The results of experimental and industrial studies to evaluation the applicability of continuous cast medium carbon steel grade 55 economically alloyed with chromium for the production of grinding balls Ø40 mm hardness groups IV and V are presented. The possibility of stable production of grinding balls of group hardness IV is shown, since low additives of Cr on the one hand contributed to the stabilization of the hardness by ½ of the radius of the ball, and on the other - increased the volume hardness by 2÷3 units of HRC. The revealed increase in the volume hardness of НRS did not allow to reach the level of values (not less than 57 units of HRS), which allows to certify products for group V. Rational technological parameters of production of grinding balls Ø 40 mm from continuously cast medium carbon steel grade 55 economically alloyed with chromium are recommended for guaranteed production by the ball-rolling mill 30 ... 80 on the IV group of hardness.