Sunny Steel offers an extensive range of EN 10305 seamless precision steel tube.
EN 10305 european standard specifies the technical delivery conditions for seamless cold drawn steel pipe of circular cross section used in hyhydraulic and pneumatic power systems.
Tubes according to this EN 10305 European standard are characterised by having precisely defined tolerances on dimensions and a specified surface roughness. The allowed pressure rates and temperatures are the responsibility of the customer in accordance with the state of the art and in application of the safety coefficients specified in the application regulations, codes or standards.
Standard and Steel grade:
- EN10305-1 E215
- EN10305-1 E235
- EN10305-1 E355
EN 10305 seamless precision steel tube shall be manufactured from hot finished seamless tubes by cold drawning. Other suitable methods of cold working are permitted. The tubes shall be delivered in the delivery condition +N which means that after the final cold drawing operation the tubes are normalized in a controlled atmosphere.
NBK means protective heat-treating under the non-oxidation enviroment to get a bright and smooth surface for the tubes.
Chemical composition(%) of EN 10305-1
| Steel grade Name |
Steel Number |
C(% max) | Si(% max) | Mn(% max) | P(% max) | S(% max) |
| E215 | 1.0212 | 0.10 | 0.05 | 0.70 | 0.025 | 0.015 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.025 | 0.015 |
| E355 | 1.0580 | 0.22 | 0.55 | 1.60 | 0.025 | 0.015 |
Mechanical and technological properties of EN 10305-1
| Yield strength (min Mpa) |
Tensile strength (min Mpa) |
Elongation (min %) |
| 215 | 290-430 | 30 |
| 235 | 340-480 | 25 |
| 355 | 490-630 | 22 |
Note:
- The yield point for the annealed (GBK)condition on delivery is at least 50% of the (ultimate) tensile strength. Depending upon the degree of deformation in the drawing operation, the yield point of tubes delivered in the cold-finished/hard (BK)and cold-finished/soft(BKW) conditions, may be increased to a level close to the tensile strength.
- In calculating the yield point, the following values are recommended : cold-finished/hard condition on delivery ≥ 80% of the tensile strength, cold-finished/soft condition on delivery ≥ 70% of the tensile strength.
Quality grade of EN 10305-1
The tubes are supplied in the following quality grades :
A) precision steel tubes intended primarily for mechanical stressing, without any particular quality requirement and without acceptance test certificate.
B) precision steel tubes intended primarily for mechanical stressing, with special quirement and exclusively with acceptance test certificate.
C) precision steel tubes with special requirement according to section 12. Theses requirements and corresponding tests must be agreed, with the customer having to specify his requirements at the time of enquiry and on ordering.
Condition on delivery of EN 10305-1:
| Term | Symbol | Explanation |
| Cold-finished/hard (cold-finished as-drawn) |
BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
| Cold-finished/soft (lightly cold-worked) |
BKW | After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
| Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
| Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |
The advantage of steel tubes designed for precision applications is their high precision with which they are manufactured, the good quality of their surface, a wide selection of dimensions and guaranteed mechanical and technological properties. It is for those reasons that the pipes are widely used in the mechanical engineering industry and in the automotive industry. Pipes for precision applications are manufactured as cold drawn pipes.
The pipes are manufactured with the diameters between 4 – 120 mm and with the wall thickness of up to 12,5 mm.
The pipes are manufactured without thermal processing or with thermal processing: normalization or annealing.
