engleski

Arc welding of grooved rails – manual metal arc welding versus flux cored arc welding

Experience collected by the members of the Chair for Railways during 15 years of the supervision of re/construction of tram tracks in the Croatian capital Zagreb and city of Osijek revealed that the largest percentage of local rail damage occurs at the welded rail joints. Poorly performed and unmaintained rail welds cause increased dynamic impacts on the vehicles and the track itself that result in reduced safety and passenger comfort, faster degradation of the track and more frequent need for maintenance of both tracks and tram vehicles. Generally, production of high quality rail welds primarily depends on the applied method of welding, welder's skill and experience and the quality of welded rails steel. The paper compares two methods of arc welding technique: classical MM AW (Manual Metal Arc Welding) method traditionally used on the Zagreb Municipal Transit System – ZET Ltd network and more up–to–date FCAW (Flux Cored Arc Welding) method which has not yet found a wider application in Croatia. A description of welding technology as well as measurement and analysis of rail surface hardness in the weld zone and rail welds tensile strength has been given. The results of the tests were supposed to answer the question whether the application of this modern welding technology, in addition to shortening the time of welding procedure, also improves the quality of the rail joints. Comparison of results led to the conclusion that the FCAW welding method is favourable for welding standard grooved rails. It is to expect that the described testing will contribute to faster adoption of this method for welding grooved rails in ZET Ltd network. Also, conducted measurements and analysis are a good background for further research and provide useful, scientifically based conclusions applicable to the everyday engineering practice.

grooved rail; manual metal arc welding; Innershield weld; hardness; tensile strength

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