Mechanical Pipe
Mechanical pipe and mechanical tubing manufactured to precise dimensional tolerances for automotive, machinery, hydraulic, and structural applications. Cold drawn and hot rolled options available.
Mechanical pipe, also known as mechanical tubing or mechanical structural tube, is a seamless steel pipe specifically designed for mechanical and structural applications. Unlike pressure pipes or line pipes, mechanical pipes are engineered to meet precise dimensional tolerances and surface quality requirements. Our mechanical pipes are manufactured through either hot rolling or cold drawing processes, ensuring excellent surface finish, uniform wall thickness, and superior mechanical properties. These pipes are widely used in automotive components, machinery manufacturing, hydraulic cylinders, construction equipment, and various structural applications where precision and reliability are critical.
Electric Resistance Welding (ERW) is a welding process that joins metal surfaces by applying pressure and passing current through the contact area. ERW steel pipes are produced from hot-rolled steel coils that are cold-formed into a cylindrical shape and longitudinally welded.
Unlike seamless pipes, ERW pipes offer excellent dimensional accuracy, uniform wall thickness, and superior surface finish. They are widely used in low to medium pressure applications and are available in round, square, and rectangular shapes.
Technical Specifications
Standards
Seamless mechanical pipe standards and grades supplied by CREATEEL for machining and structural use.
| Standard | Available Steel Grades | Description |
|---|---|---|
| ASTM A519 | 1020, 1026, 4130 | Seamless carbon and alloy steel mechanical tubing |
| EN 10305-1 | E235, E355 | Seamless cold-drawn precision steel tubes |
| DIN 2391 | St35, St45, St52 | Seamless cold-drawn precision steel tubes |
| GB/T 8162 | 10#, 20#, 45#, Q345 | Seamless steel tubes for structural purposes |
| JIS G3445 | STKM11A, STKM13A, STKM14A | Carbon steel tubes for machine structural use |
Seamless Mechanical Pipe Dimensions (OD × Wall Thickness)
Wall thickness in mm. ✓ = regularly produced by Chinese seamless mills (cold-drawn precision & hot-rolled structural). Non-standard sizes on request.
| OD (mm) | 1.5 | 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 6 | 7 | 8 | 9 | 10 | 12 | 14 | 16 | 18 | 20 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 14 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – | – | – | – |
| 16 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – | – | – | – |
| 18 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – | – | – | – |
| 20 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – | – | – | – |
| 22 | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – | – | – | – |
| 25 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 28 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 32 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 38 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 42 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 45 | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – | – | – | – |
| 50 | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – |
| 57 | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – |
| 63.5 | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – |
| 76 | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – |
| 89 | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – | – | – |
| 102 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 108 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 114 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 127 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 133 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 159 | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | – | – |
| 194 | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| 219 | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| 273 | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
Chemical Composition (%)
| Grade | C ≤ | Mn ≤ | Si ≤ | P ≤ | S ≤ |
|---|---|---|---|---|---|
| 20# | 0.17-0.23 | 0.35-0.65 | 0.17-0.37 | ≤0.035 | ≤0.035 |
| Q235 | 0.22 | 1.40 | 0.35 | 0.035 | 0.035 |
| Q345 | 0.20 | 1.70 | 0.55 | 0.030 | 0.030 |
| ASTM A53 Gr.B | 0.30 | 1.20 | — | 0.050 | 0.045 |
| API 5L Gr.B | 0.26 | 1.20 | 0.45 | 0.030 | 0.030 |
| S235 | 0.17 | 1.40 | — | 0.035 | 0.035 |
| S355 | 0.22 | 1.60 | 0.55 | 0.030 | 0.030 |
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) |
|---|---|---|---|
| Q195 | 315–430 | ≥195 | ≥33 |
| Q235 | 375–500 | ≥235 | ≥26 |
| Q345 | 470–630 | ≥345 | ≥22 |
| ASTM A53 Gr.B | ≥415 | ≥240 | — |
| API 5L Gr.B | 415–760 | ≥245 | — |
| S235 | 360–510 | ≥235 | ≥26 |
| S355 | 470–630 | ≥355 | ≥22 |
Note: Mechanical properties may vary based on pipe diameter and wall thickness. All values are minimum unless specified as range.
Available Coating & Surface Treatments
Black Paint / Varnish
Standard coating for structural and scaffolding applications. Provides basic corrosion protection.
Hot-Dip Galvanized
Zinc coating (40–120μm) for superior corrosion resistance. Ideal for outdoor and marine environments.
3PE / FBE Coating
Three-layer polyethylene or fusion bonded epoxy for oil & gas pipelines with harsh conditions.
Epoxy Coating
Internal or external epoxy lining for water supply and fire fighting systems.
Oiled / Bare
Light oil coating or bare finish for applications where further processing will be done.
PVC / PE Coating
Plastic coating for greenhouses, scaffolding frames, and decorative applications.
Packing & Shipping Details
📦 Packing Methods
- Bundles with steel straps
- Wrapped with waterproof plastic woven bag
- Ends protected by plastic caps
- Bulk in container (for large OD pipes)
- Crates for small diameter pipes
- Custom packing as per buyer requirements
🚢 Shipping Information
- MOQ: 10 tons per size
- Delivery: 15–30 days after deposit
- Port: Tianjin / Xingang, China
- Container: 20ft / 40ft GP/HQ
- Payment: T/T, L/C, D/P accepted
- Insurance: CIF terms include All Risk
💡 Tip: We offer comprehensive inspection services including mill test certificates (MTC) as per EN 10204 3.1/3.2, third-party inspection (SGS, BV, TUV), and full traceability documentation.
