Thermite welding is a common and effective method for permanently joining rails in railway construction, renovation and maintenance projects, and is widely used, especially in the implementation of long-welded rails. In this method, the exothermic reaction of thermite powder produces molten steel at a very high temperature, which, after being poured into a mold, fills the space between the two ends of the rail and creates a uniform and strong connection. The simplicity of implementation at the project site and the lack of the need for heavy electrical equipment are the main reasons for the widespread use of this process in railway operational projects.
The thermite welding process involves specific steps including preparing and accurately aligning the rail heads, installing the refractory mold, preheating, performing the thermite reaction, and finally cutting and grinding the weld. Accuracy in adjusting the rail expansion gap and controlling the preheating temperature plays a decisive role in the final quality of the weld. Any deviation in these steps can lead to metallurgical defects or reduce the mechanical strength of the joint, affecting the performance of the line.
The equipment used in thermite welding includes thermite crucible, refractory molds appropriate to the rail section, preheating torch, excess cutting tools, and final grinding machine. The selection of standard equipment and approved consumables, especially in industrial and manufacturing projects of companies, leads to uniform weld quality and reduces the need for early repairs. Coordination of this equipment with the actual conditions of the project is considered a factor in the success of field implementations.
Due to the extremely high temperatures and chemical nature of the process, it is essential to comply with safety requirements in thermite welding. The use of personal protective equipment and clothing, control of the work area, training of personnel, and adherence to approved safety guidelines are among the essential measures in this regard. Compliance with these requirements, in addition to maintaining employee safety, will ensure the stable and reliable implementation of thermite welding in the company’s actual projects.
