Complaint
DIN2391 ST52 Cold Drawn Seamless Honed Cylinder Tube
Size: 20mm-350mm
W.T.: 1mm-50mm
Shape: Round
Production type: Cold drawn
Length: Single random length/ Double random length or as customer's actual request max length is 10m
Grade: St52
| Standard | Grade | Chemical Components (%) | |||||
| Symbol | Material No. | C | Si | Mn | P | S | |
| DIN2391 | St 52 | 1.058 | ≤0.22 | ≤0.55 | ≤1.60 | ≤0.025 | ≤0.025 |
The tubes shall be manufactured from cold drawn or cold rolled processes. The tubes shall be supplied in one of the delivery conditions as follows:
| 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. |
Delivery Condition Symbol in accordance with EN10305 and DIN2391
| Symbol in accordance with EN 10305 | Symbol in accordance with DIN2391 |
| +C | BK |
| +LC | BKW |
| +SR | BKS |
| +A | GBK |
| +N | NBK |
| Mechanical properties at room temperature | |||||||||||||
| 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 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 |
