Pre-painted galvanized steel coil (PPGI), also known as color coated steel coil, is a coil product manufactured by applying one or more layers of organic coating onto metal substrates such as hot-dip galvanized steel, galvalume steel, or cold-rolled steel. The process involves surface pretreatment (degreasing, phosphating, passivation), followed by roll coating of organic paint, and finally high-temperature baking and curing. PPGI combines the high strength and excellent formability of the steel substrate with the decorative appearance and superior corrosion resistance of the organic coating.

 

In terms of substrate selection, galvanized steel (GI) offers good corrosion resistance suitable for general corrosive environments, while galvalume steel (GL) provides even better corrosion resistance and heat resistance due to its aluminum-zinc-silicon alloy coating. For coating systems, we offer a wide range of options including Polyester (PE) for general industrial buildings, Silicon-modified Polyester (SMP) for coastal areas, High Durability Polyester (HDP) for corrosive environments such as livestock facilities, and Polyvinylidene Fluoride (PVDF) for harsh conditions like power plants and chemical plants. Custom RAL colors are also available upon request to meet various architectural styles and design requirements.

Our PPGI coils are widely used in the construction industry (steel structure workshops, warehouses, roofing, wall cladding, sandwich panels, roller shutters, etc.), accounting for approximately 80% of total consumption, as well as in the home appliance industry (refrigerators, washing machines, air conditioners, etc.), transportation, furniture, and many other fields. With features such as lightweight, high strength, rich color options, easy installation, and environmental friendliness, PPGI coils are ideal high-quality materials for modern construction and manufacturing

 

Our pre-painted galvanized steel coils are available in a wide range of standard specifications to meet diverse project and processing requirements. Base metal thickness typically ranges from 0.12mm to 2.0mm, with coil widths generally from 600mm to 1500mm, among which 1000mm, 1200mm, 1219mm, and 1250mm are the most common standard widths. For coating thickness, the top coat is typically 15μm to 35μm while the back coat ranges from 5μm to 15μm. Standard coil inner diameters are 508mm or 610mm, with coil weights generally ranging from 3 to 8 metric tons. Base materials include hot-dip galvanized steel (GI) and galvalume steel (GL). Coating systems are available in Polyester (PE), Silicon-modified Polyester (SMP), High Durability Polyester (HDP), and Polyvinylidene Fluoride (PVDF). All specifications can be flexibly customized according to customer requirements.

Pre-painted galvanized steel coils are produced from hot-dip galvanized or galvalume steel coils through a continuous roll coating line. The production process begins with uncoiling and welding: base coils are uncoiled at the entry section, with successive coils welded together using a lap seam welder for continuous production. The strip first enters the chemical pretreatment stage, where degreasing, water washing, phosphating (or passivation) processes remove surface oils and impurities, forming a uniform chemical conversion film to enhance coating adhesion. The pretreated strip then enters the primer coating stage, where a primer coating (typically anti-corrosion paint) is applied to both sides of the strip using precision roll coaters, followed by high-temperature baking and curing in a curing oven. After curing, the strip enters the top coating stage, where the topcoat (color paint) and back coating are applied, followed by another pass through the curing oven for final curing. Coating thickness, color, and gloss are precisely controlled by computer-controlled systems to ensure consistent quality. Finally, the strip is cooled through air cooling and water quenching, and recoiled into finished coils by a recoiler. The entire production line is fully automated by a PLC system, ensuring high efficiency and stable production.

We offer professional slitting services for ppgi steel coils. Using our high-precision slitting line, wide galvanized coils can be slit longitudinally into narrow strips with widths typically ranging from 20mm to 600mm and thicknesses from 0.3mm to 3.0mm. The slit strips can be rewound into smaller coils or cut to straight lengths according to customer requirements, ready for subsequent stamping, roll forming, tube making, cable tray, and bracket applications. All slitting operations strictly control width tolerances and edge quality, ensuring smooth cut edges without burrs to meet precision processing requirements.

Our pre-painted galvanized steel coils are packed with standard sea-worthy export packaging to ensure they arrive in perfect condition after long-distance transportation. Since the coated surface of PPGI coils is relatively fragile, special care must be taken during packaging. The inner layer is wrapped with rust-proof paper or VCI paper to prevent scratches and oxidation; inner and outer protective rings (inner sleeves and outer boards) are fitted to prevent edge deformation and coating damage; the outer layer is fully wrapped with waterproof composite film to create a moisture barrier, secured with high-strength steel strapping, and fitted with plastic edge protectors. Before packaging, a protective film is typically applied to the surface of PPGI coils to prevent minor friction damage during transit.

Each coil typically weighs 5-6 tons. For transportation, small batch orders are typically shipped in 20-foot or 40-foot containers, with coils placed horizontally and secured with wooden mats, wedges, and steel wire ropes; large quantities are shipped by bulk carriers. All packaging materials comply with international shipping standards, ensuring smooth customs clearance and safe long-distance transport.

Pre-painted galvanized steel coils, with their high strength, lightweight, rich color options, corrosion resistance, and excellent formability, are widely used across various sectors of the national economy. In the construction industry (accounting for approximately 80% of total consumption), PPGI coils are extensively used for roofing panels, wall panels, ridges, gutters, corrugated steel sheets, sandwich panels, roller shutter doors, and portable cabins in steel structure buildings. In the home appliance industry, PPGI coils are used for manufacturing shells of refrigerators, washing machines, air conditioners, microwave ovens, and other household appliances. In the transportation sector, they are used for truck body panels, containers, bus shelters, and more. In the furniture industry, they are used for steel furniture, display racks, and shelving systems. PPGI coils are also used in agricultural buildings (greenhouses, livestock farms) and municipal facilities (noise barriers, bus stations). With their aesthetic appearance, weather resistance, fast installation, and low maintenance, PPGI coils have become indispensable high-quality materials in modern construction and manufacturing.