We design and produce MWaolloys Carbon Steel Flat Bar to meet the highest industry standards. With a blend of efficiency and expertise, we satisfy both general fabrication and demanding structural needs.
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Engineered to ASTM and EN norms.
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Offered in hot‑rolled and cold‑finished grades.
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Suited for construction, machinery, framing, and bracketing.
What is flat carbon steel?
Flat carbon steel refers to a category of low-to-medium carbon steel products manufactured in rectangular cross-sections with uniform thickness. Unlike round, square, or angled steel bars, flat variants feature parallel surfaces and straight edges, making them ideal for structural framing, machinery bases, brackets, and fabrication.
Specifications & Dimensional
⭐ Table 1: Common Grades & Mechanical Properties
Key global standards for carbon steel flat bars, with critical performance metrics:
| Grade | Standard | Yield Strength (min) | Tensile Strength (min) | Hardness (Brinell) | Carbon Content |
|---|---|---|---|---|---|
| ASTM A36 | ASTM A36 | 250 MPa (36,300 psi) | 400–550 MPa (58–80 ksi) | 119–159 HB | ≤0.26% |
| SS400 | JIS G3101 | 245 MPa (35,500 psi) | 400–510 MPa (58–74 ksi) | N/A | ≤0.29% |
| Q235 | GB/T 700 | 235 MPa (34,100 psi) | 375–500 MPa (54–72 ksi) | ≤131 HB | ≤0.20% |
| S235JR | EN 10025-2 | 235 MPa (34,100 psi) | 360–510 MPa (52–74 ksi) | ≤130 HB | ≤0.17% |
| 1018 | ASTM A108 | 370 MPa (53,700 psi) | 440 MPa (63,800 psi) | 126 HB | 0.15–0.20% |
| Q345 | GB/T 1591 | 345 MPa (50,000 psi) | 470–630 MPa (68–91 ksi) | ≤147 HB | ≤0.20% |
⚙️ Table 2: Standard Dimensions & Tolerances
Manufacturing specifications for hot-rolled carbon steel flat bars:
| Parameter | Range | Tolerance | Notes |
|---|---|---|---|
| Thickness | 1.5–60 mm (0.06–2.36 in) | ±1% | Customizable up to 100 mm |
| Width | 12–2,500 mm (0.47–98.4 in) | ±0.02% (ASTM) | Common: 15–200 mm |
| Length | 1–12 m (3.3–39.4 ft) | ±6 mm (ASTM) | Custom lengths up to 20 m |
| Edge Condition | Mill edge or sheared | N/A | Smooth edges standard |
| Surface Finish | Hot-rolled black, polished | N/A | Optional: pickled, galvanized |
📐 Manufacturing Standards & Supplementary Data
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Process: Hot-rolled (primary), cold-finished (precision).
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Tolerances:
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Thickness/Width: ±1% (general), ±0.02% for ASTM A36.
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Length: ±6 mm for 6m bars; ±1 inch for 12ft bars.
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Surface Treatments: Mill scale (as-rolled), polished, sandblasted, or coated (e.g., galvanized).
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Certifications: ISO 9001, ASTM, EN, JIS, GB 1510.
💡 Applications by Grade
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A36/SS400/Q235: Structural frames, brackets, machinery bases.
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1018: Precision parts (cold-finished), shafts, fasteners.
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Q345: High-stress components (construction, bridges).
⚖️ Flat Bars vs. Other Carbon Steel Shapes
| Type | Cross-Section | Primary Use Cases |
|---|---|---|
| Flat Bar | Rectangular | Bracing, framing, machining |
| Round Bar | Circular | Shafts, fasteners |
| Angle Bar | L-shaped | Structural supports |
| Channel Bar | U-shaped | Beams, rails |
| Item | Carbon Steel Flat Oval/Oval/Elliptical Tube |
|---|---|
| Materials | SPCC, Q195, Q215, Q345 |
| Length | 3m, 5.8m, 6m, 12m |
| Flat Oval Tube | size: 11mm 40mmx22mmx90mm, wall thickness: 0.6mm – 1.7mm |
| Oval/Elliptical Tube | size: 12mm – 88mmx15mm-88mm, wall thickness: 0.5mm – 4mm |
| Surface Paint | Annealing |
Chemical Composition of Carbon Steel Flat Bars (Weight Percentage %)
| Grade/Standard | C (Carbon) | Mn (Manganese) | P (Phosphorus) max | S (Sulfur) max | Si (Silicon) | Fe (Iron) |
|---|---|---|---|---|---|---|
| ASTM A36 | ≤0.26% | ≤1.35% | 0.040% | 0.050% | 0.15–0.40% | Balance |
| EN S235JR | ≤0.17% | ≤1.40% | 0.035% | 0.035% | ≤0.035% | Balance |
| JIS SS400 | ≤0.29% | N/A | 0.050% | 0.050% | N/A | Balance |
| AISI 1018 | 0.15–0.20% | 0.60–0.90% | 0.040% | 0.050% | 0.10–0.30% | Balance |
| GB/T Q235B | ≤0.20% | ≤1.40% | 0.045% | 0.045% | ≤0.30% | Balance |
| ISO E235 | ≤0.20% | ≤1.40% | 0.040% | 0.040% | ≤0.30% | Balance |
Key Notes on Composition
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Carbon (C):
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Defines strength/hardness (low C: ≤0.3% = weldable; medium C: 0.3–0.6% = machinable).
