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Large diameter seamless steel pipe


Large diameter seamless steel pipe
At present, China's large-diameter seamless steel tubes, the main production process for hot-rolled large-diameter seamless steel tubes and hot expanded seamless steel tubes, hot-rolled seamless steel tubes can produce non-GB size, thermal expansion seamless tube is what we often say hot Expanded pipe, a relatively low density but strong contraction of the pipe using the oblique rolling method or drawing method to expand the pipe diameter of a barn finish rolling process. The thickening of steel pipes in a short period of time can produce non-standard and special models of seamless pipes with low cost and high production efficiency. It is the current trend in the field of international pipe rolling.
Large diameter seamless steel pipe
For GB5310 steel pipe with outer diameter greater than or equal to 76 and wall thickness ≥ 14mm, Charpy V-type longitudinal impact test shall be carried out at 20°C; the average value of impact energy of the three samples shall not be lower than 40J, allowing one sample The impact energy is lower than the average but not lower than 70% of the average. Outer diameter> 219.1mm, and wall thickness ≥ 25mm steel tube can be used instead of the longitudinal mechanical properties test. The Charpy V-type transverse impact test was performed at 20°C, and the large-diameter tube was more convenient for the transverse mechanical test.
The scope of use includes general structural and mechanical structures, and a large number of structural tubes used in construction, machinery, transportation, aviation, oil extraction and other industries
Dimensional tolerance

standard Outer diameter tolerance Thickness tolerance
GB/T 8162 D<50 ±0.50mm S<4mm ±12.5%
D≥50 ±1% 4-20mm +15/-12.5%
S≥20mm ±12.5%
DIN1629 D50 ±0.50mm S2Sn +15/-10%
D48.3D48.3 ±1% 2SnS4Sn +12.5/-10%
S4Sn ±9%
ASTM A53 D<48.3 ±0.4/-0.79mm ±12.5%
D≥48.3 ±1%
ASTM A106 D<48.3 ±0.4/-0.79mm ±12.5%
D48.3-114.3 ±0.79mm
D≥114.3 ±1.59/-0.79mm
Mechanical properties:
standard Steel grade tensile strength(MPa) Yield Strength(MPa) Elongation rate
<16mm 16-30mm
GB/T 8162 10 335 205 195 24
20 390 245 235 20
35 510 305 295 17
45 590 335 325 14
16Mn 490 325 315 21
DIN 1629   <16mm >16mm  
ST35 345-460 235 225 25
ST45 440-550 255 245 21
ST55 540-645 295 285 17
ST52 490-630 355 345 22
ST45 590-730 335 325 14
ASTM A53 A 330 205  
B 415 240
ASTM A106 A 330 205  
B 415 240
C 485 275