Home > Seamless Tube > DIN 2391 / EN 10305
Inox Steel India is a leading manufacturer and global supplier of Precision Steel Tubes and Hydraulic Tubes manufactured as per DIN 2391 and EN 10305 standards, covering ST35 (E235) and ST52 (E355) grades. These tubes are widely used in high-pressure hydraulic systems, automotive components, shock absorbers, heavy machinery, instrumentation lines, and precision-engineered assemblies.
We supply to industries across GCC, Middle East, Europe, Africa, North America, and South America, with stock maintained in NBK (Normalized), BK (Cold Finished), BKW, and BKS conditions to meet diverse mechanical and dimensional requirements.
With ISO 9001, EN 10204 3.1, PED and strict metallurgical controls, our seamless cold-drawn steel tubes deliver exceptional dimensional accuracy, smooth inner bore, high pressure resistance, and superior fatigue performance—making them ideal for hydraulic cylinder manufacturing and precision engineering applications.
Precision steel tubes are seamless cold-drawn tubes manufactured with extremely tight tolerances, superior surface finish, and high structural integrity. They are essential for systems where:
Compared to standard seamless pipes, precision tubes are engineered specifically for:
Their reliability under cyclic stress and high-pressure conditions makes them indispensable in modern engineering.
Inox Steel India manufactures tubes using controlled processes that ensure dimensional accuracy and high-quality finish.
This process ensures defect-free, heavy-duty, high-pressure tubes suitable for hydraulic and pneumatic applications.
(Grades: ST35 · ST52)
| Parameter / Property | ST35 (E235 Equivalent) | ST52 (E355 Equivalent) |
| Material Type | Low Carbon Steel | High Strength Carbon/Mn Steel |
| Standard | DIN 2391 / EN 10305-1 / EN 10305-4 | DIN 2391 / EN 10305-1 / EN 10305-4 |
| Type | Precision Steel Tubes / Hydraulic Tubes | Precision Steel Tubes / Hydraulic Tubes |
| UNS / Werkstoff | 1.0308 | 1.0570 |
| Delivery Condition | NBK (Normalized), BK (Cold Finished), BKW, BKS | NBK (Normalized), BK (Cold Finished), BKW, BKS |
| Manufacturing Method | Seamless Cold Drawn Tubes | Seamless Cold Drawn Tubes |
| Tensile Strength (MPa) | 340–480 | 490–630 |
| Yield Strength (MPa) | ≥ 235 | ≥ 355 |
| Elongation (%) | 25% min | 22% min |
| Hardness | 120–160 HB | 160–190 HB |
| Density (g/cm³) | 7.85 | 7.85 |
| Chemical Composition — C (%) | ≤ 0.17 | ≤ 0.22 |
| Chemical Composition — Mn (%) | ≤ 1.20 | 1.40–1.60 |
| Chemical Composition — Si (%) | ≤ 0.35 | ≤ 0.55 |
| Chemical Composition — P (%) | ≤ 0.025 | ≤ 0.025 |
| Chemical Composition — S (%) | ≤ 0.025 | ≤ 0.025 |
| Outside Diameter (OD) | 4 mm – 120 mm | 4 mm – 120 mm |
| Wall Thickness (WT) | 0.5 mm – 12.5 mm | 0.5 mm – 12.5 mm |
| Tolerance (OD) | ±0.05 mm to ±0.20 mm | ±0.05 mm to ±0.20 mm |
| Tolerance (WT) | ±10% | ±10% |
| Length | 3M · 6M · 12M | 3M · 6M · 12M |
| Straightness Tolerance | ≤ 1 mm per meter | ≤ 1 mm per meter |
| Ovality | ≤ 0.25 × Tolerance | ≤ 0.25 × Tolerance |
| End Finish | Plain / Chamfered | Plain / Chamfered |
| Surface Finish | Phosphated · Oiled · Clean Bright | Phosphated · Oiled · Clean Bright |
| Pressure Rating | Medium Pressure | High Pressure (Hydraulic) |
| Corrosion Resistance | Good (with oil/phosphate coat) | Very Good (with coating) |
| Applications | Automotive, Instrumentation, General Engineering | Hydraulic Cylinders, Heavy Equipment, High-Pressure Lines |
| NDT – Eddy Current | ✓ | ✓ |
| NDT – Ultrasonic | ✓ | ✓ |
| Hydrostatic Test | ✓ | ✓ |
| Flattening Test | ✓ | ✓ |
| Flaring Test | ✓ | ✓ |
| Third Party Inspection | SGS · BV · TUV | SGS · BV · TUV |
| Certifications | ISO 9001 · EN 10204 3.1 | ISO 9001 · EN 10204 3.1 |
| HSN Code | 7304.31.90 | 7304.31.90 |
ST52 recommended for cyclic loading and high impact conditions
Precision tubes are ideal for: Hydraulic cylinder tubes, Fuel systems, Power steering tubes, Shock absorber tubes
EN 10204 3.1 and 3.2. CE / PED certification (depending on application)
Precision tubes manufactured as per DIN 2391 / EN 10305 are engineered for applications requiring high dimensional accuracy, smooth internal bore, cyclic load resistance, and high-pressure endurance. These tubes are essential in hydraulic systems, automotive assemblies, heavy engineering equipment, and precision components where tolerances and mechanical properties cannot be compromised.
