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The aim of the project was to establish the relationships among fatigue and fracture behaviour, level of applied stress, different residual stresses fields, microstructures and weld defects of two different grades of rail welded by thermit, metal arc and flash butt welding methods.
Two different types of rail grade have been investigated in particular: low-alloyed steel rail grade 1100 and heat-treated grade HT. Two different levels of residual stresses have been achieved on grade 1100.
Both parent materials and welded rails have been characterized in terms of chemical analysis, metallographic investigations, fatigue crack propagation behaviour, fracture toughness, hardness and residual stresses. Furthermore, full-scale tests have been carried out: static bending tests, fatigues lateral bending tests on web, fatigue longitudinal bending tests with axial pre-load.
The parent material of rail grade HT shows a better mechanical performance in comparison with rail grade 1100. This behaviour is in agreement with the results of metallographic investigations.
The fatigue behaviour of welded joints of grade 1100 is better than that of grade HT, due to a more favourable distribution of both hardness and residual stresses. Better performance of rail grade HT might be obtained by an optimization of welding parameters based on the special chemical characteristics of the rail steel. el.

Additional information

Authors: DEMOFONTI G, CSM, Rome (IT);BUDANO S, CSM, Rome (IT);VIGLIALORO C, CSM, Rome (IT);JÖLLER A, Voest-Alpine, Leoben, Donawitz (AT)
Bibliographic Reference: EUR 19988 EN (2001), pp. 158. Euro: 23.50
Availability: Available from EUR-OP sales agent URL:
ISBN: ISBN 92-894-1589-4