Cold Drawn Honed Tube: High Precision Hydraulic Cylinder Tubing
Cold Drawn Honed Tube Overview
A cold drawn honed tube combines two precision manufacturing processes: cold drawing for dimensional accuracy and surface quality, followed by honing for the ultra-smooth finish required in hydraulic cylinders.
Manufacturing Process
Combined Process Flow
1. Hot rolled seamless tube 2. Cold drawing (first pass sizing) 3. Stress relief annealing 4. Final cold drawing (closer tolerances) 5. Honing (multi-pass abrasive processing) 6. Final inspection and testing
Process Benefits
Cold Drawing Benefits
- Precise OD and ID tolerances - Excellent surface finish - Improved strength from work hardening - Consistent wall thickness
Honing Benefits
- Mirror-like bore surface (Ra 0.2-0.4μm) - Proper oil retention characteristics - Corrected out-of-round conditions - Cross-hatch pattern for lubrication
Material Selection
Common Materials
| Material | Characteristics | Applications |
|---|---|---|
| ST37 (E235) | Good formability, standard strength | Low-pressure cylinders |
| ST52 (E355) | High strength, good weldability | Standard hydraulic |
| 27SIMN | High strength, wear resistant | Heavy duty hydraulic |
| 45# (1045) | Medium carbon, high strength | High-pressure applications |
Specifications
Dimensional Range
Outer Diameter: 20-200mm Wall Thickness: 3-25mm Length: Up to 12m ID Tolerance: H8-H9 (IT8-IT9)
Surface Quality
| Grade | Surface Roughness | Application |
|---|---|---|
| Standard | Ra ≤ 0.4μm | General hydraulic |
| Premium | Ra ≤ 0.2μm | High-pressure hydraulic |
| Ultra-precision | Ra ≤ 0.1μm | Servo hydraulics |
Quality Characteristics
Geometric Accuracy
Straightness: ≤0.3mm per meter Out-of-round: ≤0.05mm Wall thickness variation: ≤5%
Mechanical Properties
After cold drawing and stress relief: ST52 Material: - Yield strength: ≥355 MPa - Tensile strength: 490-630 MPa - Elongation: ≥22% - Hardness: 180-220 HB
Applications
Hydraulic Cylinders
- Construction machinery
- Agricultural equipment
- Industrial automation
- Machine tools
Specialized Applications
Servo Hydraulic Systems
Requirements: - Ultra-smooth bore surface - Precise dimensional tolerances - Excellent dynamic stability - Minimal friction for rapid response
High-Pressure Hydraulic
Specifications: - Working pressure: 250-350 bar - Test pressure: 400-500 bar - Premium surface finish - High-strength materials
Testing and Certification
Standard Tests: - Dimensional verification - Surface roughness measurement - Hydrostatic pressure test - Hardness testing - Chemical composition analysis Optional Tests: - Ultrasonic inspection - Eddy current testing - Mechanical property testing
Conclusion
Cold drawn honed tubes represent the highest quality hydraulic cylinder tubing, combining the dimensional precision of cold drawing with the superior surface finish of multi-pass honing. These tubes provide optimal performance for demanding hydraulic applications.