GB/T8163 VS GB9948
GB/T8163 VS GB9948（The difference between GB/T8163 seamless steel pipe and GB9948 seamless steel pipe）
GB/T8163-2008 Seamless steel pipe for conveying fluid: general seamless steel pipe for conveying fluid.
GB9948-2013 Seamless steel pipe for petroleum cracking: suitable for seamless pipes of furnace tubes, heat exchanger tubes and pipelines in petroleum refineries.
Note: σb=Tensile Strength(MPa), σs=Yield Strength(MPa), δ5=Elongation(%)
| different | GB/T8163 | GB9948 | note | ||||
| Tolerance of outer diameter and wall thickness |
OD＞10～30 |
Ordinary level | high-level | OD≤30 | ±0.20 | Cold drawn (rolled) tube | |
| ±0.40 | ±0.20 | ||||||
|
WT＞1～3 |
＋15％ | ＋12.5％ | WT≤3 |
＋12％ －10％ |
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| －10％ | －10％ | ||||||
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Steel grade and
chemical composition
|
Should comply with GB/T699 or GB/T1591
C:0.07~0.13％
Mn: 0.35~0.65％
C:0.17~0.23％ Mn: 0.35~0.65％ |
C:0.07~0.14％ Mn: 0.35~0.65％ C:0.17~0.24％ Mn: 0.35~0.65％ |
High quality carbon steel: 10# 20# |
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| delivery status |
Hot rolled tube hot rolled, cold drawn (rolled) tube in heat treated state (generally annealed) |
Hot rolled tube finishing, cold drawn tube normalizing | |||||
| Mechanical properties | 10# |
σb=335~475MPa σs≥205MPa δ5≥24％ |
σb=330~490MPa σs≥205MPa δ5≥24％ |
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| 20# |
σb=410~550MPa σs≥245MPa δ5≥20％ |
σb=410~550MPa σs≥245MPa δ5≥21％ |
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| Hydrostatictest | The steel pipe shall be hydraulically tested one by one, the maximum pressure shall not exceed 19 MPa, and the withstand voltage shall be not less than 5 s, P = 2SR/D |
The steel pipe shall be hydraulically tested one by one, the maximum pressure shall not exceed 20 MPa, and the withstand voltage shall not be less than 10 s, P=2SR/D |
Suppliers can use ultrasonic testing and eddy current testing instead of hydraulic test | ||||
| Flattening test | 22≤OD≤400 and wall thickness/outer diameter ≤10% | Steel pipe with outer diameter >22~400 |
No cracks or cracks are allowed on the specimen after the flattening test |
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| Flaring test | Wall thickness ≤ 8 can be done | Wall thickness ≤ 8 and outer diameter ≤ 159 |
No cracks or cracks shall appear on the specimen |
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| Bending test | Steel pipe with outer diameter ≤22 | / |
No cracks or cracks in the bend |
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| Surface Quality |
The inner and outer surfaces of the steel pipe shall be free from cracks, folds, rolling, separation and crusting. Other defects whose depth does not exceed the negative deviation of the wall thickness are allowed to exist. |
The inner and outer surfaces of the steel pipe shall not have cracks, folds, rolling, separation, crusting and hairline defects. Other defects that do not exceed the negative deviation of the wall thickness are allowed to exist. |
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| Non-destructive testing |
Steel pipes should be ultrasonically tested one by one |
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Note: σb=Tensile Strength(MPa), σs=Yield Strength(MPa), δ5=Elongation(%)
