Octagonal ring

Octagonal metal ring gasket

The metal ring pad is made of metal material by forging and heat treatment and machining into cross section shape is the entity of octagon metallic gasket, have radial since the tight sealing effect, is a standard type R a kind of metal ring gasket, its action principle is cushion for leaning on is with flange type ladder groove (mainly the lateral) out of contact, and through the pressure sealing function to form.

Octagonal metal ring gasket installed inside a ladder type ring groove on the surface of the flange, when screw down the connecting bolt, the axial compression and up and down the ladder type slot 1, produce plastic deformation, forming a ring seal belt, establish the initial seal.After booster, under the action of medium pressure, make the ring gasket radial expansion.Gasket with trapezoidal groove cant post more tightly, self-tightening effect.Medium pressure increases, however, also can make the flange and the connecting bolt deformation, caused by a relative separation between the sealing surface, gasket seal than relative decline, thus, ring gasket can be thought of as a half since the tight closure.

Octagonal metal ring gasket mainly match with flange groove is surface contact, compared with the oval ring gasket though with flange groove or not easily, but it can be used again, and because of the cross section is made up of straight line easy processing.At the same time choose octagonal metal ring gasket material should be lower than the flange surface hardness 15 ~ 20 hb.

The cushion performance of the octagonal metal ring features:

1, high temperature resistant, resistant to high pressure, suitable for high pressure flange;
2, reliable sealing persistent;
3, to adapt to the working conditions of pressure and temperature fluctuations;

Octagonal metal ring gasket application: usually used in high temperature and high pressure steam, gas, solvent tube flange, tank, pressure vessel, the joint surface, high temperature and high pressure valve, the cover.Oil and gas industry in wellhead sealing and oil extraction tree.

Metal ring gasket first comes from the United States, in the 1920 s, the first to use in boiler, then used for manhole cover, autoclave other Windows sealed, later in the oil production and refining industry particularly valued.With the increase of temperature and pressure of the steam power plant, metal ring gasket have been used more and more widely.

Metal ring gasket main structural forms:

R type ellipse pad, standard elliptic pad is applied to the metal ring grooves of the flange.

R octagon gasket, octagon standard metal ring gasket used in standard grooves of the flange.

RX octagon gasket type, the pressure of up to 700 bar outside the first used when using this gasket sealing surface contact with flange, the base of the high pressure system will produce a high stress.RX type metal ring cushion can and standard R type ring gasket swaps.

BX type octagon gasket, resistance to high pressure (up to 1500 bar) type BX gaskets by enhancing flange gasket on the surface of the base contact pressure and the internal system to seal control myself.This gasket is suitable for the API BX flange and tenon groove.

Octagonal metal ring gasket material selection:

material Maximum hardness mark Temperature ℃
Brinell HB Rocknell HB Min Max
Soft Iron 90 56 P - 40 540
Low C/S 120 68 S - 60 500
SS410 170 86 S410 - 40 850
SS304 160 83 S304 - 250 540
SS316 160 83 S316 - 200 815
SS347 160 83 S347 - 200 870
4-6%Cr,0.5% Mo, 130 72 F5 - 40 650
Copper 80 -- C - 100 315
Aluminum 35 -- A - 200 425
Inconel 600 150 78 Y - 100 1095
Inconel 825 150 78 W - 100 1095
Monel 400 150 78 M - 100 760
Titanium 215 77 T - 200 540
Nikel 200 110 58 N - 200 760
Hastelloy B2 230 121 X1 - 100 1095
Hastelloy C276 210 110 X2 - 100 1095

The size of the octagonal metal ring gasket limit deviation:

Name of size Generation of no. Limit deviation
Ring pad pitch diameter P + / - 0.18
The width of the ring gasket A + / - 0.20
The height of the ring gasket H Plus or minus 0.4 creates
Octagonal ring cushion bottom width C + / - 0.2
23 ° Angle Plus or minus 0.5 °
Radius of ring gasket R + / - 0.4
1) as long as the ring gasket height difference of any two points less than 0.4 mm ring gasket for the tolerances of the height (H) + 1.2 mm

Octagonal metal ring gasket main performance parameters:

Coefficient of gasket
Gasket using pressure ≤42MPa
Gasket using temperature - 196 ℃ ~ 1000 ℃
Than the minimum preload pressure y=126.6-182.8MPa

Octagonal metal ring gasket technology standards:

Can provide any size of standard and non-standard, including API 6 a, ASME B16.20, DIN 2693-67, JPI - 7-23-72 - s, and other standards.

Domestic relevant standards:

GB/T 9130-1988 | steel pipe flange connection with metal ring gasket technology conditions
GB/T 9128-2003 | steel pipe flange with metal ring pad size
GB/T 9128.2 1988 | steel pipe flange connection with oval metal ring gasket
GB/T 9130-2007 | steel pipe flange with metal ring gasket technology conditions
JB/T 89-1994 | pipe flange with metal ring gasket
HG 20612-1997 | steel pipe flange with metal ring gasket system (Europe)
HG 20633-1997 | steel pipe flange with metal ring gasket (system) of America
SH, 3403-1996 | tube flange with metal ring gasket
Does the actual application condition is complex, the above parameters are for reference only do not make any guarantee is requested.

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