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Help CenterFlat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022
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Flat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022NegotiableMOQ: 5 Metric Tons -
Flat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022NegotiableMOQ: 5 Metric Tons
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Flat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022NegotiableMOQ: 5 Metric Tons
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Flat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022NegotiableMOQ: 5 Metric Tons
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Flat Steel & Cut To Length Flat Bar，GB/T 704-2008、GB/T 905-2001、GB/T 700、GB/T 1591、GB/T 3077、GB/T 13912-2022NegotiableMOQ: 5 Metric Tons
1. Product Basic Definition
Flat steel is a long strip section steel with a standard rectangular cross-section and moderately blunted edges. The general specification range is: width 12–300mm, thickness 3–60mm, with standard fixed lengths of 6m, 9m and 12m. Custom lengths are available on demand.
Unified marking standard: Width × Thickness (mm), e.g. 50×6, 100×10. With a density of 7.85g/cm³, products are delivered by theoretical weight calculation. Manufactured by negative tolerance rolling, it improves material utilization rate by 1%–5% compared with ordinary steel plates, reducing cutting loss and processing procedures. It can be used directly as finished products or as blanks for welded pipes and base materials for thin plate rolling.
2. National Implementation Standards
1. Hot rolled flat steel: GB/T 704-2008 Hot-rolled Flat Steel – Dimensions, Shapes, Weights and Permissible Deviations
2. Cold drawn / cold rolled flat steel: GB/T 905-2001
3. Carbon structural steel: GB/T 700 (Q235 series), GB/T 1591 (Q355 series)
4. Alloy structural steel: GB/T 3077
5. Hot-dip galvanized flat steel anti-corrosion standard: GB/T 13912-2022
3. Complete Product Classification System
3.1 Classification by Production Process
3.1.1 Hot Rolled Flat Steel (Mainstream & In-stock)
Process: Steel billets are heated to 1100–1250℃ for continuous hot rolling and cut to fixed lengths by cold shearing.
Appearance: With black oxide scale (black finish), vertical side edges and regular corners.
Tolerance: Width ±0.5–3mm, thickness ±0.3–0.5mm.
Performance: Excellent plasticity, toughness and weldability, easy for bending, drilling and welding.
Applications: Building steel structures, lightning protection grounding, supports, bridges and general mechanical structural parts.
Advantages: Low cost, complete thickness specifications and stable mass supply.
3.1.2 Cold Drawn / Cold Rolled Flat Steel (High Precision)
Process: Cold drawing or cold rolling at room temperature with oxide scale removal and precision finishing.
Appearance: Mirror bright surface without oxide layer, suitable for direct painting and electroplating.
Tolerance: Width ±0.05–0.2mm, thickness ±0.03–0.15mm, straightness ≤0.5mm/m.
Performance: Cold work hardening improves surface hardness with extremely high dimensional consistency.
Applications: Machine tool guide rails, precision hardware, auto parts and mechanical assembly components.
3.1.3 Forged Flat Steel (Heavy-duty & High Strength)
Process: High-temperature forging to densify the internal metallographic structure.
Features: Free of internal porosity, high impact resistance and tensile strength; preferred for thick materials above 50mm.
Applications: Heavy engineering machinery, ship bases and load-bearing parts of high-pressure equipment.
3.2 Classification by Material
3.2.1 Ordinary Carbon Flat Steel (Cost-effective)
Q235B: Yield strength ≥235MPa, tensile strength 375–500MPa. Suitable for general structures, grounding flat steel, guardrails and common supports.
Q355B (Q345B): Low-alloy high-strength steel, ideal for load-bearing structures, steel main beams, photovoltaic brackets, vehicle chassis and heavy-duty structural parts.
3.2.2 High-quality Carbon Flat Steel (Machining Special Use)
20# & 45# steel: Excellent quenching and milling performance, widely used for gear gaskets, mold gaskets, shaft matching parts and mechanical processing components.
3.2.3 Alloy Structural Flat Steel (Wear-resistant & Heavy-duty)
40Cr & 42CrMo: High strength, outstanding wear resistance and fatigue resistance, applied to wear-resistant liners, spring bases and heavy-load components of engineering machinery.
3.2.4 Galvanized Flat Steel (Outdoor Anti-rust Special)
Made of Q235B hot-rolled flat steel substrate via hot-dip galvanizing process, with zinc layer ≥85μm and salt spray resistance ≥1000 hours. It is a core profile specially used for lightning protection grounding, outdoor steel structures, photovoltaic brackets and outdoor guardrails.
