Surface Damage Regeneration in Railway Wheels

This study examines the applicability of Plasma Transferred Arc (PTA) surface treatment as an advanced technique for the refurbishment of railway wheel treads. Conventional wheel reprofiling, typically performed on semi-automatic lathes, requires the removal of a minimum of 6 mm of material from the running surface, which accelerates rim thinning and ultimately necessitates wheel replacement. Moreover, the reprofiled surfaces are not subjected to any subsequent treatment aimed at enhancing their durability. To overcome these limitations, PTA cladding was selected due to its ability to generate surface layers with superior mechanical and tribological properties. In contrast to widely used diode laser technologies, PTA enables the deposition of alloying materials in powder form, ensuring a stable, controllable, and efficient cladding process. The resulting microstructure consists of a heat-affected zone, a transition zone, and a re-melted zone, each exhibiting significantly increased hardness relative to the untreated base material. The process facilitates the incorporation of metallic particles into the surface layer, promoting the formation of a dense, wear-resistant coating. These materials possess huge potential utility regarding the wear resistance reaching even ca 10% of the base material wear in the case of 505 PTA and over 20% in the case of the 15 E material. The findings indicate that PTA surface treatment has substantial potential to extend the operational lifespan of railway wheels by providing a highly durable and mechanically robust surface, thereby reducing maintenance frequency and the associated costs.