BRAZE WELDING OF AUSTENITE-COPPER FOR RAIL TRANSPORT APPLICATIONS

Abstract

Each locomotive repair operation requires the locomotive to be taken out of service for the duration of the repair. Meanwhile, another locomotive must be substituted while the original locomotive is out of service to maintain the scheduled services. When such an operation is not possible, there may be shifts in the train schedule or delays in the implementation of planned routes, which negatively affect transport logistics. The survey conducted by experts presented in this article indicates that one of the problems associated with locomotive exploitation is cooling system failures. The aim of the article is to present a solution that increases the exploitation time of the cooling systems. The article develops optimal braze welding parameters and verifies the quality of joints produced using brazes with different chemical compositions. The proposed method provides environmental benefits due to its lower energy consumption and contributes to reducing operational damage to cooling systems. Furthermore, reducing the number of repairs decreases the number of locomotives withdrawn from service, thereby improving operational logistics. This article outlines a method for the braze welding of austenitic steel-to-copper joints used in locomotives that employs various copper electrode wires with varying silicon content. In addition, it establishes the process parameters. A copper wire containing 2% Si yielded the best results. The study also identified welding current and braze welding speed as the most critical process parameters. The article introduces a modification to the brazing-welding process for joining copper with austenitic steel in locomotive cooling systems, replacing the previously used tin-alloyed copper wires with silicon-alloyed copper wires. This study fills a research gap by determining the optimal silicon content for copper wires.