DIN 2391 St 30 Si / St 30 Al Thin Wall Seamless Steel Tubes Length 6m , 9m , 12 , 24m
ST30AL is mainly used for the production of seamless precision steel pipes and precision welded steel pipes.
| Standard | DIN 2391 |
| Grade | St 30 Si / St 30 Al / St 35 / St45 / St 52 |
| Out Dimensions | Out Dimensions |
| Wall Thickness | 0.8 mm ~30mm |
| Length | Fixed(6m,9m,12,24m) or normal length(5-12m) |
| Delivery Condition | Heat treatment,Annealed, Normalized, Normalized and Tempered |
| Packing | Beveled/black painting/ plastic caps/ in bundles/ steel strips/ wooden protection |
| Inspection and Test | Chemical Composition Inspection, Mechanical Properties Test(Tensile Strength, Yield Strength,Elongation, Flaring, Flattening, Bending, Hardness, Impact Test),Surface and Dimension Test,Nodestructive Test, Hydrostatic Test. |
| Surface treatment | Oil-dip, Varnish, Passivation, Phosphating, Shot Blasting |
Chemical Composition
Steel grade | Chemical composition, as a percentage by mass | |||||
Symbol | Material number | C | Si | Mn | P | S |
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%. | ||||||
Final supply conditions
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 followed by annealing in a controlled atmosphere. |
Normalized | NBK | The last cold forming process is followed by annealing above the upper transformation point in a controlled atmosphere. |
Condition on delivery
Steel Grade | BK | BKW | GBK | NBK | ||||
Code No. | Tensile | Elongation | Tensile | Elongation at rupture N/mm2 min | Tensile | Elongation at rupture N/mm2 min | Tensile | Elongation at rupture N/mm2 min |
St30 Si | 400 | 8 | 330 | 12 | 280 | 30 | 290-420 | 30 |
St30 Al | 400 | 8 | 330 | 12 | 280 | 30 | 290-420 | 30 |
St 35 | 440 | 6 | 370 | 10 | 315 | 25 | 340-470 | 25 |
St 45 | 540 | 5 | 470 | 8 | 390 | 21 | 440-570 | 21 |
St 52 | 590 | 4 | 540 | 7 | 490 | 22 | 490-630 | 22 |
Other Terms
Scope: This standard 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. Tubes according to this standard are mainly used where accuracy to dimension and possibly, small wall thickness and good surface condition are required.
Shape: The tubes shall be furnished in the following shapes, as specified by the purchaser: round, square,rectangular and special sections.
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