1. To obtain a fine and uniform austenitic grain size in hardening of hydroextruded steels, a post-deformation temper at 500°C is recommended. After hydroextrusion with large degrees of deformation (">30%), heating to temperatures close to the Ac1 point (750°C) with short holds (5–10 min) may be used. 2. An increase in the degree of deformation in hydroextrusion of high-speed steels leads to weakening of the relationship of austenitic grain size to the post-deformation heat-treatment cycle.