METHOD FOR MANUFACTURING GRINDING BALLS FROM STEEL (EMBODIMENTS) Russian patent published in 2023 - IPC C21D9/36 B21H1/14 

FIELD: rolling production.

SUBSTANCE: invention relates to rolling production, in particular to the heat treatment of grinding balls made of steel containing, % by weight: C 0.61-0.66, Mn 0.80-0.90, Si 0.60-0.65, Al less than 0.070, P less than 0.015, S less than 0.020, Cr 0.60-0.70, Ni 0.15-0.30, Cu less than 0.040, V 0.01-0.12, Mo 0.04-0.06, N less than 0.010, H less than 0.0003, Fe – the rest. The method includes rolling at a temperature of 950-1050°C, cooling the balls, quenching and subsequent tempering. After rolling, the balls are cooled to a temperature of 740-830°C, then the balls are hardened in a hardening medium, while the hardening duration is adjusted depending on the diameter of the balls: from 3.0 to 4.5 min for balls with a nominal diameter of 100 mm, from 3.5 min to 6.0 min for balls with a nominal diameter of 110-120 mm, and the subsequent tempering of the balls is carried out with a holding time of 160 to 320 min at a temperature of 140-260°C.

EFFECT: increasing the operational stability of the balls, obtaining grinding balls with a nominal diameter of 100 and 110-120 mm, with a bulk hardness characterized by hardness group 5 according to GOST 7524-2015, with a low gradient in production (a decrease in the hardness value from the surface to the centre of the ball).

3 cl, 3 dwg, 2 tbl