1. Seamless cold-drawn precision steel pipes E235N (St 37.4)
and E355N (St 52.4) according to EN 10305-4
a. E235N (St 37.4) – NBK
– Normalized, phosphated and oiled inside and outside
b. E235N (St 37.4) – NBK/ZN
– Normalized, electric zinc plated with Cr-VI-free passivation
c. E355N (St 52.4) – NBK
– Normalized, phosphated and oiled inside and outside
d. E355N (St 52.4) – NBK/ZN
– Normalized, electric zinc plated with Cr-VI-free passivation
2. Austenitic stainless steel pipes, seamless, cold-drawn 316L
(1.4404) according ASTM-standards
a. AISI 316L – metric sizes Fully annealed, scale free
b. TP 316L – schedule sizes Fully annealed, scale free
DIN 2391/C (DIN EN 10305-4) - Steel tubes for precision applications -
Technical delivery conditions - Part 4: Seamless cold drawn tubes for
hydraulic and pneumatic power systems
DIN 2445/2 - Seamless steel tubes for dynamic loads - Part 2: Steel
tubes for precision application in fluid systems, 100 bar to 500 bar
Material Specifications:
ST37.4 (E235N)
ST52.4 (E355N)
Finishing:
NBK, Normalized, phosphated and oiled inside and outside. The tubes are annealed above the upper transformation
point in a controlled atmosphere or under vacuum
Recommended Bend Radius
A bend radius of 3x the external tube diameter is recommended for cold
bending of tubes with tube benders or by hand. (As per Figure 1)
Welding Suitability
Tubes of ST37.4, ST52.4 are suitable for welding according to usual techniques.
The welding filler should be selected in accordance with DIN EN 1600 and DIN
EN 12072 part 1 taking into account the type of application and the welding
technique.
| DIN 2391 Mechanical properties |
| |
The final delivery condition |
Cold drawn(Mandatory)
BK1） |
Cold drawn(Soft)
BKW1） |
Cold Drawn and Stress Release
(BKS) |
Anneal
(GBK)1） |
Normalizing
(NBK)1） |
| Kinds of Steel |
|
Tensile |
Elongation |
Tensile |
Elongation |
Tensile |
Yield point |
Elongation |
Tensile |
Elongation |
Tensile |
Yield point |
Elongation |
| Steel grade |
Material number |
|
No less than |
| Rm |
A5 |
Rm |
A5 |
Rm |
ReH |
A5 |
Rm |
A5 |
Rm |
ReH2) |
A5 |
| |
|
|
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
N/mm2 |
% |
| St35 |
1.0308 |
|
-- |
-- |
-- |
-- |
-- |
-- |
-- |
-- |
-- |
340~470 |
235 |
25 |
| St37.4 |
1.0255 |
|
480 |
6 |
420 |
10 |
420 |
315 |
14 |
315 |
25 |
350~480 |
235 |
25 |
| St45 |
1.0408 |
|
580 |
5 |
520 |
8 |
520 |
375 |
12 |
390 |
21 |
440~570 |
255 |
21 |
| St52 |
1.0580 |
|
640 |
4 |
580 |
7 |
580 |
420 |
10 |
490 |
22 |
490~630 |
355 |
22 |
| St52.4 |
1.0581 |
|
-- |
-- |
-- |
-- |
-- |
-- |
-- |
-- |
-- |
500~650 |
355 |
21 |
|
| EN 10305-1 Mechanical properties |
| |
The final delivery condition |
Cold drawn
(Mandatory)
+C |
Cold drawn
(Soft)+LC |
Cold Drawn and Stress Release
(+SR) |
Anneal
(+A) |
Normalizing
(+N) |
| |
|
|
Tensile |
Elongation |
Tensile |
Elongation |
Tensile |
Yield point |
Elongation |
Tensile |
Elongation |
Tensile |
Yield point |
Elongation |
| Steel grade |
Material number |
|
No less than |
| Rm |
A5 |
Rm |
A5 |
Rm |
ReH |
A5 |
Rm |
A5 |
Rm |
ReH2) |
A5 |
| |
|
|
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
N/mm2 |
% |
| E235 |
1.0308 |
|
480 |
6 |
420 |
10 |
420 |
350 |
16 |
315 |
25 |
340~480 |
235 |
25 |
| E255 |
1.0408 |
|
580 |
5 |
520 |
8 |
520 |
375 |
12 |
390 |
21 |
440~570 |
255 |
21 |
| E355 |
1.0580 |
|
640 |
4 |
580 |
7 |
580 |
450 |
10 |
450 |
22 |
490~630 |
355 |
22 |
|
| GB3639 Mechanical properties |
| |
The final delivery condition |
Cold drawn
(Mandatory)
BK1） |
Cold drawn
(Soft)
BKW1） |
Cold Drawn and Stress Release
(BKS) |
Anneal
(GBK)1） |
Normalizing
(NBK)1） |
| |
|
Tensile |
Elongation |
Tensile |
Elongation |
Tensile |
Elongation |
Tensile |
Elongation |
Tensile |
Yield point |
Elongation |
| Steel grade |
|
No less than |
| Rm |
A5 |
Rm |
A5 |
Rm |
A5 |
Rm |
A5 |
Rm |
ReH2) |
A5 |
| |
|
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
% |
N/mm2 |
N/mm2 |
% |
| 10 |
|
410 |
6 |
375 |
10 |
335 |
12 |
335 |
24 |
335 |
205 |
24 |
| 20 |
|
510 |
5 |
450 |
8 |
430 |
10 |
390 |
20 |
410 |
245 |
20 |
| 35 |
|
590 |
4 |
550 |
6 |
520 |
8 |
510 |
17 |
530 |
315 |
17 |
| 45 |
|
645 |
4 |
630 |
5 |
610 |
7 |
590 |
14 |
600 |
355 |
14 |
|
|
|
