Concept of high temperature and high pressure fastener

01-08-2020

1、 Hg / T 20634-2009 fasteners for steel pipe flanges - (Class Series).

This standard replaces the old edition of 1997, and adds many new contents with reference to ASTM or ASME standards, and removes the clause of double head stud.


The types of fasteners for Hg 20634-2009 (Class Series) steel pipe flange include hexagon head bolt, full thread stud, i-nut and special nut.


1. The type and size of hexagon head bolt shall meet the requirements of GB / t5782. It is divided into Grade A and grade B. Performance grade: 5.6, 8.8, a2-50, a4-50, A2-70, a4-70; nominal pressure: ≤ class150 (PN20); applicable temperature: - 196 - + 400 ℃.


2. Full thread stud for pipe flange: thread size and tolerance and chamfering at both ends shall be in accordance with GB / t901. Nominal pressure: ≤ class2500 (pn420); selected 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 A320 L7 (- 100-340 ℃) suitable for low temperature and high pressure environment.


3. Nut: the type of nut used with hexagon bolt shall meet the requirements of GB / t6170; the nut used with full thread stud (special nut for pipe flange) is thickened nut.


Gb6170: performance grade: 6, 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 material (grade): 30CrMo, 35CrMo, 0Cr18Ni9, 0Cr17Ni12Mo2, A194 8, A193 b8m and A194 7 suitable for low temperature and high pressure environment; nominal pressure: ≤ class2500 (pn420). The applicable temperature is the same as the stud material.


2、 Hg / T 20613-2009 fasteners for steel pipe flanges - (PN Series). This standard replaces the old edition of 1997 and adds more new contents with reference to ASTM or ASME standards.


1. Hexagon head bolt for pipe flange: its type and size meet the requirements of gb5782 (coarse thread) and gb5785 (fine thread), and the end of bolt is chamfered end. Performance grade: 5.6, 8.8, a2-50, a4-50, A2-70, a4-70. Performance grade: 5.6, 8.8, a2-50, a4-50, A2-70, a4-70; nominal pressure: ≤ PN16; applicable temperature: - 196 - + 400 ℃.


2. Equal length double head stud for pipe flange: its type and size meet the requirements of gb901, and both ends of the stud are chamfered. Performance grade (commercial grade): 8.8, a2-50, a4-50, A2-70, a4-70. Nominal pressure: ≤ PN40; applicable temperature: - 196 - + 400 ℃.


3. Full stud for pipe flange: thread size and tolerance as well as chamfering at both ends shall be in accordance with GB / t901.


Nominal pressure: ≤ pn160; selected 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 ℃), a453660 (- 29-525 ℃), and A320 suitable for low temperature and high pressure environment L7(-100—340℃)。


4. Nut:


A. The type of nut used with hexagon bolt and stud shall meet the requirements of gb6170 and gb6171.


Performance grade: 6, 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 with full thread stud shall comply with the requirements of gb6175 and gn6176.


Optional: 30CrMo, 35CrMo, 0Cr18Ni9, 0Cr17Ni12Mo2, a1948, A193 b8m and a1947 suitable for low temperature and high pressure environment; nominal pressure: ≤ pn160. The applicable temperature is the same as the stud material.


3、 SH 3404-96 fasteners for pipe flanges.


SH 3404-96 fastener series for pipe flange. There are hexagon head bolt, equal length double head stud, full thread stud and nut.


1. The type and size of hexagon head bolt are large hexagon head bolt.


2. Equal length double head stud and full thread stud for pipe flange: thread size and tolerance and chamfer at both ends shall be in accordance with GB / t901 class B.


3. Nut: divided into I-type nut and II type nut.


Fastener materials (grades) are available: BL3 (- 20 - + 300 ℃), BL2 (- 20 - + 300 ℃), 35 ᦇ (- 20 - + 350 ℃), 25 ᦇ (- 20 - + 350 ℃), 40Cr (- 20 - + 400 ℃), 35CrMoA (- 100 - + 500 ℃), 25Cr2MoVA (- 20 - + 550 ℃), 0Cr19Ni9 (- 196 - + 700 ℃), etc.


4、 ASTM A193 / a193m-2009 alloy steel and stainless steel bolt materials for high temperature equipment. There are many grades in this standard, commonly used are: gr.b6, B7, b7m, B8, b8m, b8-2, b8m-2, B16, etc.


The suitable temperature of gr.b6, B7, b7m, B8, b8m, b8-2 and b8m-2 is ≤ 525 ℃;


Suitable temperature of gr.b16 grade: ≤ 600 ℃.


5、 ASTM A194 / a194m-2009 carbon and alloy steel bolts and nuts for high temperature and high pressure service. There are many grades in this standard, commonly used are: gr.2h, 2hm, 4, 6, 7, 7m, 8, 8m, etc.


6、 ASTM A453 / a453m-2008 high temperature resistant bolt materials with expansion coefficient similar to austenitic steel and yield strength of 50-120ksi (345-827mpa). The common grades are: gr.660a, 660B, etc.


7、 ASTM A182 / a182m-2007 forged or rolled alloy steel and stainless steel flanges, forged fittings, valves and components for high temperature service. Fasteners are usually F51, F53, F55, etc.


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