| Size: | |
|---|---|
| Quantity: | |
EN10305-1 E215 EN10305-1 E235 EN10305-1 E355
| Steel grade Name | Steel Number | C(% max) | Si(% max) | Mn(% max) | P(% max) | S(% max) |
| E215 | 1.0212 | 0.10 | 0.05 | 0.70 | 0.025 | 0.015 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.025 | 0.015 |
| E355 | 1.0580 | 0.22 | 0.55 | 1.60 | 0.025 | 0.015 |
| Yield strength(min Mpa) | Tensile strength(min Mpa) | Elongation (min %) |
| 215 | 290-430 | 30 |
| 235 | 340-480 | 25 |
| 355 | 490-630 | 22 |
| Term | Symbol | Explanation |
| Cold-finished/hard (cold-finished as-drawn) | BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
| Cold-finished/soft (lightly cold-worked) | BKW | After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
| Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
| Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |
Finishing rolling process:
Finishing rolling is a process to obtain higher precision and better surface quality by rolling the heat-treated seamless steel pipe multiple times. The specific steps include: heat treatment - pickling - cooling - finishing rolling - sizing - cutting - length - inspection - packaging. Finishing rolling can improve the precision, surface quality and mechanical properties of steel pipe.
Cold drawing process:
Cold drawing is a process of drawing the heat-treated seamless steel pipe one by one in a cold state to obtain high precision, high surface quality and high mechanical properties. The specific steps include: heat treatment - pickling - cooling - cold drawing - deoxygenation - wet pickling - cold water washing - leveling - straightening - pickling - cold water washing - oxide skin - cold drawing - sizing - straightening - pickling - cold water washing - deoxygenation - polishing - inspection - packaging. Cold drawing can significantly improve the dimensional accuracy, surface quality and mechanical properties of steel pipes.
Hot rolling production process:
Hot rolling is the process of heating the blank to a certain temperature, and then forming it into seamless steel pipe through multiple rolls. The specific steps include: heating - rolling - roll probe - sizing - cooling - trimming - rod breaking - inspection - packaging. Hot rolling can produce seamless steel pipes with large diameters and wall thickness, but the accuracy and surface quality are not as good as fine rolling and cold drawing.
These three processes have different applications in the production of seamless precision steel pipes, and the specific choice depends on the required dimensional accuracy, surface quality and mechanical properties.
| Steel grade Name | Steel Number | C(% max) | Si(% max) | Mn(% max) | P(% max) | S(% max) |
| E215 | 1.0212 | 0.10 | 0.05 | 0.70 | 0.025 | 0.015 |
| E235 | 1.0308 | 0.17 | 0.35 | 1.20 | 0.025 | 0.015 |
| E355 | 1.0580 | 0.22 | 0.55 | 1.60 | 0.025 | 0.015 |
| Yield strength(min Mpa) | Tensile strength(min Mpa) | Elongation (min %) |
| 215 | 290-430 | 30 |
| 235 | 340-480 | 25 |
| 355 | 490-630 | 22 |
| Term | Symbol | Explanation |
| Cold-finished/hard (cold-finished as-drawn) | BK | No heat treatment after the last cold-forming process. The tubes therefore have only low deformability. |
| Cold-finished/soft (lightly cold-worked) | BKW | After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits. |
| Annealed | GBK | After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum. |
| Normalized | NBK | The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum. |
Finishing rolling process:
Finishing rolling is a process to obtain higher precision and better surface quality by rolling the heat-treated seamless steel pipe multiple times. The specific steps include: heat treatment - pickling - cooling - finishing rolling - sizing - cutting - length - inspection - packaging. Finishing rolling can improve the precision, surface quality and mechanical properties of steel pipe.
Cold drawing process:
Cold drawing is a process of drawing the heat-treated seamless steel pipe one by one in a cold state to obtain high precision, high surface quality and high mechanical properties. The specific steps include: heat treatment - pickling - cooling - cold drawing - deoxygenation - wet pickling - cold water washing - leveling - straightening - pickling - cold water washing - oxide skin - cold drawing - sizing - straightening - pickling - cold water washing - deoxygenation - polishing - inspection - packaging. Cold drawing can significantly improve the dimensional accuracy, surface quality and mechanical properties of steel pipes.
Hot rolling production process:
Hot rolling is the process of heating the blank to a certain temperature, and then forming it into seamless steel pipe through multiple rolls. The specific steps include: heating - rolling - roll probe - sizing - cooling - trimming - rod breaking - inspection - packaging. Hot rolling can produce seamless steel pipes with large diameters and wall thickness, but the accuracy and surface quality are not as good as fine rolling and cold drawing.
These three processes have different applications in the production of seamless precision steel pipes, and the specific choice depends on the required dimensional accuracy, surface quality and mechanical properties.
