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%