The concept of surface hardening of structural steels is proposed on the basis of the structural theory of strength and the Charpy principle at the macro-and microgeometric levels for the purposeful formation of a structure that can effectively resist wear and fatigue. An intellectual approach to the rational choice of technological combinations capable of maximally realizing the dislocation, substructural, grain-boundary, solid solution and dispersion mechanisms of steel hardening, which makes it possible to create optimal structures on the surface of tribo-interface elements, is described. As an example of such an approach, the surface laser alloying of structural steels with nitride-forming elements with subsequent nitriding was investigated; an increase in surface hardness, strength, wear resistance by 15 times and fatigue strength by 1.5 times compared with the initial parameters of steels was shown.