Mô tả

1. OVERVIEW OF PRE-PAINTED GALVANIZED STEEL COILS

Also known as color-coated steel, coil-coated steel, or pre-painted galvanized steel (PPGI), this type of steel is cost-effective and features a protective zinc coating to prevent corrosion. The zinc layer provides anodic protection, extending the product’s service life.

2. FEATURES OF PRE-PAINTED GALVANIZED STEEL COILS

1. The coating can be applied on both sides of the metal, creating a high-quality finished surface that is uniform in color, thickness, texture, and performance.

2. High-quality PPGI improves environmental friendliness in manufacturing while addressing surface issues such as oil and dust contamination.

3. Wide range of applications in manufacturing: from metal roofing, household appliances, wall panels, beverage cans, automotive components to office equipment.

3. COATING TYPES

Coating Type	Features	Best For
Polyester (PE)	Economical, good color retention	Indoor equipment, warehouses
PVDF (Fluoropolymer)	Resistant to harsh weather, UV-resistant	Coastal buildings, stadiums
SMP (Silicone-modified Polyester)	Medium durability, better heat resistance	Industrial roofs, parking structures
PVC (Polyvinyl Chloride)	Flexible, impact-resistant, waterproof	Trailers, industrial floors
PU (Polyurethane)	High abrasion and chemical resistance	Automotive parts, machinery panels
HDP (High-Durability Polyester)	Enhanced UV and corrosion protection	Architectural cladding, solar panels

4. SPECIFICATIONS

Standards: JIS / EN / ASTM

Steel Grades: SGCC / DX51D / S250GD / DX52D / DX53D / S280GD / S320GD / S350GD

Coating Layers:

• Primer: PU or Epoxy 5µm

• Topcoat: 15–20µm

• Back primer: PU or Epoxy

• Backcoat: PE or Epoxy 5–12µm

Zinc Texture: Regular / Minimized / None

Sizes: Thickness: 0.15–1.2mm; Width: 900–1250mm

Delivery Conditions: 2/1, 2/2

5. MANUFACTURING PROCESS

The production process mainly involves two steps: galvanizing and painting.

5.1. Galvanizing
Purpose: To create a zinc coating that protects the steel from oxidation and extends product life. Two main methods:

• Hot-dip galvanizing: Steel is immersed in molten zinc at ~450°C, producing a thick and durable coating (30–275 g/m²), suitable for outdoor applications requiring high corrosion resistance.

• Electro-galvanizing: Zinc is applied through electrolysis, producing a thinner coating (10–50 g/m²) with a smooth, uniform surface, ideal for products needing precise or decorative coatings.

5.2. Painting
After galvanizing, multiple layers of paint are applied to improve adhesion, aesthetics, and corrosion resistance.

• Primer (5–20µm): Enhances adhesion between zinc layer and topcoat. Epoxy resin is commonly used for its adhesion and corrosion resistance.

• Topcoat (10–40µm): The main decorative and protective layer determining color durability, gloss, and weather resistance. Depending on requirements, common options include:

  • Polyester (PE) – economical and widely used

  • PVDF – highly weather-resistant and color-stable

  • SMP – heat-resistant, mechanically durable

• Optional back coating: Applied to the reverse side of the coil to improve corrosion resistance and reduce scratches during handling and processing.

5. APPLICATIONS OF PRE-PAINTED GALVANIZED STEEL COILS

Thanks to its corrosion resistance, mechanical strength, and aesthetic appeal, PPGI is widely used in:

• Roofing & wall panels: Industrial buildings such as factories and warehouses, as well as residential buildings, providing durability and modern aesthetics.

• Household appliances: Ideal for refrigerator, washing machine, oven, and other appliance enclosures due to durable, easy-to-clean surfaces.

• Automotive parts: Used for body panels and chassis components to enhance strength, reduce weight, and improve safety performance.

• HVAC ducts: Applied in ventilation and air-conditioning systems, offering corrosion resistance and long service life.

• Agricultural constructions: Resistant to fertilizers and chemicals, making PPGI a reliable material for barns, greenhouses, and other agricultural structures.