Hot Rolled Flat Steel Bars for Construction feature a rectangular cross-section with rounded edges. They comply with the GB/T 704-2016 standard and are primarily made from Q235B or Q355B steel. Specifications range from 12–300mm in width and 3–60mm in thickness, with standard lengths of 6m, 9m, or 12m.
1. The cross-section is a long, flat rectangle where the width significantly exceeds the thickness. It offers moderate resistance to bending and lateral stiffness with a clear load-bearing axis, making it ideal for applications involving unidirectional loads, tension ties, and clamping.
2. Typically made of carbon structural steel, the material is uniform and tough. It performs stably under static and minor dynamic loads and is resistant to brittle fracture.
3. It offers a low self-weight relative to its cross-section and high material utilization efficiency; when used as connectors or tension ties, it effectively reduces the overall structural load.
1. The flat surfaces and uniform edges ensure excellent fit, allowing for flush installation against structural components. It is suitable for applications such as clamps, edge banding, reinforcement, and tension ties.
2. Its slender profile and simple shape allow for flexible arrangement, making it adaptable to irregular areas and tight construction spaces.
3. A wide range of modular specifications—offering various combinations of width and thickness—allows for on-site customization and ensures high versatility.
1. It exhibits excellent performance in both hot and cold processing. It can be easily cut, drilled, bent, rolled, welded, and stamped without the need for complex machinery. 2. Diverse connection methods: Primarily joined via lap welding or butt welding, but can also be fastened with bolts or rivets; joint fabrication is simple.
3. Lengths can be cut as needed with minimal material waste; processing of small or irregularly shaped parts is convenient.
1. The as-rolled hot-rolled surface retains mill scale; treatments such as hot-dip galvanizing, cold galvanizing, painting, or blackening can be applied. Once treated for corrosion resistance, it is suitable for indoor, outdoor, and humid or exposed environments.
2. Mechanical properties remain stable within the standard temperature range of **-20°C to 250°C**, with no significant performance degradation.
1. Simple production processes and large-scale manufacturing result in low prices and ample stock availability, making it a highly cost-effective basic structural profile.
2. Categorized into hot-rolled flat steel and cold-drawn flat steel:
1. Hot-rolled type: Features mill scale on the surface; moderate dimensional precision; suitable for general engineering applications.
2. Cold-drawn type: High dimensional precision and smooth surface finish; suitable for precision assembly and mechanical components.
1. Weak resistance to lateral torsion and overturning; unsuitable for use as primary load-bearing beams or columns on their own; typically used as auxiliary components.
2. Thinner flat steel sections have poor resistance to localized impact and are prone to bending or deformation under excessive loads.
3. Susceptible to rapid rusting if left exposed outdoors for extended periods without corrosion protection.
1. Connecting components for steel structures
Hot-rolled flat steel bars can serve as tie bars, reinforcement plates, connection plates, and stiffeners between steel beams, columns, H-beams, and square/rectangular hollow sections. They enhance overall structural stability and are common auxiliary materials for steel structure joints.
2. Embedded parts and components
Used to fabricate embedded flat steel plates, embedded tie elements, and grounding strips; widely applied in embedded component projects for building foundations, walls, and roofing.
3. Enclosure and edge-trimming systems
Used for edge trimming and wrapping around color-coated steel panels, walls, roofs, and door/window openings; also used for pressure strips, edge-sealing frameworks, panel joint cover strips, and sealing/water-blocking components. 4. Pipe and Equipment Accessories
Pipe clamps, conduit clips, bracket straps, equipment fastening bands, and line-fixing strips; used for the organized securing of pipes and cables.
5. Power & Lightning Protection Grounding
Grounding flat bars, lightning protection down-conductors, and equipotential bonding strips for buildings, factories, power distribution rooms, and specialized equipment; materials compliant with power industry standards.
6. Guardrails, Handrails, and Walkways/Stairs
Stair tread edge trim, railing reinforcement strips, simple guardrail crossbars, and anti-slip platform strips.
7. Mechanical and Hardware Processing
Stamped parts, small equipment frames, tool accessories, hardware components, agricultural machinery parts, and custom cutting/processing of small non-standard parts.
8. Municipal and Construction Site Temporary Facilities
Hoarding reinforcement, scaffolding ties, temporary support frames, and sign base frameworks.
1. Steel Structure Engineering: Auxiliary materials for industrial plants, prefabricated buildings, steel roofing, and wall cladding systems.
