METHOD FOR PRODUCTION OF STEEL GRINDING BALLS Russian patent published in 2016 - IPC C21D9/36 B21H1/14 C21D1/02 B23P15/00 

FIELD: machine building.

SUBSTANCE: invention relates to production of grinding balls. Method comprises heating continuously cast workpiece, hot rolling on a high-rolling mill of round workpieces of appropriate size, further heating in induction device, rolling of balls at helical rolling mill at a temperature of 950-1,050 °C, cooling down balls before hardening, quenching and self-tempering balls in containers. Method incudes making a square continuously cast workpiece with a section of (100-150)×(100-150) mm. Round workpieces are heated in induction device to temperature at outlet of inductors of 1,070-1,140 °C. Cooling balls to hardening temperature 840-900°C is performed in cooling drum at a rate of its rotation in range of 6.0-22.0 rpm with temperature balance of balls along section due to rotation of balls in drum for less than 2 minutes. Hardening balls is carried out in hardening drum at rotation rate in range of 0.4-2.5 rpm with running water at temperature of 25-42 °C to temperature of balls after hardening of 125-160 °C.

EFFECT: higher operational resistance of balls, uniform hardness along section of ball, high hardness on its surface and in central area and preventing formation of cracks.

3 cl, 3 tbl