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Our Super Smooth ID Tubes (SSID) are engineered for applications requiring extremely
Our Super Smooth ID Tubes (SSID) are engineered for applications requiring extremely
Manufactured from high-strength ST52 steel, these tubes offer:
·Tight H9 tolerances for accurate fits
·Ultra-smooth inner surfaces (Ra0.4 – Ra0.8) for minimal friction
·Excellent straightness and roundness for hydraulic and precision applications
Ideal for hydraulic cylinders, pneumatic actuators, precision machinery, and tooling systems.
Key Features
·Material: ST52 steel
·Inner diameter finish: Ra0.4 – Ra0.8
·Dimensional accuracy: H9 tolerance
·Excellent straightness and roundness
·Available OD range: 60.3 – 114.3 mm
·Wall thickness: 4.75 – 6.35 mm
·Suitable for high-precision hydraulic and pneumatic systems
Technical Specifications Table
|
OD (mm) |
ID (mm) |
Wall (mm) |
Ra (ID) |
Tolerance |
|
60.3 |
50.8 |
4.75 |
0.6 |
H9 |
|
73 |
63.5 |
4.75 |
0.4 |
H9 |
|
101.6 |
88.9 |
6.35 |
0.8 |
H9 |
|
114.3 |
101.6 |
6.35 |
0.8 |
H9 |
(Custom sizes available on request)
Super Smooth ID Tubes – Surface Finish Comparison
|
OD (mm) |
ID (mm) |
Wall (mm) |
Ra (ID) |
Typical Applications |
|
73 |
63.5 |
4.75 |
0.4 |
Ultra-high precision hydraulic cylinders, tooling, aerospace components, high-performance machinery |
|
60.3 |
50.8 |
4.75 |
0.6 |
Precision hydraulic/pneumatic cylinders, industrial machinery, automotive actuators |
|
60.3 |
50.8 |
4.75 |
0.8 |
Standard hydraulic cylinders, pneumatic pistons, general-purpose precision machinery |
|
101.6 |
88.9 |
6.35 |
0.8 |
Heavy-duty hydraulic cylinders, construction and industrial machinery |
|
114.3 |
101.6 |
6.35 |
0.8 |
Large-diameter hydraulic cylinders, high-load industrial equipment |
Notes:
·Ra0.4 = ultra-smooth, minimal friction
·Ra0.6 = standard high-performance
·Ra0.8 = general-purpose hydraulic/pneumatic applications
Manufacturing Process
1. Selection of high-strength ST52 steel
2. Cold drawing or cold rolling to achieve OD and wall thickness
3. Precision honing for super smooth ID (Ra0.4 – Ra0.8)
4. Heat treatment for stress relief and optimized mechanical properties
5. Surface finishing – oiled, phosphated, or optional coatings
6. Inspection – dimensional checks, straightness, roundness, Ra measurement
7. How to Choose Super Smooth ID Tubes
Surface Finish (Ra)
·Ra0.4: Ultra-high precision (hydraulic, tooling, aerospace)
·Ra0.6: Standard high-performance (industrial machinery, automotive)
·Ra0.8: General-purpose hydraulic/pneumatic systems
Tolerance (H9 or H8)
·H9: Common for most SSID tubes
·H8: High precision for critical applications
Material (Steel Grade)
·ST52: High-strength steel for hydraulic and precision machinery
·Optional alloys for higher pressure or temperature
Size (OD x ID x Wall)
·Match cylinder or piston specifications
·Custom sizes available if standard sizes do not fit
Applications
·Hydraulic cylinders & pistons
·Pneumatic actuators
·Precision machinery & tooling
·Automotive and industrial equipment
Tips:
·Ra0.4–0.6 for high-speed or high-precision applications
·H9 tolerance ensures reliable sealing
·Verify wall thickness for hydraulic pressure rating
·Consider surface treatments for corrosion or lubrication
QUICK VIEW
Honed & SRB Tube – EN 10305-1 E355 H8 Ra0.4, Mirror ID Finish for Hydraulic Cylinder Barrels
QUICK VIEW
Honed & SRB Tube – ASTM A519 ST52 / 20MnV6 / 27SiMn, Mirror ID Finish for Hydraulic Cylinder Barrels
Suao is a professional manufacturer of high-precision cold drawn steel tubes, hydraulic tubes, and mechanical structure tubes, integrating R&D, production, inspection, and global sales. We operate two major production facilities covering over 36,000 square meters, with more than 200 employees and an annual output of 50,000+ tons, supplying customers across major industrial markets worldwide. As Suppliers of Super Smooth ID Tubes (SSID) – ST52 Steel, H9 Tolerance, Ra0.4 – Ra0.8, Ø60.3 – 114.3 mm, our integrated manufacturing capabilities include cold drawing, heat treatment, straightening, finishing, cutting, chamfering, and surface treatment. These are supported by a full range of advanced equipment for non-destructive testing, chemical analysis, and online dimensional monitoring—ensuring every tube meets stringent quality standards. We invest continuously in automation and smart manufacturing systems to enable flexible, high-mix, low-volume production. Custom Super Smooth ID Tubes (SSID) – ST52 Steel, H9 Tolerance, Ra0.4 – Ra0.8, Ø60.3 – 114.3 mm. Our products are widely used in construction machinery, hydraulic systems, automotive parts, wind energy, shipbuilding, railways, and oil & gas sectors. Certified to ISO 9001, ISO 14001, CE, and RoHS standards, Hongli is more than a manufacturer—we are a trusted long-term partner for global industrial clients.
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