Authors: I.I. Chumachkov, S.V. Konovalov, M.A. Martynov

Title of the article: Study of the influence of joint shape on the strength of welded rail joint

Year: 2024, Issue: 6, Pages: 14-27

Branch of knowledge: 2.5.8. Welding, related processes and technologies

Index UDK: 625.143.482

DOI: 10.26730/1999-4125-2024-6-14-27

Abstract: The increase in load capacity and the development of high-speed traffic on the railway network entails increased rail wear. To date, rail lashes with a length of 800 meters are manufactured in stationary conditions of rail welding enterprises by the electric contact welding method. The welded joint is superior to the link structure and is a more advanced way of connecting rails, however, the strength of the joint is currently not comparable to the strength of the base metal of the rails. During operation, the metal in the joint area deforms, cracks form, leading to discoloration of the rail head, which leads to a more intensive development of contact fatigue defects. When passing a rolling stock at a certain moment, the load from the wheel is completely concentrated in the zone of minimum mechanical properties at the place of fusion. The effect of the angle of inclination of the seam on the strength of the welded joint during contact welding has not been sufficiently studied. According to the requirements of the regulatory documentation, welding of rails with a braid is not allowed. Nevertheless, by changing the geometric parameters of the welded ends, it is possible to redistribute the load in the joint and increase its strength. Welding of rails of type R65, category DT350 steel grade 76XF was performed on a contact welding machine MSR-63.01A by pulsating reflow in the conditions of JSC EVRAZ ZSMK. The effect of the geometry of the ends on the strength of the welded joint during the three-point static bending test was investigated. The influence of the geometry of the ends of the rails on the changes in the welding process for each stage was evaluated according to the cyclogram. The redistribution of the zone of thermal influence and the fusion line relative to the ends with classical geometry was recorded, and graphs of hardness changes in the seam area were constructed. Oblique reflection of the ends increases the strength of the welded joint due to a decrease in the proportion of the seam in the cross section of the load application. Large protrusions increase the likelihood of welding defects.

Key words: Welding rails contact welding bevel

Receiving date: 03.09.2024

Approval date: 22.11.2024

Publication date: 05.12.2024

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