Carbon Steel Hex Bar — Factory Direct Supplier | Huaxia-Steel
Carbon steel hex bar combines the strength of medium-carbon steel with a six-sided geometry that fits sockets, wrenches, and machined components without extra turning. It is widely used in fasteners, tools, shafts, fittings, and agricultural machinery.
Huaxia-Steel supplies carbon steel hex bar in SAE 1045, S45C, C45, A29, and other grades, with cold drawn, peeled, and ground finishes. We cut to length and pack for export from Chinese mills direct to your warehouse.
Product Overview
Our hex bar is produced from killed or semi-killed carbon steel, cold drawn through precision dies to achieve tight across-flats tolerances and a smooth surface. It can be supplied annealed for heavy machining, normalized for better toughness, or as cold-drawn for direct use in fixtures and hardware.
- Product form: Hexagonal bar, solid section.
- Standard grades: SAE 1045, SAE 1020, SAE 1018, S45C, C45, CK45, Q235, Q345, ASTM A29.
- Surface finishes: Cold drawn, peeled, ground, polished, black.
- Delivery conditions: +C cold drawn, +A annealed, +N normalized.
Specifications and Size Range
| Parameter | Range |
|---|---|
| Across flats (AF) | 6 mm to 100 mm |
| Length | 3 m, 4 m, 5 m, 6 m; cut-to-length available |
| Tolerance | h11, h12, or as agreed; tighter on ground bars |
| Straightness | 1 mm per meter max for cold drawn; 0.5 mm/m for ground |
| Surface roughness | Ra 0.8-3.2 micrometers typical |
| Bundle weight | 1,000-3,000 kg typical |
Weight Table (Approximate)
| Across flats (mm) | Weight kg/m |
|---|---|
| 8 | 0.42 |
| 10 | 0.66 |
| 12 | 0.95 |
| 16 | 1.69 |
| 20 | 2.64 |
| 24 | 3.80 |
| 30 | 5.93 |
| 36 | 8.54 |
| 42 | 11.62 |
| 50 | 16.49 |
Available Grades
| Grade | Standard | Carbon % | Typical use |
|---|---|---|---|
| SAE 1018 | ASTM A29 | 0.14-0.20 | Low-strength fasteners, pins, fittings |
| SAE 1020 | ASTM A29 | 0.18-0.23 | General machined parts, shafts |
| SAE 1045 | ASTM A29 | 0.43-0.50 | High-strength bolts, studs, tools |
| S45C / C45 / CK45 | JIS G4051 / DIN EN 10083-2 | 0.42-0.50 | Machinery shafts, gears, hand tools |
| Q235 / SS400 | GB/T 700 / JIS G3101 | 0.14-0.22 | General structural and hardware |
Manufacturing Standards
- ASTM A29 / A29M – General requirements for carbon and alloy steel bars.
- ASTM A108 – Cold-finished carbon steel bars.
- JIS G4051 – Carbon steels for machine structural use (S45C, S48C).
- DIN EN 10083-2 – Steels for quenching and tempering (C45, C45E).
- GB/T 699 – Quality carbon structural steels (45#, 20#, Q235).
Applications
- Bolts, nuts, studs, and threaded fasteners.
- Hand tools, wrenches, sockets, and drive adapters.
- Agricultural machinery pins and linkages.
- Automotive and motorcycle components.
- Construction hardware and scaffolding fittings.
- Shafts and axles in light machinery.
Quality Assurance
Every batch of hex bar is tested and documented:
- Spectrometer chemical analysis per heat.
- Tensile test for yield, tensile strength, and elongation.
- Hardness test on delivery condition.
- Dimensional inspection across flats and length.
- Visual surface inspection for cracks, seams, and scale.
- MTC to EN 10204 3.1 as standard; 3.2 available on request.
- Third-party inspection by SGS, BV, Intertek, or TUV available.
Packaging and Shipping
Hex bars are bundled with steel straps and protected against moisture and transit damage. Standard export packing includes:
- Anti-rust oil or VCI coating.
- Plastic or woven wrap around bundles.
- Wooden crate or pallet for small sizes.
- Clear marking with grade, heat number, dimensions, and standard.
- Container loading supervised on request.
Tolerance Classes
| Tolerance class | Across-flats tolerance | Typical application |
|---|---|---|
| h11 | +0 / -0.09 mm at 10 mm AF | General machining and hardware |
| h12 | +0 / -0.15 mm at 10 mm AF | Standard commercial hex bar |
| h9 | +0 / -0.036 mm at 10 mm AF | Precision fittings and tooling |
| Ground | +/- 0.01 mm or tighter | Gauges, precision shafts, aerospace work |
Mechanical Properties by Grade
| Grade | Condition | Yield MPa | Tensile MPa | Elongation % | Hardness HB |
|---|---|---|---|---|---|
| SAE 1018 | Cold drawn | 310 | 420 | 22 | 120-160 |
| SAE 1020 | Cold drawn | 350 | 470 | 20 | 140-180 |
| SAE 1045 | Cold drawn | 450 | 620 | 15 | 180-230 |
| S45C / C45 | Normalized | 370 | 580 | 18 | 170-210 |
| S45C / C45 | Annealed | 280 | 520 | 22 | 150-190 |
Cutting and Machining Advice
Cold drawn hex bar machines cleanly with sharp high-speed steel or carbide tools. For medium-carbon grades such as 1045 and S45C, use a cutting speed of 120-180 m/min for roughing and 80-120 m/min for finishing. Apply ample coolant to prevent work hardening. For automatic bar feed machines, straightness better than 1 mm/m is recommended to avoid vibration.
