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The operating conditions for heavy rails are becoming more and more stringent. Up to now, rails with very high hardness requirements could be manufactured according to two different methods. One of these methods was to add to the analysis of grade 900 A steel some alloying elements. These rails, called natural hardened rails, had the disadvantage of poor toughness. The second technique uses the off line thermal treatment process. The disadvantage of this technology is more costly production. In order to reduce the high costs, the Métallurgique et Minière de Rodange-Athus (MMRA) in collaboration with the Centre de Recherches Métallurgiques de Liège (CRM) has developed an in line heat treatment of the rails, called CHHR (continued head hardened rails). The pilot project developed at MMRA has shown that in line heat treatment of rails is industrially feasible. The quality of the rails produced by the CHHR head hardening process has been characterized by different series of tests such as tensile tests and tests for toughness, fatigue resistance, crack propagation. wear resistance and residual stresses. In all cases, the results exceeded those of natural hardened rails. Rails produced economically by the CHHR process, show equivalent behaviour in track to those produced by the off line method.

Additional information

Authors: BOUCHOMS J, Métallurgie et Minière de Rodange-Athus (FR);RASQUIN M, Métallurgie et Minière de Rodange-Athus (FR)
Bibliographic Reference: EUR 15812 FR (1996) 166pp., FS, ECU 18.50
Availability: Available from the (2)
ISBN: ISBN 92-827-6795-7
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