Ring Type Joint Flange is a method of ensuring leak proof flange connection at high pressures. A metal ring is compressed into a hexagonal groove on the face of the flange to make the seal. This jointing method can be employed on Weld Neck, Slip-on and Blind Flange.
Standards, Dimensions & Weight
- Dimensions of Ring Joint Facings
- Ring Joint Facings ASME/ANSI B16.5 & B16.47-1
- Ring Joint Facings ASME/ANSI B16.5 & B16.47-2
- Ring Joint Facings ASME/ANSI B16.5 & B16.47-3
- Ring Joint Facings ASME/ANSI B16.5 & B16.47-4
Specifications:
- Size: 1/2” to 60”, DN 12mm to DN 1500mm
- Pressure class: Class 150 to Class 2,500, PN 2.5 to PN 250
- Facing: RF / RTJ
Material:
- Cabon steel: A105, A350 LF2
- Stainless steel: A182 F304/F304L/F316/F316L/F321
- Alloy steel: F11, F12
- Packing: plywood case and plywood pallet
Q&A:
What is ring joint flange?
A Ring Type Joint Flange is a type of flange that uses a metal ring that sits in a hexagonal groove as a gasket to seal the flange pair. The flanges seal when the bolts are tightened and the gasket is compressed into the groove making a metal to metal seal. An RTJ flange usually has a raised face with the groove machined into the face of the flange. The raised face doesn’t serve as a way to contain the pressure.
What is RTJ flange?
RTJ flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or "Coining") the gasket to make Intimate Contact inside the grooves, creating a metal to metal seal. An RTJ flange may have a raised face with a ring groove machined into it.
What is RF flange?
The Raised Face flange is the most common type used in process plant applications, and is easily to identify. It is referred to as a raised face because the gasket surfaces are raised above the bolting circle face.
Ring-Type Joint (RTJ)
The Ring Type Joint flanges are typically used in high pressure (Class 600 and higher rating) and/or high temperature services above 800°F (427°C). They have grooves cut into their faces which steel ring gaskets. The flanges seal when tightened bolts compress the gasket between the flanges into the grooves, deforming (or Coining) the gasket to make intimate contact inside the grooves, creating a metal to metal seal.
An RTJ flange may have a raised face with a ring groove machined into it. This raised face does not serve as any part of the sealing means. For RTJ flanges that seal with ring gaskets, the raised faces of the connected and tightened flanges may contact each other. In this case the compressed gasket will not bear additional load beyond the bolt tension, vibration and movement cannot further crush the gasket and lessen the connecting tension.
Ring Type Joint flange
Ring Type Joint gaskets are metallic sealing rings, suitable for high-pressure and high-temperature applications. They are always applied to special, accompanying flanges which ensure good, reliable sealing with the correct choice of profiles and material.
Ring Type Joint gaskets are designed to seal by "initial line contact" or wedging action between the mating flange and the gasket. By applying pressure on the seal interface through bolt force, the "softer" metal of the gasket flows into the microfine structure of the harder flange material, and creating a very tight and efficient seal.
Ring Type Joint gaskets
Most applied type is style R ring that is manufactured in accordance with ASME B16.20 used with ASME B16.5 flanges, class 150 to 2500. Style "R" ring type joints are manufactured in both oval and octagonal configurations.
The octagonal cross section has a higher sealing efficiency than the oval and would be the preferred gasket. However, only the oval cross section can be used in the old type round bottom groove. The newer flat bottom groove design will accept either the oval or the octagonal cross section.
The sealing surfaces on the ring joint grooves must be smoothly finished to 63 Microinches and be free of objectionable ridges, tool or chatter marks. They seal by an initial line contact or a wedging action as the compressive forces are applied. The hardness of the ring should always be less than the hardness of the flanges.
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.
What is a stub flange?
Flanged joints in pipelines are used to create a demountable joint for future disassembly to connect valves and vessels, where strength in tension is required or to joint to other materials. ... A range of Stub Flanges are available incorporating a PVC backing ring.
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| ASTM A182 Ring Type Joint Flanges |
ASTM A182 is a martensitic stainless steel. The additions of Nickel and Molybdenum, which gives it excellent sub zero notch ductility, superior to other standard 13 Cr, 410 and 420 Mod martensitic stainless steels.
UNS S41500 steel is air hardening, with little danger of thick sections cracking during heat treatment.
In addition to limiting the maximum hardness allowed to 23 HRC max, NACE MR0175 imposes heat treatment temperature restrictions.
The weldability and corrosion resistance of ASTM A182 are also excellent, being extensively used in the manufacture of Valve Bodies, Flanges, Seats, Gates, Tubulars, etc.
ASTM A182 specifies a minimum 0.2 PS value of 95 KSI. This NACE approved grade is limited to 75 KSI because of the hardness restriction.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
Chemical Requirements of ASTM A182 material (Composition, %, max)
| Symbol | C | Mn | P | S | Si | Ni | Cr | Mo |
| F304 | 0.08 | 2 | 0.045 | 0.03 | 1 | 8.0-11.0 | 18.0-20.0 | _ |
| F304L | 0.03 | 2 | 0.045 | 0.03 | 1 | 8.0-13.0 | 18.0-20.0 | _ |
| F316 | 0.08 | 2 | 0.045 | 0.03 | 1 | 10.0-14.0 | 16.0-18.0 | 2.00-3.00 |
| F316L | 0.03 | 2 | 0.045 | 0.03 | 1 | 10.0-15.0 | 16.0-18.0 | 2.00-3.00 |
| F321 | 0.08 | 2 | 0.045 | 0.03 | 1 | 9.0-12.0 | 17.0-19.0 | _ |
Note: composition of Cu, N, V, Co are none or few.
Mechanical Requirements of ASTM A182 material
| Material Symbol | Tensile Strength min, MPa | Yield point min, Mpa | Elongation min, % | Reduction of area min, % |
| ASTM A182 F304 | 515 | 205 | 30 | 50 |
| ASTM A182 F304L | 485 | 170 | 30 | 50 |
| ASTM A182 F316 | 515 | 205 | 30 | 50 |
| ASTM A182 F316L | 485 | 170 | 30 | 50 |
| ASTM A182 F321 | 515 | 205 | 30 | 50 |
