Аннотация:Seals for flange couplings in chemical and petrochemical industries are often manufactured from graphites and its composites. These materials are characterized by unique properties such as low density, high elasticity, resistance in many aggressive media etc. Mathematical models of properties of the models have been developed. Modulus of elasticity and conditional modulus taking into account elastic and plastic deformation during compression have been described. Relaxation of the materials has been discussed. Decrease in value of load on gasket has been evaluated. Computational values have been determined for GRAFLEX material and are suitable for other materials.