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Manganese (Mn):
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Enhances strength and hardenability (typically 0.30–1.65%).
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Sulfur (S) & Phosphorus (P):
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Impurities restricted to ≤0.05% (improves weldability and reduces brittleness).
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Silicon (Si):
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Deoxidizer (0.10–0.40%), boosts strength without compromising ductility.
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Trace Elements & Industry Standards
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ASTM A36: May contain Cu (copper) ≥0.20% for atmospheric corrosion resistance.
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Cold-Finished Grades (e.g., 1018): Tighter composition controls for precision machining.
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ISO 630 Structural Steel: Requires Cr (chromium) ≤0.40%, Ni (nickel) ≤0.40%.
🌍 Global Carbon Steel Price Comparison (2025)
| Region | Typical Product | Unit Price (USD/tonne) | Source & Date |
|---|---|---|---|
| China | Hot‑rolled coil / flat steel | ~ 2,900–3,136 CNY/t → USD ≈ $425–460/t | TradingEconomics (3,136 CNY/t on Jul 18) |
| Europe | HRC, CRC, HDG | ~ €650/t → USD ≈ $710/t | MEPS Europe (Jun 2024 avg: 0.65 €/kg) |
| USA | Hot‑rolled coil | $840–$910/t (spot: $890–950) | IndustrialTube Jun 2025 |
📈 Regional Overview
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China: Prices recently hovered at 3,136 CNY/t (≈ $460/t) with upward trend—6% month growth.
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Europe: Steady prices at about 0.65 €/kg (~€650/t ≈ $710/t).
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USA: Spot HRC fluctuates between $890–950/t, peaking around $950/t; warming post-tariff.
Competitive Comparison
| Feature | MWaolloys Flat Bar | Generic A36 Flat Bar | Premium Cold‑Finished 1018 |
|---|---|---|---|
| Size Range | 6–50 mm × up to 625 mm | 20–100 mm typical | 6–25 mm only |
| Tolerance | ±0.1 mm | ±0.5 mm | ±0.05 mm |
| Finish | Smooth/galvanized | Rough, hot‑rolled | Fine, cold‑finished |
| Certification | ASTM/EN per batch | Generic supplier traceability | Certified, expensive |
| Price | Competitive | Lower | Higher |
FAQs
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What are the 2025 global prices for carbon steel flat bar in China, Europe, and the USA?
In mid‑2025, average spot prices for hot‑rolled carbon steel flat bar are:-
China: ¥2,900–3,136 CNY/tonne (~ $425–460 USD)
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Europe: €650 EUR/tonne (~ $710 USD)
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USA: $840–910 USD/tonne (spot $890–950)
These figures reflect real‑time market reports and help you budget for bulk procurement.
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What dimensions, tolerances, and finishes does MWalloys Carbon Steel Flat Bar offer?
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Thickness: 6 mm–50 mm; Width: 12.7 mm–625 mm; Length: 1–15 m.
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Tolerances: Hot‑rolled ±0.5 mm; Cold‑finished ±0.05 mm.
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Finishes: Raw scale, smooth cold‑finished, hot‑dipped galvanized, painted.
This range ensures compatibility with both structural and precision‑engineering needs.
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Which material grades and certifications apply to MWalloys Carbon Steel Flat Bar?
We supply flat bars in:-
ASTM A36/A1011, SS400, Q235, Q345 (hot‑rolled).
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Cold‑finished 1018, 1045 (tight‑tolerance alloy grades).
Certified per ASTM A370 (mechanical tests) and traceable via batch heat numbers under ISO 9001 quality management.
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How do I place an order and what is the minimum quantity?
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MOQ: 500 kg per grade/size.
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Ordering: Contact our sales team via email or RFQ form.
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Delivery: Standard lead time ~ 4 weeks; expedited options available.
We support cut‑to‑length, custom bundles, and JIT delivery for streamlined project logistics.
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What are the primary applications for hot‑rolled versus cold‑finished flat bars?
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Hot‑rolled: Building frames, bracing, weldments—favored for structural strength and cost‑effectiveness.
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Cold‑finished: Machine components, precision tooling, decorative trims—chosen for superior surface finish and dimensional accuracy.
Selecting the right process maximizes performance and minimizes post‑machining work.
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How does MWalloys ensure quality and sustainability in its flat bar production?
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Quality controls: 100 % dimensional checks, spectrometry, tensile/yield testing.
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Sustainability: Electric Arc Furnace steel (≥ 30 % lower CO₂ vs. blast furnace), Environmental Product Declarations (EPDs) available.
Our QA/QC protocols and eco‑friendly sourcing align with global green‑steel initiatives.
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