2. Building M&E (Mechanical & Electrical): Electrical lightning protection grounding, plumbing/HVAC pipe supports, and conduit fixing systems.
3. Power Engineering: Grounding and conductive connections for substations, distribution rooms, and outdoor power facilities.
4. Municipal & Transportation: Road hoardings, guardrails, bus shelters, and municipal landscape components.
5. Machinery Manufacturing: General-purpose equipment, construction machinery, agricultural machinery, and hardware component processing.
6. Shipbuilding & Curtain Walls: Reinforcement of ship components, architectural curtain wall edge finishing, and door/window sub-frames.
· Hot-rolled flat steel: Cost-effective with high stock availability; suitable for general engineering use, primarily for structural ties, embedded parts, grounding, and cladding edge finishing.
· Cold-drawn flat steel: Features precise dimensions and a smooth, clean surface finish; suitable for precision machinery, components requiring high aesthetic quality, and precision assembly.
· Hot-dip galvanized flat steel: Corrosion and rust-resistant; preferred for outdoor, exposed, or humid environments and lightning protection grounding projects. Key Performance Parameters
Standards: GB/T 704-2016 "Hot-rolled flat steel," GB/T 34374-2017 "Cold-drawn flat steel"
|
Material Grade |
Yield Strength ReL (MPa) |
Tensile Strength Rm (MPa) |
Elongation After Fracture |
Application Scenarios |
|
Q235B |
≥235 |
375～500 |
≥24% |
General engineering use, tie members, edge trim, ordinary embedded parts, grounding plates |
|
Q355B |
≥355 |
470～630 |
≥21% |
Heavy-duty reinforcement, load-bearing connecting plates, mechanical equipment fittings |
General Physical Parameters
· Density: 7.85 g/cm³
· Modulus of Elasticity: 2.06 × 10⁵ MPa
· Operating Temperature: -20°C to 250°C
1. Designation Method
Width × Thickness (mm); Examples: 50×5, 80×6
2. Main Size Ranges
· Width: 12–300 mm
· Thickness: 3–60 mm
· Standard Lengths: 6m, 9m, 12m; cut-to-length available upon request
3. Dimensional Tolerances
· Hot-rolled flat steel: Width ±1.0 mm, Thickness ±0.5 mm
· Cold-drawn flat steel: Higher precision; width/thickness tolerance ≤ ±0.3 mm
4. Theoretical Weight Formula
W (kg/m) = Width (mm) × Thickness (mm) × 0.00785
5. Common Specifications and Weight per Meter
|
Size (Width × Thickness, mm) |
Theoretical Weight (kg/m) |
Main Applications |
|
20×3 |
0.471 |
Small edge trim, window & door moulding, simple tie bars |
|
25×3 |
0.589 |
Decorative moulding, pipeline fixing parts |
|
30×3 |
0.707 |
General edge trim, roof moulding, small reinforcement parts |
|
30×4 |
0.942 |
Wall tie bars, small pipe clamps |
|
40×4 |
1.256 |
Regular flat grounding steel, ordinary connecting plates |
|
40×5 |
1.570 |
Standard grounding strips, pipe clamps, enclosure moulding |
|
50×5 |
1.963 |
Main flat grounding steel, steel structure tie strips |
|
50×6 |
2.355 |
Heavy-duty tie bars, equipment reinforcement strips |
|
60×6 |
2.826 |
Large pipe clamps, beam & column stiffening strips |
|
80×6 |
3.768 |
Heavy connecting plates, widened reinforcement parts |
|
80×8 |
5.024 |
Thick load-bearing strips, auxiliary plates for equipment bases |
|
100×8 |
6.280 |
Widened heavy-load components, large hoop fittings |
1. Flat, elongated cross-section; offers good unidirectional bending resistance but low lateral stiffness. Suitable for in-plane bending, tensioning, tying, and clamping applications; unsuitable for independently withstanding high torque or lateral loads.
2. Uniform material composition with no significant stress concentration points; exhibits excellent cold-bending and stamping properties.
