In article results of a research on hardening of rollers of rolling mills which is shaping tools working in extreme conditions are considered. Bringing the resultat the same time is of researches on brand 45 harden steel, particular importance, and relevance of development which consists in implementation in productions of the new materials received in the technological ways, in particular the materials providing the best combination of parameters of structure. It is shown that one of the main objectives of work was development of technology for hardening of the rollers of the rolling mill made of brand 45 steel. For the purpose of improvement of technical and utilization properties of an experimental roller of an input box of a cage of the rolling mill, it is developed the new modes of heat treatment of carbonaceous - the structural steels providing the best combination of parameters of structure, increasing their wear resistance during the work in extreme conditions.