3.3 Classification by Surface Treatment
1. Black Hot-rolled Flat Steel: With original oxide scale, low cost, suitable for subsequent paint or anti-rust coating treatment.
2. Pickled Bright Flat Steel: Oxide scale removed with clean gray-white surface, convenient for welding and spraying.
3. Cold Drawn Bright Flat Steel: Mirror precision finished surface, no polishing required for direct assembly.
4. Hot-dip Galvanized Flat Steel: Long-term anti-rust and anti-corrosion performance, applicable to all outdoor exposure scenarios.
4. Core Specification Parameters
4.1 Conventional Size Range
Width: 12/16/20/25/30/40/50/60/80/100/120/150/200/250/300mm
Thickness: 3/4/5/6/8/10/12/14/16/20/25/30/40/50/60mm
Standard length: 6m, 9m, 12m; customizable length from 1m to 12m, supporting ultra-long processing up to 12m.
4.2 Appearance Quality Control
Side verticality: Formed by vertical rolling with clear edges and no burrs or collapsed sides. Straightness: Hot-rolled ≤2mm/m; Cold-drawn ≤0.5mm/m. Camber, distortion and end cutting inclination are all better than ordinary steel plate standards.
4.3 Theoretical Weight Calculation Formula
Weight per meter (kg/m) = Width(mm) × Thickness(mm) × 7.85 ÷ 1000
Example: 50×6 flat steel = 50×6×7.85÷1000 = 2.355kg/m
5. Core Product Advantages
1. Flexible Customization: Integrated production of fixed width, thickness and length eliminates secondary cutting for customers, saving labor and waste costs.
2. High Material Utilization: Standard rectangular cross-section without redundant margins achieves higher blanking yield than ordinary steel plates and profiles.
3. Excellent Machinability: Supports welding, bending, drilling, stamping, cutting and hot bending, compatible with most metal processing technologies.
4. Stable & Efficient Supply: Full stock of conventional specifications, controllable production cycle for bulk orders, delivery available within 5–7 days for domestic and export shipments.
5. Strong Anti-corrosion Adaptability: Optional surface treatments including hot-dip galvanizing, painting and blackening, suitable for indoor, outdoor, light and heavy working conditions.
6. Industry Application Fields
1. Construction Engineering: Steel structure connecting plates, embedded parts, curtain wall keels, stair treads, factory purlins, roof supports and reinforcement connectors.
2. Electric Power & Lightning Protection: Hot-dip galvanized flat steel for grounding busbars, substation grounding grids, photovoltaic power station grounding systems and power equipment lightning protection supports.
3. Mechanical Manufacturing: Equipment base gaskets, machine tool guide rails, fixtures, wear-resistant liners, conveyor accessories and general mechanical structural parts.
4. Automobile & Transportation: Truck frames, trailer support parts, chassis reinforcement parts, passenger car guardrail frames and traffic facility accessories.
5. Municipal Engineering: Road guardrails, bridge reinforcement parts, manhole cover frames, landscape steel structures and municipal supporting brackets.
6. Hardware & Warehousing: Fixtures, tool blanks, stamping hardware parts, warehouse shelf frames and hardware processing base materials.
7. Packaging, Delivery & Quality Warranty
1. Packaging: Black and cold-drawn flat steels are bundled with steel strips with specification and material labels at both ends. Galvanized flat steel is additionally wrapped with waterproof plastic film to prevent transportation scratches and oxidation whitening.
2. Delivery Method: Both weight weighing and theoretical length calculation settlement are available. Domestic truck transportation and export port container shipping are supported, with a conventional delivery cycle of 5–7 days.
3. Quality Warranty: Original material test certificate (MTC) including complete chemical composition and mechanical property test data is provided with goods. Unconditional return and exchange for unqualified size, material and performance.
4. Export Support: Full set of foreign trade documents including packing list, commercial invoice, certificate of origin and commodity inspection certificate can be provided to meet global export standards.
8. Selection Guidelines
1. Q235B hot-rolled flat steel is preferred for indoor general steel structures and conventional grounding projects; hot-dip galvanized flat steel is uniformly adopted for outdoor open-air scenarios.
2. Q355B low-alloy flat steel is suitable for heavy-load scenarios such as high-load factory buildings, photovoltaic brackets and vehicle chassis.
3. Cold-drawn bright flat steel is selected for precision equipment assembly and scenarios with high appearance and dimensional accuracy requirements.
4. 45# high-quality carbon steel and 40Cr alloy flat steel are preferred for heavy-duty wear-resistant mechanical processing parts and stress-bearing wear-resistant components.
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