Research on metal flow line control and mechanical anisotropy of M50 steel eccentric ball bearing ring

In this work, considering the metal flow line distribution of the machined parts, a kind of eccentric ball bearing ring with metal flow line distribution according to its contour was obtained via a high height per diameter ratio bar and insufficient lubrication. Furthermore, the microstructure evolution and mechanical properties of bearing rings after spheroidizing annealing and quenched-tempered treatment were analyzed and compared using a metallographic microscope and electron microscopy. Results show that the spheroidized annealed and quenched-tempered process cannot play a role in the refinement and dissolution of the primary carbides. The metal flow line was the main reason for the obvious mechanical anisotropy. In three related directions, the mechanical properties of the axial and circumferential directions (along the metal flow lines) are significantly better than those of the radial direction. The rapid propagation of microcracks along a carbide band is the reason for the poor mechanical properties when loading perpendicular to the metal flow line. The radial specimen after quenching and tempering exhibits a brittle fracture mode. However, the axial and radial specimens exhibit a quasi-cleavage fracture mode.