Pitch-based rigid monolithic felt: It is a product obtained by using isotropic pitch-based carbon fiber as a raw material, impregnated with resin with a high residual rate of graphitization, molding, and graphitizing and firing. Compared with other hard felts, it has better oxidation resistance, more prominent heat preservation effect, and can effectively reduce energy consumption. Graphite paper, carbon cloth and coating can be applied to the surface of the hard felt according to customer requirements.