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Cold Drawn Alloy Steel Round Bar for Mechanical Engineering Applications
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xProduct Details
| Products Name | Alloy Steel Round Bar | Diameter | 10 - 450mm |
|---|---|---|---|
| Length | 6m | Tech | Hot Rolled |
| Service | Cutting | MOQ | 1 Ton |
| Loading Port | Shanghai Port | Standard | ASTM EN GB |
Product Description
Cold Drawn Alloy Steel Round Bar for Mechanical Engineering Applications
Products Specification
|
Products Name |
Alloy Steel Round Bar |
|
Diameter |
20 - 350 mm |
|
Length |
6m or custom cutting any length as request |
|
Type |
Hot Rolled |
|
Brand |
BAOSTEEL DELTA DONGBEI HUAXI SHAGANG.etc |
|
MOQ |
1 Ton |
|
Loading Port |
Shanghai Port |
|
Packing |
packing by steel wire rope |
|
Deliver time |
5 - 7 days for stock materials |
|
Other Grade |
Q195,Q235,10#,20#,35#,45#,Q215,Q345,12Cr1Mov,15CrMo ,20Cr,40Cr,20CrMo,35CrMo,42CrMo,40CrNiMo,GCr15,65Mn,50Mn, 50Cr,3Cr2W8V,20CrMnTi,25Cr2MoVA,5CrMnMo ,38CrMoAl, 30CrMnSiA,B16,31CrMoV9 |
|
Standard |
ASTM GB EN DIN |
|
Application |
Structure and Industrial |
Cold Drawn Alloy Steel Round Bar for Mechanical Engineering Applications
Product Overview
Our Cold Drawn Alloy Steel Round Bar is a high-precision engineered material specifically designed for demanding mechanical engineering applications where dimensional accuracy, surface integrity, and consistent mechanical properties are critical. Produced from premium alloy steel grades (compliant with GB/T 3077, ISO 683-1, ASTM A322, and EN 10083), the bars undergo a controlled cold drawing process—without subsequent heat treatment—to enhance strength, straightness, and surface finish while maintaining excellent machinability.
Ideal for manufacturing shafts, pins, spindles, gears, bushings, fasteners, and precision components in automotive, aerospace, robotics, hydraulic systems, and general machinery, this product eliminates or significantly reduces the need for secondary machining—saving time, cost, and material waste.
Key Advantages of Cold Drawing
- ✅ Improved Surface Finish: Smooth, scale-free surface with roughness as low as Ra 0.8–1.6 µm
- ✅ Tighter Dimensional Tolerances: Up to h8/h9 standard (custom h7 available) per ISO 286
- ✅ Enhanced Mechanical Properties: Increased tensile and yield strength due to strain hardening (up to 15–25% higher than hot-rolled equivalents)
- ✅ Excellent Straightness: Typically ≤ 0.3 mm/m, reducing alignment issues during assembly
- ✅ Consistent Cross-Section: Uniform diameter along the entire length
- ✅ Clean & Ready-to-Use: No decarburization or oxide scale—ideal for direct CNC machining or grinding
Common Grades & Chemical Composition
| Grade (GB/T 3077) | AISI/SAE Equivalent | Key Alloying Elements (Typical %) | Primary Use Case |
|---|---|---|---|
| 20Cr | 5120 | C: 0.17–0.24, Cr: 0.70–1.00 | Case-hardened pins, small gears |
| 40Cr | 5140 | C: 0.37–0.44, Cr: 0.80–1.10 | Shafts, bolts, medium-stress parts |
| 42CrMo4 | 4140 | C: 0.38–0.45, Cr: 0.90–1.20, Mo: 0.15–0.25 | High-strength axles, tool holders |
| 35CrMo | 4135 | C: 0.32–0.40, Cr: 0.80–1.10, Mo: 0.15–0.25 | Connecting rods, heavy-duty fasteners |
| 20CrMnTi | 8620 | C: 0.17–0.23, Cr: 1.00–1.30, Mn: 0.80–1.10, Ti: 0.04–0.10 | Carburized transmission gears |
All grades feature low sulfur (S ≤ 0.025%) and phosphorus (P ≤ 0.025%) content for improved ductility and machinability.
