Fretting fatigue fracture of the supporting shaft in a rotary kiln Junbo Shi a , Ning Ding a,b, ⁎, Na Xu a , Weimin Guo a , Long Liu a , Lizong Chen a , Xiaofeng Wu a , Qishan Zang a , Chi-Man Lawrence Wu a,b, ⁎⁎ a Research Center of Failure Analysis and Engineering Safety Assessment, Shandong Academy of Sciences, Jinan, PR China b Department of Physics and Materials Science, City University of Hong Kong, Hong Kong article info abstract Article history: Received 24 October 2016 Accepted 27 February 2017 Available online xxxx The fracture failure of the supporting shaft in a rotary kiln was analyzed to determine the fail- ure mechanism. The rotary kiln was used to heating and mixing nickel ores and was supported by four group riding wheels with two wheels in each group. One of the supporting shafts was found fractured after it was used for about two years. The fracture was located at the interface between the supporting shaft and the sleeve. This location was 100–120 mm far from the tran- sition arc of the supporting shaft where high stress concentration usually occur. A failure anal- ysis was carried out, using characterization techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and so on. Obvious fatigue propagation zone caused by multi-initial cracks were observed at the circle edge of the fracture surface. Ad- hesive wear and some circumferential cracks were found on the outside surface of the supporting shaft. It was considered that fatigue due to the fretting wear between the shaft and sleeve was the most probable mechanism. © 2017 Elsevier Ltd. All rights reserved. Keywords: Fretting wear Fretting fatigue Fracture Supporting shaft Rotary kiln 1. Introduction Fatigue wear is a surface damage which is caused by the long-term effects of cyclic stress in the friction contact area. Pits, cracks and spalling are the general damage types due to fatigue wear on the contact surfaces. The gear, bearing and axle parts usually undergo alternating bending and torsion stress. Under the cooperative action of friction and wear, these components were susceptible to fatigue wear [1–3]. A special case of wear, i.e. fretting wear should not be ignored. Fretting wear usually oc- curs between two tight-fitting surfaces that are subjected to a cyclic, relative motion of extremely small amplitude [4–6]. Fretting wear often produce tiny cracks. These cracks may become crack source in subsequent fatigue load. Thus, fretting wear usually leads to catastrophic failure [7–10]. The occurrence process of fretting wear can be divided into three stages [11,12]. Firstly, normal compressive stress exists on the contact surfaces and small relative movement happened between the contact surfaces due to vibration or other alternating stress. Under such conditions, plastic deformation and adhesion wear may occur on the contact surface and a large amount of de- bris may form under the tangential force. Then, debris may be oxidized and retained in the contact surface. Abrasive wear may happen between the two tight-fitting surfaces. This working surface will become rough and soften. Finally, fretting cracks may form and fretting fatigue may further occur. Data showed that the fatigue strength of material under fretting wear conditions can be reduced by 50% to 70% that of the materials without fretting wear [4]. That's because for fretting fatigue, initial cracks Engineering Failure Analysis xxx (2017) xxx–xxx ⁎ Correspondence to: N. Ding, Research Center of Failure Analysis and Engineering Safety Assessment, Shandong Academy of Sciences, Jinan, PR China. ⁎⁎ Correspondence to: C.-M.L. Wu, Department of Physics and Materials Science, City University of Hong Kong, Hong Kong. E-mail addresses: [email protected] (N. Ding), [email protected] (C.-M.L. Wu). EFA-03056; No of Pages 7 http://dx.doi.org/10.1016/j.engfailanal.2017.02.023 1350-6307/© 2017 Elsevier Ltd. All rights reserved. Contents lists available at ScienceDirect Engineering Failure Analysis journal homepage: www.elsevier.com/locate/engfailanal Please cite this article as: J. Shi, et al., Fretting fatigue fracture of the supporting shaft in a rotary kiln, Engineering Failure Analysis (2017), http://dx.doi.org/10.1016/j.engfailanal.2017.02.023
Fretting fatigue fracture of the supporting shaft in a rotary kiln
May 20, 2023
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