Galvanized Seamless Rectangle Steel Pipe
Jointless hollow section with a zinc coated surface in schedule wall thicknesses
Specifications
Seamless Steel Pipe, Steel Pipe
Cold Drawn Precision Seamless Steel Tube
Cold drawn and cold rolled seamless tube with a bright bore and tightly held diameters
Precision seamless steel pipe is a seamless tube finished by cold drawing or cold rolling to give a high dimensional accuracy and a bright inner and outer surface. Its internal and external diameter can be accurate to within 0.2mm, which is why it is specified by hydraulic cylinder builders, bearing makers and designers of precision mechanical parts and engineering structures. It holds bending and torsional strength while keeping the component light, so a designer does not have to add wall thickness to compensate for a loose tolerance. Buying tube already close to the finished dimension removes the honing or turning pass that a hot finished tube would need before assembly.
- Product Name — Precision Seamless Steel Pipe
- Also Known As — Cold drawn precision seamless tube cold rolled precision tube
- Standards — GB/T8713-88, GB/T3639-2009, DIN2391, EN10305
- Material — ST52, Q345B, CK20, CK45, SAE1026
- Outer Diameter — 10mm - 500mm
Why It Is Specified
Key Benefits of Precision Seamless Steel Pipe
Internal and External Diameter Within 0.2mm
The cold drawing or cold rolling process holds both diameters to within 0.2mm. Mating parts can often be assembled from the tube as delivered rather than after a machining pass.
Bright Surface Inside and Out
Cold finishing leaves a high brightness surface on both bores. That matters where a seal or a bearing runs against the tube wall.
Strength Kept While Weight Comes Down
The tube holds bending and torsional strength with light weight, so a moving component does not need extra wall thickness to make up for dimensional variation.
Four Standard Families Covered
GB/T8713-88, GB/T3639-2009, DIN2391 and EN10305 are all quoted, so a drawing written to a German or European tube standard can be filled directly.
Grades Chosen for the Duty
ST52, Q345B, CK20, CK45 and SAE1026 cover general structural tube, higher strength hydraulic duty and the carbon grades used where the part will be heat treated.
Size Range From Small Bores to 500mm
Outer diameter runs from 10mm to 500mm with wall between 2mm and 50mm, so small instrument tube and large cylinder barrels come from the same source.
Problems It Solves
What This Material Removes From Your Process
Machining Allowance Eating Into Cycle Time
Hot finished tube needs a clean-up cut before it is usable. Diameters held to within 0.2mm mean less material to remove and a shorter cycle.
Seal Wear Caused by a Rough Bore
A rough inner surface chews through cylinder seals. The cold drawing process leaves a high brightness bore so the seal runs against a finished surface.
Adding Wall Thickness to Cover Tolerance
Designers often thicken a section because they cannot trust the incoming dimension. A tight tolerance tube lets the wall stay between 2mm and 50mm as calculated.
Drilling a Bore Out of Solid Bar
Producing a hollow part from bar consumes drilling time and turns steel into swarf. Precision tube arrives with the bore already formed and finished.
Drawings Written to a European Tube Standard
DIN2391 and EN10305 call-outs are often refused by mills that only work to local standards. Both are quoted here alongside GB/T8713-88 and GB/T3639-2009.
Application Scenarios
Where It Is Used
Hydraulic and Pneumatic Cylinder Barrels
ST52 and Q345B tube used as cylinder bodies where the bore accuracy and bright inner surface govern seal life.
Precision Mechanical Parts
Bushes, sleeves, spacers and drive components machined from tube that is already close to the finished dimensions.
Bearing Rings and Races
Tube supplied as the starting blank for bearing production where the bore tolerance reduces the turning allowance.
Engineering Structures and Frames
Structural members where the combination of bending strength, torsional strength and light weight is the reason a precision tube is chosen.
Conveyor Rollers and Rotating Components
Roller bodies and shafts where concentricity and a smooth outer surface affect how the assembly runs.
Defense Component Manufacturing
Precision tube is also used in the production of conventional weapon components such as barrel and shell parts where dimensional accuracy governs the machining route.
Who It Is For
Buyers Who Specify This Product
- Hydraulic cylinder manufacturers buying honed quality barrel tube in ST52 or Q345B
- Machine shops sourcing near net size tube blanks for bushes sleeves and spacers
- Bearing producers ordering tube as a ring blank to cut the turning allowance
- Design engineers working to a DIN2391 or EN10305 drawing call-out
- Conveyor and roller manufacturers specifying concentric tube for rotating assemblies
- Component buyers replacing bar stock with tube to remove a drilling operation
Technical Data
Specifications and Technical Features
Values below come from the product data published by Shandong Tianyu Metal Products. Confirm the exact grade and size against your order.
