Ring joint gaskets (RTJ) are designed for high pressures and depending on the profile of the ring they are able to seal up the working pressure up to 1500 bar and temperatures up to 1000 °C.
Due to a small contact/sealing surface (metal/metal) and a suitable composition of materials, the contact surfaces of the flange together with the correct choice of the gasket material the ring joint gaskets provide an excellent tightness of the joints.
Ring joint gaskets are offered in two basic profiles: oval - KT 21-R, or octagonal - KT 31-R.
For higher pressures from 700 to 1500 bar, we recommend applying types KT 51-RX and KT 61-BX.
To ensure a good sealing effect of the ring joint gaskets it is necessary to pay close attention to the surface treatment at the point of the contact of the ring and the contact surface of the flange.
In case of leaks and the impossibility to seal up the flange joint using RTJ we can offer a solution by means of the VCS system (Very Critical Services).
Standard profiles shapes
RTJ KT 11
circular cross section
RTJ KT 21-R
oval cross section
RTJ KT 31-R
octagonal cross section
RTJ KT 41-L
lens cross section
RTJ KT 51-RX
octagonal cross section with spec. shape
RTJ KT 61-BX
octagonal cross section with hole
STANDARD METAL MATERIALS
| material | AISI / ASTM | specification acc. to EN 10027-1 | specification acc. to EN 10027-2 | BS | ČSN/CZ | temperature (°C) | hardness | density | ||
| min | max | max HB | max HV | (g/cm3) | ||||||
| carbon steel | 238-C | RSt. 37.2 CS | 1.0038 | D/40B | 11 375 | -40 | +500 | 90 | 56 | 7,85 |
| low carbon steel | - | M2 / ARMCO | 1.1003 | S/LCS | - | -60 | +500 | 120 | 68 | 7,85 |
| F5 (5Cr 1/2 Mo) | A182-F5 | 12CrMo 195 | 1.7362 | - | - | -40 | +650 | 130 | 72 | 7,83 |
| stainless steel | 304 | X5CrNi 18 10 | 1.4301 | 304S 15/16/31 | 17 240 | -250 | +550 | 160 | 83 | 7,9 |
| stainless steel | 304L | X2CrNi 19 11 | 1.4306 | 304 S11 | 17 249 | -270 | +550 | 160 | 83 | 7,9 |
| stainless steel | 309 | X15CrNiSi 20 12 | 1.4828 | 309 S24 | 17 251 | -110 | +1000 | 160 | 83 | 7,9 |
| stainless steel | 316 | X5CrNiMo 17 12 2 | 1.4401 | 316 S31/33 | 17 346 | -200 | +550 | 160 | 83 | 7,9 |
| stainless steel | 316L | X2CrNiMo 18 14 3 | 1.4404 | 316 S11/13 | 17 349 | -200 | +550 | 160 | 83 | 7,9 |
| stainless steel | 316Ti | X6CrNiMoTi 17 12 2 | 1.4571 | 320 S31 | 17 348 | -270 | +550 | 160 | 83 | 7,9 |
| stainless steel | 321 | X6CrNiTi 18 10 | 1.4541 | 321 S12/49/87 | 17 247 | -270 | +550 | 160 | 83 | 7,9 |
| stainless steel | 347 | X10CrNiNb189 | 1.4550 | 347S31 | - | -250 | +500 | 160 | 83 | 7,9 |
| stainless steel | 410 | X6Cr13 | 1.4000 | 410S21 | 17 020 | -20 | +850 | 170 | 86 | 7,8 |
DIMENSIONS
| RTJ style | standards for RTJ used with flanges | |
| RTJ standard | flange standard | |
| R | ASME B16.20 / API 6A / ISO 7483 | ASME B16.5 / ASME B16.47-A / BS 1560 / MSS-SP44 / API 6A/6B / ISO 7005 |
| RX | ASME B16.20 / API 6A | ASME B16.5 / BS 1560 / MSS-SP44 / API 6B / ISO 7005 |
| BX | ASME B16.20 / API 6A | API 6A-6BX |
Table of recommended Seating stress
| material | recommended seating stress at 20°C | |||
| AISI/ASTM | min (N/mm2) | opt (N/mm2) | max (N/mm2) | |
| carbon steel | D | 235 | 350 | 525 |
| low carbon steel | LCS/S | 265 | 400 | 600 |
| A182 F5 | A182 F5 | 400 | 600 | 900 |
| stainless steel | 304 | 335 | 500 | 750 |
| stainless steel | 316 | 335 | 500 | 750 |
| stainless steel | 321 | 335 | 500 | 750 |
| stainless steel | 347 | 335 | 500 | 750 |