An increase in the wear life of locomotive wheels is considered desirable from the locomotive builder and railroad user points of view. If a wheel has a longer service life, economics are improved due to less locomotive out-of-service time, reduced maintenance repair costs and reduced wheel renewal costs. This paper discusses possible alternative materials and microstructures that could be used for longer-life locomotive wheels, and also tires. If locomotive builders and users consider wheel rim hoop compression essential, then microalloying and increased carbon content are perhaps the most likely courses of action to improve wheel life. If rim hoop compression is not considered essential, a wide range of alternatives become possible including bainitic and martensitic microstructure monobloc wheels and tires. Small additions of selected elements to Class C wheel steel could improve wear performance. Australian railroads, in concert with an Australian wheel manufacturer, used such additions to produce freight car wheels in the hardness range of 363-401 HBN. An improvement in tread wear resistance of 14% was noted in railway service. One possibility is to use higher carbon rail steel, with or without microalloying elements, as wheel steel. Hou et al. tested the wear and adhesion characteristics of various different materials and suggested that a 'Super Rail Steel' could be used since it exhibited high friction (adhesion) and low wear. This 'Super Rail Steel' had a composition (0.76% C, 0.95% Mn, 0.5% Si, 0.020% S, 0.030% P, 0.07% V and 0.5% Cr) and a hardness of only 346 HBN. Researchers at Nippon Steel investigated the possibility of a hypereutectoid steel for rails. A 20% improvement in wear resistance over conventional heat treated eutectoid rail steel was found in laboratory testing. The highest hardness levels are possible using a martensitic microstructure. Untempered martensite could be produced with hardness up to about 65 Rockwell C, but toughness would be very low. Martensite is formed due to rapid cooling from austenite and involves a diffusionless transformation to a strained, body centered tetragonal lattice structure.
Some possible alternatives for longer-life locomotive wheels
Einige mögliche Alternativen für Lokomotivräder mit längerer Lebensdauer
2005
6 Seiten, 6 Bilder, 22 Quellen
Conference paper
English
IMECE2002-33236 Some Possible Alternatives for Longer-Life Locomotive Wheels
British Library Conference Proceedings | 2005
|IMECE2002-33236 Some Possible Alternatives for Longer-Life Locomotive Wheels
British Library Conference Proceedings | 2002
|Engineering Index Backfile | 1912
Engineering Index Backfile | 1931
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