The chemical composition, mechanical properties：
standard | Grade | chemical composition (%) | |||||||
C | Mn | Si | Cr | Ni | Cu | P.S | |||
GB/T8163 | 10 | 0.07～0.13 | 0.35～0.65 | 0.17～0.37 | ≤0.15 | ≤ 0.30 | ≤ 0.25 | ≤ 0.030 | |
20 | 0.17～0.23 | 0.35～0.65 | 0.17～0.37 | ≤0.25 | ≤ 0.25 | ≤ 0.25 | ≤ 0.030 | ||
Q345 | 0.12～0.20 | 1.20～1.60 | 0.20～0.55 |
|
|
| ≤ 0.030 | ||
Mechanical Properties | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | ||||||
10 | 335～475 | ≥ 205 | ≥ 24 | ||||||
20 | 410～550 | ≥ 245 | ≥ 20 | ||||||
Q345 | 490～665 | ≥ 325 | ≥ 21 | ||||||
Dimensions and Tolerances:
Steel pipe type | Pipe sizes | Tolerance | ||
mm | Normal | expert | ||
Hot rolled (extrusion, expanding tube | Outside Diameter | All | +1%（min+0.50） | - |
Wall Thickness | All | +15%（min +0.45） | - | |
-12.5%（min -0.40） | ||||
Cold drawing (rolling) tube | Outside Diameter | 6~10 | +0.20 | +0.15 |
>10~30 | +0.40 | +0.20 | ||
>30~50 | +0.45 | +0.30 | ||
>50 | +1% | +0.8% | ||
Wall Thickness | ≤1 | +0.15 | +0.12 | |
>1~3 | +15% | +12.5% | ||
-10% | -10% | |||
>3 | +12.5% | +10% | ||
-10% | ||||
* note: not less than 351 mm in diameter thermal expanding, wall thickness tolerance of +18 | ||||
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