Brand:KWK Steel
Model:DIN2391
Application:
Cold drawn or cold rolled precision seamless steel tubes for hydraulic pressure and pneumatic services.
For Auto. use, machinery use, oil cylinder tube, motorcycle shock reducer use, auto shock reducer inner cylinder, etc.
Size:
O.D.: 6.0-650.0mm W.T.: 1.0-65mm Length: Max.12000mm
Steel Grade and Chemical Composition(%)
Standard | Grade | C≤ | Si≤ | Mn | P≤ | S≤ |
DIN2391 | St35 | 0.18 | 0.35 | ≥0.40 | 0.025 | 0.025 |
St45 | 0.22 | 0.10-0.35 | ≥0.40 | 0.025 | 0.025 | |
St52 | 0.22 | 0.55 | ≤1.60 | 0.025 | 0.025 |
Final Supply Condition
Symbol | Designation | Description |
BK | Cold finished(hard) | Tubes do not undergo heat treatment following the final cold forming and, thus, have a rather high resistance to deformation. |
BKW | Cold finished(soft) | 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) |
BKS | Cold finished and stress-relieved | 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. |
GBK | Annealed | The last cold forming process is followed by annealing in a controlled atmosphere. |
NBK | Normalized | The last forming process is followed by annealing above the upper transformation point in a controlled atmosphere. |
Mechanical Properties
Rm:Tensile Strength(Mpa) ReH:Yield Point(Mpa) A%:Elongation Mpa=N/mm2
Standard | Grade | BK | BKW | BKS | GBK | NBK | |||||||
Rm≥ | A%≥ | Rm≥ | A%≥ | Rm≥ | ReH≥ | A%≥ | Rm≥ | A%≥ | Rm≥ | ReH≥ | A%≥ | ||
DIN2391 | St35 | 480 | 6 | 420 | 10 | 420 | 315 | 14 | 315 | 25 | 340-470 | 235 | 25 |
St45 | 580 | 5 | 520 | 8 | 520 | 375 | 12 | 390 | 21 | 440-570 | 235 | 21 | |
St52 | 640 | 4 | 580 | 7 | 580 | 420 | 10 | 490 | 22 | 490-630 | 355 | 22 | |
