Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"Bartosz Firlik"

Influence of operation on tram wheels and rails surface layer condition DOI:10.15199/28.2017.4.6

  1. INTRODUCTION Tramway are a common city transportation of special performance and functionality. To increase tram transport effectiveness and safety, better understanding of wheel-rail contact wear is required. The most severe wear of wheel is observed on the running gear, especially on the rolling surface. Problems regarding the durability of the of the wheel-rail contact are associated with many different forms of wear caused by the surface contact friction and fatigue. In literature, models for calculating the of wheel-rail load could be found [1]. It should be underline that, not only rolling friction in wheel-rail contact is present, but mixed: rolling-slip (sometimes, in the case of rail curves, wheel flanges are exposed to almost pure sliding friction [2, 3]). In case of wheel-rail interaction rolling contact fatigue (RCF) wear can occur [4]. Fatigue wear in this friction pair can proceed as spalling or shelling. Slides in curves, speeding up, braking etc. can cause heating of the surface layer above austenitizing temperature in a very short time (e.g. a few seconds) which leads to the formation of martensite. Then, further movement of the tram and cyclic loading of the wheel cause spalling. For instance, those slips at the wheel-rail contact are considered to be the common reason of faster wheel wear of diesel multiple units in district of Wielkopolska [5]. Heating (due to friction) above austenitizing temperature is a reason of so-called ‘white layers’ formation. Mostly, the phenomenon of the white layers creation takes place in the cutting hard steels. White layers could arise as a consequence of dynamic processes affecting intensive deformation and the related with them thermal effects [6, 7]. Because of their high hardness and brittleness they can favour spalling wear. Such layers were observed in the case of rail [6, 8] and also in case of tram wheels of Solaris Tramino after 146 000 km of approximate total millage [9]. The p[...]

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