| Standard | PN-EN 10305-1 | PN-EN 10297-1 | DIN 2391 |
| Description | Seamless cold drawn steel tubes. | Seamless circular steel tubes for mechanical and general engineering purposes. Non-alloy and alloy steel tubes. | Seamless precision steel tubes |
| Pipe types | Steel grades | Resistance properties | |||||||||||
| +C | +LC | +SR | +A | +N | |||||||||
| Rm [MPa] | A% | Rm [MPa] | A% | Rm [MPa] | Re [MPa] | A% | Rm [MPa] | A% | Rm [MPa] | Re [MPa] | A% | ||
| Precision E235, E255, E355 According to PN-EN 10305-1 |
E235 | 480 | 6 | 420 | 10 | 420 | 350 | 16 | 315 | 25 | 340- 480 | 235 | 25 |
| E255 | 580 | 5 | 520 | 8 | 520 | 375 | 12 | 390 | 21 | 440- 570 | 255 | 21 | |
| E355 | 640 | 4 | 580 | 7 | 580 | 450 | 10 | 450 | 22 | 490- 630 | 355 | 22 | |
| C34E | 590 | 5 | 540 | 7 | – | – | – | 440 | 22 | >\= 460 | 280 | 21 | |
| C45E | 720 | 4 | 670 | 6 | – | – | – | 510 | 20 | >\= 540 | 340 | 18 | |
PN-EN 10297-1
Tubes for mechanical purposes, hot rolled and cold drawn.
| Minimum mechanical properties | ||||||||||||
| Pipe type | Steel grades | Delivery condition | Upper yield limit Re MPa | Tensile strength Rm MPa | Elongation A% |
|||||||
| Seamless circular steel tubes for mechanical and general engineering purposes E235, E275, E355, According to PN-EN 10297-1 | For T in mm | For T in mm | 1 | t | ||||||||
| <\= 16 | >16 <\=40 | >40 <\=65 | >65 <\=80 | >80 <\=100 | <\=16 | >16 <\=40 | >40 <\=65 | |||||
| E235 | +A lub+N | 235 | 215 | 205 | 195 | 360 | 360 | 360 | 340 | 340 | 25 | |
| E275 | +A lub+N | 275 | 255 | 245 | 235 | 410 | 410 | 410 | 380 | 380 | 22 | |
| E355 | +A lub+N | 354 | 345 | 315 | 295 | 490 | 490 | 410 | 470 | 470 | 20 | |
DIN 2391
Seamless precision steel tubes
Grades: St35, St45, St52
| Pipe types | Steel grades | Minimum resistance properties | |||||||||||
| +C | +LC | +SR | +A | +N | |||||||||
| Rm [MPa] | A% | Rm [MPa] | A% | Rm [MPa] | Re [MPa] | A% | Rm [MPa] | A% | Rm [MPa] | Re [MPa] | A% | ||
| Precise seamless steel pipes St35, St45, St52 According to DIN 2391 | St 35 | 480 | 6 | 420 | 10 | 420 | 350 | 14 | 315 | 25 | 340- 470 | 235 | 25 |
| St 45 | 580 | 5 | 520 | 8 | 520 | 375 | 12 | 390 | 21 | 440- 570 | 255 | 21 | |
| St 52 | 640 | 4 | 580 | 7 | 580 | 420 | 10 | 490 | 22 | 490- 630 | 355 | 22 | |
The yield limit for the annealed delivery condition (GBK) is at least 50% of the tensile strength value. Depending on the level of deformation, the yield limit can be higher in the case of pipes in the cold-finished – hard (BK) and cold-finished – soft (BKW) delivery conditions and amount to a value that is close to the tensile strength value.
In order to calculate the yield limit, it is recommended to apply the following values: delivery condition
Drawn b.t >\=80% of tensile strength
Drawn b.m >\=70% of tensile strength
In the case of pipes with the outside diameter <\= 30mm whose wall thickness is <\=3mm, the yield limit value is lower by 10N/mm2
A review of the test scope for pipes with acceptance testing certificatese
| Tests | Test scope |
Person responsible for test execution | |
| No | Type | ||
| 1 | Tensile testing | 1 test pipe for every batch 1 sample | As agreed |
| 2 | Flattening test | At one of the test pipe ends according to no 1, 1 sample | As agreed |
| 3 | Expansion testing | At one of the test pipe ends according to no 1, 1 sample | As agreed |
| 4 | Roughness verification | If agreed: test pipe according to no 1, 1 sample | Manufacturer |
| 5 | Dimension verification | All pipes | As agreed |
| 6 | Surface inspection | All pipes | As agreed |
| 7 | Tightness testing | If agreed: all pipes | Manufacturer |
| 8 | Non-destructive testing | If agreed: all pipes | Manufacturer |