EN 10305 Seamless Cold Drawn Precision Steel Tube Supplier
For Hydraulic & Pneumatic Systems – E235, E355
OD 6~204mm | WT 1~18mm | Cold Drawn
Product Overview
Our EN 10305 seamless cold drawn precision steel tubes are specifically designed for hydraulic and pneumatic systems, precision machinery, and automotive applications. Manufactured by the cold drawing process at our Wuxi facility, these tubes offer tight dimensional tolerances, excellent surface finish, and consistent mechanical properties.
Applicable Standards:
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EN 10305-1 – General precision tubes
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EN 10305-4 – Hydraulic/pneumatic power systems (with pressure testing)
Key Specifications:
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Standard: EN 10305-1 / EN 10305-4
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Grades: E235 (St37.4), E355 (St52.4 – most popular)
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Outer Diameter: 6mm – 204mm (Standard Stock: 19mm – 89mm)
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Wall Thickness: 1mm – 18mm
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Length: 3m – 12m (Custom lengths available)
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Manufacturing Process: Cold Drawn (Seamless)
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Delivery Conditions: BK, BKW, NBK, GBK, +C, +SR, +N, +QT
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Surface Finish: As-drawn / Bright / Oiled / Phosphated
✅ EN 10305 certified – Current European standard for precision tubes
✅ Cold drawn seamless – Tight tolerances, excellent surface finish
✅ E355 grade – ≥355 MPa yield – most popular for hydraulic cylinders
✅ Multiple delivery conditions – BK, BKW, NBK – match to application
✅ 100% NDT and pressure testing available – Guaranteed integrity
✅ EN 10204 Type 3.1 MTC provided with heat number
✅ Factory direct – Competitive pricing and fast delivery
Steel Grade Overview
| Grade | DIN Equivalent | Yield (MPa) | Tensile (MPa) | Delivery Condition | Application |
|---|---|---|---|---|---|
| E235 | St37.4 | ≥235 | 340-480 | BK, BKW, NBK | General precision engineering |
| E355 | St52.4 | ≥355 | 490-640 | BK, NBK | Hydraulic cylinders – most common |
💡 E355 is the most popular grade for hydraulic cylinder applications – excellent balance of strength, ductility, and weldability.
Delivery Conditions – EN 10305
| Symbol | Description | Application | Surface |
|---|---|---|---|
| BK | Cold drawn / as-drawn | Maximum strength | Dull |
| BKW | Cold drawn + light finishing | Chrome plating prep | Bright |
| NBK | Normalized | Good strength + ductility | Dull/satin |
| GBK | Annealed | Soft, machinable | Dull |
💡 NBK (normalized) is the most popular delivery condition for hydraulic cylinders – good strength with excellent ductility and weldability. BKW is recommended for chrome plated piston rods.
Chemical Composition
| Grade | C max | Si max | Mn | P max | S max |
|---|---|---|---|---|---|
| E235 | 0.17 | 0.35 | 0.40-1.20 | 0.025 | 0.025 |
| E355 | 0.22 | 0.55 | 1.00-1.60 | 0.025 | 0.025 |
💡 Low carbon content ensures excellent weldability and formability for precision applications.
Mechanical Properties – E355 (Most Popular)
| Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) | Surface |
|---|---|---|---|---|
| BK | 560-780 | ≥450 | ≥10 | Dull |
| NBK | 490-640 | ≥355 | ≥22 | Dull/satin |
| BKW | 520-700 | ≥400 | ≥14 | Bright |
💡 E355 NBK provides the best combination of strength (≥355 MPa yield) and ductility for hydraulic cylinder barrels .
Manufacturing Process – Cold Drawing
Cold Drawing Process for Precision Tubes:
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Hot rolled tubes are pickled to remove scale
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Cold drawing precisely reduces the diameter – achieves tight tolerances
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Heat treatment – BK (as-drawn), BKW (finish drawn), NBK (normalized) as specified
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Straightening – ensures straightness for hydraulic applications
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Precision cutting – to exact customer length
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100% NDT and pressure testing – guarantees integrity (EN 10305-4 requires hydrostatic test)
Grade Selection – Hydraulic Cylinder Applications
| Working Pressure | Recommended Grade | Delivery Condition | Yield Strength |
|---|---|---|---|
| Up to 160 bar (2,300 PSI) | E235 | NBK | ≥235 MPa |
| 160-250 bar (2,300-3,600 PSI) | E355 | NBK | ≥355 MPa |
| 250-350 bar (3,600-5,000 PSI) | 42CrMo4 | +QT | ≥550 MPa |
💡 E355 NBK is the most common choice for standard hydraulic cylinder applications .
Dimensional Tolerances – ISO H8, H9, H10
| OD (mm) | Tolerance H8 (μm) | Tolerance H9 (μm) | Tolerance H10 (μm) |
|---|---|---|---|
| 6-10 | ±22 | ±36 | ±58 |
| 10-18 | ±27 | ±43 | ±70 |
| 18-30 | ±33 | ±52 | ±84 |
| 30-50 | ±39 | ±62 | ±100 |
| 50-80 | ±46 | ±74 | ±120 |
💡 H9 or H10 is standard for hydraulic cylinders – H8 for ultra-precision applications.
Surface Roughness Capability
| Processing Level | Ra (μm) | Application |
|---|---|---|
| Cold drawn (BK) | ≤1.6-3.2 | General precision |
| Finish drawn (BKW) | ≤0.8-1.6 | Chrome plating prep |
| Honed | ≤0.1-0.2 | Ultra-smooth hydraulic barrels |
💡 Honing is available upon request for hydraulic cylinder barrels requiring ultra-smooth internal surfaces.
Key Applications
| Industry | Application | Recommended Grade |
|---|---|---|
| Hydraulics | Cylinder barrels (standard) | E355 NBK |
| Hydraulics | Cylinder barrels (high pressure) | 42CrMo4 +QT |
| Hydraulics | Piston rods | E355 BKW |
| Pneumatics | Cylinder tubes | E235 NBK |
| Automotive | Shock absorber tubes | E355 |
| Machine Building | Guide tubes, shafts | E355 |
DIN 2391 Cross-Reference
| EN 10305 | DIN 2391 (Withdrawn) |
|---|---|
| E235 | ST35 |
| E355 | ST52 |
💡 EN 10305 is the current European standard that supersedes DIN 2391. For legacy projects, we supply both.
Why Choose Our EN 10305 Precision Tubes?
| Advantage | Description |
|---|---|
| Cold drawn precision | Tight tolerances – ISO H8, H9, H10 |
| E355 NBK in stock | Most popular hydraulic grade – ready to ship |
| Multiple delivery conditions | BK, BKW, NBK – all available |
| Metric dimensions | Standard European sizes – 19-89mm stock |
| Full traceability | EN 10204 3.1 MTC with heat number |
| In-house processing | Cutting, honing, skiving available |
Contact for Quote
📧 Email: yjhtrade@gmail.com
📞 WhatsApp: +86 15106174543
🌐 Website: www.hzhmetals.com / www.wuxihengzhihui.com
Contact Person: Alice Yuan
Reply within 24 hours.
Tags: EN 10305 Precision Tube Hydraulic Cylinder Tube Cold Drawn Tube E355 Seamless Precision Tube EN 10305-4
