The invention relates to a process for manufacturing a single part for a turbomachine by diffusion welding. The process comprises steps consisting in: producing a blank of the part around a mandrel (12), the blank comprising a plurality of independent superposed coaxial annular ring layers (10) made of metal wire, the layers being stacked one on top of the other around the mandrel; and subjecting the blank to an isostatic hot compression so as to obtain the single part; and optionally machining this part.