The Exploration of the Possibility of Using Continuous-Cast 55 Grade Steel in the Manufacturing of 40-mm-in-Diameter Grinding Balls of IV and V Hardness Class

Results of a field–experimental study on the applicability of continuous-cast medium-carbon 55 grade steel sparingly alloyed with chromium to the manufacturing of hardness IV and V class grinding balls 40 mm in diameter are presented. The possibility of the stable production of hardness IV class grinding balls is shown since chromium added in small quantities facilitates the hardness stabilization over the half of the ball radius and increases the volumetric hardness by 2–3 HRC figures. The established increase in the volumetric hardness did not allow for the HRC 57 level to be reached to certify the balls as the hardness V class products. Rational process variables have been recommended to ensure the production of 40-mm-in-diameter grinding balls for the V hardness class of continuous-cast medium-carbon 55 grade steel on the ShPS 30–80 ball-rolling mill.