DIN 2391 St52 — formally renamed under EN 10305-1 to E355 — is the precision cold-drawn seamless steel tube that the global hydraulic-cylinder industry runs on. It is the barrel of every double-acting cylinder on a hydraulic excavator, every press ram, every tipper hoist, every injection-moulding machine clamp, and almost every farm-tractor implement cylinder. RP Sales stocks DIN 2391 St52 in honed (H8) and skived-and-roller-burnished (SRB) inner-surface options in the 25 mm to 250 mm ID range that covers the bulk of Indian hydraulic-cylinder OEM demand, and coordinates larger bores from European and Asian mills on indent.
What DIN 2391 St52 is and the EN 10305-1 transition
DIN 2391 was the German standard for seamless cold-drawn precision steel tubes from the 1970s through the early 2000s, when it was superseded by the European harmonised EN 10305 family. EN 10305-1 covers cold-drawn seamless tubes for precision applications, with E235, E255, E275, E355, E410 and E460 being the grade designations. The St52 trade name maps directly to E355 — the same chemistry, the same minimum properties — but Indian OEM datasheets and purchase orders still routinely call out “DIN 2391 St52”, and the mill test certificate will normally reference both designations.
The reason St52 / E355 dominates hydraulic-cylinder service is the balance: 355 MPa minimum yield gives ample wall strength for typical 100 to 350 bar working pressures with reasonable wall thickness; the 490 to 630 MPa tensile band gives good fatigue life under cyclic loading; the controlled chemistry (lean carbon, microalloy-restricted) gives clean machinability after honing without surface tearing.
Bore finish — honed vs skived-and-roller-burnished
| Parameter | Honed (H8) | Skived & Roller-Burnished |
|---|---|---|
| Bore tolerance | ISO H8 (typ.) | ISO H8 (typ.), H7 on indent |
| Surface roughness Ra | ≤ 0.4 µm | 0.2 – 0.4 µm |
| Process | Cold-draw + honing stones | Single-pass skiving + cold roll-burnishing |
| Optimal ID range | Up to ~250 mm | Up to ~700 mm; faster on large bores |
| Typical lead time | Ex-stock to 2 weeks | 2 to 4 weeks |
Chemistry & mechanical properties
- Carbon (C): 0.22 % max — controlled lean carbon for cold-drawing and machining.
- Manganese (Mn): 1.60 % max
- Silicon (Si): 0.55 % max
- Yield strength: 355 MPa minimum
- Tensile strength: 490 to 630 MPa
- Elongation: 22 % minimum (longitudinal)
Why buy from an Indian distributor for an “import” spec
DIN 2391 St52 is a European specification, but the search results for the term are dominated by Chinese mills competing on FOB pricing. The headline FOB price often looks compelling — until you add ocean freight, customs duty, inland logistics from Mundra / Nhava Sheva to your factory, FX risk, the MOQ trap (typical Chinese mill MOQs run 5 to 15 MT per size per draw), and the 60 to 90 day lead time. RP Sales is the alternative: ex-yard stock in Kanpur on common sizes, INR billing, 30-day credit terms for repeat buyers, no MOQ trap, and the same DIN 2391 St52 / EN 10305-1 E355 specification on the mill MTC.
Related catalogue and reference pages: precision tubes overview, hydraulic-cylinder application guide, seamless pipes, precision tube price list, MTC documentation, glossary of pipe terms, request a quote.
FAQ — DIN 2391 St52 hydraulic cylinder tube
What does DIN 2391 St52 mean and how does it relate to EN 10305-1 E355?
What is the difference between honed (H8) and skived-and-roller-burnished tubes?
What bore tolerances and roughness can I specify?
What OD and wall thickness range do you supply?
What is the chemical composition and what mechanical properties should I expect?
Why buy from RP Sales (India) instead of direct from China?
Updated: