Galvanized Steel + Paint – Zinc-coated steel with primer and factory-applied decorative paint layers.
Z30–Z275 Zinc Options – Zinc coating selected according to corrosion, forming and project requirements.
PE SMP HDP PVDF Coatings – Multiple paint systems available for different service environments.
Custom RAL Colors – Thickness, width, color, gloss, coating thickness and coil weight can be customized.
Complete Export Documents – MTC, COO and full commercial and shipping documentation available.
Pre-Painted Galvanized Iron, commonly abbreviated as PPGI, is galvanized steel that receives a factory-applied organic coating system before being formed into roofing panels, wall cladding, sandwich panels, appliance components or other finished products.
Although the traditional trade name uses the word "iron," modern PPGI is normally manufactured from galvanized steel rather than pure iron. The galvanized substrate provides zinc-based corrosion protection, while the primer and finish coatings add color, surface protection and the required appearance.
Henan GDD supplies PPGI for roofing manufacturers, roll-forming factories, sandwich-panel producers, steel distributors and industrial fabricators. Steel grade, zinc coating, paint system, color, gloss, thickness, width, coil ID and coil weight can be selected according to the customer's production line and final application.
For repeat or replacement projects, buyers can provide an existing MTC, coil label or purchase specification. Reviewing the complete coating system is usually more reliable than matching only the RAL color and nominal thickness.
| Item | Specification |
|---|---|
| Product Name | Pre-Painted Galvanized Iron / PPGI / Prepainted Galvanized Steel |
| Substrate | Hot-Dip Galvanized Steel / GI Steel |
| Common Grades | DX51D+Z, DX52D+Z, DX53D+Z, S250GD+Z, S280GD+Z, S320GD+Z, S350GD+Z, SGCC, SGCH or Equivalent |
| Common Standards | EN 10169, EN 10346, ASTM A755/A755M, JIS G3312 or Customer Specification |
| Thickness | Approximately 0.12 – 1.20 mm or Customized According to Grade and Mill Capability |
| Width | Typically 600 – 1250 mm or Customized |
| Zinc Coating | Approximately Z30 – Z275 g/m² Total Both Sides or Customized According to Applicable Specification |
| Common Zinc References | Z30, Z40, Z60, Z80, Z100, Z120, Z140, Z180, Z200, Z225, Z275 or Agreed Coating Mass |
| Zinc Coating Structure | Normally Double-sided; Differential or Special Single-side Requirements Subject to Mill Confirmation |
| Paint System | PE, SMP, HDP, PVDF or Customized Organic Coating System |
| Top Coating Thickness | Typically 10 – 35 μm or Customized According to Paint System |
| Back Coating Thickness | Typically 5 – 25 μm or Customized |
| Color | RAL Colors, Customer Samples or Customized Color Matching |
| Finish | Glossy, Semi-gloss, Matte, Wrinkle, Textured, Embossed, Wood Grain or Customized |
| Coil ID | 508 mm / 610 mm or Customized |
| Coil Weight | Typically 3 – 8 MT or Customized According to Customer Equipment |
| Edge | Mill Edge / Slit Edge |
| Processing | Slitting, Cut-to-length, Corrugating, Profiling and Customized Processing |
| Applications | Roofing, Wall Cladding, Sandwich Panels, Appliances, Doors, Ceilings, Roll-formed Profiles and Industrial Fabrication |
| Inspection | Dimensions, Zinc Coating, Paint Thickness, Color, Gloss, Surface Appearance, Mechanical Properties and Third-party Inspection Where Required |
| Available Documents | MTC, Certificate of Origin, Export License Where Applicable, Commercial Invoice, Packing List, Bill of Lading and Customs Documents |
| Packing | Waterproof Wrapping, Protective Steel Sheet, Edge Protectors, Steel Straps and Seaworthy Export Packing |
| Trade Terms | EXW, FOB, CFR, CIF |
Zinc coating and paint specifications should be confirmed separately. A description such as "0.50 mm PPGI, RAL 9003" does not fully define the product because substrate grade, zinc coating, paint system, paint thickness, back coating and dimensional tolerances can all affect price and service performance.
Pre-Painted Galvanized Iron is galvanized steel that has been cleaned, chemically pretreated, primed, painted and cured on a continuous coil-coating line before being delivered to the fabricator.
The term PPGI comes from "Pre-Painted Galvanized Iron," although the metallic substrate used today is normally galvanized steel.
Unlike steel that is painted after roofing sheets or panels have already been formed, PPGI receives its coating under controlled factory conditions while the material is still in coil form.
PPGI is not simply a steel coil with one layer of colored paint.
