Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel
Damage in bearings is closely associated with the presence of microstructural alterations, known as white etching areas (WEAs) and white etching cracks (WECs). One of the main reasons for the creation of these microstructural alterations is the presence of defects in the material, such as non-metall...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-06-01
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| Series: | Metals |
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| Online Access: | https://www.mdpi.com/2075-4701/13/6/1113 |
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| author | Ksenija Nikolic Jelle De Wispelaere Gopalakrishnan Ravi Stijn Hertelé Tom Depover Kim Verbeken Roumen H. Petrov |
| author_facet | Ksenija Nikolic Jelle De Wispelaere Gopalakrishnan Ravi Stijn Hertelé Tom Depover Kim Verbeken Roumen H. Petrov |
| author_sort | Ksenija Nikolic |
| collection | DOAJ |
| description | Damage in bearings is closely associated with the presence of microstructural alterations, known as white etching areas (WEAs) and white etching cracks (WECs). One of the main reasons for the creation of these microstructural alterations is the presence of defects in the material, such as non-metallic inclusions. Manganese sulfides and aluminum oxides are widely reported in the literature as the most common types of non-metallic inclusions found in bearing steels. This study classifies 280 non-metallic inclusions in an investigated bearing steel according to several criteria: bonded/debonded with the matrix, size, shape, orientation angle, depth below the raceway surface, and chemical composition. Contrary to the findings in the literature, this investigation reports that the chemical composition of the inclusion (MnS + Al<sub>2</sub>O<sub>3</sub>) is of secondary importance when considering factors for damage initiation. The orientation of the microstructural alterations is observed to coincide with the high-stress regions, indicating a relation between the formation of butterfly wings and the white etching crack. In our investigation, butterfly wings typically exhibit a 45-degree pattern originating from the non-metallic inclusions. Conversely, the white etching crack starts from the non-metallic inclusion at a shallower angle in correspondence to the raceway. This can be attributed to the stress state, which corresponds to a region where extensive white etching cracks are formed. In conclusion, the microstructural observations demonstrate that the state of non-metallic inclusion—i.e., whether they are bonded or not to the steel matrix—plays an essential role in initiating rolling contact fatigue damage. |
| first_indexed | 2024-03-11T02:09:06Z |
| format | Article |
| id | doaj.art-4de9f07ae4ea48bf8b22346272beaea5 |
| institution | Directory Open Access Journal |
| issn | 2075-4701 |
| language | English |
| last_indexed | 2024-03-11T02:09:06Z |
| publishDate | 2023-06-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Metals |
| spelling | doaj.art-4de9f07ae4ea48bf8b22346272beaea52023-11-18T11:36:59ZengMDPI AGMetals2075-47012023-06-01136111310.3390/met13061113Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing SteelKsenija Nikolic0Jelle De Wispelaere1Gopalakrishnan Ravi2Stijn Hertelé3Tom Depover4Kim Verbeken5Roumen H. Petrov6Department Electromechanical, Systems & Metal Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Electromechanical, Systems & Metal Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Electromechanical, Systems & Metal Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Electromechanical, Systems & Metal Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Materials, Textiles and Chemical Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDepartment Electromechanical, Systems & Metal Engineering, Ghent University, Technologiepark 46, 9052 Ghent, BelgiumDamage in bearings is closely associated with the presence of microstructural alterations, known as white etching areas (WEAs) and white etching cracks (WECs). One of the main reasons for the creation of these microstructural alterations is the presence of defects in the material, such as non-metallic inclusions. Manganese sulfides and aluminum oxides are widely reported in the literature as the most common types of non-metallic inclusions found in bearing steels. This study classifies 280 non-metallic inclusions in an investigated bearing steel according to several criteria: bonded/debonded with the matrix, size, shape, orientation angle, depth below the raceway surface, and chemical composition. Contrary to the findings in the literature, this investigation reports that the chemical composition of the inclusion (MnS + Al<sub>2</sub>O<sub>3</sub>) is of secondary importance when considering factors for damage initiation. The orientation of the microstructural alterations is observed to coincide with the high-stress regions, indicating a relation between the formation of butterfly wings and the white etching crack. In our investigation, butterfly wings typically exhibit a 45-degree pattern originating from the non-metallic inclusions. Conversely, the white etching crack starts from the non-metallic inclusion at a shallower angle in correspondence to the raceway. This can be attributed to the stress state, which corresponds to a region where extensive white etching cracks are formed. In conclusion, the microstructural observations demonstrate that the state of non-metallic inclusion—i.e., whether they are bonded or not to the steel matrix—plays an essential role in initiating rolling contact fatigue damage.https://www.mdpi.com/2075-4701/13/6/1113bearing steelwhite etching crackswhite etching areanon-metallic inclusionsdamagerolling contact fatigue |
| spellingShingle | Ksenija Nikolic Jelle De Wispelaere Gopalakrishnan Ravi Stijn Hertelé Tom Depover Kim Verbeken Roumen H. Petrov Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel Metals bearing steel white etching cracks white etching area non-metallic inclusions damage rolling contact fatigue |
| title | Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel |
| title_full | Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel |
| title_fullStr | Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel |
| title_full_unstemmed | Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel |
| title_short | Confirming Debonding of Non-Metallic Inclusions as an Important Factor in Damage Initiation in Bearing Steel |
| title_sort | confirming debonding of non metallic inclusions as an important factor in damage initiation in bearing steel |
| topic | bearing steel white etching cracks white etching area non-metallic inclusions damage rolling contact fatigue |
| url | https://www.mdpi.com/2075-4701/13/6/1113 |
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