The viscoplastic properties of microalloyed medium carbon steel 38G2F specimens subjected to quenching from 900°C and tempering at 650°C followed by cooling in various media are studied by analyzing the results of tensile and impact bending tests. The parameters controlling metal embrittlement during room-temperature tests are found for the stages (periods) on stress–strain and impact bending curves. Based on the revealed correlations between the parameters of static and dynamic tests (between true stress Sf, impact toughness KCV, and relative reduction of area φf to failure and static fracture toughness a), we proposed a new approach for estimating the viscoplastic properties of steels in various structural-phase states.