3. Stable shear performance; suitable for use as lap connectors, waterstops, and tie bars.
|
Category |
Forming Process |
Precision & Surface Condition |
Core Performance |
Application Scenarios |
|
Hot Rolled Flat Steel |
Hot rolling |
Oxide scale on surface, ordinary dimensional precision |
Good toughness, excellent weldability, high cost performance |
Steel structure tie bars, embedded parts, edge trims, general grounding bars, general construction site use |
|
Cold Drawn Flat Steel |
Precision cold drawing |
Smooth bright surface, precise dimensions |
High straightness, tight tolerance, good appearance |
Precision machinery fittings, decorative components, high-precision assembly parts |
|
Hot-dip Galvanized Flat Steel |
Hot rolling / cold drawing + hot dip galvanizing |
Uniform zinc coating, anti-rust property |
Excellent corrosion & weather resistance, stable electrical conductivity |
Outdoor grounding, open-air structural parts, humid environments, power engineering projects |
1. Cold-bending Performance: Capable of 180° cold bending at room temperature without cracking or delamination at the bend; suitable for on-site bending and shaping.
2. Welding Performance: Due to low carbon content, these hot-rolled flat steel bars are suitable for arc welding and gas-shielded welding; they yield strong welds that are resistant to cracking.
3. Stamping/Punching: Easy to punch and cut; low processing difficulty; suitable for mass production of small, irregularly shaped parts.
4. Electrical Conductivity: Pure carbon steel offers good electrical conductivity and is a standard material for lightning protection and grounding projects.
1. Base Condition: Hot-rolled "black" finish (mill scale); prone to rusting; anti-corrosion treatment is mandatory for outdoor use.
2. Common Anti-corrosion Processes & Reference Specifications
o Hot-dip galvanizing: Average zinc coating thickness ≥65μm; outdoor service life of 12–18 years.
o Cold galvanizing / Painting: Zinc coating / paint film thickness of 20–40μm; primarily for indoor or dry environments.
o Blackening / Passivation: Rust prevention only (no decorative finish); used for internal mechanical components.
1. Primary: Lap welding, butt welding (standard for steel structures and grounding projects).
2. Secondary: Bolting, riveting, clip/clamp fastening.
Suitable
Steel structure bracing/reinforcement, roof/wall edge trim strips, embedded parts, lightning protection/grounding, pipe clamps/brackets, stair handrail edging, simple guardrails, small mechanical hardware parts.
Unsuitable
Standalone primary load-bearing beams or columns, components subject to high-frequency alternating impact, high-pressure load-bearing components.
|
width (mm) |
thickness (mm) | |||||||||||
| 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 14 | 16 | |
| theoretical weight ( k g / m ) | ||||||||||||
|
10 12 14 16 18 20 22 25 28 30 32 35 40 45 50 55 60 65 70 |
0.24 0.28 0.33 0.38 0.42 0.47 0.52 0.59 0.66 0.71 0.75 0.82 0.94 1.06 1.18 |
0.31 0.38 0.44 0.50 0.57 0.63 0.69 0.78 0.88 0.94 1.00 1.10 1.26 1.41 1.57 1.73 1.88 2.04 2.22 |
0.39 0.47 0.55 0.63 0.71 0.78 0.86 0.98 1.10 1.18 1.26 1.37 1.57 1.77 1.96 2.16 2.36 2.55 2.75 |
0.47 0.57 0.66 0.75 0.85 0.94 1.04 1.18 1.32 1.41 1.51 1.65 1.88 2.12 2.36 2.59 2.83 3.06 3.30 |
0.55 0.66 0.77 0.88 0.99 1.10 1.21 1.37 1.54 1.65 1.76 1.92 2.20 2.47 2.75 3.02 3.30 3.57 3.85 |
0.63 0.75 0.88 1.00 1.13 1.26 1.38 1.57 1.76 1.88 2.01 2.20 2.51 2.83 3.14 3.45 3.77 4.08 4.40 |
1.15 1.27 1.41 1.55 1.77 1.98 2.12 2.26 2.47 2.83 3.18 3.53 3.89 4.24 4.59 4.95 |
1.26 1.41 1.57 1.73 1.96 2.20 2.36 2.55 2.75 3.14 3.53 3.93 4.32 4.71 5.10 5.50 |
1.73 1.90 2.16 2.42 2.59 2.76 3.02 3.45 3.89 4.32 4.75 5.18 5.61 6.04 |
1.88 2.07 2.36 2.64 2.83 3.01 3.30 3.77 4.24 4.71 5.18 5.65 6.12 6.59 |
2.75 3.08 3.30 3.52 3.85 4.40 4.95 5.50 6.04 6.59 7.14 7.69 |
3.14 3.53 3.77 4.02 4.40 5.02 5.65 6.28 6.91 7.54 8.16 8.79 |
Address
Tianjin International Metal Logistics Park, Jinan Economic Development Zone (East Zone), Jinan District, Tianjin, China
Tel
