Pre-Painted Galvanized Steel Coil
Color finished galvanized coil that leaves the roll former ready to install
Specifications
GI/PPGI Steel Coil
Hot Dipped Galvanized Steel Coil in G250 to G550
Full width zinc coated coil in structural and commercial grades for roll forming lines
Galvanized steel coil is full width steel strip coated with zinc by hot dipping or by electro galvanizing and wound for direct feeding into a roll forming or stamping line. Roofing sheet producers, framing manufacturers and general fabricators specify it when the finished part will be exposed and cannot be sent out for galvanizing after forming. Taking the coil already coated removes the post galvanizing subcontract, its transport time and the distortion a thin formed section picks up in a zinc bath. Grades cover G250, G350, G450, G550, A36, SS400, S275jr and A653 with zinc coating from G20 through Z350.
- Product Name — Galvanized Steel Coil
- Also Known As — GI coil zinc coated steel coil
- Steel Grade — G250 G350 G450 G550 A36 SS400 S275jr A653
- Zinc Coating — G20 G30 G40 G60 G90 Z150 Z275 Z350
- Galvanizing Technology — Hot dipped or electro
Why It Is Specified
Key Benefits of Galvanized Steel Coil
Corrosion Protection Applied Before Forming
The zinc layer is on the strip when it reaches your line, so the part leaves the press already protected and does not need a coating subcontractor.
Structural Grades up to G550
G250, G350, G450 and G550 let a designer take thickness out of a section while keeping load capacity, which shows up directly in the weight of a shipped structure.
Eight Zinc Classes to Choose From
Coating is specified as G20, G30, G40, G60, G90, Z150, Z275 or Z350, so an indoor stud and an exposed purlin can be bought on the same order at different zinc weights.
Hot Dipped or Electro on the Same Order
Hot dipping gives the heavier layer for outdoor work and electro galvanizing gives the thin even surface that paints well, and both routes are available.
Familiar Designations for Export Drawings
A36, SS400, S275jr and A653 are quoted alongside the G grades, so a drawing written to an American, Japanese or European designation can be supplied without a substitution argument.
Factory Direct From China
Coil is sold direct from the works in Shandong with ISO9001, BV, SGS and RoHS documents, which shortens the chain between the galvanizing line and your decoiler.
Problems It Solves
What This Material Removes From Your Process
Sending Formed Parts Out for Galvanizing
Post galvanizing adds a subcontractor, a transport leg and a distortion risk on thin sections. Coil that arrives coated removes the whole stage from the route card.
Sections Heavier Than the Design Needs
Using a commercial grade forces extra thickness to reach the load. Moving to G450 or G550 lets the section come down in gauge while the structure keeps its capacity.
One Zinc Weight for Every Part
Buying a single coating class means indoor parts carry zinc they do not need while exposed parts may not carry enough. Specifying per part across G20 to Z350 fixes both ends.
Paint Lifting off a Heavy Zinc Layer
A thick spangled surface is not always the right base for paint. Electro galvanized coil gives the thin even layer a paint line expects.
Drawings Written to Foreign Designations
An export order quoting A36, SS400 or S275jr does not have to be reworked into a local grade because those designations are supplied as ordered.
Application Scenarios
Where It Is Used
Roofing and Wall Sheet Production
Corrugated and trapezoidal profiles roll formed straight from coil for roofing and cladding on industrial buildings.
Light Steel Framing Manufacture
Studs, tracks and joists formed from G450 and G550 coil where high strength thin gauge sections carry the design load.
Purlin and Girt Roll Forming
C and Z sections produced continuously from coil for portal frame buildings, using a heavier zinc class where the member is exposed.
HVAC Duct and Enclosure Fabrication
Ductwork, cabinets and enclosures stamped and folded from electro galvanized coil that will later be painted.
Greenhouse and Solar Mounting Structures
Frame members and mounting rails formed from Z275 or Z350 coated coil for structures that stay outdoors for their whole life.
General Fabrication and Bracketry
Sheared blanks, brackets and folded parts where a coated coil removes a finishing operation from the shop.
Who It Is For
Buyers Who Specify This Product
- Roofing sheet producers feeding coil directly into corrugating and trapezoidal lines
- Light steel framing manufacturers specifying G450 and G550 for thin gauge sections
- Purlin roll formers buying heavier zinc classes for exposed building members
- HVAC and enclosure fabricators taking electro galvanized coil for painted assemblies
- Solar mounting and greenhouse builders sourcing Z275 and Z350 coated coil
- Importers and service centers holding coated coil stock for regional forming shops
Technical Data
Specifications and Technical Features
Values below come from the product data published by Shandong Tianyu Metal Products. Confirm the exact grade and size against your order.
