Paper 17: Study of Sintered Carbides and Surface-Treated Materials for Unlubricated and Elevated Temperature Rolling Elements

Abstract

Materials and surface treatments potentially suitable for unlubricated and elevated temperature rolling bearings have been compared, wear resistance being assessed by loss of weight under unlubricated conditions. Tungsten carbide was superior to other materials tested. Grain size of the tungsten carbide and the amount of matrix material can have a considerable effect on performance. Use of solid film lubricants can eliminate or reduce wear. Soft nitriding can also be beneficial. Metallurgical investigations of some selected failed specimens have been carried out.

Dark etching regions under rolling contact fatigue: A review

“…The development of the DERs starts with the formation of ferrite microbands. The terms used in the literature to describe the ferrite microbands [54] include ferrite [14], slip motions [15], troostite/mechanical troostite [23,24,55,56], tempered martensite [31,55,57], upper bainite/ microslip/ deformation bands [31], dark needles [29], needle like structure [28], acicular structures [58] and elongated cells [35]. The term ‘martensite decay’ is commonly used when the actual product of microstructure alteration is unclear.…”

“…The emergence of WEBs after about stress cycles is typically observed in conjunction with the formation of lenticular carbides [26]. Lenticular carbides have been identified as cementite but without partition of Cr and Mn [55]. It can be hypothesised that the formation and growth of lenticular carbides adjacent to WEBs is related to the dissolution of tempered carbides and RC and the subsequent re-precipitation of cementite.…”