Manufacturing Process
Our seamless steel pipes are manufactured through a rigorously controlled 12-step hot rolling process — from billet heating to final inspection — ensuring uniform mechanical properties, precise dimensions, and defect-free surfaces.
Billet Inspection & Cutting
Continuous-cast round billets are ultrasonically tested for internal defects, then cut to required lengths by abrasive sawing or shearing.
Rotary Hearth Heating
Billets are heated uniformly to 1200–1280°C in a rotary hearth furnace to achieve optimal plasticity for piercing while preventing overheating or decarburization.
Mannesmann Piercing
The heated billet is pierced over a pointed mandrel between two skewed rolls to form a hollow shell (mother tube), typically achieving a 3–4:1 elongation ratio.
Mandrel Mill Rolling
The hollow shell is rolled over a retained mandrel through a 5–8 stand continuous mandrel mill to reduce wall thickness and achieve uniform OD/WT dimensions.
Mandrel Extraction & Reheating
The mandrel is stripped from the shell; the shell is then reheated to ~950°C in an induction furnace before entering the stretch-reducing mill.
Stretch Reducing / Sizing
The pipe passes through 20–24 stands of stretch-reducing mill to achieve the final OD with tight tolerance (±0.5% OD) and uniform wall thickness, without an internal mandrel.
Cooling Bed Cooling
Pipes are transferred to a walking-beam cooling bed for slow, uniform air cooling to prevent bending and residual stress buildup.
Hot/Cold Straightening
Pipes are straightened by multi-roll cross-roll straighteners (6-roll or 10-roll) to achieve straightness ≤1 mm/m and eliminate ovality.
Cutting & End Facing
Pipes are cut to commercial lengths (5.8m/6m/11.8m/random) and both ends are faced and beveled (30°+5°) for welding, with burrs removed.
NDT & Hydrostatic Testing
100% ultrasonic testing for wall thickness and laminations, eddy current testing for surface cracks, and hydrostatic pressure testing to API/GB standards.
Surface Inspection & Marking
Visual and dimensional inspection of OD, WT, length, and surface quality; stenciling grade, heat number, OD×WT, standard, and manufacturer mark.
Final Packaging & Shipping
Pipes are bundled with steel strips, end-protected with plastic caps or bevel protectors, slung with lifting tags, and loaded for shipment with mill test certificates.
Applications
Where our products deliver proven performance across industries worldwide.
Hydraulic & Pneumatic Cylinders
Honed and skived tube for cylinder barrels offers ID tolerance H8/H9 and surface finish Ra ≤ 0.4 μm, ready for seals — the core of hydraulic cylinder manufacturing.
✓ EN 10305-1/-4, H8 honed bore
Machine Building & Automation
Precision tube frames, guide columns, and spindles for machine tools and automation lines benefit from tight tolerances, straightness, and machinability.
✓ ST52/E355, tight OD/ID tolerance
Automotive Components
Drive shafts, steering columns, shock absorber tubes, and axle components use mechanical tube for its strength-to-weight and fatigue performance.
✓ Automotive PPAP-capable supply
Compressed Gas & Pressure Vessel Parts
Accumulator shells, gas cylinders, and pressure components use thick-wall mechanical tube with uniform wall and clean steel chemistry.
✓ Pressure-vessel-grade chemistries
Bearings, Sleeves & Bushings
Machinable carbon and alloy grades feed turned bearing sleeves, bushings, and rollers where consistent machinability reduces cycle time.
✓ Free-machining and alloy options
General Mechanical Fabrication
Conveyors, lifts, agricultural machinery, and material handling equipment use mechanical tube in the broadest range of shapes and grades.
✓ Round, square, rectangular sections
Frequently Asked Questions
What is mechanical pipe (precision tube)?＋
Mechanical pipe is welded or seamless tube produced to tighter dimensional and surface tolerances than structural pipe, intended for machining, honing, and component manufacturing rather than pressure piping codes.
What standards does your mechanical pipe comply with?＋
EN 10305-1 (seamless cold-drawn), EN 10305-2 (welded cold-drawn), EN 10305-4 (hydraulic/pneumatic), ASTM A513/A519, and ST37/ST52 equivalents.
What tolerances can you hold on OD, ID, and wall?＋
Cold-drawn precision tube typically holds OD to ISO h9/h10, ID to H8/H9 after honing, wall ±5–10%, and straightness ≤ 1 mm/m — tighter on request.
Do you supply honed and skived-and-rolled tube?＋
Yes — honed tube with Ra ≤ 0.4 μm and H8/H9 bore, ready for cylinder assembly, in diameters from 40 mm to 500 mm.
What grades are available for cylinder and machinery use?＋
E235 (ST37), E355 (ST52), 27MnB5, 42CrMo4, and other alloy grades with heat treatment options.
What is the minimum order quantity and lead time?＋
MOQ is flexible for stock sizes (from 5 tons); honed/custom sizes typically 4–8 weeks. Contact us for a firm quotation.
Can you supply cut-to-length and machined components?＋
Yes — cutting, chamfering, threading, and complete machined cylinder components to your drawings.
How is quality verified?＋
Dimensional reports, eddy-current or ultrasonic testing, mechanical tests per lot, surface roughness measurement on honed bores — all documented.
What end finishes are available?＋
Plain, chamfered, threaded, crowned, or welded-ready ends; protective end caps for shipping.
What documentation comes with my order?＋
EN 10204 3.1 certificates, dimensional and surface-finish reports, and heat traceability; third-party inspection on request.
Ready to Order Mechanical Pipes?
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