EN 10305-1 C45E honed seamless steel tube is a cold-drawn precision tube in medium-carbon grade C45E (material number 1.1191) whose bore is finished by honing to ID tolerance H8-H9 and surface roughness Ra 0.2-0.4 um, so it ships ready to assemble as a hydraulic or pneumatic cylinder barrel. The number that decides your wall thickness is the yield you design to - 340 MPa in the +N state, about 420 MPa in +SR, and 490 MPa or more in +QT - not a single fixed value. This page covers the grade, the bore specification and the ordering decisions that separate a correct barrel from a rejected one.
A c45e honed tube is a finished component, not a steel grade. The base metal - C45E, material number 1.1191 - is only half the specification; the other half is the finished bore. Two tubes of identical chemistry but different honing quality behave like different products on the same cylinder, because the seal runs against the bore, not against the certificate. The part is therefore defined by four independent decisions: the standard (EN 10305-1:2016, or EN 10305-4:2016 for hydraulic power systems), the grade (C45E), the delivery condition, and the bore specification (ID tolerance, roughness, straightness).
GNEE Pipe supplies c45e honed tube for hydraulic cylinder applications across outside diameters up to 380 mm (14.96 in) and lengths up to 12 m (39 ft), with EN 10204 3.1 material certificates and third-party inspection on request. Send your ID x wall, delivery condition and quantity for a quotation. Request a quote with your ID x wall and Ra.
Technical Specifications
| Parameter | Capability |
|---|---|
| Grade / material number | C45E / 1.1191 (CK45, AISI 1045, JIS S45C, GB 45#) |
| Standard | EN 10305-1:2016 (cold-drawn seamless precision); EN 10305-4:2016 for hydraulic power systems |
| Outside diameter (OD) | Up to 380 mm (14.96 in); larger bores route to EN 10297-1 |
| Inside diameter (ID) | 20-400 mm (0.79-15.75 in) |
| Wall thickness | 2-40 mm (0.08-1.57 in), typical 3-25 mm |
| Length | Up to 12 m (39 ft); longer by agreement |
| ID tolerance | ISO H8 default; H9 available; H7 for servo cylinders |
| Bore roughness (Ra) | 0.2-0.4 um honed; 0.2 um or better by SRB |
| Straightness | Less than or equal to 0.5 mm/m (0.5 mm per 1000 mm); 0.3 mm/m on request |
| C45E delivery condition | +C, +LC, +SR, +A, +N; +QT by separate agreement |
| Certification | EN 10204 3.1 material certificate; third-party inspection (SGS / BV / TUV) available |
The finished bore is the second half of the specification. A C45E honed tube ID tolerance H8 H9 is the default pairing (H8 standard, H9 optional, H7 for servo cylinders), the C45E honed tube Ra 0.2-0.4 um finish is achieved by honing, SRB reaching Ra 0.2 um or better, and the C45E honed tube straightness is held to less than or equal to 0.5 mm/m.
Chemical Composition
The C45E chemical composition follows EN 10305-1:2016 Table 5 (cast analysis, E-grade). Carbon at 0.42-0.50% is what makes C45E heat-treatable - and what forces preheat when the barrel is welded. Phosphorus and sulfur are tightened in the E-grade for batch consistency.
| Element | C45E (1.1191) min | C45E (1.1191) max |
|---|---|---|
| Carbon (C) | 0.42 | 0.50 |
| Silicon (Si) | 0.15 | 0.40 |
| Manganese (Mn) | 0.50 | 0.80 |
| Phosphorus (P) | - | 0.030 |
| Sulfur (S) | 0.020 | 0.035 |
| Chromium + Molybdenum + Nickel | - | 0.63 |
Mechanical Properties
C45E mechanical properties by delivery condition follow EN 10305-1:2016 Table 6. The cold-worked conditions (+C, +LC, +SR, +A) are quoted for minimum tensile strength and elongation; the standard derives Rp0.2 from Rm by formula, so a single yield floor is not tabulated for those states. Only +N gives a fixed ReH, which is the barrel design baseline. +QT values are not in the standard table and must be specified by the purchaser.
