Intramold Hadfield steel modification with different disperse modifiers containing boron, tungsten and titanium carbides, ferrotitanium and carbon as the active phase has been carried out. To improve the wettability, modifiers have been preliminary treated with copper powder in a planetary centrifugal mill. It has been revealed that the microstructure of steel samples produced contains austenite and carbides precipitating inside and along the grain boundaries. Considerable increase of tensile strength by 14.5, 18.0 and 9.0 % is characteristic for steel samples treated with modifiers containing boron carbide (active phase concentration – 0.056 %), mixture of tungsten and titanium carbides (0.033 %) and titanium carbide (0.083 %), correspondingly. Besides, the application of the mixture of tungsten and titanium carbides has allowed improving percent elongation by 40%. The application of modifiers containing boron carbide and mixture of tungsten and titanium carbides favours uniform distribution of carbides and considerable decrease of grain size; grain size (according State Standard 5639) corresponds to two points (actual medium grain diameter is 0.387-0.694 and 0.338-0.581 mm correspondingly). The size of test sample grain is more than three points (actual medium grain diameter is 2.325-3.168 mm). Steel grain in the other modified samples corresponds to three and more points.