Abstract:The contact characteristics of end-face in the carbon graphite and tungsten carbide matched mechanical seal under dry operating condition were investigated. Taking account of the effects of the material properties of the seal ring and the mating ring, interaction between the end faces of contact asperities, direction of friction motion and frictional heat-flow, a three-dimensional thermo-mechanical coupling model of rotational friction between a rough entity and a smooth rigid entity was established. The instantaneous dry friction processes were numerically simulated by the ABAQUS finite element analysis software. The results showed that the true contact area of the rough face increased approximately linearly with the increase of the external load. Moreover, with the increase of external load and sliding velocity, the maximum contact pressure of the rough face was maintained in the range of 415～432 MPa, which is “self-limiting”. The temperature distribution on the sealing end face was uneven, the increase of external load and velocity will lead to the increase of the overall temperature of the end face. The position of the maximum temperature on the rough surface was affected by the local contact pressure, the local sliding velocity and the local heat transfer. It is necessary for the containment seal in API682 that the medium pressure should be less than or equal to 0.07 MPa, which could prevent the temperature rise of the sealing ring from being too high during dry friction. The studies provides a reference for exploring the thermal damage, friction and wear problems of the end faces of a mechanical seal, and may help the design of the mechanical seal under dry operating condition.