The formation of the structure of the metal matrix of wear-resistant cast irons and its effect on their mechanical properties are investigated. As found out, it is useful to add 0.15–0.20% Ti and 0.15–0.25% of rare earth metals at the final stage of melting (after additive) in order to improve the structure, to neutralize the influence of harmful impurities, and to enhance wear resistance of the cast irons, which contain chromium and manganese. Enhanced hydroabrasive wear resistance of the parts of some mechanisms of thermal-power plants is achieved by reduced content of such alloying elements as chromium and manganese that increases the service life. It is recommended to use chromium–manganese cast irons with a manganese content of up to 2.5–2.7% for the fabrication of cast wear-resistant parts, and to heat treatment such cast irons with careful selection of the optimal austenitizing temperature and isothermal holding. The effect of isothermal annealing on reducing the hardness of chromium–manganese cast iron to 39–40 HRC to further facilitate machining of parts is presented.