Effect of vacuum-degassing on the nonmetallic-inclusion content of bearing steel

Metallurgist ◽  
1984 ◽  
Vol 28 (9) ◽  
pp. 311-313 ◽  
Author(s):  
V. L. Pilyushenko ◽  
B. P. Krikunov ◽  
Yu. M. Nerovnyi ◽  
A. F. Kablukovskii ◽  
E. F. Mazurov ◽  
...  
JOM ◽  
1966 ◽  
Vol 18 (1) ◽  
pp. 62-68 ◽  
Author(s):  
C. P. Church ◽  
T. M. Krebs ◽  
J. P. Rowe

2011 ◽  
Vol 284-286 ◽  
pp. 1258-1261 ◽  
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung

The maximum nonmetallic inclusion size and void of bearing steel has been analyzed using statistics of extreme values (SEV) in this study, and the influence of the maximum nonmetallic inclusion and void size on fatigue life of bearing steel has been discussed as well. Scanning electron microscopy (SEM) was used to measure the inclusion and void size, and the identification of inclusion type has been carried out by energy dispersive spectrometer (EDS). The results show that there are small hard round oxides or sharp TiN inside or beside the soft MnS strip in steels, single MnS strips and small clustered Al2O3 are also present. Most of voids in steels are branched rod-like or feathery, and the size of void is much smaller than inclusion for all steels. Therefore, the void is not the fatigue orgin for bearing steels. By adopting the criterion of return period (T) at 200, a serial analysis shows that the relation between inclusion/void size and fatigue life for steels is inverse proportion except B steel. This results from that larger inclusion could not only initialize crack, but also increase the propagation path of crack and accelerate fracture.


2014 ◽  
Vol 939 ◽  
pp. 11-18 ◽  
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung

In this study, we predicted the maximum nonmetallic inclusion size of bearing steel using statistics of extreme values (SEV) approach, and discussed that the influence of aluminum content on the nonmetallic inclusion characteristic and fatigue life of bearing steel. The inclusion size and type was measured and identified by a scanning electron microscopy (SEM) and an energy dispersive spectrometer (EDS) respectively. The result shows that most inclusions in steels are oxysulfide and alumina cluster. A tendency was also found that the alumina size increases with increasing aluminum content, but the oxysulfide size almost remains unchanged. Furthermore, alumina clusters were formed in steel if more deoxidizer aluminum was added to the molten steel during metallurgical process. In addition, the fatigue life of steel is inversely proportional to alumina size, but it seems independent of oxysulfide size. Therefore, this study suggests that the dominant factor of influence on the fatigue life of bearing steel is alumina instead of oxysulfide. The results reported here would be beneficial to steel manufacturers attempting to improve the fatigue resistance of bearing steels.


2020 ◽  
Vol 92 (1) ◽  
pp. 2000364
Author(s):  
Gong Cheng ◽  
Lifeng Zhang ◽  
Ying Ren ◽  
Wen Yang ◽  
Xiaolei Zhao ◽  
...  

2011 ◽  
Vol 189-193 ◽  
pp. 3592-3595 ◽  
Author(s):  
Ho Hua Chung ◽  
Chin Chuan Hsu

The maximum nonmetallic inclusion size and type of bearing steel has been analyzed using statistics of extreme values (SEV) in this study, and the influence of reduction in area on the maximum nonmetallic inclusion size and the fatigue life of bearing steel have been discussed as well. Scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) are used to measure the inclusion size and identify the inclusion type respectively. By adopting the criterion of return period (T) at 200, a serial analysis shows that with increasing the reduction in area of steel, the predicted inclusion size for √area max is decreasing, and the fatigue life is prolonging. This results from the defragment of hard inclusion during rolling process, and the decrease of concentration of stress around the inclusion.


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