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镀锌钢卷: 生产流程, 牌号和应用
镀锌钢卷, 通常称为 GI 线圈, is a low carbon steel coil coated with a layer of zinc through a hot-dip galvanizing process. The zinc layer protects the steel from corrosion by acting as both a barrier and a sacrificial anode, extending the service life of the product by many years. This article explains how galvanized steel coil is produced, what the common grades and zinc coatings are, and where GI coil is used.
How Galvanized Steel Coil Is Produced
- Cold rolled or hot rolled steel coil is first cleaned in alkaline and acid baths to remove oil, rust and scale.
- The cleaned strip passes through a flux solution, then enters a bath of molten zinc at about 450-460 degree C.
- A controlled layer of zinc is deposited on both surfaces of the strip by the hot-dip process.
- The coated strip is cooled, passivated, oiled or chromated to protect the fresh zinc surface.
- The strip is rewound into coil, slit to required widths, or cut to length according to customer requirements.
Common Grades
The most common base metal grades for galvanized coil are DX51D (在 10346), SGCC (JIS G3302) and CS type B (ASTM A653). These low carbon grades offer excellent formability for bending, stamping and roll forming. For higher strength applications, grades such as DX52D, S350GD or structural grades can be supplied.
Zinc Coating Designations
| Zinc designation | Zinc coating (g/m2) | Typical applications |
|---|---|---|
| Z80 | 80 | Indoor panels, light furniture |
| Z120 | 120 | Roofing sheets, general forming |
| Z180 | 180 | Building profiles, cable trays |
| Z220 | 220 | Outdoor structures, agricultural equipment |
| Z275 | 275 | Heavy-duty roofing, guardrails, 汽车零件 |
Surface Finishes
- Regular spangle: crystalline zinc pattern, standard choice for general use.
- Minimized spangle: fine, uniform appearance, suitable for visible applications.
- Zero spangle: smooth uniform surface, ideal for painting and powder coating.
- Skin-passed: improved flatness and surface quality for demanding forming.
Key Applications
- Building and construction: roofing sheets, 墙板, purlins, cable trays
- Home appliances: washing machines, 冰箱, air conditioner casings
- 汽车: chassis parts, silencer shells, 结构件
- Agriculture: silos, grain dryers, livestock equipment
- General industry: steel furniture, 包装, 容器, ducts
Advantages of Galvanized Steel Coil
- Long service life with minimal maintenance
- Excellent corrosion resistance at low cost compared to stainless steel
- Good formability and paintability
- Available in a wide range of thicknesses, widths and zinc coatings
- Fully recyclable and environmentally friendly
Conclusion
Galvanized steel coil is a cost-effective, corrosion-resistant material that underpins countless building, appliance and industrial products. QIDAMT supplies DX51D and SGCC galvanized coils with zinc coatings from Z80 to Z275, in regular, minimized or zero spangle finishes, with mill test certificates and prompt delivery. Contact us today for a quote.
