A New Method of Rail Head Hardening of Standard-Gauge Rails for Improved Wear and Damage Resistance

• Published in: Steel research international 2013-01, Vol.84 (1), p.13-19
• Main Authors: Kuziak, Roman, Zygmunt, Tomasz
• Format: Article
• Language: English
• Subjects: Cooling; Cross sections; fatigue; Hardening; Immersion; Mechanical properties; Metallurgy; pearlitic structure; rail head hardening process; Rails; Steel hardening; Steel products; Structural steels; Thermal cycling; wear; Wear resistance
• ISSN: 1611-3683; 1869-344X
• DOI: 10.1002/srin.201200140

A new method of cyclic‐accelerated cooling of the head of pearlitic rails to increase their performance in service was described in this paper. It is essentially based upon the head's immersion in aqueous polymer solution. However, as opposed to the methods developed so far, the head's immersion is performed cyclically by raising and lowering the level of the cooling solution, dividing the entire process into fast and slow cooling stages. When the intervals of the fast and slow cooling stages are properly defined, there is no necessity to control the time of the entire process to prevent the bainite/martensite formation. The most important effect of the cyclic cooling is that the entire time of the process can be adjusted to obtain fine pearlitic structure in the whole cross‐section of the head. Applying this technology, the head hardened rails were produced at Huta Królewska S.A. and tested successfully in track. This paper describes a new method of in line rail head hardening process consisting in cyclic immersion of rail's head in the aqueous polymer solution. The method enables very uniform hardening of rail's head without sadden drop in hardness. The head hardened rails were produced with the application of the new method and tested in the severe exploitation conditions giving positive results.