High-carbon bearing steel and preparation method thereof

A high-carbon bearing steel, wherein the chemical composition consists of:

• C:
• 0.95-1.1 wt %, Cr:
• 0.40-1.8 wt %, Mn:
• 0.15-0.75 wt %, Si:
• 0.15-0.30 wt %, Nb:
• 0.08-0.20 wt %, Mo:
• 0.02-0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities;
• wherein a total content of Nb and Mo is 0.10-0.30 wt %, the high-carbon bearing steel has a tensile strength of 2510 MPa to 2590 MPa, and a contact fatigue life L10 of not less than 6.5×107 times.

A method of making a high-carbon bearing steel wherein the high-carbon bearing steel consists of C:

• 0.95-1.1 wt %, Cr:
• 0.40-1.8 wt %, Mn:
• 0.15-0.75 wt %, Si:
• 0.15-0.30 wt %, Nb:
• 0.08-0.20 wt %, Mo:
• 0.02-0.20 wt %, P≤0.015 wt %, S≤0.01 wt %, the remaining is Fe and unavoidable impurities;
• wherein a total content of Nb and Mo is 0.10-0.30 wt %, consisting of the steps of:
• smelting raw materials of the high-carbon bearing steel to obtain steel ingots, wherein the steel ingots have a chemical composition corresponding to the chemical composition of the high-carbon bearing steel;
• homogenizing the steel ingots and then processing them into bars;
• successively spheroidizing annealing, quenching, and tempering the bars to obtain the high-carbon bearing steel,
• wherein a process of spheroidizing annealing comprises holding the bars at 800-860° C. for 0.5-12 hours, then cooling down to 680-740° C. and holding for 0.5-12 hours, and finally cooling in air to room temperature,
• a temperature for quenching is 820-860° C., a holding time is 0.10-1.0 hours, and a cooling for quenching is oil quenching, and
• a temperature for tempering is 130-200° C., a holding time is 0.5-3.5 hours, and a cooling for tempering is air cooling.