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The types of fasteners for HG 20634-2009 (Class series) steel pipe flanges include hexagon head bolts, full threaded studs, I-type nuts and special nuts.　　

　　 1. The type and size of hexagon head bolts should meet the requirements of GB/T5782. There are A and B levels. Performance level: 5.6, 8.8, A2-50, A4-50, A2-70, A4-70; nominal pressure: ≤Class150 (PN20); applicable temperature: -196—+400℃.　　

　　2. Full-threaded studs for pipe flanges: The thread size and tolerances and the chamfering at both ends are in accordance with GB/T901. Nominal pressure: ≤Class2500 (PN420); selection of materials (grade): 35CrMo (-100-525℃), 25Cr2MoV (>-20-575℃), 42CrMo (-100-525℃), 0Cr18Ni9 (-196-800℃) ), 0Cr17Ni12Mo2 (-196-800℃), A193 B8 CL.2 (-196-525℃), A193 B8M CL.2 (-196-525℃), A453 660 (-29-525℃), including applicable A320 L7 (-100—340℃) in a low temperature and high pressure environment.　　

　　3. Nuts: The type of nuts used in conjunction with hexagonal bolts should meet the requirements of GB/T6170; the nuts used in conjunction with full-threaded studs (special nuts for pipe flanges) are thickened nuts.　　

  • Metric Hex Flange Nut
  • Metric Hex Flange Nut
  • Metric Hex Flange Nut

GB6170: Performance level: Class 6, Class 8, A2-50, A4-50, A2-70, A4-70; Nominal pressure: ≤Class150 (PN20); Applicable temperature: >-20—+300, -196—+ 400℃; Nominal pressure: ≤Class150 (PN20).　　

　　Special-grade nut materials (grades) are optional: 30CrMo, 35CrMo, 0Cr18Ni9, 0Cr17Ni12Mo2, A194 8, A193 B8M and A194 7 suitable for low temperature and high pressure environments; nominal pressure: ≤Class2500 (PN420). The applicable temperature is equivalent to the stud material.

HG/T 20613-2009 “Fasteners for Steel Pipe Flanges”-(PN series). This standard replaces the old version in 1997 and adds more new content with reference to ASTM or ASME standards.　　 　　

1. Hexagon head bolts for pipe flanges: their type and size meet the requirements of GB5782 (coarse thread) and GB5785 (fine thread), and the end of the bolt adopts a chamfered end. Performance level: 5.6, 8.8, A2-50, A4-50, A2-70, A4-70. Performance level: 5.6, 8.8, A2-50, A4-50, A2-70, A4-70; Nominal pressure: ≤PN16; Applicable temperature: -196—+400℃.　

2. Equal-length double-ended studs for pipe flanges: The type and size meet the requirements of GB901, and the two ends of the stud adopt chamfered ends. Performance level (commodity level): 8.8, A2-50, A4-50, A2-70, A4-70. Nominal pressure: ≤PN40; applicable temperature: -196—+400℃

3. Full stud studs for pipe flanges: the thread size and tolerance, and the chamfering requirements at both ends are in accordance with GB/T901.　　

Nominal pressure: ≤PN160; selection of materials (grades): 35CrMo (-100—525°C), 25Cr2MoV (>-20—575°C), 42CrMo (-100—525°C), 0Cr18Ni9 (-196—800°C), 0Cr17Ni12Mo2 (-196—800°C), A193 B8 CL.2 (-196—525°C), A193 B8M CL.2 (-196—525°C), A453 660 (-29—525°C), including those suitable for low temperature and high pressure Environmental A320 L7 (-100-340℃).

Nut: 　　 　　

A. The type of nuts used in conjunction with hexagonal bolts and studs should meet the requirements of GB6170 and GB6171.　　 　　 Performance level: Class 6, Class 8, A2-50, A4-50, A2-70, A4-70; Nominal pressure: ≤PN16-PN40; Applicable temperature: >-20—+300, -196—+400℃.　　 　　

B. The form and size of the nut used in conjunction with the full-threaded stud is in accordance with the requirements of GB6175 and GN6176.　　

Optional: 30CrMo, 35CrMo, 0Cr18Ni9, 0Cr17Ni12Mo2, A194 8, A193 B8M and A194 7 suitable for low temperature and high pressure environments; nominal pressure: ≤PN160. The applicable temperature is equivalent to the stud material.