| Delivery condition | Tensile Rm (MPa) | Yield ReH / Rp0.2 (MPa) | Elongation A (%) |
|---|---|---|---|
| +C (cold drawn, hard) | Greater than or equal to 720 | derived from Rm | Greater than or equal to 4 |
| +LC (lightly cold worked) | Greater than or equal to 670 | derived from Rm | Greater than or equal to 6 |
| +SR (stress relieved) | Greater than or equal to 600 | derived from Rm (about 420 in practice) | Greater than or equal to 15 |
| +A (annealed) | Greater than or equal to 510 | derived from Rm | Greater than or equal to 20 |
| +N (normalized) | 540-720 | ReH Greater than or equal to 340 | Greater than or equal to 18 |
| +QT (quenched and tempered) | order-specified (typical 700-850) | order-specified (typical Greater than or equal to 490) | order-specified |
Delivery Condition and the Number That Decides Your Design
The one number that decides your barrel wall is the yield you design to, and that number is set by the delivery condition - not by the grade name. For a C45E barrel the practical floors are: +N normalized, ReH 340 MPa (most common, the standard baseline); +SR stress-relieved, about 420 MPa (lower residual stress, easier to weld); and +QT quenched and tempered, 490 MPa or more (heavy-duty bores, ordered separately). The spread matters in money: at the same wall, moving from +N to +QT raises the admissible pressure by roughly 44% (490 divided by 340). Quoting a single value - for example taking the +N tensile floor of 540 MPa and calling it the yield - overstates capacity by about 59% and is the single most common cause of an undersized barrel. State the condition on the order, then design to its yield.
Grade Comparison - C45E vs E355 vs 42CrMo4
The practical C45E vs E355 honed tube decision comes down to carbon content and weldability: C45E is the heat-treatable medium-carbon choice, E355 the low-carbon weldable choice.
| Property | C45E (1.1191) | E355 (1.0580) | 42CrMo4 (1.7225) |
|---|---|---|---|
| Carbon class | Medium (0.42-0.50%) | Low (about 0.18-0.22%) | Medium alloy (about 0.38-0.45% + Cr Mo) |
| +N yield (MPa) | 340 | 355 | not a precision-tube default |
| Heat-treatable? | Yes (Q+T, induction) | No | Yes (through-hardening) |
| Weldable without preheat? | No (preheat 150-250 C) | Generally yes | No (higher preheat) |
| Typical use | Wear parts, hardened bores | Welded, lighter barrels | Heavy-duty, high-strength bores |
Selecting the Right Grade and Finish
C45E vs AISI 1045 vs E355 - which barrel steel
| Grade | When to choose | Standard route |
|---|---|---|
| C45E / 1.1191 | Need wear resistance and post-machining hardening; medium pressure; weldable with preheat | EN 10305-1:2016 (also EN 10305-4 for hydraulic systems) |
| AISI 1045 | Same steel, US-spec purchase order or ASTM route | ASTM A519 1045 (see A519 1045 honed tube) |
| E355 / 1.0580 | Prioritize weldability and lower weight; no hardening required | EN 10305-1:2016 (also EN 10305-4) |
Where higher strength is needed, move to 42CrMo4 / AISI 4140 honed tube rather than over-specifying C45E.
Honed vs SRB - choosing the bore finish
Both finish the bore to a precision tolerance. The honed tube vs SRB tube choice is driven by seal type, volume and cost, not by a simple "better" - most buyers accept either provided the ID tolerance and Ra are met. Honing removes material with stones and gives Ra 0.2-0.4 um with a cross-hatch that retains lubricant; SRB skives and roller-burnishes, work-hardens the surface and reaches Ra 0.2 um or better.
Applications
C45E honed tube is specified wherever a finished, ready-to-assemble cylinder barrel must carry moderate to high pressure, shock loading and long stroke cycles without secondary boring. Five application groups cover most orders:
Hydraulic Cylinder Barrels
The dominant use. A honed C45E barrel carries the bore, the seal running surface and the pressure boundary in one cold-drawn, finished part - mobile, agricultural and industrial cylinders alike.
Pneumatic Cylinder Barrels
Lower pressure than hydraulics, but the same finish requirement: a clean, cross-hatched bore that the seal tracks without scoring. C45E in +N or +SR is the default.
Mobile and Construction Equipment Cylinders
Excavators, loaders, cranes and dump trucks need barrels that resist denting, wear and side loads. C45E in +N or +QT gives the margin; larger bores route to EN 10297-1.
Industrial Press and Injection-Machine Cylinders
High cycle counts and long strokes demand a bore with stable geometry. The honed finish keeps seal compression predictable over millions of cycles.
Machined Load-Carrying Parts
Beyond cylinders, C45E precision tube is turned into shafts, bushings, pistons and guide bars - any part that is machined and then hardened.
Test and inspection
Dimensional inspection. OD, wall, ID tolerance (H8-H9) and straightness are checked against the ordered Option; the bore is gauged at multiple points along the length.
Surface and roughness. Bore Ra is verified with a profilometer; the cross-hatch and absence of scoring are inspected visually.
