Carbon Steel Flat Bar — Factory Direct Supplier | Huaxia-Steel
Carbon steel flat bar is one of the most versatile steel products — used in machinery frames, brackets, base plates, and structural supports. Its rectangular cross-section makes it easy to cut, drill, and weld without specialized tooling.
Huaxia Steel supplies hot-rolled and cold-drawn carbon steel flat bar to ASTM, GB, JIS, and EN standards, with mill-direct pricing.
Product Specifications
Size Range
| Parameter | Hot-Rolled | Cold-Drawn |
|---|---|---|
| Width | 10–200 mm | 10–100 mm |
| Thickness | 3–60 mm | 2–25 mm |
| Length | 3–6 m (random) or fixed | 3–6 m |
| Tolerance (width) | ±0.5–1.0 mm | ±0.1–0.3 mm (h9–h11) |
| Tolerance (thickness) | ±0.3–0.5 mm | ±0.05–0.15 mm |
Manufacturing Standard
| Standard | Scope |
|---|---|
| GB/T 702 | Hot-rolled section steel (China) |
| ASTM A29/A29M | General requirements for carbon steel bars |
| JIS G3191 | Hot-rolled flat bar (Japan) |
| EN 10058 | Hot-rolled flat bar for general use (Europe) |
Available Grades
| Grade | Standard | C (%) | Yield (MPa) | Tensile (MPa) | Application |
|---|---|---|---|---|---|
| Q235B | GB/T 700 | 0.20 | 235 | 375–500 | General structural |
| A36 | ASTM A36 | 0.26 | 250 | 400–550 | Structural, machinery |
| SS400 | JIS G3101 | 0.20 | 245 | 400–510 | General structural |
| S235JR | EN 10025 | 0.20 | 235 | 360–510 | European structural |
| Q345B | GB/T 1591 | 0.20 | 345 | 470–630 | High-strength structural |
| A572 Gr.50 | ASTM A572 | 0.23 | 345 | 450+ | High-strength structural |
| 1020 | AISI/SAE | 0.20 | 245 | 395–420 | Machined components |
| 1045 | AISI/SAE | 0.45 | 310 | 565 | Shafts, gears (QT) |
Surface Conditions
| Condition | Description | Typical Use | Price Impact |
|---|---|---|---|
| Hot-rolled black | Mill oxide surface | Structural, welding | Base |
| Pickled & oiled | Acid-descaled | Painting, fabricating | +3–5% |
| Cold-drawn (bright) | Smooth, precision tol. | CNC machining, shafts | +15–25% |
| Galvanized | Hot-dip zinc coating | Outdoor, corrosion resistance | +28–35% |
Dimensional Tolerance (Hot-Rolled, GB/T 702)
| Width (mm) | Thickness ≤6 mm | Thickness 6–10 mm | Thickness >10 mm |
|---|---|---|---|
| 10–25 | ±0.40 | ±0.40 | ±0.50 |
| 25–50 | ±0.50 | ±0.50 | ±0.60 |
| 50–100 | ±0.70 | ±0.70 | ±0.80 |
| 100–150 | ±0.90 | ±0.90 | ±1.00 |
| 150–200 | ±1.10 | ±1.10 | ±1.20 |
Quality Assurance
- **MTC per EN 10204 3.1** — chemistry + mechanical properties
- **Dimensional inspection** — width, thickness, straightness at 3 locations per bundle
- **Surface inspection** — no cracks, seams, or inclusions per ASTM A29
- **Third-party inspection** — SGS, BV, TUV available on request
Packaging and Shipping
| Package Type | Description |
|---|---|
| Bundle | 3–6 m lengths, strapped (1–3 tons per bundle) |
| Wooden pallet | For cold-drawn precision bar |
| Container loading | 20’/40′ GP, 20–28 tons per container |
| Marking | Grade, size, heat number painted per bar |
FOB Pricing (2025–2026)
| Grade | Size (mm) | Condition | FOB ($/ton) | MOQ |
|---|---|---|---|---|
| Q235B | 40×5 | Hot-rolled | 580–650 | 5 tons |
| Q235B | 100×10 | Hot-rolled | 590–660 | 5 tons |
| A36 | 50×6 | Hot-rolled | 610–680 | 5 tons |
| SS400 | 75×8 | Hot-rolled | 590–660 | 5 tons |
| 1020 | 30×5 | Cold-drawn | 720–880 | 3 tons |
| 1045 | 50×10 | Hot-rolled | 650–720 | 5 tons |
FAQ
**Q: What is the difference between flat bar and plate?**
A: Flat bar is rolled as a section (width ≤200 mm, with rounded edges), while plate is rolled as a flat sheet and cut to width. Flat bar has better dimensional consistency in width. Plate is cheaper for wide sections (>200 mm).
**Q: Can you supply flat bar in custom lengths?**
A: Yes. Standard length is 3–6 m random. We can cut to fixed lengths (e.g., 1.5 m, 3.0 m, 6.0 m) with ±50 mm tolerance. Custom cutting adds 2–3% to price.
**Q: What surface finish is best for painting?**
A: Pickled & oiled is the most economical paintable surface. For powder coating, specify pickled then sweep-blasted (Sa 1) for optimal adhesion.
Get a Quote for Carbon Steel Flat Bar
**[Contact Huaxia Steel →](https://www.huaxia-steel.com/contact/)** — specify grade, width, thickness, length, quantity, and surface condition. We will confirm pricing and lead time within 24 hours.
