| Popis: |
In this study, scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to measure the inclusion size and identify the inclusion type respectively. The evaluated maximum nonmetallic inclusion size of bearing steel has been obtained using statistics of extreme values (SEV), and the influence of oxygen content on the maximum nonmetallic inclusion size and the fatigue life of bearing steel have also been discussed. By adopting the criterion of return period (T) at 200, the serial analyses show that the predicted inclusion size formax is proportional to the oxygen content of steel, but the relation between fatigue life and oxygen content of steel is inverse proportion. This results from the defragment of hard inclusion during rolling process, and the decrease of concentration of stress around the inclusion. |