Mechanical verification. Tensile and, for +N, yield are confirmed from the heat; hardness may be checked on +QT.
Non-destructive testing. Eddy current or ultrasonic testing is applied per EN 10305-4 for hydraulic systems (and on request for Part 1); EN 10204 3.1 certificates accompany each heat.
Cleanliness and preservation. The bore is cleaned, oiled and capped to protect the finished surface during transit.
Send your ID x wall, delivery condition (+N / +SR / +QT), ID tolerance and Ra - our technical team will confirm the specification against EN 10305-1:2016 (or EN 10305-4:2016) and return a quotation with lead time within 24 hours. Contact GNEE Pipe today.
Why Source C45E Honed Tube from GNEE Pipe
As a C45E honed tube supplier, GNEE Pipe ships bore-ready barrels from one quality system rather than brokering mixed stock.
One steel, many standards. We supply C45E / CK45 / AISI 1045 / 1.1191 to EN 10305-1, EN 10305-4, ASTM A519 and GB/T 3639 from one quality system, so your cross-standard orders stay consistent.
Bore-ready barrels. H8-H9, Ra 0.2-0.4 um, straightness less than or equal to 0.5 mm/m, with EN 10204 3.1 certificates and third-party inspection (SGS / BV / TUV) on request.
Proven export supply. GNEE serves 160+ customers across hydraulic, mobile-equipment and industrial markets from Tianjin, with integrated machining and preservation.
Technical quoting. Send ID x wall, delivery condition and Ra; our team returns a specification-confirmed quote with lead time, and flags standard-year and condition mismatches before they become rejects.
FAQ
What is an EN 10305-1 C45E honed seamless steel tube?
It is a cold-drawn precision steel tube in medium-carbon grade C45E (material number 1.1191) whose bore has been honed or skived and roller-burnished to a finished ID tolerance of H8 to H9 and a surface roughness of Ra 0.2 to 0.4 um, so it arrives ready to assemble as a hydraulic or pneumatic cylinder barrel without secondary boring.
Is C45E the same as CK45, 1045 and 1.1191?
Yes - they are the same 1.1191 steel under different standard names. C45E is the current EN grade, CK45 (or Ck45) is the legacy German DIN name, AISI 1045 is the US grade and 1.1191 is the European material number. A drawing that says CK45 and a certificate that says C45E are asking for the identical tube.
What yield strength should I design a C45E honed barrel to?
Design to the yield of the delivery condition you order, not a single fixed number. In the as-delivered +N (normalized) state the standard floor is ReH 340 MPa; +SR (stress-relieved) gives about 420 MPa; and +QT (quenched and tempered), which you must specify separately, typically reaches 490 MPa or more. Using the wrong single value is the most common cause of an undersized or oversized barrel.
EN 10305-1 or EN 10305-4 - which standard do I cite?
Both are current 2016 editions and both cover seamless cold-drawn C45E tube. Part 1 is the general precision-tube standard for mechanical engineering; Part 4 is the hydraulic and pneumatic power-systems sub-part, which adds bore cleanliness, tighter surface roughness and mandatory non-destructive testing. For a pressure-bearing cylinder barrel, cite EN 10305-4; for a general precision part, Part 1 is sufficient.
What ID tolerance and surface finish does a C45E honed tube have?
The default bore tolerance is ISO H8, with H9 available and H7 for servo or high-precision cylinders. Honing delivers a surface roughness of Ra 0.2 to 0.4 um; skiving and roller burnishing (SRB) reaches Ra 0.2 um or better, with a cross-hatch angle of 30 to 45 degrees that retains lubricant.
Can C45E honed tube be welded?
Yes, but it is a medium-carbon steel with a carbon equivalent of about CE_IIW 0.56, so it needs preheat of 150 to 250 degrees C and post-weld stress relief to avoid cracking. Confirm the exact procedure with your welding engineer, especially for heavy walls.
What are the size limits of EN 10305-1 C45E honed tube?
EN 10305-1 covers seamless cold-drawn tube with outside diameter up to 380 mm. For honed barrels the practical bore range is about 20 to 400 mm, with wall thickness typically 2 to 40 mm and lengths up to 12 m. Above 380 mm OD, route the order to EN 10297-1.
Is C45E the same as E355 for a cylinder barrel?
No. C45E (1.1191) is a medium-carbon heat-treatable steel with 0.42 to 0.50 percent carbon, while E355 (1.0580) is a low-carbon fine-grain structural steel. C45E can be quenched, tempered or induction-hardened for wear parts; E355 is chosen for weldability and lower weight. They are not interchangeable, and a barrel designed to one yield value must not be quoted against the other.