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GB 9948 Seamless steel tubes for petroleum cracking |
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Standard: GB 9948
Equivalent Standards: ASTM A335, ASTM A213, EN 10216-2, ISO 9329-2 |
Material: 12CrMo
Equivalent Materials: T2, P2, STBA20 |
Chemistry Composition |
C, % |
Si, % |
Mn, % |
P, % |
S, % |
Cr, % |
Ni, % |
Cu, % |
Mo, % |
0.08-0.15 |
0.17-0.37 |
0.40-0.70 |
0.025 max |
0.015 max |
0.40-0.70 |
0.30 max |
0.20 max |
0.40-0.55 |
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Mechanical Properties |
Tensile Strength , MPa |
Yield Strength, MPa |
Elongation, % |
Impact (KV2)/J |
Hardness (HBW) |
410-560 |
205 min |
21 min |
40 (OD≥76mm & WT≥14mm) |
156 max |
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Outside Diameter & Tolerance |
Hot Rolled |
Outside Diameter, mm |
Tolerance |
Ordinary |
Advanced |
OD≤54 |
±0.50mm |
±0.30mm |
54<OD≤325 |
±1% |
±0.75% |
OD>325 |
±1% |
- |
Cold Drawn |
Outside Diameter, mm |
Tolerance |
Ordinary |
Advanced |
OD≤25.4 |
±0.15mm |
- |
25.4<OD≤40 |
±0.20mm |
- |
40<OD≤50 |
±0.25mm |
- |
50<OD≤60 |
±0.30mm |
- |
OD>60 |
±0.75% |
±0.50% |
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Wall thickness & Tolerance |
Hot Rolled |
Wall Thickness, mm |
Tolerance |
Ordinary |
Advanced |
WT≤20 |
+15%/-10% |
±10% |
WT>20 |
+12.5%/-10% |
±10% |
Cold Drawn |
Wall Thickness, mm |
Tolerance |
Ordinary |
Advanced |
WT≤3.0 |
±0.30mm |
±0.20mm |
WT>3 |
±10% |
±7.5% |
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GB 9948 specifies the classification, code, size, shape, weight, technical requirements, test methods, inspection rules, packaging, marking and quality certificate of seamless steel tubes for petroleum cracking. GB 9948 is applicable to seamless steel tubes for furnace tubes, heat exchanger tubes and pressure piping for petrochemical industry.
GB 9948规定了石油裂化用无缝钢管的分类、代号、尺寸、外形、重量、技术要求、试验方法、检验规则、包装、标志和质量证明书。GB 9948适用于石油化工用炉管、热交换器管和压力管道用无缝钢管。 |
Manufacture: tubes to GB 9948 shall be manufactured by hot rolled or cold drawn.
Heat Treatment: the tubes shall be produced by heat treated as normalizing & tempering.
Inspection & Test: chemistry composition analysis, tension test, flattening test or bending test, flaring test, hardness test (alloy & stainless), impact test, macroscopic examination, non-metallic inclusions, microstructure, intergranular corrosion test (stainless), NDT, surface inspection and dimension check. |
Length: 4000mm; 6000mm; 9000mm; 12000mm; and so on.
Max developed length: 30 meters, also U bending, finning, studded process can be provided.
Option: shot blasting on the outside surface to remove mill scale, make the surface matte colour; surface polishing as preparation work done for further processing, for instance finning. |
Keyword: GB T 9948, High Pressure Steel Pipe, Heat Exchanger Steel Tubes, Furnace Tubes, Piping |
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