Typical Industries Served
- Automotive and motorcycle OEMs.
- Agricultural and construction machinery.
- Hand tool and power tool manufacturers.
- General engineering and maintenance workshops.
- Electrical and telecommunications hardware.
Order Example
A typical order might read: “Carbon steel hex bar, SAE 1045, cold drawn, h11 tolerance, 19 mm across flats, 6 m length, 5 tonnes, anti-rust oil, MTC to EN 10204 3.1.” This level of detail avoids ambiguity and ensures the supplier quotes the exact product you need.
Quality Grades and Certification
Besides commercial quality, we can supply turned, ground, and polished (TGP) bars for precision applications. TGP bars offer tighter diameter tolerance, better straightness, and superior surface finish than cold-drawn bars. They are commonly used for linear motion shafts, hydraulic piston rods, and precision tooling. Certification options include EN 10204 3.1, 3.2, and mill test reports to ASTM or JIS standards.
Comparison with Round Bar
Hex bar and round bar are often interchangeable for turned parts, but hex bar offers advantages for specific applications. The flat faces allow wrenching without marring, making hex bar ideal for fasteners and tooling. In automatic bar feed machines, hex bar can be held more securely by collets designed for polygonal stock. However, round bar is usually preferred when the part will be turned on a lathe to a finished cylindrical shape because round stock feeds more smoothly and wastes less material.
Anti-Corrosion and Storage
Carbon steel hex bar is susceptible to rust during ocean transport. We apply anti-rust oil and VCI film to protect the surface. For long-term storage, keep bars in a dry warehouse with low humidity. If surface rust appears, light oxidation can usually be removed by solvent cleaning or light abrasive blasting before machining.
Custom Sizes and Special Requirements
Besides standard metric sizes, we can supply inch sizes and non-standard across-flats dimensions. Custom orders require confirmation of minimum quantity and lead time. Common special requirements include:
- Chamfered or rounded ends.
- Drilled center holes for long bars.
- Pre-cut lengths for CNC bar feeders.
- Specific straightness class for automatic machining.
- Increased sulfur content (resulfurized grades) for improved machinability.
Lead Time and Order Quantities
| Order type | Typical quantity | Lead time |
|---|---|---|
| Stock sizes | 1-10 tonnes | 1-2 weeks |
| Mill production | 10-50 tonnes | 3-5 weeks |
| Custom sizes | 5 tonnes minimum | 4-6 weeks |
| Ground precision bars | 100 kg minimum | 2-4 weeks |
Export Documentation
We prepare full documentation for customs clearance and project records:
- Commercial invoice and packing list.
- Bill of lading or airway bill.
- Mill test certificate to EN 10204 3.1 or 3.2.
- Certificate of origin (Form A, CO, or regional FTA certificate).
- Third-party inspection report when requested.
Machining Speed and Feed Recommendations
For efficient machining of medium-carbon hex bar, use sharp tools and adequate coolant. Recommended starting parameters for SAE 1045 in the normalized condition are: cutting speed 120-180 m/min, feed 0.15-0.25 mm/rev, and depth of cut 2-5 mm for roughing. For finishing, reduce depth of cut to 0.5-1 mm and use a cutting speed of 150-200 m/min. Carbide inserts generally last longer than high-speed steel for production runs.
Frequently Asked Questions
What is the difference between hex bar and hexagon rod?
There is no technical difference; the terms are used interchangeably in different markets.
Can hex bar be galvanized?
Yes, hex bar can be hot-dip galvanized for outdoor use, although the threaded or machined surfaces may need protection.
What tolerance is standard for cold drawn hex bar?
h11 is the most common standard tolerance for commercial cold drawn hex bar.
Is SAE 1045 hex bar weldable?
Yes, but preheat to 150-250 degrees C is recommended for sections above 12 mm to avoid cracking.
Why Buy Carbon Steel Hex Bar from Huaxia-Steel
- Direct mill pricing with no trading layer.
- Wide size range from 6 mm to 100 mm across flats.
- Multiple grades and finishes for machining or direct use.
- Cut-to-length service to reduce your scrap and handling.
- Full documentation and third-party inspection support.
- Consolidated container shipments with other carbon steel products.
Request a Quote
Send us the grade, across-flats dimension, length, quantity, and finish you need. We will reply with a detailed offer, mill certificate sample, and delivery schedule within one working day.
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