One of the oldest welding methods involves using a large amount of heat produced by powerful exothermic reactions of metallic oxides. This maximally efficient process is also used to weld rail tracks. The process can be applied in two ways: either by using the heat produced by thermite welding, during which the filler material is melted and the rails are perfectly bonded, or by heating the rails to a high temperature, and then force-pressing and forging them together.
Unlike the other welding process, thermite welding (TW) doesn’t need to produce a high-temperature arc. Instead, it uses the heat resulting from a strong exothermic reaction. Usually, the reactants used in thermite welding operations are metals and metallic oxides.
Iron and aluminum oxide powders are used to join railroad tracks. In the beginning, the ends of the railway tracks are placed and aligned according to predetermined dimensions. Refractory material is placed on the mold assembly where the heating of the thermite occurs, and where the exothermic reaction will take place.
When the railway tracks are heated to the required temperature, the melted reaction products are poured into the mold to fill the gap between the rail tracks. After cooling, the entire assembly is removed, and a finishing operation will be performed to create a perfect joint of the rail tracks.