A typical structure starts with the steel substrate. Zinc coatings are applied to both surfaces of the steel, followed by surface pretreatment. The exposed side then receives primer and a decorative top coat, while the reverse side normally receives a suitable back coating.
In simplified form, the exposed side consists of steel substrate, zinc coating, pretreatment, primer and topcoat. The reverse side normally consists of steel, zinc, pretreatment and back coating.
Each layer has a different function. The steel provides mechanical strength, zinc provides metallic corrosion protection, pretreatment improves coating adhesion, primer supports corrosion resistance and adhesion, and the finish coat provides color, weather resistance and surface appearance.
PPGI manufacturing normally begins with a hot-dip galvanized steel coil that already meets the required base-steel grade, thickness, width and zinc coating specification.
The GI substrate is checked for dimensions, zinc coating and surface condition before entering the coating process.
Oil, dust and surface contaminants are removed so that subsequent chemical treatment and paint layers can bond consistently to the galvanized surface.
A controlled pretreatment is applied to improve paint adhesion and support corrosion performance between the zinc surface and primer.
Primer is applied to provide a stable interface between the metallic substrate and finish coat. Primer selection depends on the coating system and intended service environment.
The visible side receives the required finish coat, while the reverse side normally receives a back coating selected according to application requirements.
The coated strip passes through controlled curing ovens so that the paint system develops its required adhesion and film properties.
After curing, the strip is cooled and inspected for paint thickness, color, gloss, surface appearance and coating defects.
The finished PPGI strip is recoiled, labeled and packed for downstream roll forming, cutting or international shipment.
GI and PPGI share a similar galvanized steel base, but the finished surfaces are different.
Ordinary GI normally retains its silver-gray zinc surface and is often used for HVAC ducts, framing, fabrication and products that do not require factory-applied decorative color.
PPGI adds pretreatment, primer and organic coatings over the galvanized substrate. This creates a finished color and provides another protective barrier between the environment and zinc coating.
For roofing and wall cladding, PPGI is frequently selected because the material can be roll formed directly into finished colored panels without requiring a separate post-painting operation.
Paint alone does not replace the role of the galvanized substrate.
The organic coating acts primarily as a barrier and decorative layer, while zinc provides additional protection to the underlying steel, particularly around small scratches, forming areas and exposed cut edges.
This is why two PPGI coils with identical RAL color and paint thickness can have different long-term performance when their zinc coating masses are significantly different.
Standard hot-dip galvanized substrates used for PPGI are normally zinc coated on both sides.
When a coating designation refers to total coating mass, the stated value generally represents the combined zinc coating on both surfaces under the applicable specification.
For example, a nominal total coating of 100 g/m² distributed approximately equally would correspond to roughly 50 g/m² on the front side and 50 g/m² on the reverse side.
The actual distribution is subject to production control and applicable tolerances, so this simple division should be treated as an explanatory estimate rather than a substitute for formal coating measurement.
True single-sided galvanized steel is different from normal PPGI substrate.
In a true single-side configuration, one surface receives a defined zinc coating while the other surface remains uncoated or receives another specified treatment.
This is a specialized requirement and is not the standard construction for most hot-dip galvanized PPGI products.
If a customer requires single-sided galvanizing, the coated side, required zinc mass and condition of the opposite surface should be specified separately and mill capability must be confirmed before quotation.
Differential galvanizing means both sides contain zinc but the coating mass is intentionally different between the two surfaces.
It can be considered where one surface requires greater corrosion protection than the other.
Differential hot-dip coating is not available from every coating line, so buyers should specify the required coating mass for Side A and Side B rather than simply requesting "one-side galvanized."
In many commercial export quotations, Z30 is used to indicate approximately 30 g/m² total zinc coating across both surfaces.
If approximately equally distributed, this would be around 15 g/m² on each side.
Z30 is a light zinc coating and is generally considered for relatively protected or cost-sensitive applications where the customer's technical specification permits it.
Z30 is not a formal coating class in every international standard, so the actual coating mass and test requirement should be clearly written into the purchase specification.
Z40 is commonly used commercially to indicate approximately 40 g/m² total zinc coating across both surfaces.
An approximately equal distribution would correspond to around 20 g/m² on each surface.
Like Z30, Z40 is considered a relatively light metallic coating. It may be commercially attractive for indoor or protected applications but should not automatically be selected for demanding outdoor exposure.
Z100 generally refers to approximately 100 g/m² total zinc coating across both surfaces under commonly used EN-style terminology.
If the coating is approximately equal, each side contains around 50 g/m² of zinc.
