EN 10305 – 1 Steel tubes for precision applications – Technical delivery conditions – Part 1: Seamless cold drawn tubes
This Part of EN 10305 specifies the technical delivery conditions for seamless cold drawn steel tubes of circular cross section for precision applications.
Tubes according to this Part of EN 10305 are characterized by having precisely defined tolerances on dimensions and a specified surface roughness. Typical fields of application are in the vehicle, furniture and general engineering industries.
Delivery conditions
| Designation | Symbol | Description |
| Cold drawn / hard | +C | No heat treatment after the final cold drawing process. |
| Cold drawn / soft | +LC | After the final heat treatmant there is a suitable drawing pass. |
| Cold drawn and stress relieved | +SR | After the final cold drawing process there is a stress relief heat treatment in a controlled atmosphere. |
| Annealed | +A | After the final cold drawing process the tubes are annealed in a controlled atmosphere. |
| Normalized | +N | After the final cold drawing operation the tubes are normalized in a controlled atmosphere. |
| Chemical composition (cast analysis)a | |||||||
| Steel name | Steel number | C | Si | Mn | P | S b | Al |
| max. | max. | max. | max. | max. | min. | ||
| E215 | 1.0212 | 0.10 | 0.05 | 0.70 | 0.03 | 0.03 | 0.025 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.03 | 0.03 | – |
| E355 c | 1.0580 | 0.22 | 0.55 | 1.60 | 0.03 | 0.03 | – |
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 taken to prevent the addition of undesirable elements from scrap or other materials used in the steel making process.
b See option 2
c Addition of Nb, Ti and V are permitted at the discretion of the manufucturer. The content of these elements shall be reports.
Option 2: 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 resulphurising the steel after maximum desulphurisation or alternatively by using a low oxygen process.
Mechanical properties at room temperature
| Steel grade | Minimum values for the delivery condition a,b | ||||||||||||
| Steel name | Steel number | +C c | +LC c | +SR | +A d | +N | |||||||
| Rm Mpa | A % | Rm Mpa | A % | Rm Mpa | ReH Mpa | A % | Rm Mpa | A % | Rm Mpa | ReH e Mpa | A % | ||
| E215 | 1.0212 | 430 | 8 | 380 | 12 | 380 | 280 | 16 | 280 | 30 | 290 to 430 | 215 | 30 |
| E235 | 1.0308 | 480 | 6 | 420 | 10 | 420 | 350 | 16 | 315 | 25 | 340 to 480 | 235 | 25 |
| E355 | 1.0580 | 640 | 4 | 580 | 7 | 580 | 450 f | 10 | 450 | 22 | 490 to 630 | 355 | 22 |
a Rm: tensile strength ; ReH: upper yield strength; A: elongation after fracture.
b 1 MPa = 1 N/mm2.
c Depending on the degree of cold work in the finishing pass the yield strength may nearly be as high as the tensile strength. For calculation purposes the following relationships are recommended:
– for delivery condition +C: ReH ≥ 0.8 Rm;
– for delivery condition +LC: ReH ≥ 0.7 Rm.
d For calculation purposes the following relationship is recommended: ReH ≥ 0.5 Rm.
e For tubes with outside diameter ≤ 30 mm and wall thickness ≤ 3 mm the ReH minimum values are 10 MPa lower than the values given in this Table.
f For tubes with outside diameter > 160 mm: ReH ≥ 420 MPa.
