In order to improve the service life of HAR rubber sealing rings,a new radial asymmetric flat sealing structure was proposed.Compared with the traditional symmetrical flat sealing ring,the radial asymmetric sealing contact area is smaller,thus reducing the heat and wear caused by the rotation of the inner ring moving sealing surface.By testing the properties of hydrogenated nitrile rubber (HNBR) and nitrile rubber (NBR),suitable rubber sealing ring materials were selected.The finite element models for radial asymmetric flat sealing rings and traditional symmetrical flat sealing ring were established,and the sealing performance of the two structures were compared.The sealing performance of radial asymmetric flat sealing rings was evaluated under different environmental pressures and temperatures,and on-site application verification was conducted.The simulation results show that the radial asymmetric flat sealing ring has higher contact stress and better sealing performance.Meanwhile,its Mises stress is significantly lower than that of traditional symmetrical flat sealing rings,proving that radial asymmetric flat sealing is more suitable for long-term stable operation.The on-site application results also verify that under high temperature and high pressure conditions,the sealing performance of the radial asymmetric flat sealing ring is reliable and has high practical value.