Vanadium - Transforming Possibilities

Development of a Low Carbon Vanadium-Copper-Chromium Rail Steel of Improved Weldability for Curves And Points in European Railways

Abstract:

In Europe, rails for normal service contain 0.4 to% carbon and 0.8 to 1.2% manganese. Higher carbon and/or manganese steels are used in track locations where severe wear occurs, such as tight curves, marshalling yards, points and switches. These higher carbon steels are more difficult to weld and are subject to fatigue failure, especially at points and switches.

A study was conducted at Ghent University to develop a lower carbon steel which would be more easily weldable and yet wear resistant enough to be used in locations of high wear. Strengthening was done with additions of copper, chromium, and vanadium, and the effects of these elements on tensile properties of 0.4% carbon steel presented. Based on these laboratory studies, production heats were made in Luxembourg of a steel containing approximately 0.4% C, 1.4% Mn, 0.5% Si, 0.4% Cu, 0.8% Cr, 0.2%Ni, and 0.17% V. These heats were rolled into 50 and 60 kg/m rails. Yield strengths ranged from 610 to 862 N/mm2 (88 to 124 ksi) while tensile strengths ranged from 990 to 1160N/mm2 (144 to 168 ksi). Service performance was evaluated over 2 years at 9 track sites in the Belgian Railway System, including severe curves.

Profile measurements of these low-carbon rails revealed that their wear resistance is at least equal to that of higher carbon as-rolled grades. The steel has also given satisfactory performance for over 2 years in points where high-carbon rails failed due to fatigue and where conventional low-carbon manganese steel rails would have to be replaced after 12 months. 

Keywords:

vanadium, rail steel, weldability.

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