Cr-Mo family steels are widely applied in the petrochemical industry, subjected to creep, may have their mechanical properties degraded in service, undergoing changes in their microstructure, therefore, understanding the heat treatment routes of these materials is of great relevance to good mechanical performance is obtained. This research aimed to investigate the influence of Quenching heat treatment on the microstructure and mechanical properties of the 2.25Cr-1Mo steel. For this, specimens were heated to 1,223 K in an argon atmosphere for 2 h and cooled in mineral oil. The microstructural characterization showed a predominance of the martensitic phase, XRD analyzes identified M 7 C 3 , M 23 C 6 and M 6 C carbides in the grain boundaries. Vickers microhardness tests showed that treated samples raised their hardness to 388 HV and tensile tests confirmed that the heat treatment optimized the mechanical performance of the steel at temperatures of 300, 773 and 873 K.