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Views: 0 Author: Site Editor Publish Time: 2026-08-14 Origin: Site
The performance of a hydraulic cylinder depends heavily on the dimensional accuracy and surface condition of its cylinder barrel. Even a high-quality piston and sealing system can experience leakage, stick-slip movement or premature wear when the tube bore is rough, oversized, undersized or out of round.
For this reason, honed tubing for hydraulic cylinders is normally manufactured with a controlled inner diameter, low surface roughness and consistent bore geometry. Among international hydraulic cylinder manufacturers, H8 tolerance, Ra 0.4 μm surface finish and the SRB process are three of the most frequently specified requirements.
As a China-based hydraulic cylinder honed tube manufacturer, Fengdie Metal supplies precision-finished cylinder tubing manufactured from cold-drawn seamless steel tubes. Available processing includes conventional honing and skiving and roller burnishing, helping OEM cylinder manufacturers reduce internal machining and assembly time.
Buyers can view our hydraulic cylinder honed tubing specifications or contact us for a customized bore, wall thickness and material recommendation.
Honed tubing is a precision steel tube whose internal surface has been finished by an abrasive honing process or a related bore-finishing method. It is also commonly called:
Hydraulic cylinder honed tube
Honed cylinder tubing
Hydraulic cylinder barrel tube
Honed bore tubing
Precision honed steel tube
Seamless cylinder tube
Ready-to-hone or ready-to-use cylinder tubing
The tube bore forms the working surface along which the piston and seals travel. Its inner diameter, roundness, straightness and surface texture directly influence cylinder efficiency.
Compared with an ordinary seamless steel pipe, finished honed cylinder tubing can offer:
H8 or H7 inner diameter tolerance
Ra 0.2–0.4 μm surface roughness
Controlled roundness and cylindricity
Reduced friction between the seal and bore
More stable piston movement
Improved hydraulic sealing performance
Reduced downstream boring and grinding
Faster cylinder barrel assembly
Fengdie Metal also supplies precision seamless steel tubing for customers who require cold-drawn tube blanks, mechanical tubing or material for further honing and machining.
H8 refers to an ISO hole-basis tolerance class applied to the finished internal diameter. In an H8 bore, the lower deviation is zero and the permitted dimensional variation is above the nominal size.
For example, an H8 bore specified as 100 mm does not mean ±0.054 mm. It generally means:
100.000 mm to 100.054 mm
This distinction is important when preparing drawings and purchase orders. Writing “H8” together with an incorrect symmetric tolerance can create inspection disputes between the buyer and the honed tubing manufacturer.
| Nominal bore diameter | Typical H8 tolerance | Acceptbale bore range |
| 40 mm | +0.039/0 mm | 40.000–40.039 mm |
| 50 mm | +0.039/0 mm | 50.000–50.039 mm |
| 63 mm | +0.046/0 mm | 63.000–63.046 mm |
| 80 mm | +0.046/0 mm | 80.000–80.046 mm |
| 100 mm | +0.054/0 mm | 100.000–100.054 mm |
| 125 mm | +0.063/0 mm | 125.000–125.063 mm |
| 160 mm | +0.063/0 mm | 160.000–160.063 mm |
| 200 mm | +0.072/0 mm | 200.000–200.072 mm |
| 250 mm | +0.072/0 mm | 250.000–250.072 mm |
Surface roughness is commonly expressed as Ra, the arithmetic average deviation of the surface profile. For hydraulic cylinder bores, Ra ≤0.4 μm is a widely requested specification.
A properly finished Ra 0.4 bore can help:
Reduce friction during piston movement
Limit abrasive wear on hydraulic seals
Improve oil-film distribution
Reduce stick-slip at low operating speeds
Minimize internal leakage
Extend cylinder and seal service life
However, a lower Ra value is not automatically better. A surface that is polished too smooth may have insufficient valleys to retain lubricant. Hydraulic seal performance depends on the complete surface texture, not only one Ra number.
For demanding cylinder applications, buyers should consider specifying:
Ra surface roughness
Rz or maximum profile height
Cross-hatch angle
Bearing area or plateau characteristics
Bore roundness
Straightness
Cylindricity
Cleanliness after machining
A professional honed tube manufacturer should evaluate these requirements together rather than treating Ra as the only quality indicator.
Excellent bore geometry correction
Controlled cross-hatch surface
Good lubricant retention
Suitable for small and medium production batches
Applicable to thick-wall and special-grade tubes
H8 tolerance is routinely achievable
H7 tolerance may be available for selected specifications
Conventional honing is often preferred when the original bore requires geometry correction or when buyers need a specific surface texture for hydraulic sealing.
