Analysis of Influence of Aluminum Content on Inclusion Characteristic and Fatigue Life of Bearing Steel Using Statistics of Extreme Values

2014 ◽  
Vol 939 ◽  
pp. 11-18 ◽  
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung
Keyword(s):  
Fatigue Life ◽  
Nonmetallic Inclusion ◽  
Aluminum Content ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Inclusion Size ◽  
Bearing Steel ◽  
Dominant Factor ◽  
Bearing Steels ◽  
Alumina Cluster

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.

Study on the Influence of Inclusion and Void on Fatigue Life of Bearing Steel Using Statistics of Extreme Values

2011 ◽  
Vol 284-286 ◽  
pp. 1258-1261 ◽  
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung
Keyword(s):  
Fatigue Life ◽  
Nonmetallic Inclusion ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Inclusion Size ◽  
Bearing Steel ◽  
Propagation Path ◽  
Void Size ◽  
Inclusion Type ◽  
Bearing Steels

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.

The Influence of Argon Flow on Inclusion Characteristic and Fatigue Life of Continuous Casting Bearing Steels

2011 ◽  
Vol 418-420 ◽  
pp. 972-976
Author(s):  
Chin Chuan Hsu ◽  
Ho Hua Chung
Keyword(s):  
Fatigue Life ◽  
Continuous Casting ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Casting Process ◽  
Inclusion Size ◽  
Bearing Steel ◽  
Inclusion Type ◽  
Bearing Steels ◽  
Argon Flow

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 by using statistics of extreme values (SEV). The influence of argon flow of the continuous casting process on the inclusion characteristics of bearing steels has been estimated, the influence of size and type of inclusion of bearing steel on its fatigue life have been discussed as well. It was found that most inclusions in steels are oxysulfide and alumina cluster. With the decreasing of the argon flow, the inclusion size gets larger and the amount of cluster-type inclusion also increases. In addition, by adopting the criterion of return period (T) at 200, the serial analyses show that the relation between predicted inclusion size for max and the argon flow is inverse proportion, but the fatigue life of steel is proportional to argon flow. A correlation among argon flow, inclusion size and fatigue life of bearing steel has been established in this study.

Study on the Influence of Reduction in Area on Fatigue Life of Bearing Steel Using Statistics of Extreme Values

2011 ◽  
Vol 189-193 ◽  
pp. 3592-3595 ◽  
Author(s):  
Ho Hua Chung ◽  
Chin Chuan Hsu
Keyword(s):  
Fatigue Life ◽  
Nonmetallic Inclusion ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Inclusion Size ◽  
Rolling Process ◽  
Bearing Steel ◽  
Inclusion Type ◽  
Hard Inclusion ◽  
Reduction In Area

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.

Study on the Influence of Oxygen Content on Fatigue Life of Bearing Steel Using Statistics of Extreme Values

2011 ◽  
Vol 287-290 ◽  
pp. 879-882 ◽  
Author(s):  
Ho Hua Chung ◽  
Chin Chuan Hsu
Keyword(s):  
Fatigue Life ◽  
Nonmetallic Inclusion ◽  
Oxygen Content ◽  
Extreme Values ◽  
Energy Dispersive Spectrometer ◽  
Inclusion Size ◽  
Rolling Process ◽  
Bearing Steel ◽  
Inclusion Type ◽  
Hard Inclusion

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.

scholarly journals Quantitative Analysis of Inclusion Engineering on the Fatigue Property Improvement of Bearing Steel

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 476 ◽  
Author(s):  
Chao Gu ◽  
Min Wang ◽  
Yanping Bao ◽  
Fuming Wang ◽  
Junhe Lian
Keyword(s):  
Fatigue Life ◽  
Quantitative Analysis ◽  
Critical Size ◽  
Fatigue Behavior ◽  
Fatigue Cracks ◽  
Fatigue Property ◽  
Bearing Steel ◽  
Fatigue Properties ◽  
Bearing Steels ◽  
Inclusion Distribution

