EN 10305-1 seamless precision steel tube

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:

EN 10305 seamless precision steel tube shall be manufactured from hot finished 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