Product Overview
Carbon steel bright bar (bright drawn/ground bar) is cold-finished carbon steel round, square, hex, and flat bar with a smooth, scale-free, “bright” surface and tight dimensional tolerance. It is the feedstock of choice for CNC turning, automatic lathes, shafts, and precision components where hot rolled bar would need expensive additional machining. Huaxia-Steel supplies bright bar from 3 mm to 100 mm diameter in C10–C45, 1018–1045, S20C–S50C, and equivalent grades, as drawn, peeled, or ground + polished, with straightened lengths and chamfered ends.
Specifications
| Parameter | Range | Standard / Tolerance |
|---|---|---|
| Diameter (round) | 3 – 100 mm | h9–h11 per EN 10278 / ±0.02–0.08 mm |
| Hex across flats | 5 – 60 mm | h11 |
| Square / flat | 5 – 80 mm | h11 / drawn profile |
| Length | 3000 – 6000 mm (fixed) | 0 / +15 mm typical; cut blanks ±0.5 mm |
| Straightness | ≤ 0.5 mm/m standard | ≤ 0.1 mm/m precision on request |
| Surface roughness | Drawn Ra ≤ 1.6 µm; ground Ra ≤ 0.8 µm | Per EN 10278 process codes |
Available Grades
| Standard | Grades | Typical Use |
|---|---|---|
| EN 10277 | C35, C45, C55, 36SMn14 | European machined parts |
| JIS G3123 / G3505 | S20C, S45C, S50C, SUM24L | Japanese-spec shafting, fasteners |
| ASTM A108 | 1018, 1045, 1117, 1144, 12L14 | North American machining |
| GB/T 3078 | 20#, 45#, 40Cr equivalent | Chinese standard cold-drawn |
Manufacturing Standards
- Cold drawing: hot rolled bar is pickled, drawn through a carbide die (10–30% area reduction) — raises yield by 20–40%, tightens tolerance to h9–h11, and produces the bright surface.
- Peeling: a lathe-type cutting pass removes 1–3 mm of hot rolled surface; used for larger diameters where drawing forces are impractical.
- Grinding & polishing: centerless grinding to h8/h9 and polish for shafts and visible surfaces.
- Straightening & cutting: precision straightening, chamfered or sawn ends, bar-end marking with grade and heat number.
- Heat treatment options: normalized, quenched & tempered (S45C/C45 QT), or stress-relieved after drawing — supply condition stated on the MTC.
Applications
- CNC-turned shafts, pins, rollers, and bushings
- Hydraulic and pneumatic cylinder rods (ground + chrome-ready)
- Gears, sprockets, and spline blanks (S45C/C45)
- Fasteners and cold-formed parts (1018, C10)
- Free-machining parts from 12L14 / SUM24L where finish and cycle time matter
Quality Assurance
- EN 10204 3.1 MTC with chemistry, tensile, hardness, and heat treatment state
- Dimensional check with micrometers/pin gauges: 5+ points per bar for ovality and size
- Straightness check on V-blocks per length
- Surface: no seams, laps, or die marks beyond class; decarb-free surface confirmed by microstructure sampling on request
- UT testing (SEP 1927 / GB/T 5777) on request for QT-grade bar
- Heat numbers etched on every bar, matched to certificate line by line
Packaging & Shipping
- Rust-preventative oil + kraft or VCI wrap per bundle; oiled paper between ground bars
- Wooden crates for ground/polished bars; bundles for drawn bar
- End caps and edge protection; bundles strapped and labeled with grade, size, heat, quantity
- Container or break-bulk loading with photos before shipment
Why Buy Bright Bar from Huaxia-Steel?
- Drawn, peeled, and ground lines in one plant — consistent finish and tolerance per process
- Tolerance classes h9/h10/h11 certified and measured, not just claimed
- Cut-to-blank service (±0.5 mm) saves your lathe loading time
- Both QT-condition and as-drawn supply with full traceability
FAQ
1. What is the difference between bright bar and black bar?
Black (hot rolled) bar has mill scale, ±1% or looser tolerance, and lower yield. Bright bar is cold-finished: scale-free surface, h9–h11 tolerance, 20–40% higher yield, better machinability — worth the 10–25% premium whenever parts are turned from it.
2. Which grade should I choose for machined shafts?
S45C / C45 / 1045 is the default for shafts needing strength after QT. Use 1018/S20C for light-duty parts and weldments; 12L14/1144 for high-volume automatic turning.
3. Does cold drawing increase hardness?
It raises yield and tensile through strain hardening and increases measured hardness somewhat, but for full QT properties specify quenched-and-tempered supply condition.
4. Can you supply decarb-free ground bar?
Yes — grinding removes the cold-drawn decarburized skin entirely; specify h8/h9 ground + decarb-free microstructure requirement on the order.
5. What is the minimum order?
Standard sizes from 1 ton per grade/size; mixed-size and cut-blank orders negotiable per shipment.
Get a Quote
Send grade, size, tolerance class, and supply condition — factory-direct carbon steel bright bar with EN 10204 3.1 certification, quotation within 24 hours.
