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White-etching matter in bearing steel. Part II: Distinguishing cause and effect in bearing steel failure


Type

Article

Change log

Authors

Solano-Alvarez, W 
Bhadeshia, HKDH 

Abstract

The premature failure of large bearings of the type used in wind turbines, possibly through a mechanism called “white-structure flaking”, has triggered many studies of microstructural damage associated with “white-etching areas” created during rolling contact fatigue, although whether they are symptoms or causes of failure is less clear. Therefore, some special experiments have been conducted to prove that white-etching areas are the consequence, and not the cause, of damage. By artificially introducing a fine dispersion of microcracks in the steel through heat treatment and then subjecting the sample to rolling contact fatigue, manifestations of hard white-etching matter have been created to a much greater extent than samples similarly tested without initial cracks. A wide variety of characterization tools has been used to corroborate that the white areas thus created have the same properties as reported observations on real bearings. Evidence suggests that the formation mechanism of the white-etching regions involves the rubbing and beating of the free surfaces of cracks, debonded inclusions, and voids under repeated rolling contact. It follows that the focus in avoiding early failure should be in enhancing the toughness of the bearing steel in order to avoid the initial microscopic feature event.

Description

Keywords

4014 Manufacturing Engineering, 40 Engineering, 7 Affordable and Clean Energy

Journal Title

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

Conference Name

Journal ISSN

1073-5623
1543-1940

Volume Title

45

Publisher

Springer Science and Business Media LLC
Sponsorship
Funding by CONACyT, the Cambridge Overseas Trust, and the Roberto Rocca Education Programme is highly appreciated and acknowledged.