The fatigue property is significantly affected by the inner inclusions in steel. Due to the inhomogeneity of inclusion distribution in the micro-scale, it is not straightforward to quantify the effect of inclusions on fatigue behavior. Various investigations have been performed to correlate the inclusion characteristics, such as inclusion fraction, size, and composition, with fatigue life. However, these studies are generally based on vast types of steels and even for a similar steel grade, the alloy concept and microstructure information can still be of non-negligible difference. For a quantitative analysis of the fatigue life improvement with respect to the inclusion engineering, a systematic and carefully designed study is still needed to explore the engineering dimensions of inclusions. Therefore, in this study, three types of bearing steels with inclusions of the same types, but different sizes and amounts, were produced with 50 kg hot state experiments. The following forging and heat treatment procedures were kept consistent to ensure that the only controlled variable is inclusion. The fatigue properties were compared and the inclusions that triggered the fatigue cracks were analyzed to deduce the critical sizes of inclusions in terms of fatigue failure. The results show that the critical sizes of different inclusion types vary in bearing steels. The critical size of the spinel is 8.5 μm and the critical size of the calcium aluminate is 13.5 μm under the fatigue stress of 1200 MPa. In addition, with the increase of the cleanliness of bearing steels, the improvement of fatigue properties will reach saturation. Under this condition, further increasing of the cleanliness of the bearing steel will not contribute to the improvement of fatigue property for the investigated alloy and process design.

Improvement of Rolling Contact Fatigue Life of Bearing Steel by Quenching and Partitioning Process

2012 ◽  
Vol 706-709 ◽  
pp. 2152-2157 ◽  
Author(s):  
Kwan Ho Kim ◽  
Jae Seung Lee ◽  
Duk Lak Lee
Keyword(s):  
Fatigue Life ◽  
Silicon Content ◽  
Retained Austenite ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Quenching And Partitioning ◽  
Bearing Steels ◽  
Contact Fatigue Life

Over the decades, the rolling contact fatigue life of bearing steels has been enhanced mainly by the decrease in total oxygen content in the steels which was accomplished by improving steelmaking processes or facilities. However, it has almost been kept constant in the level of 5 ppm since 1990s and, therefore, it is necessary to find out other methods to enhance the RCFL. It is a well-known fact that the RCFL of bearing steels is maximized with the adequate amount of retained austenite and increasing silicon content results in the increase of the resistance to softening during tempering. In the present study, in order to take advantage of the effects of retained austenite and increasing silicon content, a new through-hardening heat treatment, quenching and partitioning (Q&P), has been chosen in place of the conventional quenching and tempering. One of the distinct differences between tempering and partitioning is no fine carbide precipitation during partitioning, leading to the stabilization of retained austenite due to the diffusion of carbon atoms from martensite, which can be realized by increasing silicon content. On the other hand, the increase of silicon content retarded the spheroidization behavior of cementites, requiring higher annealing temperature to assure the complete spheroidization. A new high carbon chromium bearing steel through-hardened by Q&P process showed superior RCFL characteristics to the conventional steel and process.

scholarly journals The Influence of Aluminum Content on Oxidation Resistance of New-Generation ODS Alloy at 1200 °C

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1478 ◽  
Author(s):  
Luděk Stratil ◽  
Vít Horník ◽  
Petr Dymáček ◽  
Pavla Roupcová ◽  
Jiří Svoboda
Keyword(s):  
Oxidation Resistance ◽  
Cross Sections ◽  
Aluminum Content ◽  
Energy Dispersive Spectrometer ◽  
Oxide Dispersion Strengthened ◽  
Xrd Analysis ◽  
Al Content ◽  
Α Al2o3 ◽  
New Generation ◽  
Ods Alloy

The aim of the paper is to evaluate the effect of aluminum content on the oxidation resistance of new-generation of oxide dispersion strengthened (ODS) alloy at 1200 °C. Three grades of the alloy of chemical composition Fe-15Cr-xAl-4Y2O3 with different Al contents x = 0.3 wt.%, 2.0 wt.% and 5.5 wt.% are prepared by mechanical alloying. The alloys are consolidated by high temperature rolling followed by heat treatment. To study the oxidation resistance the samples are isothermally aged in the air for 1 h, 4 h, 16 h and 64 h at 1200 °C. The oxidation kinetics, composition and formation mechanism of the oxide layers are analyzed. The weight gain of prepared steels is estimated. The kinetics of oxidation is studied on metallographic cross-sections of the exposed samples by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) analysis. The oxides on the surfaces are identified by X‑ray diffraction (XRD) analysis. The Al content significantly enhances the oxidation resistance of the alloy. For a sufficiently high Al content in the alloy a compact oxide layer of α‑Al2O3 on the surface is formed, which significantly suppresses further oxidation process.

Fatigue life analysis of shot-peened bearing steel

2012 ◽  
Vol 26 (6) ◽  
pp. 1747-1752 ◽  
Author(s):  
Sang-Jae Yoon ◽  
Jung-Hoon Park ◽  
Nak-Sam Choi
Keyword(s):  
Fatigue Life ◽  
Bearing Steel ◽  
Life Analysis ◽  
Fatigue Life Analysis
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