Metal & Oil & Gas News –
|
Types of steel tubes |
Outer diameters |
wall thickness |
||
|
Cold-rolled tubes |
Rube size(mm) |
tolerances (mm) |
Tube sizes (mm) |
Tolerances (mm) |
|
＞30～50 |
±0.3 |
≤30 |
±10％ |
|
|
＞50～219 |
±0.8％ |
|||
|
Hot-rolled tubes |
＞219 |
±1.0％ |
＞20 |
±10％ |
Mechanocal properties：
|
Standard code |
Models of steel tubes |
Tensile strength（MPa） |
Yield strength（MPa） |
Elongation（％） |
|
GB/T5312 |
320 | 320～410 | ≥195 | ≥25 |
| 360 | 360～480 | ≥215 | ≥24 | |
| 410 | 410～530 | ≥235 | ≥22 | |
| 460 | 460～580 | ≥265 | ≥21 | |
| 490 | 490～610 | ≥285 | ≥21 |
Chemical compisition:
|
Standard code |
Models of steel tubes |
Chemical compisition（％） |
||||
|
C |
Si |
Mn |
P |
S |
||
|
GB/T5312 |
320 |
≤0.16 |
≤0.35 |
0.40～0.70 |
≤0.035 |
≤0.035 |
|
360 |
≤0.17 |
≤0.35 |
0.40～0.80 |
≤0.035 |
≤0.035 |
|
|
410 |
≤0.21 |
≤0.35 |
0.40～1.20 |
≤0.035 |
≤0.035 |
|
|
460 |
≤0.22 |
≤0.35 |
0.80～1.40 |
≤0.035 |
≤0.030 |
|
|
490 |
≤0.23 |
≤0.35 |
0.80～1.50 |
≤0.035 |
≤0.030 |
|
Note：
residual elements:Cr≤0.25％，Mo≤0.10％，Ni≤0.30％，Cu≤0.30％aggregate≤0.70％
