
DIN 2391 standard specifies the Seamless steel tubes used forMechanical and Automobile.
The main products of steel / steel grade: DIN2391-1(ST35, ST45, ST52).
Application:

| OD(mm) | Wall Thickness Unit(mm) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2 | 2.5 | 3 | 3.5 | 4 | 4.5 | 5 | 6 | 6.5-7 | 7.5-8 | 8.5-9 | 9.5-10 | 11 | 12 | |
| Φ25-Φ28 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ32 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ34-Φ36 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ38 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ40 | ● | ● | ● | ● | ● | |||||||||
| Φ42 | ● | ● | ● | ● | ● | |||||||||
| Φ45 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ48-Φ60 | ● | ● | ● | ● | ● | ● | ● | |||||||
| Φ63.5 | ● | ● | ● | ● | ● | ● | ● | |||||||
| Φ68-Φ73 | ● | ● | ● | ● | ● | ● | ||||||||
| Φ76 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ80 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ83 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ89 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ95 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ102 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ108 | ● | ● | ● | ● | ● | ● | ● | ● | ● | ● | ||||
| Φ114 | ● | ● | ● | ● | ● | ● | ● | ● | ● | |||||
| Φ121 | ● | ● | ● | ● | ● | ● | ● | ● | ● | |||||
| Φ127 | ● | ● | ● | ● | ● | ● | ● | ● | ● | |||||
| Φ133 | ● | ● | ● | ● | ● | ● | ● | ● | ● | |||||
| Φ140 | ● | ● | ● | ● | ● | ● | ● | ● | ||||||
| Φ146 | ● | ● | ● | ● | ● | ● | ● | ● | ||||||
| Φ152 | ● | ● | ● | ● | ● | ● | ● | ● | ||||||
| Φ159 | ● | ● | ● | ● | ● | ● | ● | ● | ||||||
| Φ168 | ● | ● | ● | ● | ● | ● | ● | ● | ||||||
|
Grade |
Chemical Composition(%): | ||||
|---|---|---|---|---|---|
| C max | Si max | Mn | P max | S max | |
| St 35 | 0.17 | 0.35 | ≥0.40 | 0.025 | 0.025 |
| St 45 | 0.21 | 0.35 | ≥0.40 | 0.025 | 0.025 |
| St 52 | 0.22 | 0.55 | ≤1.60 | 0.025 | 0.025 |
| Steel grade | Chemical Composition(%): | ||||||
|---|---|---|---|---|---|---|---|
| Steel name | Steel number | C max | Si max | Mn | P max | S max | Al min |
| E215 | 1.0212 | 0.10 | 0.05 | 0.70 | 0.025 | 0.025 | 0.025 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.025 | 0.025 | - |
| E355 | 1.0580 | 0.22 | 0.55 | 1.60 | 0.025 | 0.025 | - |
| Steel Grade | Minimum values for the delivery condition | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Steel Name | Steel Number | BK | BKW | BKS | GBK | NBK | |||||||
| Rm | A % | Rm | A % | Rm | ReH | A % | Rm | A % | Rm | ReH | A % | ||
| Mpa | Mpa | Mpa | Mpa | Mpa | Mpa | Mpa | |||||||
| St 30 Si | 1.0211 | 430 | 8 | 380 | 12 | 380 | 280 | 16 | 280 | 30 | 290 to 420 | 215 | 30 |
| St 30 Al | 1.0212 | 430 | 8 | 380 | 12 | 380 | 280 | 16 | 280 | 30 | 290 to 420 | 215 | 30 |
| St 35 | 1.0308 | 480 | 6 | 420 | 10 | 420 | 315 | 14 | 315 | 25 | 340 to 470 | 235 | 25 |
| St 45 | 1.0408 | 580 | 5 | 520 | 8 | 520 | 375 | 12 | 390 | 21 | 440 to 570 | 255 | 21 |
| St 52 | 1.0580 | 640 | 4 | 580 | 7 | 580 | 420 | 10 | 490 | 22 | 490 to 630 | 355 | 22 |
| Inspection or test types | Test frequency | |
|---|---|---|
| Internal test | Acceptance test | |
| Chemical analysis | M | M |
| Tensile testing | M | One per tested batch |
| Flattening test or extension test | M | Two per tested batch |
| Dimension verification | M | M |
| Visual inspection | M | M |
| NDT in order to identify leaks | Individual | Individual |





