Product Overview
Cold drawn hexagonal bars are precision-finished steel profiles produced by drawing hot-rolled wire or bars through a tungsten carbide die at room temperature. This mechanical reduction process increases tensile strength, achieves tight dimensional tolerances, and delivers a clean, scale-free surface finish.
Engineered specifically for automated CNC machining and high-speed fastener production, our cold-drawn hex bars eliminate preliminary turning operations, reduce tool wear, and ensure consistent feed rates in multi-spindle screw machines.
Technical Specifications
|
Parameter |
Specification Range |
|
Product & Material Description |
Cold Drawn Hexagonal Bar / Cold Drawn Hex Steel Bar |
|
Size Range (Across Flats) |
6 mm to 80 mm (1/4 inch to 3 inches) |
|
Standard Grades |
Carbon Steel: AISI 1018, 1045, 12L14, 1215 Alloy Steel: AISI 4140, 8620 Stainless Steel: 303, 304, 316 (upon request) |
|
Dimensional Tolerance |
ISO h11, h10, h9 (or custom limits per ASTM A29 / EN 10278) |
|
Standard Lengths |
3,000 mm, 5,800 mm, 6,000 mm, or custom cut lengths |
|
Straightness |
Max 1.0 mm per 1,000 mm (stricter tolerances available for high-RPM applications) |
|
Surface Condition |
Cold drawn, smooth, free of heavy scale, optional centerless ground or polished |
|
Associated Standards |
ASTM A29, EN 10277, DIN 178, JIS G4804, AS 1444 |
Product Advantages
Optimized Machinability:
Cold drawing cold-work hardens the outer skin while retaining a stable core, reducing stringy chips and improving surface finish during high-speed turning and threading.
Precise Across-Flat Dimensions:
Controlled drawing reductions maintain strict cross-sectional symmetry, ensuring correct fit in collets and chucks without slippage.
Reduced Secondary Processing:
Eliminates initial rough turning steps on hexagonal components, lowering raw material waste and cycle time per part.
Enhanced Mechanical Properties:
Yield and tensile strengths increase by 20% to 40% compared to hot-rolled equivalents, reducing the need for subsequent heat treatment in structural applications.
Applications
Fastener Production: Hex nuts, bolts, socket screws, and threaded inserts requiring high dimensional accuracy.
Hydraulic & Fluid Power: Valve bodies, hose fittings, adapters, and manifold components machined on multi-axis CNC lathes.
Automotive Components: Steering linkage parts, fuel system connectors, and transmission fasteners.
Industrial Hardware: Hand tools, wrench sockets, mechanical linkages, and architectural hardware fittings.
Customization & Processing
Custom Length Tolerances:
Precision cutting services down to +/-0.5 mm tolerances, deburring, and chamfering ends for automated feeder systems.
Tailored Heat Treatment:
Annealed, normalized, or quenched and tempered (QT) conditions available to match specific hardness or ductility requirements.
Special Steel Grades:
Sourcing and drawing specialized carbon or alloy compositions based on client mechanical property specifications.
In-House Processing Assets:
Integrated drawing benches, straightening machines, eddy current flaw detectors, and high-speed carbide saws operating under ISO 9001 process controls.
Quality Control & Inspection
Every production batch undergoes strict verification before dispatch:
Dimensional Verification: Laser micrometer checking across flats (AF) and corner radii at continuous intervals along the bar length.
Non-Destructive Testing (NDT): 100% inline or offline eddy current testing to detect surface seams, laps, and internal micro-cracks.
Mechanical Testing: Tensile testing, yield strength measurement, and Brinell/Rockwell hardness testing performed per ASTM/EN standards.
Metallurgical Analysis: Spectrometric chemical composition analysis and microstructure examination (grain size, decarburization depth).
Documentation: Each shipment includes an EN 10204 3.1 Mill Test Certificate detailing exact chemical and mechanical test results.
Packaging & Shipping
Standard Bundling: Securely strapped with high-tensile steel bands in hexagonal bundles weighing 1,000 kg to 2,000 kg.
Surface Protection: Anti-rust oil coating applied to all bare metal surfaces; optional VCI (Volatile Corrosion Inhibitor) wrapping for overseas container transport.
Moisture Protection: Plastic film wrapping applied over bundles to prevent oxidation during sea freight.
Clear Labeling: Weatherproof barcoded tags indicating steel grade, heat number, size, piece count, and bundle weight for traceable warehouse management.
FAQ
Q: What is the standard manufacturing length tolerance for cold drawn hex bars?
A: Standard production lengths are supplied at +50/-0 mm, but exact fixed lengths down to +/-1 mm can be processed via our in-house precision saws.
Q: How do you prevent twisting or bending during the cold drawing process?
A: Bars pass through multi-roll precision straightening machines post-drawing to maintain a straightness runout within 1.0 mm/m, preventing vibration in high-RPM CNC lathes.
Q: Can you provide 3.1 Mill Test Certificates with chemical and mechanical data?
A: Yes. Every order ships with an EN 10204 3.1 certified test report verifying actual heat analysis, tensile strength, and hardness values.
Q: What is the minimum order quantity (MOQ) for custom steel grades or non-standard sizes?
A: MOQ typically depends on rolling and drawing mill schedules, generally starting at 2 metric tons per size/grade combination. Smaller trial batches may be available from stock inventory.
Q: Do cold drawn hex bars require stress relief annealing before heavy machining?
A: For standard free-machining grades like 12L14 or low-carbon 1018, cold drawing residual stresses are minimal. For deep slotting or severe asymmetric removal on alloy grades like 4140, stress-relieving is recommended to prevent warping.
Q: What anti-rust measures are used for ocean freight export?
A: Bars are coated with solvent-deposited rust preventive oil, bundled with steel strapping, and wrapped in moisture-resistant woven plastic sheets or heavy-duty VCI film upon request.
Request a Quote
To receive a competitive quotation for your cold drawn hex steel bar requirements, please provide the following details:
• Steel Grade (e.g., AISI 1045, 4140, 12L14)
• Size (Across Flats in mm or inches)
• Required Quantity (Metric Tons or Pieces)
• Length Requirements (Standard 6m or Custom Cut)
• Destination Port for Shipping Calculation
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