Increasing Wear Strength and Life Cycle of Tamping Machine Tool by Silicon Carbide Coating for Railway Maintenance

When a train passes continuously over a section of the track, the track gradually moves away from the intended vertical and horizontal alignment with time and repeated use. Regular maintenance on the track, such as leveling, lifting, lining, and tamping, is necessary to maintain the optimal geometry of the track. Ballast is leveled and squeezed by hydraulic rams in tamping machines. The tamping is a process of ballast packing under railway tracks. In current system a set of tungsten carbide chips are attached either by welding or by coating on tamping tool tip made of EN24 steels. These tungsten carbide chips directly come in contact with the ballasts. After few tamping works, gradually these chips torn out and need to be replaced after certain period. Tungsten carbide is a costly material, therefore this research deals with replacement of tungsten carbide with silicon carbide (easily available cheaper) coating used for tamping tools tip. The study consists of microstructural examination of both materials. The SEM analysis shows that SiC coatings provide a more uniform, dense, and defect-free surface with finer grain structures. SiC coatings adhere better to the EN24 steel substrate, as seen in optical microscopy images. Result shows that tungsten carbide-coated sample exhibited the higher average wear rate, and the silicon carbide-coated sample displayed the lower average wear rate.