Study on Rolling and Hot Delivery Spheroidizing Annealing of GCr15 Bearing Steel

In order to optimize the annealing process of GCr15 bearing steel, the deformation-induced hot rolling and hot delivery process was proposed. Combined with the traditional isothermal spheroidizing annealing process, a new hot delivery isothermal spheroidizing annealing process was designed. The effect of secondary isothermal time on the microstructure of samples was studied. The study shows that with the extension of the second isothermal time, the homogeneity of the microstructure increases first and then decreases; when the isothermal time is 1 h, the homogeneity is the best. The Vickers hardness and impact energy of the sample changes with the microstructure; when the isothermal time is 1 h, the Vickers hardness is 210 HV, and the impact energy of half sample is 37.4 J.