Galvanized Coil
Galvanized Steel Coil/Sheet refers to a steel product made from either cold-rolled or hot-rolled steel coils, where one or more layers of metallic zinc are continuously applied to the surface via a galvanizing process. This zinc coating acts as a sacrificial protective layer, effectively shielding the steel substrate from corrosion and rusting in natural environments—and thereby significantly extending the material's service life. Combining the strength and toughness of steel with zinc's outstanding corrosion resistance, it is an economically efficient and widely used type of anti-corrosion steel.
Product Categories:
Galvanized Coiled Steel
Keywords:
Detailed introduction
Core Production Process : How to achieve corrosion prevention?
It is mainly divided into two types: hot-dip galvanizing and electrogalvanizing, each with distinct characteristics and applications.
1. Hot-Dip Galvanizing (HDG)
Process: Substrate → Cleaning → Annealing → Immersion in molten zinc bath (approx. 460°C) → Air knife for thickness control → Cooling → Passivation/Oiling.
Features:
The zinc layer is thick, offering exceptionally long-lasting corrosion protection and providing cathodic protection—even if the coating suffers minor scratches, it continues to safeguard the steel substrate.
Zinc flower crystals are visibly present on the surface (available in standard, minimum, and zero zinc flower varieties).
Highly cost-effective, making it the preferred choice for fields such as construction and structural components.
2. Electro-Galvanizing (EG)
Process: Substrate → Cleaning → Zinc ions are electrochemically deposited onto the steel strip surface via an electrolytic cell.
Features:
The zinc layer is thin and uniform, with a smooth, fine surface free of zinc bloom.
It exhibits better formability and weldability than hot-dip galvanizing.
Primarily used in applications with high surface quality requirements, such as appliance housings, automotive components, and color-coated substrates.
Key Performance Metrics and Terminology Explained
Coating Weight/Thickness:
The core metric for assessing corrosion resistance. Unit: g/m² (total weight per square meter, applied on both sides). Common grades include: Z60, Z90, Z120, Z180, and Z275 (e.g., Z180 indicates a total coating weight of 180 g/m² on both sides). The higher the value, the stronger the corrosion protection capability.
Base Steel Grade:
Commercial grade (CQ - DX51D): Standard processing, such as bending.
Mechanical Interlock Grade (DQ - DX52D): Used for seam locking and hemming.
Deep-drawing grade (DDQ - DX53D): Used for stretch forming.
Ultra-deep-drawing grade (EDDQ - DX54D): Used for complex deep-drawn parts.
High-strength steel (HSS - HX340LAD): Used for lightweight design.
Surface Treatment:
Chromate Passivation (C): Prevents "white rust" formation during storage and transportation.
Chrome-free passivation (U): An environmentally friendly rust-prevention treatment.
Oiling (O): Prevents rust.
Phosphating (P): Enhances coating performance and lubricity.
Surface Spangle:
Plain zinc flower (R): Clearly visible patterns visible to the naked eye.
Minimum Zinc Spangle (M): The pattern is fine and evenly distributed.
Zinc-free (F): The surface is uniform and consistent, making it the ideal substrate for color coating.
Product Specifications and Standards
Common standards include: China National Standard (GB/T), European Standard (EN), American Standard (ASTM), German Standard (DIN), and Japanese Standard (JIS).
Common specifications:
Thickness: Base plate thickness ranges from 0.25mm to 3.0mm (commonly 0.3mm–2.0mm)
Width: 600mm - 2000mm
Coating: Z30 - Z600 (commonly Z60-Z275)
Delivery format: Steel coils (inner diameter 610/508 mm) or flat sheets
Main application areas
Galvanized steel coils are the "anti-corrosion armor" of modern industry, with applications found everywhere.
Architecture field (primary application):
Roofing & Wall Systems: Factory buildings, warehouses, airports.
Structural components: light steel framing, purlins, trusses, guardrails, and rolling doors.
Home appliance manufacturing:
The outer casings and internal structural components of refrigerators, washing machines, air conditioners, microwave ovens, water heaters, and more—often made using electrogalvanized or small-zinc-spangle hot-dip galvanized steel as the base material for color-coating.
Automotive Industry:
Body panels, chassis components, fuel tanks, and more (often made from high-strength galvanized steel).
General Hardware & Home Essentials:
Ventilation ducts, grain silos, file cabinets, furniture, and appliance casings.
Product Applications
Home appliance industry
Kitchen Equipment Industry
Amusement Ride Industry
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Automotive industry
Construction industry
Construction Materials Industry
Amusement Ride Industry
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Mechanical Manufacturing Industry
Railway Systems Industry
Pipeline Systems Industry
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