Tolerance on Dimensions
| Pipe types | Pipe Szie(mm) | Tolerances |
| Hot rolled | OD | All | ±1% (min ±0.50mm) |
| WT | All | +15%, -12.5% |
| Cold drawn | OD | 6～10 | ±0.20mm |
| 10～30 | ±0.40mm |
| 30～50 | ±0.45mm |
| >50 | ±1% |
| WT | ≤1 | ±0.15mm |
| >1～3 | +15% -10% |
| >3 | +12.5% -10% |
Chemical composition and mechanical properties
| Standard | Grade | Chemical composition | Mechanical Properties |
| C | Si | Mn | P | S | Cr | Ni | Cu | Tensile Strength(Mpa) | Yield Strength(Mpa) | Elongation(%) |
| GB/T8163 | 10 | 0.07-0.14 | 0.17-0.37 | 0.35-0.65 | ≤0.035 | ≤0.035 | ≤0.15 | ≤0.25 | ≤0.25 | 335-457 | ≥205 | ≥24 |
| 20 | 0.17-0.24 | 0.17-0.37 | 0.35-0.65 | ≤0.035 | ≤0.035 | ≤0.25 | ≤0.25 | ≤0.25 | 410-550 | ≥245 | ≥20 |
| Q345 | 0.12-0.20 | 0.20-0.55 | 1.20-1.60 | ≤0.045 | ≤0.045 | - | - | - | 490-665 | ≥325 | ≥21 |