Thin Wall DIN 2391 Normalized Seamless Steel Tubes With Phosphating Surface , St35 Precision Tube

Steel grade

Chemical composition, as a percentage by mass

Symbol

Material number

C
max.

Si
max.

Mn

P
max.

S
max.

St 30 Si

1.0211

0.10

0.30

<=0.55

0.025

0.025

St 30 Al

1.0212

0.10

0.05

<=0.55

0.025

0.025

St 35

1.0308

0.17

0.35

<=0.40

0.025

0.025

St 45

1.0408

0.21

0.35

<=0.40

0.025

0.025

St 52

1.0580

0.22

0.55

<=1.60

0.025

0.025

The following alloying elements may be added: Nb: <=0,03%; Ti: <=0,03%; V: <=0,05%; Nb + Ti + V: <=0,05%.

Designation

Symbol

Description

Cold finished (hard)

BK

Tubes do not undergo heat treatment following the final cold forming and, thus, have a rather high resistance to deformation.

Cold finished (soft)

BKW

The final heat treatment is followed by cold drawing involving limited deformation. Appropriate further processing allows a certain degree of cold forming (e.g. bending, expanding).

Cold finished and stress-relieved

BKS

Heat treatment is applied following the last cold forming process. Subject to appropriate processing conditions, the increase in the residual stresses involved enables both forming and machining to a certain degree.

Annealed

GBK

The last cold forming process is follow