| Product Name | Precision Seamless Steel Pipe |
|---|---|
| Also Known As | Cold drawn precision seamless tube cold rolled precision tube |
| Standards | GB/T8713-88, GB/T3639-2009, DIN2391, EN10305 |
| Material | ST52, Q345B, CK20, CK45, SAE1026 |
| Outer Diameter | 10mm - 500mm |
| Wall Thickness | 2-50mm |
| Length | 5.8m, 6m, 2-12m or customized |
| Diameter Accuracy | Internal and external diameter accurate to within 0.2mm |
| Technique | Cold drawing or cold rolling |
| Surface | High brightness inner and outer surface |
| Place of Origin | China |
| Certificate | Mill test certificate |
Technical Features
- Produced by cold drawing or cold rolling for dimensional accuracy and surface brightness
- Internal and external diameter accurate to within 0.2mm
- Standards GB/T8713-88 GB/T3639-2009 DIN2391 and EN10305
- Materials ST52 Q345B CK20 CK45 and SAE1026
- Outer diameter 10mm to 500mm
- Wall thickness 2mm to 50mm
- Length 5.8m 6m 2-12m or customized
- Seamless hollow section with no joint around the circumference
Materials
- ST52 higher strength structural tube steel used for hydraulic cylinder bodies
- Q345B low alloy high strength structural steel
- CK20 low carbon quality steel for general precision components
- CK45 medium carbon quality steel for parts that will be heat treated
- SAE1026 carbon steel for machined and welded components
Certification
- ISO9001
- BV
- SGS
- RoHS
- Mill test certificate supplied with each shipment
Manufacturing
How It Is Made and Processed
Seamless hot rolled mother tube produced from billet
Pickling and preparation of the tube surface
Cold drawing or cold rolling to the ordered outer diameter and wall thickness
Heat treatment where the grade and delivery condition require it
Straightening and dimensional gauging on both diameters
Cutting to 5.8m 6m 2-12m or a customized length
Protection end capping and packing for export
Quality Control
Checks Before It Ships
- Internal and external diameter gauged against the 0.2mm accuracy requirement
- Wall thickness checked across the 2mm to 50mm ordered dimension
- Inner and outer surface inspected for brightness and freedom from scoring
- Straightness checked over the full cut length
- Mill test certificate issued against the ordered ST52 Q345B CK20 CK45 or SAE1026 grade
- Ends capped and packing checked before loading
Customization
What We Can Change on Your Order
- Outer diameter selected anywhere between 10mm and 500mm
- Wall thickness set between 2mm and 50mm for the design calculation
- Cut length customized rather than taking 5.8m 6m or 2-12m stock lengths
- Grade chosen from ST52 Q345B CK20 CK45 or SAE1026 to suit machining or heat treatment
- Tube supplied to the GB DIN2391 or EN10305 standard named on your drawing
- Delivery condition agreed where the part will be heat treated after machining
Comparison
Precision Seamless Steel Pipe Against the Alternatives
| Hot finished seamless tube | Cold drawing holds internal and external diameter to within 0.2mm and leaves a bright surface, so the machining allowance is far smaller. |
|---|---|
| Solid round bar drilled and bored | The bore is already formed and finished, which removes the drilling operation and the swarf that goes with it. |
| Welded precision tube | The seamless route leaves no joint around the section, which matters where the bore runs against a seal or a bearing. |
| Thicker walled structural tube | Bending and torsional strength are retained with light weight, so the section does not have to be thickened to cover a loose incoming tolerance. |
Use Guide
Specifying Handling and Welding Notes
- State the bore tolerance you actually need since the 0.2mm accuracy applies to both internal and external diameter
- Choose CK45 where the finished part will be hardened and CK20 or SAE1026 where it will be welded or lightly machined
- Specify ST52 or Q345B for hydraulic cylinder barrels that carry working pressure
- Protect the bright bore in storage and keep the end caps on until the tube goes to the machine
- Confirm the standard on the order because GB/T3639-2009 DIN2391 and EN10305 set different delivery conditions
- Send the finished component drawing so the outer diameter and wall can be picked to leave the least machining stock
Questions Buyers Ask
Precision Seamless Steel Pipe FAQ
How accurate are the diameters on this tube?
Internal and external diameter can be accurate to within 0.2mm. Tell us the tolerance your part actually needs so the right cold finishing route is chosen.
What size range do you produce?
Outer diameter runs from 10mm to 500mm and wall thickness from 2mm to 50mm. Sizes outside that are treated as a customized enquiry.
Which grade should I use for a hydraulic cylinder barrel?
ST52 and Q345B are the usual choices for cylinder bodies. CK20, CK45 and SAE1026 are better suited to machined components and parts that will be heat treated.
Can you supply to DIN2391 or EN10305?
Yes. GB/T8713-88, GB/T3639-2009, DIN2391 and EN10305 are all covered. Put the standard on the purchase order so the delivery condition matches.
What lengths are available and can you cut to size?
5.8m, 6m and 2-12m are standard, and a customized cut length can be arranged. Send your cutting list with the drawing.
Is cold drawn or cold rolled better for my part?
Both processes are used to reach the accuracy and brightness. The choice depends on the size, the wall thickness and the surface you need, so send the drawing and we will advise.
How is the tube protected in transit?
Ends are capped and the bundles are packed to keep the bright inner and outer surfaces free from damage and moisture during shipment.
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