The process is slower than SRB, but it provides greater flexibility for customized cylinder barrel production.
SRB stands for skiving and roller burnishing. It combines two operations in one continuous pass.
First, skiving tools remove a thin layer of material from the inner surface. Next, burnishing rollers apply pressure to plastically deform and flatten the remaining microscopic peaks.
The process produces a smooth, dimensionally controlled bore while increasing production efficiency.
| Comparison | Conventional honed tube | SRB tube |
| Processing method | Abrasive stones rotate and reciprocate | Skiving cuts while rollers burnish |
| Typical surface | Controlled cross-hatch | Smooth plateau or mirror-like finish |
| Typical roughness | Ra 0.2–0.4 μm | Ra ≤0.2–0.4 μm |
| Typical bore tolerance | H8; H7 may be available | Commonly H8 |
| Geometry correction | Very good | Depends more on initial tube straightness and bore condition |
| Production speed | Relatively slower | Significantly faster |
| Surface layer | Material removed by abrasion | Surface is cut and cold-worked |
| Suitable volume | Small batches and customized sizes | Medium and high-volume production |
| Typical application | Specialized or precision cylinders | Standardized OEM cylinder production |
Honed and SRB cylinder tubing is widely used in:
Excavators and earthmoving machinery
Agricultural tractors and harvesters
Mining and drilling equipment
Forklifts and material-handling systems
Cranes and aerial work platforms
Garbage trucks and mobile hydraulic systems
Hydraulic presses and injection-molding machines
Industrial automation equipment
Marine and offshore cylinders
Pneumatic cylinders
Hydraulic cylinder repair and replacement projects
To receive an accurate quotation, provide the following information:
| Required information | Example |
| Material grade | E355 / ST52.3 |
| Manufacturing standard | EN 10305-1 |
| Inner diameter | 100 mm |
| Bore tolerance | H8 |
| Outer diameter | 120 mm |
| Wall thickness | 10 mm |
| Surface roughness | Ra ≤0.4 μm |
| Processing method | Honing or SRB |
| Tube length | 6,000 mm |
| Straightness | According to drawing |
| End processing | Cut and chamfered |
| Inspection document | EN 10204 3.1 |
| Quantity | 100 pieces |
| Packaging | Oiled, capped and export packed |
Fengdie Metal supplies factory-direct honed tubing for hydraulic cylinders, precision seamless steel tubes and customized cylinder barrel solutions.
Our manufacturing and supply capabilities include:
Conventional honing and SRB processing
H8 inner diameter tolerance
Ra 0.2–0.4 μm surface finish options
Carbon steel and alloy steel grades
Custom ID, OD, wall thickness and length
Cutting, chamfering and CNC processing
Material traceability and inspection reports
Small trial orders and volume OEM production
Moisture-resistant export packaging
International shipping support
Customers who need customized dimensions can learn more about our OEM precision tube processing capabilities or review the company’s precision tubing manufacturing background.
H8 is one of the most common inner diameter tolerances for hydraulic cylinder tubing. H7 may be specified for applications requiring tighter bore control, while other tolerances can be manufactured according to the cylinder design.
Yes. Ra ≤0.4 μm is commonly used for hydraulic cylinder bores. However, seal performance also depends on Rz, cross-hatch pattern, bearing area, roundness, lubrication and seal material.
A seamless steel tube describes the tube’s manufacturing construction. A honed tube is a tube with a precision-finished internal surface. A seamless tube can be used as the starting material for producing honed cylinder tubing.
Honing uses abrasive stones to gradually finish and correct the bore. SRB uses skiving tools followed by roller burnishing in one pass. Honing offers strong geometry correction and surface-texture control, while SRB provides faster production for standardized volumes.
Yes. Properly controlled skiving and roller burnishing can produce H8 bore tolerance and Ra ≤0.4 μm. The final result depends on the base tube quality, equipment, tooling and inspection controls.
E355/ST52 is widely used for general hydraulic cylinders. SAE 1026 provides good cold-drawing and welding characteristics, while C45/1045 and 42CrMo/4140 are suitable for higher-strength applications. The final grade should be selected according to pressure, load, welding and operating environment.
Yes. Fengdie Metal can provide custom cutting, chamfering, cleaning, oiling and end-cap protection. Additional machining can be completed according to customer drawings.
Provide the material, standard, ID, OD, wall thickness, bore tolerance, roughness, length, quantity, end processing, inspection documentation and destination port.
