EN 10305-1

EN 10305-1 is the European Standard applications for specifies steel tubes. The technical delivery conditions for seamless cold drawn steel tubes of circular cross section for precision applications with specified outside diameter D <= 380 mm. NOTE This document may also be applied to other types of cross section and other suitable processes. Tubes according to this document are characterized by having precisely defined tolerances on dimensions and a specified maximum surface roughness.

EN 10305-1 Precision Steel Tube

EN 10305-1 Precision Steel Tube for precision applications of motor-car construction, pneumatic and hydraulic operating mechanisms.

Typical fields of application are in the automotive, furniture and general engineering industries.

Steel tubes for precision applications – Technical delivery conditions – Part 1: Seamless cold drawn tubes.

Seamless Precision Steel Tubes according to EN 10305-1

Standard and Steel grade:

  • EN10305-1 E215/E235/E355


  • high precision and high brightness, the inner and outer surface of the tubes have high cleanness without oxid
  • mechanical properties of the final tubes also come out excellent
  • promising no leakage under high pressure
  • no deformation after cold-bent and no cracks when flaring and flattening
  • ensuring the efficient operation in all service.

DIN 2391-81 Part 2 Seamless Precision steel tubes(DIN2391-81)

Standard DIN 2391 defines the technical delivery conditions for seamless precision steel tubes according to DIN 2391 Part 1 which are made from the steel grades listed in section 5.
Tubes according to this Standard are mainly used where accuracy to dimension and, possibly, small wall thicknesses and good surface condition are required.

Table1, Chemical composition(%) (cast analysis)a

Steel grade % by mass
Name Number C Si Mn P Sb Al
Max Max Max Max Max Min
E215 1.0212 0.1 0.05 0.7 0.025 0.025 0.025
E235 1.0308 0.17 0.35 1.2 0.025 0.025
E355c 1.058 0.22 0.55 1.6 0.025 0.025

a Elements not included in this table(but see footnote c) shall not be intentionally added to the steel without the agreement of the purchaser, except for elements which may be added for finishing the cast. All appropriate measures shall be taknen to prevent the additon of undesirable elementts from scrap or other materials used inthe steel making process.
b For the steel grades E235 and E355 a controlled sulphur content of 0.015% to 0.040% is specified to support machinability. It shall be obtained by result phursing the steel after maximum desulphurisation or alternatively by using a low oxygen process.
c Additions of Nb, Ti and V are permitted at the discretion of the manufacturer. The content of these elements shalll be reported.

Permissible deviations of the product analysis from the specified limits on cast analysisi given Table1

Element Limiting value for cast analysis in accordance with Table 1 in % by mass Permissible deviation of the roduct analysisi in % by mass.
C 0.22 0.02
Si 0.55 0.05
Mn 1.50 0.1
P 0.025 0.005
S 0.040 ±0.005
Al 0.025 -0.005

Mechanical properties at room temperature

Name Number +Cc +LCc
Rm /MPa A% Rm /MPa A%
E215 1.0212 430 8 380 12
E235 1.0308 480 6 420 10
E355 1.058 640 4 580 7
Name +SR +Ad +N
Rm /MPa ReH /MPa A% Rm /MPa A% Rm /MPa ReH /MPa A%
E215 380 280 16 280 30 290-430 215 30
E235 420 350 16 315 25 340-480 235 25
E355 580 450 10 450 22 490-630 355 22


a Rm:拉伸强度;ReH:上屈服点(但见表11.1);A:断裂后的伸长率.交货条件标识见表1。

b  1MPa=1N/mm2

c 根据冷加工处理的程度,屈服强度可能接近于拉伸强度一样大。为了计算目的,推荐下面的关系式:




e 对于外径小于等于30mm,壁厚小于等于3mm的管材,ReH的最小值比本表中的小10MPa

f 外径大于160mm的管材,ReH≥420MPa

Diameter tolerances for heat treated tubes

T/D-ratio Tolerance limits
0.05 1
0.05T/D0.025 1.5
0.025 2

Quality grade

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:

Term Symbol Explanation
(cold-finished as-drawn)
BK No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.
(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.
PDFView the PDF catalogue of EN 10305-1Seamless precision steel tubes
Related products
A tube, or tubi
Precision Steel
The NORSOK stan
MSS SP-75 speci