Z100 is frequently requested for PPGI roofing and general construction products where buyers need more metallic protection than very light commercial zinc coatings.
Z275 represents a considerably heavier zinc coating, with a nominal combined coating mass of approximately 275 g/m² across the two surfaces under commonly used EN-style terminology.
Heavier zinc coating provides a larger zinc reserve, but complete service performance still depends on paint quality, environment, cut edges, forming damage, maintenance and installation.
Z275 should therefore be selected because the specification or service environment requires it rather than simply assuming the highest coating mass is always the best economic choice.
One common purchasing mistake is treating a Z coating designation and an ASTM G designation as the same number.
EN-style zinc coating terminology is normally expressed in grams per square metre, while ASTM A653 uses coating designations such as G30, G60 and G90 based on a different unit and designation system.
A buyer changing between standards should therefore compare the actual coating mass and standard requirements instead of matching the numbers directly.
Zinc coating is only one part of the PPGI protection system, but it remains an important specification.
Lower zinc coating can reduce material cost for suitable protected applications. Higher coating mass provides more metallic zinc and may be appropriate for more demanding environments.
The correct coating should be selected together with paint type, paint thickness, project location and expected service conditions.
Polyester, commonly abbreviated as PE, is one of the most widely used paint systems for Pre-Painted Galvanized Iron.
PE provides a practical balance of cost, color availability, formability and general outdoor performance.
It is commonly selected for standard roofing, wall panels, ceilings, general building materials and indoor manufacturing applications.
Actual coating performance depends on paint formulation, film thickness, substrate and service environment rather than the PE name alone.
Silicone Modified Polyester, or SMP, modifies polyester chemistry to improve selected weathering and hardness characteristics.
It can be used for roofing and exterior building components where the buyer requires a performance level above general-purpose polyester.
Paint formulation varies between coating suppliers, so required performance should be defined through the applicable specification rather than relying only on the SMP abbreviation.
High Durability Polyester, commonly referred to as HDP, is designed to provide improved durability compared with conventional general-purpose polyester systems.
HDP is considered for roofing and cladding projects where longer-term exterior appearance and weather resistance are important but PVDF is not specifically required.
Color retention, film properties and warranty conditions depend on the actual coating system and supplier specification.
PVDF coating systems are commonly specified for architectural applications requiring strong color retention and resistance to long-term outdoor weathering.
They are often considered for higher-value building façades, exterior cladding and projects exposed to demanding sunlight and weather conditions.
PVDF generally costs more than basic PE systems, so its use should be matched with the expected service environment and project specification.
Paint selection should start with the service environment rather than budget alone.
General indoor or standard building applications can often use PE. Projects requiring increased exterior durability may consider SMP or HDP. Architectural applications requiring stronger long-term weathering and color-retention performance may specify PVDF.
Factors such as UV exposure, humidity, coastal salt, industrial pollution, required appearance and expected service period should be considered when selecting the coating system.
PPGI normally uses different coating constructions on its exposed and reverse surfaces.
The exposed side typically receives primer plus the main decorative topcoat. The reverse side usually receives a thinner back coat because it may not experience the same visual or environmental exposure.
A common commercial configuration might use approximately 15–25 μm on the top side and a thinner coating on the reverse side, although actual specifications vary considerably.
Buyers should state both top and back coating requirements when these parameters are important to the finished product.
Paint thickness affects appearance, coverage and protective performance, but thicker is not automatically better in every application.
Coating formulation, primer, curing, adhesion and substrate preparation all influence the finished performance.
A well-controlled coating system at the specified film thickness is generally more useful than comparing products only by the highest claimed micrometre value.
RAL references are widely used to communicate PPGI color requirements for international building-material projects.
Common requests include white, blue, gray, red, brown, green and other architectural colors.
However, the same RAL reference can appear slightly different depending on gloss, texture, paint chemistry, lighting and production batch.
For projects requiring strict color matching, Henan GDD recommends approving a physical sample or agreed color reference before mass production.
Not all Pre-Painted Galvanized Iron uses a smooth glossy finish.
Matte, wrinkle and textured surfaces can provide a lower-gloss appearance and create greater visual differentiation for roofing and architectural products.
Surface texture can also affect perceived color, so sample confirmation is particularly useful for decorative projects.
Decorative wood-grain finishes can be produced for selected PPGI applications where customers require the appearance of timber with the processing advantages of coated steel.
Typical applications include doors, interior panels, decorative cladding and fabricated building products.
Wood pattern, color, gloss and repeat layout should be confirmed through an approved sample before mass production.
Roofing is one of the most common applications for Pre-Painted Galvanized Iron.
