Standard:GB9948-1988
Application: For manufacturing of furnace tubes, heat exchangers and pipelines in refineries
Tolerance on Dimensions
| Pipe Types | Pipe Size (mm) | Tolerances | |
| Hot Rolled | OD | ≤159 | ±1.0% |
| >159 | ±1.20% | ||
| WT | ≤20 | ±12.5% | |
| >20 | ±10.0% | ||
| Cold Drawn | OD | ≤30 | ±0.20mm |
| 30-50 | ±0.30mm | ||
| >50 | ±0.8% | ||
| WT | ≤3 | +12% -10% | |
| >3 | ±10% | ||
Chemical composition and mechanical properties
| Grade | Chemical Composition | Mechanical Properties | |||||||||
| C | Mn | Si | Cr | Mo | Ni | S | P | Tensile Strength(Mpa) | Yield Strength(Mpa) | Elongation(%) | |
| 10 | 0.07-0.14 | 0.35-0.65 | 0.17-0.37 | ≤0.15 | - | ≤0.25 | ≤0.035 | ≤0.035 | 330-490 | ≥205 | ≥24 |
| 20 | 0.17-0.24 | 0.35-0.65 | 0.17-0.37 | ≤0.25 | - | ≤0.25 | ≤0.035 | ≤0.035 | 410-550 | ≥245 | ≥21 |
| 12CrMo | 0.08-0.15 | 0.40-0.70 | 0.17-0.37 | 0.40-0.70 | 0.40-0.55 | ≤0.30 | ≤0.035 | ≤0.035 | 410-560 | ≥205 | ≥21 |
| 15CrMo | 0.12-0.18 | 0.40-0.70 | 0.17-0.37 | 0.80-1.10 | 0.40-0.55 | ≤0.30 | ≤0.035 | ≤0.035 | 440-640 | ≥235 | ≥21 |
| 1Cr2Mo | ≤0.15 | 0.30-0.60 | 0.50-1.00 | 2.15-2.85 | 0.40-0.65 | - | ≤0.035 | ≤0.035 | ≥390 | ≥175 | ≥22 |
| 1Cr5Mo | ≤0.15 | ≤0.60 | ≤0.60 | 4.00-6.00 | 0.45-0.60 | ≤0.60 | ≤0.035 | ≤0.035 | ≥390 | ≥195 | ≥22 |
