The Effect of Cold Ring Rolling on the Heat Treatment Microstructure and Wear Resistance of GCr15 Bearing Steel

By means of cold ring rolling (CRR), quenching and tempering treatments, microstructure observation, and mechanical‐property tests, the effects of CRR on the heat treatment microstructure and wear resistance of GCr15 bearing steel are studied. The results show that, CRR reduces the size of carbides in the spheroidized microstructure and increases their quantity. The carbide particle size before and after CRR are 1.264 and 0.697 μm, respectively. After solution treatment and quenching, the number of undissolved carbides significantly decreases in the CRR samples. When the solution treatment time is 20 min, the carbide size in the steel without and with CRR is 0.684 and 0.628 μm, indicating that CRR promotes carbide dissolution during solution treatment. After tempering, the CRR steel exhibits an increase in carbide precipitation, and a great number of particulate carbides are precipitated. The hardness of the CRR steel after tempering is notably enhanced, and the wear resistance is improved. When the solution treatment time is 15 min under the same quenching and tempering conditions, the CRR steel achieves the highest hardness of HRC 62.0 and the best wear resistance with the wear loss of only 4.73 × 10 −5 mg (N m) −1 .