Master coils are fed into roll-forming lines and shaped into corrugated, trapezoidal, tile-profile or other roofing sheets.
Important raw-material parameters include thickness, steel strength, zinc coating, top paint system, coating thickness, color, width and maximum coil weight.
Buyers should also consider the local environment because inland, industrial and coastal roofing projects can have different corrosion and coating requirements.
PPGI is used for exterior and interior wall panels in warehouses, factories, commercial buildings and prefabricated structures.
Wall cladding often places more emphasis on long-term appearance and color consistency because large areas of material remain visible.
For multi-batch projects, color references and coating systems should remain consistent across deliveries where possible.
Sandwich-panel manufacturers use painted steel skins around insulation cores such as EPS, PU, PIR or mineral wool.
Surface coating, steel thickness and bonding characteristics should be selected according to the panel manufacturing process.
Customers should specify whether the material will be used on the exterior or interior surface because paint and back-coat requirements may differ.
Prepainted galvanized steel is also used for cabinets, appliances, doors, ceiling systems and fabricated products.
These applications can require tighter control of surface appearance, gloss, color and scratch resistance than standard roofing material.
Steel formability should also be matched with downstream bending and forming operations.
DX51D galvanized substrate is widely used for general PPGI roofing and roll-forming applications.
It provides practical forming performance for standard profiles where severe deep drawing is not required.
A complete DX51D PPGI specification should also identify zinc coating, paint system, paint thickness, width, color and surface finish.
Structural galvanized grades such as S250GD, S280GD, S320GD and S350GD can be used when the finished profile requires higher strength.
Higher-strength steel can benefit selected structural profiles but may also affect bending and roll-forming behavior.
Grade selection should therefore follow the profile design and forming capability rather than automatically replacing a softer grade with a stronger one.
A technically useful PPGI inquiry should contain more information than color and thickness.
Buyers should specify steel grade, thickness, width, zinc coating, paint system, top and back coating thickness, RAL color, surface finish, coil ID, preferred coil weight and quantity.
The application should also be provided because roofing, exterior cladding, sandwich panels and appliances have different priorities.
If the buyer currently uses material from another supplier, an existing MTC or coil specification provides a useful technical reference.
Matching the color does not mean the coating system is equivalent. PE and PVDF coils can use the same RAL color but offer different coating structures and costs.
Two PPGI coils can use the same paint and appearance while using significantly different galvanized substrates.
A total Z100 coating does not normally mean Z100 on each side. Buyers should clarify total and per-side requirements before purchase.
Z30 is frequently used commercially, but it is not a formal coating designation under every international standard.
The reverse side of roofing or panel material can still experience humidity and condensation. Back-coat specifications should not be ignored when service conditions are demanding.
A 7-ton coil may be technically correct but unusable on a production line designed for a maximum 3-ton or 5-ton coil.
A typical roofing manufacturer serving a cost-sensitive market may require DX51D PPGI with a relatively light zinc coating, standard PE paint and a common RAL color.
In this situation, the customer should confirm that the proposed zinc coating meets the actual service environment rather than selecting Z30 or Z40 only because it provides a lower purchase price.
Coil width and maximum coil weight are also reviewed to match the customer's roll-forming equipment.
A building-envelope customer may prioritize color retention and outdoor durability more heavily than a general roofing distributor.
For this type of project, the technical review can include higher zinc coating, HDP or PVDF paint, specified top-coat thickness and approved physical color samples.
The final specification is based on the project environment and engineering requirements rather than using the same PPGI construction as an indoor panel.
A sandwich-panel factory may require different colors and thicknesses for exterior and interior panel skins while maintaining compatible coil widths and controlled coil weight.
The customer normally pays close attention to surface consistency, adhesion, profile forming and compatibility with its continuous panel-production line.
A steel distributor changing suppliers may provide the current coil label or MTC showing grade, thickness, zinc coating and coil dimensions.
Henan GDD can compare these parameters together with paint type, coating thickness and color before preparing a replacement quotation.
These examples describe typical procurement scenarios. Customer names, confidential prices and proprietary project specifications are not published without authorization.
Once a PPGI specification has been approved on a customer's production line, consistency usually becomes more important than basic product descriptions.
Repeat buyers commonly monitor actual thickness, width, zinc coating, color difference, gloss, paint thickness, forming performance, coil weight and packing condition.
Color consistency deserves particular attention when material from separate production batches will be installed next to each other on the same building.
PPGI quality inspection can include base-metal dimensions, zinc coating, paint thickness, surface appearance, gloss and color comparison according to the approved specification.