Mechanical Properties (As Cold Drawn)
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) | Typical Machinability |
|---|---|---|---|---|---|
| 20Cr | 540–690 | ≥345 | ≥16 | 156–207 | Excellent |
| 40Cr | 785–930 | ≥590 | ≥12 | 217–269 | Good |
| 42CrMo4 | 850–1000 | ≥655 | ≥12 | 241–285 | Moderate (requires sharp tools) |
| 35CrMo | 735–885 | ≥540 | ≥13 | 207–255 | Good |
| 20CrMnTi | 590–735 | ≥390 | ≥15 | 163–217 | Excellent (pre-carburizing) |
Note: Cold drawing increases strength but slightly reduces ductility compared to annealed conditions. For maximum toughness, post-draw heat treatment (e.g., quenching & tempering) can be applied upon request.
Dimensional Specifications
| Parameter | Standard Range | Custom Options Available |
|---|---|---|
| Diameter | 6 mm – 100 mm | Up to 120 mm (subject to grade) |
| Length | 2,000 – 6,000 mm | Cut-to-length (±1 mm tolerance) |
| Diameter Tolerance | h9 (standard), h8 (common), h7 (on request) | Per ISO 286 or customer drawing |
| Straightness | ≤ 0.3 mm per meter | ≤ 0.15 mm/m (precision grade) |
| Surface Roughness | Ra 0.8–1.6 µm | Ra ≤ 0.4 µm (with additional polishing) |
| Packaging | Oiled, bundled, plastic-wrapped on wooden pallets | VCI paper, export crates |
Manufacturing Process
- Hot-Rolled Bar Input: Sourced from continuously cast, fully killed steel with ultrasonic inspection.
- Pickling & Phosphating: Removes scale and prepares surface for cold drawing.
- Cold Drawing: Passed through a die at room temperature to reduce diameter and improve properties.
- Straightening: Precision roller or stretch-straightening for optimal geometry.
- Final Inspection: Dimensional checks, visual surface review, and batch testing.
- Optional: Stress relieving (～550–650°C) to minimize distortion during machining (available on request).
Why Choose Cold Drawn Over Hot-Rolled or Ground Bars?
| Feature | Hot-Rolled Bar | Cold Drawn Bar | Precision Ground Bar |
|---|---|---|---|
| Surface Finish | Rough, scaled | Smooth, clean | Mirror-like (Ra < 0.8 µm) |
| Dimensional Tolerance | ±0.5 mm or worse | ±0.05–0.1 mm | ±0.01 mm (h6/h7) |
| Strength | Standard | Enhanced (strain hardened) | As-heat-treated |
| Machining Allowance | High | Low to none | Minimal or none |
| Cost Efficiency | Low material cost | Balanced performance/cost | Higher cost, high precision |
| Best For | Structural frames | Mass-produced precision parts | Critical-fit components |
Cold drawn bars offer the optimal balance for high-volume mechanical parts requiring reliability without the expense of grinding.
Applications in Mechanical Engineering
- Automotive: Transmission shafts, steering columns, valve stems
- Industrial Machinery: Pump shafts, guide rods, eccentric cams
- Agricultural Equipment: PTO shafts, linkage pins
- Hydraulics & Pneumatics: Piston rods, cylinder spindles
- Robotics: Joint axes, actuator components
- Tooling: Die holders, ejector pins, mold cores
Quality Assurance
- Full mill test reports (MTRs) per EN 10204 3.1
- ISO 9001:2015 certified production
- Batch traceability via heat number
- Optional ultrasonic testing (UT) or magnetic particle inspection (MPI) for critical applications
- Compliance with RoHS and REACH regulations
Ordering Guidelines
To ensure optimal performance, please provide:
- Desired steel grade (e.g., 42CrMo4 / AISI 4140)
- Required diameter and length
- Tolerance class (e.g., h8)
- Surface finish preference
- Quantity and delivery terms
- Special requirements (e.g., stress relief, cut-to-length, certification level)
Samples and technical support are available for design validation.
Conclusion
The Cold Drawn Alloy Steel Round Bar is a cornerstone material in modern mechanical engineering—delivering superior consistency, reduced machining costs, and reliable performance across thousands of industrial applications. By leveraging the natural strengthening effects of cold working and stringent process control, we provide a ready-to-machine solution that accelerates production cycles and enhances component quality.
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