The technological characteristics and advantages of cylinder tube roll forming
Release time:
2026-03-26
Hydraulic cylinder tube rolling is a non-cutting cold plastic precision machining process. Its core is to apply high pressure to the inner wall of the tube by the rolling head, so that the surface metal flows plastically, and at the same time achieves finishing, strengthening and dimensional correction. It is the mainstream and efficient solution for the precision machining of hydraulic cylinder barrels.
(Applicable for 20#, 45#, 40Cr, 27SiMn and other common cylinder tube internal rolling)
1. Basic Process Parameters
| Item | Parameter Range | Remarks |
|---|---|---|
| Machining allowance before rolling | 0.08–0.15 mm (single side) | Excessive allowance causes out-of-round; insufficient reduces finishing effect |
| Rolling speed | 30–80 r/min | Lower speed for deep holes and large diameters |
| Rolling feed rate | 0.10–0.30 mm/r | Higher for rough rolling, lower for finish rolling |
| Rolling pressure | 80–200 MPa | Lower pressure for harder materials and thinner walls |
| Rolling passes | 1–2 passes | Single pass for general use; double pass for high precision |
2. Recommended Parameters by Material
| Material | Hardness before rolling | Rolling Pressure | Target Surface Roughness |
|---|---|---|---|
| 20# Steel | HB 120–160 | 80–120 MPa | Ra ≤ 0.2 μm |
| 45# Steel | HB 180–220 | 120–160 MPa | Ra ≤ 0.15 μm |
| 40Cr | HB 200–240 | 140–180 MPa | Ra ≤ 0.1 μm |
| 27SiMn | HB 220–260 | 160–200 MPa | Ra ≤ 0.08 μm |
3. Dimensional Accuracy Control Index
| Accuracy Item | Achievable Value After Rolling |
|---|---|
| Inner hole dimensional accuracy | IT6–IT7 |
| Roundness | ≤ 0.003–0.005 mm |
| Cylindricity | ≤ 0.005–0.01 mm/m |
| Surface roughness | Ra 0.05–0.2 μm |
| Surface hardening layer depth | 0.20–0.50 mm |
4. Cooling and Lubrication Requirements
- Cutting fluid: Emulsified fluid / hydraulic oil / special rolling oil
- Requirements: Adequate flooding to remove heat, reduce friction, and improve surface finish
5. Common Problems and Adjustments
| Problem | Cause | Adjustment Method |
|---|---|---|
| Surface chatter marks | Excessively high speed, unstable pressure | Reduce rotation speed and feed rate |
| Oversized dimension | Excessive rolling allowance | Reduce pre-rolling allowance and pressure |
| Insufficient surface finish | Excessively fast feed, insufficient pressure | Increase pressure, reduce feed rate |
| Inner wall scoring | Worn rolling head, impurities | Replace rolling elements, filter cutting fluid |
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