| NPS (Inch) | OD (mm) | Wall (mm) | Approx. Weight (kg/m) |
| ½″ | 12 | 1.5 | 1.10 |
| ¾″ | 19 | 2.0 | 2.20 |
| 1″ | 25 | 2.5 | 3.60 |
| 1.5″ | 38 | 3.0 | 6.80 |
| 2″ | 50 | 3.5 | 9.80 |
Full OD × WT table available for OD 4–120 mm and WT 0.5–12.5 mm on request.
| Grade | OD Range | Condition | INR/kg (F.O.B Mumbai) | USD/kg (F.O.B India) | Typical Use |
| ST35 (E235) | 4–120 mm | NBK | ₹ 85 – ₹ 135 | $1.10 – $1.65 | Automotive, Pneumatics |
| ST35 (E235) | 4–120 mm | BK (Cold Finished) | ₹ 95 – ₹ 150 | $1.25 – $1.90 | Fuel lines, Precision |
| ST52 (E355) | 6–120 mm | NBK | ₹ 105 – ₹ 165 | $1.35 – $2.10 | Hydraulic Cylinders |
| ST52 (E355) | 6–120 mm | BK | ₹ 120 – ₹ 185 | $1.60 – $2.35 | Heavy Machinery |
Prices vary based on OD, WT, delivery condition & TPI requirement.
Inox Steel India conducts strict quality checks on every tube manufactured.
Certifications Provided: EN 10204 3.1 MTC, PED Certification (on request), ISO 9001:2015, CE Marking (where required).
Inox Steel India is among the most trusted names when searching for a “DIN 2391 / EN 10305 Precision Steel Tube Supplier near Alankar Cinema, Mumbai.”
We manufacture and supply ST35 (E235) and ST52 (E355) cold-drawn seamless tubes in NBK, BK, BKW, and BKS conditions for hydraulic, pneumatic, automotive, and precision engineering applications. With a strong stockholding capacity, dedicated quality control, and global export network via JNPT, Mundra & Hazira ports, our tubes reach customers in India, GCC, Europe, Africa, USA, Canada, and South America with consistent quality and on-time delivery. Whether you need hydraulic cylinder tubes, precision machined tubes, fuel lines, or shock absorber tubes, we guarantee dimensional accuracy, smooth internal finish, and high-pressure performance.
| Industry | Applications | Preferred Grades |
| Hydraulic Cylinder Manufacturing | Cylinder barrels · Telescopic cylinders · Piston tubes | ST52 |
| Automotive Industry | Shock absorber tubes · Fuel lines · Steering tubes | ST35 / ST52 |
| Heavy Engineering & Machinery | Excavators · Loaders · Cranes | ST52 |
| Pneumatic Systems | Precision air circuits | ST35 |
| Oil & Gas & Instrumentation | Control lines · Gauge lines | ST35 |
| Construction Equipment | Hydraulic boom tubes | ST52 |
| Agriculture Equipment | Hydraulic pumps · Lift systems | ST52 |
| General Engineering & Fabrication | Precision machined components | ST35 |
To ensure damage-free delivery, every tube is packed with export-grade protection.
Export Ports: JNPT Port (Mumbai) | Mundra Port (Gujarat) | Hazira Port (Surat). We ship containers regularly to GCC, Europe, Africa, and the Americas.
Our team responds within 24 hours with: Material recommendation (ST35 / ST52), Delivery condition (BK / NBK / BKW / BKS), Pricing (INR + USD), and Lead time & documentation.
52-A, Mulji Thackersi Bldg, Islampura Street, Shop No. 10, Near Alankar Cinema, Mumbai – 400 004
alloy@inoxsteelindia.in
+91 9930796690
ST52 (E355) is significantly stronger with higher tensile (490–630 MPa) and yield (≥355 MPa) strength. Yes. ST52 is the industry standard for high-pressure hydraulic cylinder barrels. NBK is best for bending and forming operations. The HSN code is 7304.31.90. Yes — all tubes can be supplied with 3.1 or 3.2 certification. Yes, we export regularly to UAE, Oman, Saudi Arabia, Germany, Italy, Poland, and the UK. Which is stronger — ST35 or ST52?
Are ST52 tubes suitable for hydraulic cylinders?
What delivery condition is recommended for bending?
What is the HSN Code for precision steel tubes?
Do you supply tubes with EN 10204 3.1 certification?
Do you export to the Middle East and Europe?
Our precision cold-drawn tubes deliver tight tolerances, excellent smoothness, high pressure capability, and long service life. Whether you require tubes for hydraulic cylinders, automotive assemblies, or structural applications — Inox Steel India ensures uncompromised quality.