Visual inspection also checks for scratches, coating damage, dents, edge defects, contamination and other surface conditions.
Where specified, coating adhesion, bending performance and other tests can be reviewed according to the applicable material standard or purchase contract.
A Mill Test Certificate helps identify the material supplied under an order and provides a technical reference for the galvanized substrate and relevant production specifications.
Depending on the mill and product specification, documentation can include grade, dimensions, zinc coating, mechanical properties, coil identification and other applicable test information.
Coil numbers and labels support traceability between the delivered material and corresponding production documents.
Customers requiring specific certificate items should confirm them before order placement.
Independent third-party inspection can be arranged according to the agreed purchase-contract scope.
Inspection can cover dimensions, surface appearance, zinc coating information, paint specifications, color, product identification, quantity, packing and documentation.
Any additional laboratory testing should be agreed before production so that sampling methods, test standards and acceptance criteria can be confirmed.
Henan GDD supports international PPGI shipments with technical, commercial and customs documentation prepared according to contract and destination-country requirements.
Available documents can include MTC, Certificate of Origin, export license where applicable, commercial invoice, packing list, bill of lading and customs declaration documents.
Product photographs, coil-label photographs, inspection photographs, packing photographs and container-loading photographs can also be supplied according to agreed order requirements.
Destination-specific conformity documents, legalization, chamber endorsement or other special import requirements should be confirmed before order placement.
Pre-Painted Galvanized Iron requires careful protection because damage to the painted surface can affect both appearance and corrosion protection.
Export packing can include waterproof wrapping, protective steel sheet, inner and outer edge protectors, reinforced steel straps and supporting skids.
Coil labels can identify steel grade, thickness, width, zinc coating, color, coil number, net weight and customer shipping marks.
During loading, coil weight distribution and suitable securing should be planned to limit movement during international transportation.
Henan GDD supplies Pre-Painted Galvanized Iron to roofing manufacturers, sandwich-panel factories, roll-forming companies, steel distributors and industrial fabricators.
We support different galvanized substrates, zinc coating masses, PE/SMP/HDP/PVDF systems, RAL colors, coating thicknesses and coil specifications.
For customers comparing Z30, Z40, Z100 or Z275 products, the actual coating requirement can be reviewed in g/m² to reduce confusion between commercial terminology and formal standards.
Existing MTCs, coil labels, physical color samples and purchase specifications can be reviewed before quotation to improve material matching.
Our related coated-steel range also includes GI Steel Coil, Galvanized Steel Sheet, PPGL and Galvalume products, allowing customers to consolidate multiple coated-steel requirements where appropriate.
MTC, Certificate of Origin, export license where applicable and complete commercial and shipping documentation can be provided according to contract requirements.
PPGI commonly stands for Pre-Painted Galvanized Iron. In modern steel trade, the product is normally prepainted galvanized steel manufactured from a galvanized steel substrate.
GI normally retains its metallic zinc surface, while PPGI adds pretreatment, primer and organic paint coatings over the galvanized substrate to provide color and additional barrier protection.
The standard galvanized substrate used for PPGI is normally zinc coated on both surfaces. Special differential or single-side specifications should be confirmed separately.
Normally no. Under commonly used EN-style terminology, Z100 represents approximately 100 g/m² total zinc coating across both surfaces, subject to the applicable specification.
They are commonly used commercially to describe approximately 30 g/m² and 40 g/m² total zinc coating respectively. Because they are not formal coating classes in every standard, the actual g/m² requirement should be clearly confirmed.
There is no single best coating for every project. PE is widely used for general applications, while SMP and HDP can provide enhanced durability. PVDF is commonly selected for demanding architectural applications requiring stronger long-term weathering and color retention.
Yes. RAL colors and customized colors can be produced. For strict color matching, an approved physical sample or agreed reference is recommended.
Yes. MTC, Certificate of Origin, export license where applicable, commercial invoice, packing list, bill of lading and other agreed export documents can be provided.
Please provide steel grade, thickness, width, zinc coating, paint system, top and back coating thickness, RAL color, surface finish, coil ID, preferred coil weight, quantity, destination port and required documentation.
Looking for Pre-Painted Galvanized Iron for roofing, wall cladding, sandwich panels, roll forming or industrial manufacturing?
Send Henan GDD your required grade, thickness, width, zinc coating, paint type, coating thickness, RAL color, surface finish, coil ID, coil weight, quantity, destination port and documentation requirements.
If your current specification only states information such as "0.50 mm PPGI, Z40, RAL 9003," you can also send your existing MTC, coil label or supplier specification. We can review the substrate, zinc coating and paint construction before preparing the quotation.
