Ring Joint Gasket 
A solid metal gasket that is softer than the mating flange material that is virtually ‘crushed’ into the flange face, creating a seal by filling imperfections and leak paths with gasket material. Under high sealing stress the gasket deforms but not the flange. They are used predominantly in the petrochemical industry (offshore oil platforms, refineries) due to the high service pressures required in their processes. Ring joint gaskets are machined to exact specifications and tight tolerances and come in a number of styles.

Ring Joint Gasket Styles
R        Oval or octagonal
RX     Self-energizing gasket
BX     Used in API spec 6A flanges
Materials
Common materials used for the manufacture of ring joint gaskets:
·Soft Iron
·Low Carbon Steel
·Stainless Steel
·Monel®
·Inconel®
·Incoloy®
·Hastelloy®
Hardness of Materials
On compression of the flange assembly, it is imperative that the ring joint gasket be significantly softer than the flange groove so that the gasket plastically deforms and not the groove. The use of harder ring joint gaskets can result in flange groove damage.
For this reason, ring joint gaskets are supplied with the following maximum hardness values:

R Style Ring Joint Gaskets
The type R oval configuration is the original ring joint design followed by the type R octagonal.
Both styles are interchangeable on the modern flat bottom groove, however only the oval style can be used in the old type round bottom groove.
Style R ring type joints are designed to seal pressure up to 6,250 psi in accordance with ASME B16.5 pressure ratings and up to 5,000 psi in accordance with API 6A pressure ratings.

Nominal Pipe Size1/2 – 24 inch26 – 36 inch26 – 36 inch1-1/2 – 20 inch

Class and Standard150 – 2500 ASME B16.5 and BS1560300 – 600 MSS SP44 and BS3293900 MSS SP44API Spec. 6A

Tolerances

Series 'R' manufactured to the standards ASME B 16.20 - API Spec. 6A BS EN 12560-5
Dimensions in inch

Series 'R' manufactured to the standards ASME B 16.20 - API Spec. 6A BS EN 12560-5
Dimensions in inch

Series 'R' manufactured to the standards ASME B 16.20 - API Spec. 6A BS EN 12560-5
Dimensions in inch

RX Style Ring Joint Gaskets
The Style RX ring type joint is manufactured in accordance with API 6A and ASME B16.20, to suit API 6B and ASME B16.5 flanges.
The Style RX is designed to fit the modern flat bottom groove, and is interchangeable with the standard Style R ring type joint. However, since the Style RX is significantly taller than a Style R, larger flange make up distances will result.
Style RX ring type joints are designed to seal pressures up to 6,250 psi in accordance with ASME B16.5 pressure ratings, and up to 5,000 psi in accordance with API 6A pressure ratings. Selected sizes incorporate a pressure passage hole to allow for pressure equalization each side of the sealing faces.

Nominal Pipe Size1-1/2 – 20 inch

Class and Standard720 – 5000 API 6B Flanges

Tolerances

A ---------------- + 0.008, - 0.000
H ---------------- + 0.008, - 0.000
OD -------------- + 0.010, - 0.000
C ---------------- + 0.006, - 0.000
D ---------------- + 0.000, - 0.030
E ----------------± 0.02
23o ------------ ± 1/2o
　
　


 
Series 'RX' manufactured to the standards ASME B 16.20 - API Spec. 6A
Dimensions in inch

Series 'RX' manufactured to the standards ASME B 16.20 - API Spec. 6A
Dimensions in inch

BX Style Ring Joint Gasket
The Style BX ring type joint is manufactured in accordance with API 6A.
All BX ring type joints incorporate a pressure passage hole to allow for pressure equalization each side of the sealing faces. On assembly, metal to metal contact of the flange faces is achieved. The Style BX is not interchangeable with any other style, and is only suited for API 6BX flanges. Style BX ring type joints are designed to seal pressure up to 20,000 psi in accordance with API 6A pressure ratings.

Nominal Pipe Size1-11/16 – 21-1/4 inch

Class and Standard5000 – 20000 API 6BX Flanges

Tolerances

A ---------------- + 0.008, - 0.000
H ---------------- + 0.008, - 0.000
D --------------- ± 0.02
OD -------------- + 0.000, - 0.005
ODT ----------- ± 0.002
C ---------------- + 0.006, - 0.000
23o ------------ ± 1/4o
　
 
　


 


Series 'BX' manufactured to the standards ASME B 16.20 - API Spec. 6A
Dimensions in inch

Ordering Information
When ordering ring joint gaskets please specify the following:
●Gasket style and number
●Material
●Nominal pipe size and pressure rating or specific gasket dimensions if other than standard