; mill order (special width, Z275, restricted tolerance): 4–6 weeks |
| Packing | Coil eye-to-sky on cradle, VCI + PE, 3 × 7–8 t per 20'; sheet packs 2–3 t on skids |
| Container / truck | 20' ≈ 21 t · 40' HC ≈ 24–25 t · truck 22–24 t |
| Documents | Commercial invoice, packing list per coil, EN 10204 3.1, certificate of origin; SASO / SONCAP / EAC / PVoC on request |
| Payment | 30% advance, balance against B/L copy; irrevocable L/C at sight accepted via our London office |
Certificates and documents
EN 10204 3.1 inspection certificate for every coil (heat number, chemistry, yield/tensile/elongation, coating mass); certificate of origin; on request SASO/SABER (KSA), SONCAP (Nigeria), EAC (Kazakhstan), PVoC (Kenya), CE for structural grades used in EN 1090 components. Third-party inspection (SGS, BV) in Dilovası before loading.
How to order
Send grade, thickness × width (or gauge), coating class, form (coil / sheet / strip), quantity in tons or containers, destination port and Incoterm. We reply within one working day with the USD price, coil weights, number of containers and loading date; stock items load within 5–10 working days.
Standards
- EN 10346 (continuously hot-dip coated steel flat products)
- EN 10143 (tolerances on dimensions and shape)
- ASTM A653 / A653M (G60, G90)
- JIS G3302 (SGCC, SGCH)
- GOST 14918 (08пс ХП/ПК)
- ISO 3575
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: DX51D+Z · DC01 (cold-rolled base) · S250GD · S350GD
Frequently asked questions
What is a GI sheet?
A galvanized iron (GI) sheet is cold-rolled low-carbon steel (DX51D, 0.30–4.00 mm) coated on both sides with 100–275 g/m² of zinc by hot dipping. It is used for roofing, ducting, purlins, cable trays and panel skins; "GI" is the trade name, EN 10346 calls it DX51D+Z and ASTM A653 G60/G90.
What is the price of 1 kg of GI sheet?
Divide the per-ton band by 1 000: at an indicative 880–1 050 USD/MT FOB Istanbul for 0.50 mm DX51D+Z140, one kilogram is about 0.88–1.05 USD before freight and duty. Thicker sheet (1.2–4.0 mm) is cheaper per kg, Z275 coating dearer.
What is the difference between GI sheet and galvanized coil?
None in the material — coil is the continuous strip as it leaves the galvanizing line; GI sheet is the same strip cut to length (2 000–3 000 mm). Coil is cheaper per ton and loads more per container; sheet is ready for shops without a decoiler.
GI or aluminium — which is better for roofing?
GI is stronger, cheaper (about a third of aluminium per m² at equal thickness) and easier to fix; aluminium is lighter and does not rust at cut edges. For most warehouses and sheds GI Z200–Z275 or aluzinc is the economical choice; aluminium is chosen for very corrosive or weight-critical roofs.
What is the difference between AC sheets and GI sheets?
AC (asbestos-cement or fibre-cement) sheets are brittle, heavy (12–16 kg/m²) and cannot be curved; GI sheets weigh 3–6 kg/m², span further between purlins, are fully recyclable and do not carry the asbestos health issue. GI needs a coating class matched to the climate; AC does not corrode.
Which zinc coating should I specify?
Z140 for inland roofing, ducting and general use; Z200 for urban and industrial air; Z275 (G90) within 5 km of the coast or in the Gulf humidity. For unpainted structures expected to last more than 25 years consider zinc-magnesium (ZM) or aluzinc.
What sizes and thicknesses are in stock?
0.30–4.00 mm in widths 1 000 and 1 250 mm from stock, 1 200 and 1 500 mm for most thicknesses; sheets 2 000, 2 500 and 3 000 mm long; coils 5–25 t, ID 508/610 mm.
What is the HS code for galvanized steel sheet?
7210.49 for plain hot-dip galvanized flat products ≥600 mm wide, 7210.41 for corrugated, 7212.30 for slit strip under 600 mm. The code is stated on the invoice and used for the SASO/SONCAP certificate.
How many tons of coil fit in a 20-foot container?
About 21 t: three coils of 7 t, or two of 10 t, loaded eye-to-sky on cradles. A 40' HC takes 24–25 t; port and road weight limits, not the box, set the ceiling.
Do you supply DX51D with a mill certificate?
Yes — every coil ships with an EN 10204 3.1 certificate showing heat number, chemistry, mechanical properties and zinc coating mass; 3.2 (inspector-countersigned) on request.