A Novel Approach to Rail Welding: Aluminothermic Angle Welding

摘要

Modern railroads design is based in a continuous railway that is usually joined by electric flash butt welding (EFBW) and thermite welding (TW). This approach is used to increase safety and reduce maintenance costs associated with bolted joints. Unfortunately, TW joints have a coarser microstructure and are prone to metallurgical defects resulting in a region of lower structural and mechanical characteristics in a way that most of all failures on rail occurs in TW joints. This work reports the initial test results obtained with novel approach to the TW geometry. Conventional TW joints are at a 90 degree angle with the railway as a result of this all the longitudinal, thermal and residual stresses that the rail is subjected has to be fully supported by the TW joint. In this work TW joints at 30 and 45 degree angle with the railway were performed. Fatigue tests, metallurgical characterization, and hardness profiles were performed on the joints. The results indicated a satisfactory behavior to the angle welds. However, some improvements in mold design and welding procedures must be made to the new technique be approved by all subjected related norms.