Ring Joint Gaskets

The oval cross section ring joint gasket was the first ring joint gasket initially standardized. Later developments resulted in other styles. If the RTJ flange was designed using the older version of the standard (round bottom groove), then it should be used only with oval ring joint gaskets. Octagonal section, for flat bottom flange grooves, is easier to install and its use is recommended for new applications. However either can be used with corresponding newer flat bottom grooves.

Style RX is a pressure-activated gasket. Its shape is designed to use the fluid pressure to increase the sealability. The outside sealing surface of the gasket makes the initial contact with the flange seating the gasket. As the internal pressure of the piping or equipment is increased, the contact pressure between gasket and flange also increases. High seating pressures are created increasing the sealability. This design characteristic makes this gasket style more resistant to vibrations, pressure surges and shocks that occur during oil well drilling. Style RX is interchangeable with oval and octagonal ring gaskets, using the same flange, if the flange groove is flat bottom.

Style BX gasket has a square cross section with beveled corners and is designed for use only in flanges API 6BX. Style BX is recommended for pressures from 5000 psi up to 20, 000 psi. The average diameter of the gasket is slightly greater than that of the flange groove. This way when the gasket is seated it stays pre-compressed by the outside diameter creating a high seating stress.

Ring joint gaskets are available in a wide range of materials, including exotic metals, depending on the application.

RTJ Material Hardness & Sizes

  • Material Hardness Conversion Scale
  • Material Hardness
  • Size Designations for Oval or Octagonal Rings
  • RX Gaskets for API 6B Flanges
  • BX Gaskets for API 6BX Flanges

 

Material Hardness Conversion Scale

Material Hardness Conversion Scale
Rockwell "B" Brinell 3000 Kg. Load Rockwell "B" Brinell 3000 Kg. Load
100 241 60 95
95 210 55 89
90 183 50 83
85 163 40 75
80 146 30 67
75 134 20 62
70 122 10 57
65 108    

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Material Hardness

Material Hardness
Material Designation Maximum Maximum
Hardness Hardness
Rockwell B Brinell
Soft Iron D 56 90
Low Carbon Steel S 68 120
4-6 Chrome F-5* 72 130
304 Stainless Steel S304 83 160
316 Stainless Steel S316 83 160
347 Stainless Steel S347 83 160
410 Stainless Steel S410 86 170

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Size Designations for Oval or Octagonal Rings

Size Designations for Oval or Octagonal Rings
Nominal Pipe Size Flange Pressure Rating
150# 300-600# 900# 1500# 2500#
1/2 - R-11 R-12 R-12 R-13
3/4 - R-13 R-14 R-14 R-16
1 R-15 R-16 R-16 R-16 R-18
1-1/4 R-17 R-18 R-18 R-18 R-21
1-1/2 R-19 R-20 R-20 R-20 R-23
2 R-22 R-23 R-24 R-24 R-26
2-1/2 R-25 R-26 R-27 R-27 R-28
3 R-29 R-31 (R-30 for lapped joint) R-31 R-35 R-32
3-1/2 R-33 R-34 - - -
4 R-36 R-37 R-37 R-39 R-38
5 R-40 R-41 R-41 R-44 R-42
6 R-43 R-45 R-45 R-46 R-47
8 R-48 R-49 R-49 R-50 R-51
10 R-52 R-53 R-53 R-54 R-55
12 R-56 R-57 R-57 R-58 R-60
14 R-59 R-61 R-62 R-63 -
16 R-64 R-65 R-66 R-67 -
18 R-68 R-69 R-70 R-71 -
20 R-72 R73 R-74 R-75 -
22 R-80 R-81 - - -
24 R-76 R-77 R-78 R-79 -
26 - R-93 R-100 - -
28 - R-94 R-101 - -
30 - R-95 R-102 - -
32 - R-96 R-103 - -
34 - R-97 R-104 - -
36 - R-98 R-105 - -

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RX Gaskets for API 6B Flanges

RX Gaskets for API 6B Flanges

API Ring Number

Sizes of Flange (Inches)

Gasket Weight lbs.

