Hot-Dip Galvanized Steel Flat Bar is a rectangular steel section made from hot-rolled steel and coated with zinc through the hot-dip galvanizing process. Rongheng supplies Q235B and Q355B flat bars in standard and custom dimensions for grounding, steel fabrication, supports, brackets and other outdoor steel applications.
The flat bar is galvanized after sizing and processing, allowing the zinc coating to cover the main surfaces, edges and exposed areas of the finished section. Standard zinc coating starts from ≥65 μm, with 80–100 μm available for projects requiring a thicker coating.
| Item | Specification |
| Product | Hot-Dip Galvanized Steel Flat Bar |
| Base Material | Q235B, Q355B |
| Base Steel Standard | GB/T 704-2008 |
| Galvanizing Standard | GB/T 13912-2020 |
| Common Sizes | 20×3, 30×3, 40×4, 50×5, 60×6, 80×8, 100×10 mm |
| Custom Width | 20–200 mm |
| Custom Thickness | 3–20 mm |
| Standard Length | 6 m |
| Custom Length | 3–9 m |
| Standard Zinc Coating | ≥65 μm |
| Thicker Zinc Coating | 80–100 μm |
| Width Tolerance | ±0.7 mm |
| Thickness Tolerance | ±0.5 mm |
| Surface | Silver-gray hot-dip galvanized finish |
| Processing | Cutting, punching, bending, beveling |
Commonly supplied sizes include 40×4 mm, 50×5 mm and 60×6 mm. Non-standard width, thickness and fixed length can be arranged according to the required dimensions.
The zinc coating can be selected according to the exposure environment and project specification.
| Zinc Coating | Typical Requirement |
| ≥65 μm | Standard outdoor applications |
| 80–100 μm | Projects requiring a thicker zinc coating or stronger outdoor exposure |
For quotation and production, the specification should include section size, steel grade, zinc coating requirement, length and quantity. For example: 50×5 mm, Q235B, hot-dip galvanized, zinc coating ≥80 μm, 6 m length.
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Grounding & Lightning Protection Used as grounding conductors and connection members in electrical and photovoltaic projects. |
Steel Fabrication Used for connection plates, reinforcement pieces, supports and brackets. |
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Curtain-Wall Systems Processed into connection and supporting components according to drawings. |
Municipal Steelwork Used for guardrail reinforcement and other outdoor steel components. |
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Equipment & Rack Components Used for bases, supports, clamps and other fabricated components. |
Custom Fabrication Cut, punched, bent or beveled according to the required dimensions. |
| Section | Typical Use | Key Consideration |
| Flat Bar | Horizontal grounding conductors and connections | Flat surface is convenient for laying, fixing and joining |
| Round Steel | Grounding electrodes and circular-section applications | Selected according to grounding system design |
| Angle Steel | Structural and certain grounding-related applications | Provides a different section geometry and connection method |
The appropriate section should be determined by the grounding design, required cross-section, connection method and applicable electrical or structural requirements.
The normal production route is:
Hot-Rolled Steel → Cutting & Sizing → Surface Preparation → Degreasing & Pickling → Fluxing → Drying → Hot-Dip Galvanizing → Cooling & Passivation → Zinc Coating Inspection → Dimensional Inspection → Packing
Galvanizing is applied after the steel section has been prepared to the required dimensions. The process provides zinc coverage over the main surfaces and edges of the finished flat bar.
Rongheng can supply standard straight lengths or arrange additional processing before delivery according to the order requirements.
For processed parts, the drawing or processing dimensions should be confirmed before quotation, including cut length, hole diameter, hole position, bend angle and bevel requirements.
Inspection covers the base steel, dimensions, galvanizing and finished condition.
Material certificates and galvanizing inspection records can be supplied according to order requirements. Third-party inspection can also be arranged when required.
The normal surface appearance is silver-gray after hot-dip galvanizing. Minor zinc flow marks, surface variations or small zinc features may occur during galvanizing and should be evaluated against the applicable product and coating requirements.
Galvanized flat bar should be stored in a dry, ventilated area and kept away from standing water. Bundles should be raised from the ground, and prolonged contact with wet packaging should be avoided.
Passivation treatment can be arranged to help reduce the risk of white rust during storage and transportation.
| Requirement | Available Range |
| Common Stock Sizes | 40×4, 50×5, 60×6 mm |
| Commonly Supplied Sizes | 20×3–100×10 mm |
| Custom Width | 20–200 mm |
| Custom Thickness | 3–20 mm |
| Standard Length | 6 m |
| Custom Fixed Length | 3–9 m |
For export orders, supply can be coordinated with material certificates, galvanizing inspection records, processing, moisture-resistant packing and shipping preparation.
The available base steel grades are Q235B and Q355B. The required grade should be specified together with the section size and applicable standard.
The standard zinc coating is ≥65 μm. A thicker coating of 80–100 μm can also be arranged according to the project requirement.
Common sizes include 20×3, 30×3, 40×4, 50×5, 60×6, 80×8 and 100×10 mm. Custom widths of 20–200 mm and thicknesses of 3–20 mm are available.
Yes. The standard length is 6 m, while fixed lengths from 3–9 m can be arranged according to the order.
Yes. Cutting, punching, bending and beveling can be arranged before delivery. Processing requirements should be confirmed from the drawing or specified dimensions.
Yes. Welding can locally damage the zinc coating. Areas affected by welding or significant cutting should be cleaned and repaired with a suitable zinc-rich coating where required.
Yes. Flat bar is commonly used for horizontal grounding conductors and grounding connections. The required size and steel specification should follow the grounding system design and applicable electrical requirements.
Hot-dip galvanizing applies zinc through immersion in molten zinc after the steel has been prepared. It is commonly selected for outdoor steel where a galvanized coating is required. Electrogalvanizing uses an electrochemical process and generally produces a thinner coating.
Yes. The order can specify the required zinc coating, such as ≥65 μm or 80–100 μm, together with the steel grade, dimensions and length.
Please provide the section size, steel grade, zinc coating requirement, length, quantity, processing requirements and delivery destination. A drawing can be provided when punching, bending or other fabrication is required.
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Secondary Arterial Road No. 2-1, Expansion Area of Daqiuzhuang Industrial Zone, Jinghai District, Tianjin, China
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