Method for treating M50NiL bearing steel, strengthened M50NiL bearing steel and bearing

The invention discloses a method for treating M50NiL bearing steel, strengthened M50NiL bearing steel and a bearing. The method comprises steps as follows: (1) nitrogen ion and carbon ion co-permeation is performed on the surface of the M50NiL bearing steel with ion beams; (2) first rare-earth ions are implanted into the surface of the M50NiL bearing steel obtained in the step (1) with ion beams; (3) second rare-earth ions are implanted into the surface of the M50NiL bearing steel obtained in the step (2) with ion beams; (4) implantation treatment is performed on the M50NiL bearing steel obtained in the step (3) with ion beams; (5) metal ions and gas ions are alternately implanted into the surface of the M50NiL bearing steel obtained in the step (4) with ion beams, so that the strengthened M50NiL bearing steel is obtained. With the method, the wear resistance and the contact fatigue resistance of the M50NiL bearing steel can be remarkably improved, implantation and low-energy bombardment diffusion permeation treatment are completed once with the method, environmental pollution and high energy consumption caused by traditional heat treatment are obviously reduced, and the treatment efficiency is improved.