Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of hdg coil in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
What is HDG Steel Coil?
Hot-dip galvanized (HDG) steel coil is a carbon steel product coated with a layer of zinc through a continuous hot-dip galvanizing process. The steel strip is immersed in a molten zinc bath at approximately 450–460°C, forming a metallurgical bond between zinc and steel.
This zinc coating acts as a protective barrier that significantly improves corrosion resistance, making HDG steel coil one of the most widely used materials in construction, automotive manufacturing, agricultural equipment, and industrial applications.
HDG coils are commonly manufactured according to international standards such as ASTM A653, EN 10346, and JIS G3302, ensuring consistent mechanical properties and coating quality.
Manufacturing Process
The HDG steel coil is produced through a continuous galvanizing line (CGL):
Cold rolled steel preparation
Cleaning and degreasing
Annealing in controlled atmosphere
Immersion in molten zinc bath (≈460°C)
Air knife control for coating thickness
Cooling and solidification
Surface treatment (oiled / chromated / dry)
Coil winding and packaging
This controlled process ensures uniform coating, strong adhesion, and long-term corrosion protection.
Specifications – HDG Coil
| Property | Metric (SI) | Imperial (US) | Remarks |
|---|---|---|---|
| Base Steel | Cold Rolled Steel (CR) | Cold Rolled Steel | ASTM A653 / JIS G3302 |
| Coating Type | Zinc (Hot-Dip Galvanized) | Zinc (Hot-Dip Galvanized) | GI / Z coating |
| Coating Mass | Z30 – Z275 g/m² | 0.10 – 0.90 oz/ft² | Both sides total |
| Thickness Range | 0.20 – 2.00 mm | 0.008 – 0.079 inch | Custom thickness available |
| Width Range | 600 – 1250 mm | 23.6 – 49.2 inch | ±3 mm tolerance |
| Coil Weight | 3 – 10 MT | 6,600 – 22,000 lbs | Per customer requirement |
| Inner Diameter (ID) | 508 / 610 mm | 20 / 24 inch | Standard export size |
| Surface Finish | Smooth, Spangle, Zero Spangle | – | Optional |
| Tensile Strength | 270 – 550 MPa | 39 – 80 ksi | Depends on steel grade |
| Yield Strength | ≥ 230 MPa | ≥ 33 ksi | – |
| Elongation | ≥ 20% | – | ASTM A653 requirement |
| Tolerance (Thickness) | ±0.02 mm | ±0.0008 inch | Standard EN 10143 |
| Tolerance (Width) | ±3 mm | ±0.12 inch | Standard JIS G3302 |
Zinc Coating Types
Z30 – Z80 → Light corrosion protection (indoor use)
Z100 – Z140 → General construction use
Z180 – Z275 → Heavy-duty outdoor & coastal environments
Higher zinc coating provides longer service life and better resistance to moisture, salt, and industrial environments.
Chemical Composition (Typical % of Base Steel)
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.12 – 0.25 |
| Manganese (Mn) | 0.30 – 0.80 |
| Phosphorus (P) | ≤ 0.04 |
| Sulfur (S) | ≤ 0.05 |
| Silicon (Si) | 0.10 – 0.50 |
| Iron (Fe) | Balance |
Mechanical Properties
HDG steel coil maintains excellent mechanical performance from its cold rolled substrate:
High tensile strength
Good elongation and formability
Excellent bending and stamping performance
Stable dimensional accuracy
These properties make it suitable for deep drawing and complex forming processes.
Key Properties
Corrosion Resistance
The zinc coating acts as a sacrificial barrier. Even if the steel substrate is scratched, the zinc will corrode first, protecting the steel underneath. This makes HDG Coils ideal for outdoor applications, such as roofing, fencing, and construction in harsh environments.
Durability
With enhanced corrosion resistance, HDG Coils have a long lifespan. They can withstand years of exposure to weather, moisture, and other environmental factors without significant degradation, reducing the need for frequent replacements and maintenance.
Good Formability
Our HDG Coils maintain excellent formability, allowing for easy shaping and processing into various products. Whether it's being rolled into sheets for roofing or formed into complex structures for industrial applications, the coil can be worked with precision.
Applications
HDG steel coil is widely used in multiple industries:
Construction
Roofing sheets
Wall panels
Structural framing systems
Automotive Industry
Car body panels
Chassis components
Reinforcement parts
Home Appliances
Washing machine panels
Refrigerator shells
Air conditioning units
Industrial Use
Electrical enclosures
HVAC duct systems
Storage racks
HDG vs GI vs Galvalume Comparison
| Property | HDG Steel Coil | GI Coil | Galvalume Coil |
|---|---|---|---|
| Coating | Pure Zinc | Pure Zinc | Al-Zn Alloy |
| Corrosion Resistance | High | Medium | Very High |
| Heat Resistance | Medium | Medium | High |
| Surface Appearance | Bright / Spangle | Dull | Smooth |
| Cost Level | Medium | Low | High |
| Main Application | Construction / Auto | General use | Roofing / Long life |
👉 HDG offers the best balance between cost and corrosion protection for most industrial applications.
