Bright Bars Technical Catalogue
Precision tolerance bright steel bars produced by cold drawing, peeling and grinding processes
Processing Methods
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Steel Grades
Cold Drawing
Cold drawing is the process of pulling hot-rolled steel bars through a die at room temperature to improve dimensional tolerance, surface quality, and mechanical properties. It is the most common bright bar production method.
Dimension & Tolerance Table
| Profile | Size Range (mm) | Tolerance | Standard | Surface (Ra) |
|---|---|---|---|---|
| Round | 4 - 20 | h9 | EN 10278 | ≤ 1.6 µm |
| Round | 20 - 50 | h9 | EN 10278 | ≤ 2.0 µm |
| Round | 50 - 90 | h10/h11 | EN 10278 | ≤ 3.2 µm |
| Hexagon | 6 - 30 | h9 | EN 10278 | ≤ 1.6 µm |
| Hexagon | 30 - 70 | h10/h11 | EN 10278 | ≤ 2.5 µm |
| Square | 8 - 30 | h9 | EN 10278 | ≤ 2.0 µm |
| Square | 30 - 60 | h10/h11 | EN 10278 | ≤ 3.2 µm |
| Flat | 10x5 - 80x20 | h11 | EN 10278 | ≤ 3.2 µm |
| Flat | 80x20 - 150x30 | h11 | EN 10278 | ≤ 3.2 µm |
Key Features
- Precise dimensional tolerance (h9/h10/h11)
- Improved surface quality (Ra 0.8 - 3.2 µm)
- Enhanced tensile strength and yield strength
- Smooth surface suitable for CNC and automatic lathes
- Chamfering and cut-to-length service
- Fast machining on high-speed machines
- Low scrap rate - material savings
- Raw surface suitable for coating processes
- Wide profile range (round, hexagon, square, flat)
- Defect-free products for safety-critical parts
Applications
- Automotive parts (shafts, pistons, axles)
- Hydraulic and pneumatic cylinder bodies
- CNC automatic lathe machining
- Machine manufacturing industry
- Bolts, nuts, and fasteners
- Furniture and appliance components
- Gear and bearing shafts
- Agricultural machinery parts
Technical Notes
- Cold drawing increases tensile strength by 15-20%.
- h9 tolerance is applied as standard for diameters below 50mm.
- For diameters above 50mm, h10 or h11 tolerance is preferred.
- Flat profiles have separate tolerances for width and thickness.
- Standard length: 3000-6000mm, custom cutting available on request.
- Chamfering provides easy feeding into automatic machines.
- Cold drawn products should be selected prior to heat treatment.
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Detailed Technical Information and Quotation
Contact our expert team for detailed technical documents, application recommendations, and custom size quotations regarding this product type.
Get Technical SupportWhat is bright steel?
Bright steel is hot-rolled bar finished cold — by cold drawing, peeling/turning or grinding — to a precise size and clean surface. Typical tolerances: h9/h11 for cold drawn, h6–h9 for ground bar (ISO 286). With its scale-free bright surface, tight tolerance and straightness, it often needs no further machining (EN 10277).
Cold drawing vs peeling vs grinding
Cold drawing: the bar is pulled through a die; strain hardening raises yield strength by ~10–20% and gives h9/h11 tolerance — the most economical bright product. Peeling (turning): the surface layer is machined off, removing surface cracks and decarburization without adding residual stress — ideal for large diameters and Q&T grades. Grinding: the tightest tolerance (h6–h9) and the best finish (Ra ≤ 0.8 µm) — for shafts and pins. Typical grades: C45, 42CrMo4, 11SMn30, 16MnCr5.
Frequently Asked Questions
Bright steel vs hot rolled — what is the difference?+
Bright steel is cold finished: scale-free surface, h6–h11 tolerance and high straightness; hot rolled has scale and wide tolerances and is usually bought for further machining.
Does cold drawing increase strength?+
Yes; strain hardening typically raises yield strength by 10–20%, with slightly reduced ductility. Stress-relief annealing is applied where needed.
When is peeled (turned) bar preferred?+
For large diameters, quenched-and-tempered grades, and when surface defects/decarburization must be fully removed — it gives a clean surface without adding residual stress.
Which tolerances are standard for bright steel?+
h9 or h11 for cold drawn, h6–h9 for ground bar (ISO 286-2, EN 10277).
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