By methods of sclerometry (with registration of acoustic emission) and amplitude-independent internal friction the change of substructure and rheological and strength properties of carbon steel after heat treatment (hardening + tempering) and subsequent finishing-hardening friction treatment (abrasive grinding + polishing) has been investigated. Significant differences have been established in the change in the strength, rheological, and dissipative properties of martensite from the properties of medium and high tempered structures formed by friction processing. It is shown that, in contrast to highly tempered steel after abrasive impact, the degree of hardening of hardening of quenched martensite increases with increasing strain rate in scratch testing, indicating a different mechanism of strain hardening of these structures under friction treatment conditions. Exceptionally high acoustic-emission activity of hardening martensite (to 20 µm) caused by hardening treatment, as well as the rapid growth of the temperature background of internal friction, is due to the formation of ultradisperse (nanocrystalline) structure, which is characterized by high contact strength and relaxation capacity. Additional hardening of quenching martensite in the process of friction treatment, accompanied by an increase of relaxation resistance is caused by dynamic strain aging and dynamic stress tempering. The less pronounced acoustic-emission activity and low level of internal friction of tempering martensite (Ttemp = 200°C) indicate an increase in the elasticity of the structure with a decrease in the relaxation capacity, the level of which was stably maintained with a change in the speed of friction treatment. Highly tempered steel (Ttemp = 600°C) undergoes mechanical work hardening due to friction-activated surface plastic deformation, which is accompanied by a rapid decrease in dissipative (relaxation) capacity with the transfer of fracture processes under the friction surface. The analysis of experimental data is carried out in the context of the problem of creating wear-resistant materials, which at high strength should also have sufficient relaxation (damping) capacity.