Our Factory's HDG Coils
Our factory is equipped with advanced production lines and strict quality control systems.
Customizable Specifications
We offer HDG Coils in a wide range of thicknesses, widths, and zinc coating weights to meet specific project requirements. Whether you need a thin coil for delicate applications or a thick one for heavy-duty use, we've got you covered.
High-Quality Assurance
Every coil undergoes rigorous testing for quality, including checks for coating thickness, adhesion, and mechanical properties. This ensures that our customers receive products that meet international standards and perform optimally in their intended applications.
Hdg coil classification, product range and properties
Standards applied in different countries to set the requirements for hot dipped galvanized steel coils specify steel grade and size ranges for these products. Hot dipped galvanised coils are classified based on the following features:
● Application of coated steel (profiling, cold forming, manufacture of steel structures)
● Chemical composition of coating material (pure zinc, zinc-iron/zinc-aluminium/aluminium-zinc/zinc-magnesium alloys, etc)
● Thickness/weight of protective coating
►HDG coils according to European standards
Galvanised steel coils as per the European EN 10346, can be coated with zinc, zinc-iron alloy, zinc-aluminium alloy, aluminium-zinc alloy or aluminium-silicon alloy:
● Zinc coating (Z) is achieved by dipping the prepared strip into a bath with molten alloy, containing at least 99% zinc. This is the most common and traditional way of protecting rolled steel from corrosion.
● Zinc-iron coating (ZF) is formed by dipping a strip into a bath of molten zinc (at least 99% zinc) with further annealing to form a zinc-iron coating with an Fe content of 8-12%. Such coating is stronger than the traditional zinc coating and has better adhesion with substrate steel due to mutual diffusion between the iron and zinc in the surface layers. That is why this coating is less exposed to lamination or pitting under impact, mechanical stresses or deformation of treated products.
● Zinc-aluminium coating (ZA) is applied to rolled steel by dipping it into a bath of zinc and about 5% aluminium with a minor content of mishmetal (mix of metals). Rolled steel with such coating has better formability and corrosion protection properties compared with zinc-coated steel.
● Aluminium-zinc coating (AZ) is applied by dipping steel into a bath of molten metal consisting of 55% aluminium and 1. 6% silicon (with the remaining being taken up by zinc). The combined action of these metals ensures the best corrosion protection compared with other coatings.
● Aluminium-silicon coating (AS) is created by dipping steel into a bath of molten metal containing aluminium and 8-11% silicon. Galvanized steel coil with such coating is highly resistant to oxidation at high temperature (up to 650°C) and highly resistant to chemical corrosion.
Looking for high-quality HDG Coil? We provide GI coils in various grades, thicknesses, and widths, fully compliant with international standards.
Our address
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Phone Number
+86 15769214734
Inspection & Quality Assurance
Every HDG Coil undergoes rigorous quality inspection:
Raw Material Verification: Steel grade and zinc quality check
Coating Thickness Measurement: Both sides checked with calibrated gauges
Tensile & Yield Tests: Mechanical properties verified per ASTM / EN
Surface Inspection: Visual and spangle check
Bend & Forming Tests: Confirm formability and adhesion
Corrosion Test: Salt spray (ASTM B117) optional
Third-Party Verification: SGS / BV / TUV available before shipment
Documentation Supplied:
Mill Test Certificate (EN 10204 3.1/3.2)
Coating Thickness & Surface Inspection Report
Packing List & Certificate of Origin
Packaging & Shipping
Packaging: Waterproof paper + steel strip + wooden pallet
Coil ID: 508 / 610 mm standard
Weight: 3–10 tons per coil
Marking: Grade, zinc coating, coil number, manufacturer logo
Delivery: 15–25 days depending on quantity
Shipping: Sea-worthy export packing suitable for long transport
FAQ – HDG Coil
Q1: What is HDG Coil?
A1: HDG Coil is hot-dip galvanized steel coil coated with zinc for corrosion protection.
Q2: What does Z275 mean?
A2: Z275 indicates a zinc coating mass of 275 g/m² (both sides).
Q3: Can HDG Coil be painted?
A3: Yes, it is the standard base for pre-painted galvanized steel (PPGI).
Q4: What is the typical service life?
A4: 15–30 years under normal atmospheric conditions.
Q5: What standards do you follow?
A5: ASTM A653, EN 10346, JIS G3302.
Q6: Can you provide cut-to-length sheets?
A6: Yes, we offer slitting, cut-to-length, and roll forming services.
Q7: What thickness and width tolerances are offered?
A7: Thickness ±0.02 mm, width ±3 mm.
Q8: Can HDG Coil be exported internationally?
A8: Yes, standard seaworthy packaging ensures safe shipment worldwide.
Q9: Is HDG Coil magnetic?
A9: Yes, it is ferromagnetic as it's based on carbon steel.
Q10: Do you provide third-party inspection?
A10: Yes, SGS, BV, or TUV inspection is available upon request.
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