METHOD OF PRODUCING HOT-ROLLED SECTIONS FOR MAKING LARGE-SIZE BEARINGS Russian patent published in 2025 - IPC C21D8/06 C21D1/02 C21D6/00 

FIELD: ferrous metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, in particular to a method for producing rolled products for the manufacture of balls, rollers and rings for large rolling bearings. Method for production of hot-rolled sections for production of large-size bearings includes electroslag remelting (ESR) of continuously cast billet from steel “ШХ15” for production of ingots with weight of more than 5 t, heating of ingots with simultaneous homogenisation according to stepped mode, rolling to reworking billet with subsequent cooling, hot rolling of billets and cooling, characterized by that ESR is performed in furnace with average deposition rate of 330-390 kg/h according to single-electrode circuit of electric current supply with remelting of one electrode, at that, as a consumable electrode, a continuously cast steel workpiece of “ШХ15-В” grade is used, during remelting, argon is fed into the cavity of the crystallizer with a flow rate of 5-30 l/min, and before switching on the furnace, the crystallizer is filled with argon, after the end of remelting, the ingot is held in crystallizer for 1.5 hours, and after the ingot is dispensed from the crystallizer, the ingot is cooled to temperatures of 300 °C in electric wells for 18 hours or in thermoses for up to 20 hours, after cooling the ingots are annealed according to the mode: heating at a rate of not more than 70 °C to 680 °C and holding for 7 hours, heating of annealed ingots for rolling to a rework billet is carried out with simultaneous homogenisation in the temperature range of 1,000-1,240 °C and total heating duration for 20 hours according to the stepped mode with holding at 1,140 °C for 3 hours, with exposure at 1,180 °C for 3 hours, with exposure at 1,200 °C for 2 hours, with exposure at 1,240 °C for 2 hours, with exposure at 1,180 °C for up to 6 hours, wherein during hot rolling up to 70% deformation is carried out in roughing stand at temperature 1,140±10 °C with total drawing of not less than 10, and remaining part of deformation – in finishing stands, which begins after cooling at temperature of 1,080-1,100 °C, deformation end temperature in finishing stands is maintained equal to 950-980 °C, after deformation, cooling is carried out to temperature of 700-730 °C at rate of 5-7 °C/s, then cooling in unheated wells at rate of 25-35 °C/h, after which annealing is performed at 800 °C.

EFFECT: higher quality of rolled stock due to elimination of carbide liquation, reduction of structural banding and residues of carbide net in hot-rolled state (not more than 2 points).

1 cl, 1 tbl, 1 ex