STUDY OF EXOTHERMIC WELDED JOINT GRINDING BY "SPENO" RAIL GRINDERS

Exothermic welding joint is one of most common welded joints used in Europe. Latvian railway also uses exothermic welding for its rails in crossing pieces, station and railroad haul sections. Rail grinders are used to extend lifespan and maintain the tread surface of the rail's head and to remove and eliminate defects in the surface layer and to reduce corrugated rail wear. Rail grinders supplied by the company "Speno" are used in Latvian railways. This article will discuss the quality of grinding of exothermic welding joint of rail profile 60 E1 by "Speno" rail grinder. The research also includes analysis of ground rails in the Latvian railway during 2014, 2015, 2016, 2017 and 2018. First, detailed hardness of metal has been determined: on the tread surface, head, web and base, according to the Brinell scale by using the modern equipment "Tinius O Olsen" Fikrmware Version 1.07, FH-31 Series. Second, the chemical composition of an exothermic welding joint of rail steel (in head, web, base) has been examined with the optical emission spectrometer "ARC-MET 8000 Mobile Lab". The obtained data have been compared to standard technical documentation provided by the manufacturer. And third, in the final stage of the study, the structure of the exothermic welding joint of rail steel was determined and the main conclusions drawn concerning the quality of grinding and its impact on exothermic welding joints of rail profile 60 E1.