This standard specifies the type, size and technical conditions of octagonal and elliptical metal ring gaskets for steel pipe flanges (European system). This standard is applicable to metal ring gaskets for ring-joined neck-welded steel pipe flanges and integral steel pipe flanges with a nominal pressure PN of 6.3 MPa (63 bar)-25.0 MPa (250 bar) as specified in HG 20592. HG 20612-1997 Metal Ring Gaskets for Steel Pipe Flanges (European System) HG20612-1997 Standard Download Decompression Password: www.bzxz.net

Metal ring gaskets for steel pipe flanges
(European system)
HG 20612—97
, subject content and scope of application
This standard specifies the types, sizes and technical provisions of octagonal and round metal ring gaskets for steel pipe flanges (European system). This standard is applicable to metal ring gaskets for ring-joined neck butt-welded pipe flanges and integral steel pipe flanges with a nominal pressure PN of 6.3MPa (63bar) to 25.0MPa (250bar) as specified in HG20592. 227
GB1220
HG20592
JB4726~-4728
Referenced standards
Technical conditions for high-quality carbon structural steel
"Stainless steel bars"
"Steel pipe flange types, parameters (European system)\&Forged steel parts for pressure vessels"
3 Gasket use conditions
The maximum operating temperature of F is specified in Table 31. Table 3-1 Gasket
The maximum operating temperature of gaskets
Tree shaking
10 or 08
OCr18Ni9
oCr17Ni12Mo2
GB 1220wwW.bzxz.Net
Most commercial temperature,
Gasket type and size
Metal ring gaskets are divided into octagonal and elliptical metal ring gaskets according to the shape of the knocking surface, as shown in Figure 4.0.1, octagonal gasket
Elliptical gasket
Figure 4.01 Type of gasket
4.0.2 The dimensions of octagonal and elliptical metal ring gaskets shall be in accordance with the provisions of Table 4.0.2. RA/2
4.0:3 The gasket dimensions listed in Table 4.0.2 are applicable to steel pipe flanges of the two steel pipe outer diameter series A and B listed in HG20592.
Tai 402
Dimensions of octagonal and elliptical metal ring gaskets PN6.3MPa(63har)
Octopagonal
Ring plane
Continued Table 4. 0. 2
PN16.oMPs(160bar)
Octagon
Oval
FN25.OMPat2EGhar)
Octagon:Oval
Ring plane
Ring plane
"Technical requirements
5.0.1 The hardness value of the metal ring gasket material shall be 3040HB lower than that of the flange material, and its maximum value shall not exceed the provisions of Table 5.0.1.
5.0.2 The hardness of the metal ring gasket shall be uniform and measured over the entire circumference. The average hardness of the four symmetrical parts shall comply with the provisions of Table 5.0.1.
Table 5. 0. 1
10 or 0%
CCr18Ni9
OCri7Ni12M2
Hardness value of metal ring gasket materials
10 or 08
Maximum hardness value (HB)
Metal ring gaskets should be made of forgings after appropriate heat treatment and machining. Forgings should meet the requirements of 15.0.3
grade of JB4726~4728. Metal ring gaskets are not allowed to be welded. 5.0. 4
The limit deviation of the metal ring gasket shall be as specified in Table 5.0.4. Table 5.0.4
Pitch diameter P
Broken width A
Ring height H or
Environmental impact surface width C
Angle 23°
Corner radius
Dimensional limit deviation of metal ring gasket
Limit deviation
±0.40r-1
Note: As long as the height difference between any two points of the metal broken gasket does not exceed 0.4mm, the limit deviation of the ring quotient B or H may be +1.2mm. 5.0.5 The sealing surface of the metal ring gasket (the inclined surface of the angled gasket or the arc surface of the circular gasket) shall not have scratches, sulfur marks, cracks and defects, and the surface roughness shall not exceed Ral.6
5.0.6 The surface of the metal ring gasket made of 10 or 08 steel shall be coated with anti-rust oil after inspection. 232
Marking and packaging
6.0.1 The ring gaskets shall be packaged according to the type, specification and material, and shall be accompanied by a product quality inspection certificate when delivered, and the items specified in 6.0.2 shall be marked with a steel stamp on the outside of each metal ring gasket. 6.0.2 Marking content
（1）Standard number (HG20612):
(2)Nominal diameter (mm)
(3)Nominal pressure (（MPa)
（4)Material code (see Table 5.0.1).
6.0.3 Marking example
Octagonal metal ring gasket with nominal diameter of 100mm, nominal pressure of 10.0MPa (100bar), and material of 0Cr18Ni9, is marked as:
HG20612
Octagonal gasket
Additional instructions: Proposer, editor and main drafter of this standard Proposer: Equipment Design Technology Center Station, Ministry of Chemical Industry Chemical Process Piping Design Technology Center Station, Ministry of Chemical Industry Editor: Equipment Design Technology Center Station, Ministry of Chemical Industry Main drafter: Ying Daoyan Yu Jun
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