RING TYPE JOINT
TYPE R OCTAGONAL
A number of ring joint styles are available designed for specific flange types:
- NB1/2” to 24” Class Rating150 to 2500B ASME B16.20
- NB26” to 36” Class 300 to 900 ASME B16.20 Series A
- NB1 1/2” to 20” Class API 6A
Applications:
- Used for high pressure applications.
Typical Properties:
- High integrity seal at high pressures.
- The octagonal cross section has a higher sealing efficiency than the oval and would be the preferred gasket.
- Suitable for flat bottom groove flanges.
- Available in Ring numbers R11 to R105.
Common Materials
| Material | Brinell Hardness | Temperature limitations | Identification | |||
| Soft iron | 90 | -60 to +400⁰C | D | |||
| Low carbon steel | 120 | -40 to +500⁰C | S | |||
| 4%-6% Cr 1/2% Mo: F5 | 130 | -125 to +500⁰C | F5 | |||
| Stainless steel 304 /304L | 160 | -250 to +650⁰C | S304 or 304L | |||
| Stainless steel 316 /316L | 160 | -196 to +800⁰C | S316 or 316L | |||
| Stainless steel 321 | 160 | -250 to +870⁰C | S321 | |||
| Stainless steel 347 | 160 | -250 to +870⁰C | S347 | |||
| Stainless steel 410 | 170 | -20 to +500⁰C | D9S410 | |||
| Inconel 625 | – | 1000⁰C | 625 | |||
| Incoloy 825 | – | 1000⁰C | 825 | |||
| Hastelloy C-276 | – | 1000⁰C | C-276 | |||
| Duplex | – | 800⁰C | S31803 | |||
| Titanium | – | 540⁰C | TI | |||
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.