| Product Name | Galvanized Steel Coil |
|---|---|
| Also Known As | GI coil zinc coated steel coil |
| Steel Grade | G250 G350 G450 G550 A36 SS400 S275jr A653 |
| Zinc Coating | G20 G30 G40 G60 G90 Z150 Z275 Z350 |
| Galvanizing Technology | Hot dipped or electro |
| Form | Full width coil |
| Related Product | Aluminum zinc coated steel coil |
| Size | Customized |
| Place of Origin | China |
| Supply | China factory direct sales |
| Certificate | ISO9001 BV SGS RoHS and mill test certificate |
Technical Features
- Steel grades G250 G350 G450 G550 A36 SS400 S275jr and A653
- Zinc coating classes G20 G30 G40 G60 G90 Z150 Z275 and Z350
- Hot dipped galvanizing for heavier zinc and outdoor service
- Electro galvanizing for a thin even surface under paint
- Supplied as full width coil for direct decoiling
- Also available as aluminum zinc coated coil
- China factory direct supply with ISO9001 BV SGS and RoHS documents
Materials
- Structural base steel in G250 G350 G450 and G550
- Commercial and structural grades A36 SS400 S275jr and A653
- Zinc coating applied by hot dip or electro galvanizing
- Aluminum zinc coating where a galvalume surface is ordered instead
Certification
- ISO9001
- BV
- SGS
- RoHS
- Mill test certificate supplied with each shipment
Manufacturing
How It Is Made and Processed
Cold rolling the base steel to coil gauge
Cleaning and annealing ahead of the coating line
Hot dip galvanizing or electro galvanizing to the ordered class
Skin passing and levelling for surface and flatness
Chemical passivation and oiling as ordered
Recoiling and weighing
Eye or side wrapping with edge protectors for export loading
Quality Control
Checks Before It Ships
- Base grade verified against the ordered G or A designation
- Zinc coating class checked against the ordered G or Z code
- Coil surface inspected for spangle uniformity and coating continuity
- Flatness and edge condition checked after skin passing
- Coil weight and inner diameter confirmed against the order
- Mill test certificate issued for the grade and coating supplied
Customization
What We Can Change on Your Order
- Steel grade ordered from G250 through G550 or as A36 SS400 S275jr A653
- Zinc coating class ordered anywhere from G20 through Z350
- Hot dipped or electro galvanizing route chosen per coil
- Coil weight and inner diameter matched to your decoiler
- Aluminum zinc coated coil supplied where a galvalume surface is preferred
- Coil slit to narrower strip where a forming line needs it
Comparison
Galvanized Steel Coil Against the Alternatives
| Uncoated cold rolled coil | Corrosion protection arrives with the coil, so the formed part skips the galvanizing or painting stage that bare coil forces on the shop. |
|---|---|
| Aluminum zinc coated galvalume coil | Zinc coated coil is the usual choice where parts are welded and touched up, while an aluminum zinc surface is chosen mainly for reflectivity and heat exposure. |
| Hot dip galvanizing after fabrication | Pre coated coil avoids the bath, so a thin gauge section does not distort and there is no subcontract turnaround to schedule around. |
| Pre painted PPGI coil | Plain galvanized coil leaves the final color and paint system to you, which suits fabricators who already run a paint line. |
Use Guide
Specifying Handling and Welding Notes
- Match the zinc class to the exposure and keep Z275 or Z350 for anything permanently outdoors
- Use electro galvanized coil where the assembly is painted and a thin even coating is wanted under the primer
- Check the section design against G450 or G550 before ordering a lower grade in a thicker gauge
- Confirm coil inner diameter and maximum weight against your decoiler before the coils are wound
- Seal or touch up cut edges and welds on exposed parts because those areas lose the coil coating
- Keep coils indoors and wrapped until use because trapped moisture between wraps causes white storage staining
Questions Buyers Ask
Galvanized Steel Coil FAQ
Which grades can you supply in galvanized coil?
G250, G350, G450 and G550 for structural work, plus A36, SS400, S275jr and A653 where a drawing calls those designations.
What zinc coating classes are available?
G20, G30, G40, G60, G90, Z150, Z275 and Z350. The class is chosen for how exposed the finished part will be.
Should we take hot dipped or electro galvanized coil?
Hot dipped for outdoor and structural duty where a heavier zinc layer is wanted. Electro galvanized where the part is painted and needs a thin, even coating.
Can you supply aluminum zinc coated coil instead?
Yes. Aluminum zinc coated coil is supplied from the same works if a galvalume surface suits the application better than plain zinc.
Do you sell direct from the factory?
Yes. Coil is sold as China factory direct sales from Shandong, which keeps the chain between the coating line and your decoiler short.
What documents come with the coil?
A mill test certificate for the grade and coating supplied, with ISO9001, BV, SGS and RoHS documents available on request.
Can the coil be slit before shipment?
Yes. Coil can be slit to narrower strip if your forming line runs a fixed width. Send the width and coil weight your decoiler takes.
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