SYMPOSIA PAPER Published: 08 September 2020
STP162320190084

Influence of Steel Cleanliness on RCF and WEC Formation

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It is well known that the amount and size of nonmetallic inclusions (NMIs) in bearing steel determines its performance in terms of classical rolling contact fatigue (RCF), especially if the bearing is subjected to high loads. Therefore, decreasing the NMI content in steel is seen as a key factor in prolonging the lifetime of bearing parts. Furthermore, it is presumed that the white etching cracks (WECs) formed in bearings as a consequence of so-called “additional loads” acting during time in service (e.g., electrical current, strong dynamics, critical additives) originate at very small size NMIs. Therefore, it is speculated in the literature that a cleaner steel should have a positive impact on this failure mechanism as well. In this study, bearing component tests with steels exhibiting different levels of cleanliness have been conducted. To start, classical RCF tests were performed, which are known to be highly sensitive to NMI content in the material. In addition, WEC tests with defined WEC-provoking additional loads were conducted to identify the role of NMIs for this nonclassical fatigue mechanism. It is observed that the microscopic cleanliness strongly affects the lifetime if classical material fatigue is the dominating failure mode, and that so-called superclean steels such as XCS3 have superior performance compared to standard qualities. In contrast, the formation of WECs is unaffected from the level of microscopic cleanliness.

Author Information

Blass, Toni
Schaeffler Technologies AG & Co. KG, Schweinfurt, DE
Xu, Xiaohong
Jiangyin Xingcheng Special Steel Works. Co., Ltd.,, Jiangyin City, CN
Wunder, Kirsten
Schaeffler Technologies AG & Co. KG, Schweinfurt, DE
Trojahn, Werner
Schaeffler Technologies AG & Co. KG, Schweinfurt, DE
Geng, Ke
Jiangyin Xingcheng Special Steel Works. Co., Ltd.,, Jiangyin City, CN
Li, Feng
Jiangyin Xingcheng Special Steel Works. Co., Ltd.,, Jiangyin City, CN
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Details
Pages: 26–49
DOI: 10.1520/STP162320190084
ISBN-EB: 978-0-8031-7693-5
ISBN-13: 978-0-8031-7692-8