Against the backdrop of the continuous upgrading of material durability and aesthetics demands in the global construction, home appliance, and automotive industries, PPGI steel sheets are becoming the mainstream choice in the market due to their dual advantages of "galvanized protection+color coating decoration". This composite material, which is made of hot-dip galvanized or aluminum zinc plated sheet as the substrate and coated with organic coatings such as polyester and fluorocarbon after surface pretreatment, not only has a salt spray resistance test of over 500 hours, but also achieves more than 200 color choices through RAL color card customization. From home appliance shells to building curtain walls, from automotive components to industrial containers, PPGI steel sheets are reshaping industry application standards with their "high cost-effectiveness+personalization" characteristics.

1. Definition and Composition

PPGI steel sheet, also known as pre coated galvanized steel plate, is a composite metal material made of hot-dip galvanized sheet or aluminum zinc coated sheet as the substrate, which is coated with organic coating after surface chemical treatment. Its core structure consists of three layers: the bottom layer is a 40-60g/㎡ zinc layer (aluminum zinc plated plate containing 5% aluminum), the middle layer is the substrate (thickness 0.12-1.5mm), and the surface layer is anti-corrosion coatings such as polyester, silicon modified polyester or fluorocarbon resin, with a total thickness of 0.15-1.2mm.

2. Production process and characteristics

The manufacturing of PPGI steel sheets needs to be completed through a four stage color coating production line:
(1) Entrance section: unwinding, sewing, pressure roller adjustment of tension to ensure uniform substrate transportation;
(2) Pre treatment stage: alkaline washing and degreasing to remove oil stains, passivation treatment to enhance coating adhesion;
(3) Coating section: Double sided coating is carried out using roller coating technology, which undergoes "initial coating+baking+fine coating+baking" two coatings and two baking curing, with a coating thickness of 10-25 μ m (topcoat) and 5-20 μ m (back coat);
(4) Export section: Wind cooled and coiled, supporting customized processing such as slitting and pressing.
This material combines the anti-corrosion properties of galvanized sheet (salt spray resistance test ≥ 500 hours) with the decorative properties of the coating. It can be customized with 1925 colors of RAL color cards and biomimetic patterns such as wood and brick patterns.

3. Application Fields and Advantages

(1) Home appliance industry: 75% of global home appliance casings use PPGI steel sheets, such as Haier refrigerator side panels using 0.5mm thick fluorocarbon coating plates, which are fingerprint resistant and scratch resistant;
(2) In the field of architecture, as roof tiles and wall panels, its lightweight (density 7.85g/cm 3) and weather resistance (PVDF coating color retention period ≥ 15 years) are superior to traditional color steel;
(3) Transportation facilities: The high-speed railway platform canopy is made of 0.8mm thick PPGI steel sheet, which can withstand temperature differences of -40 ℃ to 80 ℃ without deformation;
(4) Industrial equipment: The shell of mining machinery is coated with 1.2mm thick epoxy resin board to resist acid and alkali corrosion.

4. Association and Differences with Perforated Galvanized Sheet

PPGI steel sheet and perforated galvanized steel plate are both derivatives of galvanized steel plate, but their functional focus is different:
(1) Process complementarity: Perforated galvanized sheet is punched to form holes, suitable for ventilation and filtration scenarios; PPGI steel sheets are coated to enhance corrosion resistance and aesthetics, and can be used in combination. For example, perforated PPGI steel sheets for building curtain walls have both drainage and decorative functions;
(2) Performance difference: The weather resistance of PPGI steel sheet coating is better than that of ordinary galvanized plate, while the perforated structure may reduce local corrosion resistance, which needs to be compensated by increasing the coating thickness (such as ≥ 80 μ m);
(3) Cost comparison: Taking 0.5mm thick plate as an example, the price of PPGI steel sheet is about 6900-7000 yuan/ton. Perforated galvanized plate has a processing fee that is 10% -15% higher, but the material consumption per unit area is reduced by 20%, resulting in similar overall costs.
PPGI steel sheets are widely used in industries such as construction, automotive, and home appliances, especially in environments that require long-term exposure to weather and other corrosive elements, such as roofs, exterior walls, car bodies, and home appliance casings, providing long-lasting performance protection. Its coating materials are diverse, including polyester paint, epoxy resin, fluorocarbon resin, etc., which can be selected according to different usage environments and needs.