5.Structure of raceway no. 1 materi

5.Structure of raceway no. 1 material on a macroscopic and microscopic scaleFurther macro- and microscopic research was carried out for the lower raceway of machine 1 (100,000 service hours). The upper raceway of this bearing was suitable for further exploitation.In Figs. 8 and 9, the macroscopic views of sections of the ball raceway (after being etched with 3% solution of HNO3) are shown. For the majority of the section, a homogenous macrostructure with some dendrite structure is observed. Additionally, in the region of raceway surface and ball interaction, there is a layer about 5 mm thick of darker colour than the rest of the surface. In this layer, one can observe macroscopic effects of the bearing being in service for 18 years, as on the left-hand side there is material flow out due to plastic deformation (Fig. 9a) with dimensions of 2.0 mm 3.3 mm and a lack of continuity near the outer surface of the raceway. From the other side, as shown in Fig. 9b, the material is subjected to plastic flow shown by the trapezoidal shape extending over the raceway surface. On the semi-circular outline of the raceway, there are several pittings visible.