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Help CenterFlat Steel & Stock Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMo
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Steel Wire & Stock Steel Wire，Q195、Q215、Q235、SWRM10、SWRM12、35#、45#、50#、SWRH45A、65#、70#、80#、SWRH72A、SWRH82ANegotiableMOQ: 5 Metric Tons -
Steel Wire & Stock Steel Wire，Q195、Q215、Q235、SWRM10、SWRM12、35#、45#、50#、SWRH45A、65#、70#、80#、SWRH72A、SWRH82ANegotiableMOQ: 5 Metric Tons
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Steel Wire & Stock Steel Wire，Q195、Q215、Q235、SWRM10、SWRM12、35#、45#、50#、SWRH45A、65#、70#、80#、SWRH72A、SWRH82ANegotiableMOQ: 5 Metric Tons
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Steel Wire & Stock Steel Wire，Q195、Q215、Q235、SWRM10、SWRM12、35#、45#、50#、SWRH45A、65#、70#、80#、SWRH72A、SWRH82ANegotiableMOQ: 5 Metric Tons
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Steel Wire & Stock Steel Wire，Q195、Q215、Q235、SWRM10、SWRM12、35#、45#、50#、SWRH45A、65#、70#、80#、SWRH72A、SWRH82ANegotiableMOQ: 5 Metric Tons
1. Product Definition
Flat steel is a long strip steel section with a rectangular cross-section and slightly rounded edges. Its standard dimensions cover a width of 12～300mm and a thickness of 3～60mm. The standard fixed lengths are 6m, 9m and 12m, with customized lengths available on demand. It can be used directly as a finished product or as raw materials for welded pipe billets and thin plate rolling. It is a universal basic profile widely applied in construction and machinery industries.
2. Product Classification (Three Major Categories)
2.1 Classification by Production Process
1. Hot Rolled Flat Steel (Mainstream in the Market)
Manufactured by rolling steel billets at a high temperature of 1000～1250℃, followed by air cooling and shearing. It features a black surface with oxide scale, relatively large dimensional tolerance, excellent plasticity and toughness, good weldability and high cost performance. Dominant in thick specifications, it is the preferred material for building structures and lightning protection grounding, complying with GB/T702 and YB/T4212 standards.
2. Cold Drawn / Cold Rolled Flat Steel (Precision Grade)
Processed by cold drawing or precision rolling at room temperature. It boasts a mirror bright surface, high dimensional accuracy, square edges and minimal tolerance. Cold hardening endows it with relatively high hardness and superior processing precision. It is applied to precision equipment and mold accessories, with a cost about 30% higher than hot rolled flat steel.
3. Forged Flat Steel (Special Grade)
Formed by forging, it has a dense internal metallographic structure, strong load-bearing capacity and impact resistance. It is mostly used for heavy-duty engineering machinery and special spring accessories, produced in small-batch customization.
2.2 Classification by Raw Material Grade
1. Mild Carbon Flat Steel (Q235B)
The most versatile steel grade with a yield strength ≥235MPa and tensile strength ranging from 375MPa to 500MPa. It features easy welding and bending performance. It is the main material for building embedded parts, steel structure supports, and 40×4/50×5 lightning protection grounding flat steel, conforming to GB/T700 standard.
2. High-strength Low-alloy Flat Steel (Q345B)
Manganese-based alloyed steel with a yield strength ≥345MPa, featuring better load-bearing capacity and impact resistance than Q235B. It is widely used in bridges, engineering machinery chassis and vehicle girders, complying with GB/T1591 standard.
3. High-quality Carbon Flat Steel (20#, 45#)
With pure chemical composition and stable mechanical properties, it supports heat treatment and quenching. It is suitable for gears, shaft sleeves and machine tool base plates, complying with GB/T699 standard.
4. Alloy Flat Steel (40Cr, 42CrMo)
It has high wear resistance and strength, applicable to heavy-duty gears and hydraulic accessories.
2.3 Classification by Surface Treatment
1.Black Hot Rolled Flat Steel: Original rolled blank without surface treatment
2. Hot-dip Galvanized Flat Steel: Full zinc immersion anti-corrosion treatment, specially used for lightning protection and outdoor embedded engineering (40×4 is the national standard matching specification for grounding)
3. Cold Galvanized / Polished Flat Steel: Precision polished bright surface, for decoration and precision parts
3. Conventional Specification Parameters
3.1 Common Dimensions (Thickness × Width, mm)
- Thin gauge: 3×20, 4×25, 4×40 (commonly used for grounding), 5×50
- Medium gauge: 6×60, 8×80, 10×100, 12×120
- Thick gauge: 16×100, 20×150, 30×200
Standard lengths: 6m, 9m, 12m; non-standard cutting and customized lengths are supported
3.2 Theoretical Weight Calculation Formula
Weight per meter (kg) = Thickness (mm) × Width (mm) × 0.00785
Example: 40×4 flat steel: 40×4×0.00785 = 1.256kg/m
4. Core Product Advantages
1. Complete Specifications: Full range of size options, which can replace steel plates for direct blanking, eliminating steel plate cutting loss and increasing material utilization rate by 5%～10%.
2. Regular Shape: Adopting precision vertical rolling technology, it features vertical sides, clear edges and corners and excellent straightness. The camber and dimensional error are better than the national standards for hot rolled steel plates.
3. Convenient Processing: It can be directly processed by welding, bending, punching and galvanizing, adapting to the assembly line production of steel structures.
4. Flexible Delivery: Conventional sizes are in stock. Non-standard specifications can be customized within 5～7 days (Tianjin Port is the main shipping port for foreign trade).
5. Adopted National Standards
1. Dimensional tolerance for hot rolled steel bars: GB/T702-2017 Hot Rolled Steel Bars - Dimensions, Shapes, Weights and Allowable Deviations
2. Q235 grade: GB/T700; Q345 grade: GB/T1591; High-quality carbon steel: GB/T699
3. General specification for hot rolled flat steel: YB/T4212-2010
6. Main Application Fields
1. Construction Engineering: Steel structure connectors, embedded parts, factory purlins, stair treads, lightning protection grounding (40×4/50×5 galvanized flat steel)
2. Power Industry: Substation grounding grid, distribution cabinet supports
3. Mechanical Manufacturing: Equipment bases, base plates, guide rails, supports, non-standard frames
4. Vehicle and Shipbuilding: Vehicle frame accessories, cabin structures, container parts
5. Hardware Products: Tool blanks, hoops, furniture hardware accessories
7. Delivery and Quality Inspection Instructions
1. Delivery Status: Three types including hot rolled black surface, cold drawn bright surface and hot-dip galvanized; settlement by weighed weight or theoretical weight is available.
2. Factory Inspection: Material quality certificates are provided for each batch, with tests on yield strength, tensile strength, elongation and chemical composition.
3. Packaging: Bundled packing (1～3 tons per bundle) with specification and grade labels on each end, delivered by truck or container shipping.
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