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Help CenterFlat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMo
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Flat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMoNegotiableMOQ: 5 Metric Tons -
Flat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMoNegotiableMOQ: 5 Metric Tons
-
Flat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMoNegotiableMOQ: 5 Metric Tons
-
Flat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMoNegotiableMOQ: 5 Metric Tons
-
Flat Steel & Export Flat Steel，Q235B、Q345B、20#、45#、40Cr、42CrMoNegotiableMOQ: 5 Metric Tons
Detailed Description of Flat Steel Products
I. Product Definition
Flat Steel, also known as flat iron, is a long strip of steel with a rectangular cross-section and slightly blunt edges, belonging to the category of section steel.
Width: 12–300 mm
Thickness: 3–60 mm
Length: Usually 5–15 m, can be cut to custom lengths
II. Production Process
Hot-Rolled Flat Steel (Mainstream)
Steel billet heating → high-temperature rolling → cooling → fixed-length cutting
Surface: Hot-rolled original color with slight oxide scale
Features: Low cost, good strength and toughness, easy to weld
Cold-Drawn Flat Steel
Cold drawing of hot-rolled billet at room temperature → finishing → straightening
Surface: High finish and high dimensional accuracy
Features: Small tolerance, good surface quality, suitable for precision machining
Forged Flat Steel
Formed by high-temperature forging with dense structure
Features: High strength, good toughness, used for heavy-load/special working conditions
III. Material and Grade
Carbon Structural Steel (Most Commonly Used)
Q235B: Yield strength ≥ 235 MPa, tensile strength 375–500 MPa, easy to weld, low price, suitable for general structures
Q345B: Low-alloy high-strength steel, strength about 50% higher than Q235, used for heavy-load structures
High-Quality Carbon Steel
20# and 45#: More stable composition and mechanical properties, used for mechanical parts and tools
Alloy Steel
40Cr and 42CrMo: High strength and wear resistance, used for heavy-load parts such as shafts and gears
IV. Specifications and Theoretical Weight
Expression method: Width × Thickness (mm)
Common specifications and theoretical weight (kg/m):
Specification |
Theoretical Weight |
Specification |
Theoretical Weight |
20×3 |
0.47 |
50×5 |
1.96 |
25×4 |
0.79 |
60×6 |
2.83 |
30×3 |
0.71 |
80×8 |
5.02 |
40×4 |
1.26 |
100×10 |
7.85 |
Theoretical weight formula: W (kg/m) = 0.00785 × Width × Thickness
V. Executive Standards
GB/T 704-2008 Dimensions, Shape, Weight and Allowable Deviations of Hot-Rolled Flat Steel
GB/T 700-2006 Carbon Structural Steel
GB/T 1591-2018 High-Strength Low-Alloy Structural Steel
GB/T 13912-2020 Technical Requirements for Hot-Dip Galvanized Coatings
VI. Product Features
Flexible Specifications: Customizable width, thickness and length to reduce cutting loss
Precise Dimensions: Controllable tolerance for hot-rolled products, higher precision for cold-drawn products (up to ±0.05 mm)
Diverse Surfaces: Hot-rolled black surface, cold-drawn smooth surface, galvanized, painted, polished, etc.
Good Processability: Easy to weld, drill, bend and cut
High Cost-Effectiveness: Compared with steel plates, no need for cutting, high utilization rate and low cost
VII. Main Applications
Construction Engineering: Roof trusses, escalators, guardrails, steel structure supports, grounding flat steel
Mechanical Manufacturing: Bases, brackets, guide rails, tools, agricultural machinery parts
Steel Structures: Steel gratings, platforms, stair treads, trench covers
Automotive/Transportation: Vehicle frames, bumpers, trailer components
Anti-Corrosion Environments: Chemical industry, food industry, pharmaceutical industry, marine engineering (galvanized)
VIII. Surface Treatment
Black Surface (Hot-Rolled Original Color): Lowest cost, used for non-exposed/general structures
Hot-Dip Galvanizing: Strong corrosion resistance, zinc layer ≥ 85 μm, service life 15–30 years, used for outdoor/underground
Cold Galvanizing (Electrogalvanizing): Bright surface, thin zinc layer, used for indoor/mild corrosion environments
Painting/Brushing: Rust prevention + coloring, customizable colors
Polishing/Brushing: Used for decorative surfaces
IX. Packaging and Delivery
Packaging: Bundled (1–5 tons per bundle), with labels at both ends indicating specifications, material, batch number and standard
Delivery Status: Hot-rolled (black surface), cold-drawn (smooth surface), galvanized, fixed-length
Quality Certificate: Provide material certificate (furnace number, composition, mechanical properties)
X. Selection Suggestions
General Structures/Non-Corrosive Environments: Choose Q235B hot-rolled flat steel for the highest cost-effectiveness
Outdoor/Humid/Underground: Choose Q235B hot-dip galvanized flat steel
Heavy Load/High Strength: Choose Q345B or 45# flat steel
Precision Machining/Appearance Requirements: Choose cold-drawn smooth flat steel
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