PPGL (Pre-Painted Galvalume Steel) is a high-performance construction and industrial material widely used in roofing, façades, appliances, marine components, and lightweight structures. It combines the durability of aluminum-zinc alloy coatings with the aesthetic flexibility of organic coatings, making it ideal for environments requiring corrosion resistance, lightweight properties, and decorative appeal. Wanzhi Group, a leading steel manufacturer from China, specializes in producing and customizing PPGL with various specifications, coatings, and surface effects.
PPGL Introduction
PPGL stands for pre-painted galvalume steel, derived from galvalume steel (GL). It consists of a galvalume steel substrate (55% aluminum, 43.4% zinc, and 1.6% silicon) coated with organic layers such as PE, SMP, PVDF, or HDP. PPGL is typically supplied in coils or pre-cut sheets.
Structure
PPGL comprises four layers:
Substrate: Galvalume steel (Al-Zn alloy coated steel).
Chemical Conversion Layer: Chromate or zirconium-based pretreatment for adhesion.
Primer: 5–20 μm epoxy/polyester resin.
Topcoat: 10–40 μm organic coating .
Mechanical Property Parameters
| Item | Typical Value |
|---|---|
| Tensile Strength | 200 MPa – 450 MPa |
| Elongation | 12% – 25% |
| Pencil Hardness | 1H – 2H |
| Bending Performance | 0T – 1T |
Corrosion and Weathering Resistance
| Test | Performance |
|---|---|
| Salt Spray Test | ≥ 1000 hours (PVDF coating) |
| Humidity Resistance | 1000 hours (40°C, 95% humidity) |
| UV Aging | 2500 hours QUV (gloss retention ≥85%) |
PPGL Specifications
Wanzhi Group produces and sells the popular prepared steel PPGI PPGL, the main difference between the two is the base material, the specifications and coatings are very similar. The difference between the two is that the substrates are different and the specifications and coatings are very similar. You can choose the more cost-effective solution according to your application needs.
Parameter Range
| Property | Value |
|---|---|
| Thickness | 0.15 mm – 1.2 mm |
| Width | 600 mm – 1250 mm (customizable) |
| Coating Type | PE, SMP, PVDF, HDP, Antimicrobial |
| Coating Thickness | 5 μm – 40 μm |
| Substrate Grades | AZ150, AZ185, SGLCC, DX54D+AZ |
Aluminum-Zinc Coating Parameters
| Item | Specification |
|---|---|
| Coating Weight | 30 g/m² – 350 g/m² |
| Alloy Composition | 55% Al, 43.4% Zn, 1.6% Si |
| Surface Treatment | Chromated or chrome-free (eco-friendly) |
Coating parameters
| Item | Parameter Range |
|---|---|
| Coating Type |
|
| Coating Thickness |
|
| Surface Effect | Matte, high gloss, wood grain, stone grain, customized printing |
PPGL Applications
Construction: Lightweight roofing, curtain walls, building facades, noise barriers, refrigeration equipment.
Marine: Ship interiors, offshore platforms, coastal infrastructure.
Appliances: oven panels, refrigerator linings, HVAC systems.
Transportation: High-speed train interiors, truck linings, body components.
Energy: Solar mounting structures, heat sinks, solar panel backsheets.
PPGL Benefits
Excellent corrosion resistance: Aluminum self-repairing oxide layer + organic coating can effectively prevent oxidation and corrosion in environments such as humid or acidic environments.
Weather resistance: the coating is resistant to UV rays and extreme weather conditions, extending its service life.
Lightweight: 30% lighter than PPGI, reducing structural loads, very popular in some high-strength applications.
Thermal conductivity: Highly efficient heat dissipation, suitable for electronic equipment and energy systems.
Aesthetics and flexibility: PPGL surfaces can be coated with a variety of colors and patterns to meet different decorative needs.
Cost-effective: low maintenance costs and lower life cycle costs.
Manufacturing Process
PPGL is made of cold rolled carbon steel or hot rolled carbon steel treated with galvanized aluminum and painted.
Steel substrate preparation:
- Use low carbon steel substrate.
- Remove oil, oxidation and other impurities from the surface of the substrate.
Aluminum plating treatment:
- Aluminum Plating Layer: After the substrate is treated, a layer of aluminum coating is applied to the surface of the steel plate by hot aluminizing process (or electroplating aluminum process). This aluminum coating provides good corrosion resistance and heat reflection.
- Aluminum Coating Thickness: The thickness of the aluminum coating varies depending on the customer’s needs and the application environment, and usually ranges from 20-100 g/m².
Coating process:
- Coatings are selected according to the application requirements, usually polyester (PE), polyvinylidene fluoride (PVDF), epoxy resin or other special functional coatings.
- The coating is rolled onto the surface of the galvanized steel.
- After plating, the coating is cured at high temperatures for better adhesion to the substrate.
Cooling and cutting:
- After the coating is completed, the steel sheet is passed through a cooling section to cure the coating and achieve the proper hardness.
- It is cut into different widths, lengths or coils as required for further processing or direct use.
Quality Inspection:
- The coating is quality checked to ensure that there are no defects such as scratches, blistering, peeling, etc.
Packing & Shipping:
- Rolled into coils or cut into sheets, packed with rustproof paper or plastic film, galvanized iron.
Finished products of PPGL
PPGL is easy to press, bend, and suitable for complex molding, and can be made into a variety of prepainted galvalume steel finished products.Wanzhi Group provides further processing services, supplying color coated steel coils and roofing sheets, profiles, steel structures and so on.
- Color coated steel sheet: It is highly decorative by applying polyester coating in various colors.
- Coils and sheets: PPGL steel can be processed into coils or flat sheets, adapting to the processing needs of different sectors.
- Roof tile materials: the coating effectively blocks UV rays and increases weather resistance.
- Three-dimensional wall decorative panels: good appearance, with a certain degree of strength and durability.
- Home appliance shell: PPGL home appliance board not only has beautiful appearance, but also has certain corrosion resistance and durability.
PPGL Supplier – Wanzhi Group
We have 3 color coated production lines, which can produce PPGL coil and sheet with thickness of 0.12-1.5mm and width of 600-1250mm. Meanwhile, we also have molding machines and slitting machines in our factory, which can provide further processing service for different applications. If you need samples or product quality certificates, please feel free to contact us.
- Services: PPGL ODM/OEM, custom sizes/coatings, free samples.
- Production Capacity: 600,000 tons/year.
- Delivery: 5–45 days for standard orders.
PPGL Quality Standard
The quality test of PPGL includes coating thickness, adhesion, corrosion resistance, erosion resistance, dimensional accuracy, weatherability, fire resistance and so on. The quality of prepared steel needs to comply with international standards such as ASTM, JIS, EN, GB, ISO, etc., and also needs to have a quality inspection certificate to ensure the quality.
Quality Inspection
Coating Thickness
- Method: Tested with a coating thickness gauge
- Requirement: Uniform coating thickness.
Adhesion
- Method: Scribing and tensile test
- Requirements: The coating is tightly bonded to the aluminum-zinc alloy steel substrate, with strong adhesion and no peeling or detachment.
Corrosion resistance:
- Method: Salt spray test over 40 hours
- Requirement: Stability of the coating under various environmental conditions.
Appearance quality
- Method: Visual inspection.
- Requirements: the surface should be free of bubbles, cracks, scratches, oil, dust and other defects.
Dimensional accuracy
- Method: Measuring method
- Requirements: Width, thickness and length error control within ±1mm.
Weather resistance
- Requirements: good ultraviolet aging resistance, long-term exposure to outdoor sunlight does not fade, peeling.
Fire resistance
- Requirements: according to the need to meet the relevant fire standards.
Quality Certifications
ISO 9001, ISO 14001, CE, RoHS.
Compliance with ASTM A792, JIS G3321.
PPGL vs. PPGI/PPAL/Stainless Steel
| Dimension | PPGL (Pre-coated Aluminum Zinc Steel) | PPGI (Pre-coated Galvanized Steel) | PPAL (Pre-coated Aluminum Plate) | Stainless Steel (e.g., 304/316) |
| Base Material | Aluminum-zinc steel (55% Al, 43.4% Zn, 1.6% Si) + Organic coating | Galvanized steel (pure zinc layer) + Organic coating | Aluminum base material + Organic coating | Stainless steel base material (e.g., 304 contains Cr/Ni, 316 contains Mo) |
| Corrosion Resistance | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ |
| Weight | ⭐⭐⭐⭐ | ⭐ | ⭐⭐⭐⭐⭐ | ⭐ |
| Strength & Hardness | 200–450 MPa, surface hardness 1H–2H | 270–550 MPa, surface hardness 2H–3H | 70–150 MPa, low hardness | 500–800 MPa, surface hardness up to 5H |
| Processability | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐ |
| Thermal/Electrical Conductivity | High thermal conductivity, suitable for heat dissipation | Low thermal conductivity, good insulation | Extremely high thermal conductivity, good electrical conductivity | Low thermal conductivity, poor electrical conductivity |
| Appearance & Aesthetic | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ |
| Cost | Medium | Low | High | Extremely high |
| Service Life | 20–25 years (PVDF coating) | 10–20 years (depending on coating type) | 25–30 years (aluminum base material, resistant to aging) | 50+ years (no coating, resistant to extreme environments) |
| Typical Applications | Marine engineering, coastal buildings, electronic heat dissipation structures | General construction roofing/walls, household appliance casings | Decorative facades, lightweight billboards, indoor decoration | Chemical equipment, medical devices, high-end building structures |
FAQ – Prepainted Steel PPGL
Q: Why choose PPGL over PPGI for coastal areas?
A: PPGL’s aluminum-zinc substrate resists salt spray corrosion better than zinc-based PPGI.
Q: Which one is better for high temperature environment, PPGL or PPAL?
A: PPGL’s aluminum-zinc coating has better temperature resistance (≤300°C), while PPAL’s aluminum substrate is easy to soften at high temperature (melting point 660°C).
Q: Can PPGL be used for deep-drawing?
A: Yes, select substrates with ≥18% elongation (e.g., DX54D+AZ).
Q: How to prevent coating scratches during installation?
A: Use protective films and avoid abrasive tools.
Q: Can stainless steel replace PPGL for roofing?
A: Yes, but it is expensive and heavy, PPGL is more economical and practical.
Q: How to deal with PPGL coating after damage?
A: Small area can be repaired locally, large area needs to replace the plate. Regular inspection of coating integrity can extend the service life.
PPGL is the optimal choice for projects demanding lightweight, corrosion resistance, and aesthetic versatility. Contact Wanzhi Group for tailored solutions and price list!