This paper details the field-testing approach and results of thermite welds used in railway applications. Rail steels made from R260 grades are welded by two different processes: the standard process according to EN standards, and the innovative ‘ALFONS’ technology. Welds are introduced in the same testing location to ensure comparable loading conditions in the aim of studying their degradation behaviours. The total testing-period is 6 months. During the in-service period, the surface hardness of the running band, in the welded area, is recurrently measured. For an accurate assessment of field results, a vehicle/track interaction (VTI) model evaluated the expected dynamic loads induced by the initial vertical irregularities.

The simulations show that the highest dynamic load at the wheel/rail contact happens at the location of the maximum absolute gradient, in accordance with previous research. Particularly, dipped welds show relatively high dynamic forces inducing a high loss of the transversal profile. In respect of the field results, the comparison of initial and final surface hardness indicates a significant increase for ‘ALFONS’ welds over the welded areas. Additionally, all welds depicted a cyclic increase and decrease of the running band hardness. This result is discussed according to the ratcheting susceptibility of welds and eventual wear progression. For a testing-period of 10 weeks, the gauge corner of one ‘ALFONS’ weld developed a crack. The assessment of the longitudinal profiles revealed changes of the vertical irregularities that may modify the dynamic loads, and further the rolling contact fatigue mechanisms and degradation rates.

本文详细介绍了铁路应用中铝热焊缝的现场测试方法和结果。由 R260 等级制成的轨道钢通过两种不同的工艺焊接：符合 EN 标准的标准工艺和创新的“ALFONS”技术。在相同的测试位置引入焊缝，以确保可比较的加载条件，以研究其降解行为。总测试期为6个月。在使用期间，运行带在焊接区域的表面硬度被反复测量。为了准确评估现场结果，车辆/轨道相互作用 (VTI) 模型评估了由初始垂直不规则引起的预期动态载荷。

根据先前的研究，模拟表明轮轨接触处的最高动态载荷发生在最大绝对梯度的位置。特别是，浸渍焊缝表现出相对高的动态力，导致横向轮廓的高损失。就现场结果而言，初始和最终表面硬度的比较表明，“ALFONS”焊缝在焊接区域的显着增加。此外，所有焊缝都表现出运行带硬度的循环增加和减少。这个结果是根据焊缝的棘轮敏感性和最终的磨损进展来讨论的。在 10 周的测试期间，一个“ALFONS”焊缝的量规角出现了裂纹。