720-960 2000lbs.

2900- lbs.

3000- lbs.

5000- lbs.

RX20

1-1/2

-

1-1/2

1-1/2

0.527

RX23

2

-

-

-

1.15

RX24

-

-

2

2

1.33

RX26

2-1/2

-

-

-

1.42

RX27

-

-

2-1/2

2-1/2

1.5

RX31

3

-

3

-

1.73

RX35

-

-

-

3

1.91

RX37

4

-

4

-

2.09

RX39

-

-

-

4

2.27

RX41

5

-

5

-

2.54

RX44

-

-

-

5

2.72

RX45

6

-

6

-

2.96

RX46

-

-

-

6

3.66

RX47

-

-

-

8*

8.56

RX49

8

-

8

-

3.79

RX50

-

-

-

8

5.36

RX53

10

-

10

-

4.56

RX54

-

-

-

10

6.45

RX57

12

-

12

-

5.36

RX63

-

-

-

14

26.4

RX65

16

-

-

-

6.63

RX66

-

-

16

-

9.39

RX69

18

-

-

-

7.52

RX70

-

-

18

-

20.14

RX73

20

-

-

-

11.63

RX74

-

-

20

-

22.1

RX82

-

1

-

-

0.79

RX84

-

1-1/2

-

-

0.88

RX85

-

2

-

-

0.88

RX86

-

2-1/2

-

-

1.79

RX87

-

3

-

-

1.98

RX88

-

4

-

-

3.22

RX89

-

3-1/2

-

-

2.98

RX90

-

5

-

-

6.82

RX91

-

10

-

-

17.1

RX99

-

-

8*

-

3.31

RX201

-

-

-

1-1/4

0.25

RX205

-

-

-

1-3/4

0.3

RX210

-

-

-

2-1/2

0.75

RX215

-

-

-

4

1.5

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BX Gaskets for API 6BX Flanges

BX Gaskets for API 6BX Flanges

API Ring Number

Nominal Flange Bore (Inches)

Gasket Weight lbs.

2,000 psi

3,000 psi

5,000 psi

10,000 psi

15,000 psi

20,000 psi
               

BX-150

-

-

-

1-11/16

1-11/16

-

0.295

BX-151

-

-

-

1-13/16

1-13/16

1-13/16

0.337

BX-152

-

-

-

2-1/16

2-1/16

2-1/16

0.425

BX-153

-

-

-

2-9/16

2-9/16

2-9/16

0.632

BX-154

-

-

-

3-1/16

3-1/16

3-1/16

0.875

BX-155

-

-

-

4-1/16

4-1/16

4-1/16

1.22

BX-156

-

-

-

7-1/16

7-1/16

7-1/16

4.14

BX-157

-

-

-

9

9

-

6.55

BX-158

-

-

-

11

11

-

9.6

BX-159

-

-

-

13-5/8

-

-

14.41

BX-160

-

-

13-5/8

-

-

-

6.75

BX-161

-

-

16-3/4

-

-

-

10.437

BX-162

-

-

16-3/4

-

-

-

4.375

BX-163

-

-

18-3/4

-

-

-

14.375

BX-164

-

-

-

-

-

-

21

BX-165

-

-

21-1/4

-

-

-

18.375

BX-166

-

-

-

-

-

-

27.5

BX-167

26-3/4

-

-

-

-

-

18

BX168

-

26-3/4

-

-

-

-

24.5

BX-169

-

5-1/8

-

-

-

-

-

BX-170

-

6-5/8

-

-

-

-

-

BX-171

-

8-9/16

-

-

-

-

-

BX-172

-

11-5/32

-

-

-

-

-

BX-303

-

30

-

-

-

-

-

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