The regularities of the phase and structural transformations during decarburization of a high-carbon Fe–V–C alloy are studied. The eutectic $L$ → $\gamma$ + VC transformation is established by the geometric thermodynamics method and metallographic analysis. This transformation is accompanied by a diffusion redistribution of the carbide-forming elements ahead of the crystallization front. Decarburization in a liquid–solid state allows forming a favourable structure with VC fibres oriented perpendicularly to the surface in the near-surface zone. Structural changes, which occur under deformation in a liquid–solid state, in preliminary decarburized synthetic vanadium-containing cast iron are investigated. The regularities of structure formation in various diffusion zones during subsequent carburization are revealed. As shown, the subsequent carburization of a pre-decarburized Fe–V–C alloy under special conditions makes it possible to obtain a natural composite with high wear resistance in the surface layer. Secondary hardness and heat resistance of carbonized layer of vanadium-containing cast iron deformed in a liquid–solid state after the final heat treatment are studied.