METHOD FOR MANUFACTURING GRINDING BALLS FROM STEEL Russian patent published in 2023 - IPC B21H1/14 C21D9/36 C22C38/20 

FIELD: rolling production.

SUBSTANCE: heat treatment of grinding balls made of steel containing, wt.%: C 0.6-0.65; Mn 0.80-0.90; Si 0.80-0.90; Al 0.080-0.085; P less than 0.015; S less than 0.020; Cr 0.80-0.85; Cu 0.15-0.20; N less than 0.010; H less than 0.0003; iron is the rest. The method includes rolling the balls, cooling the balls, hardening and subsequent tempering of the balls. After rolling, the balls are cooled to a temperature of 780-820°C, then the balls are subjected to hardening in a hardening medium, while the hardening duration is adjusted depending on the diameter of the balls: - for balls with a nominal diameter of 100 mm from 3.0 to 4.0 min, for balls with a nominal diameter of 110-120 mm from 3.5 to 5.0 min, and the subsequent tempering of the balls is carried out with a holding time of 180 to 300 min at a temperature of 140-260°C.

EFFECT: increasing the operational stability of balls with a nominal diameter of 100-120 mm, 4 groups of hardness, corresponding to sufficient hardening capacity to a depth corresponding to half the radius of the ball, but at the same time excluding the occurrence of internal stresses and jamming of the discharge grate after the operation of the ball to the required diameter.

2 cl, 3 dwg, 1 tbl, 1 ex