Abstract: An improvement to the sealing ring of U.S. Pat. No. 4,085,951 is disclosed, wherein the sealing ring is of a special design including an in situ sealing flange generating corner, and the stepped thread pin and box members have been modified in the shoulder areas between the thread sections thereof to provide a pressure transmitting area for transmitting torque to the ring, and to provide room for the in situ sealing flange to form and extend beyond the faces of the improved ring.With the improved design, the sealing ring is capable of retaining hot gases or liquids with a pressure differential in at least a given direction across the sealed joint exceeding the yield pressure of the rubber or plastic of which the ring is made.