Effect of WC Content on the Microstructure and Wear Performance of Laser Cladding Fe‐Based Coatings on ER8 Carbon Steel

Wheels, as the core load‐carrying parts of electric multiple unit (EMU) trains, are prone to wear and tear during long‐term use. In this work, Fe/tungsten carbide (WC) composite coatings with varying WC contents are prepared on ER8 carbon steel for EMU train wheels using laser cladding with a semiconductor laser. WC content is taken as the key variable in the experiment. The microstructure, hardness, and wear performance of the coatings are primarily analyzed. These results indicate that the coating without WC particles outperforms the substrate. The addition of WC particles leads to grain refinement and the formation of M 23 C 6 , M 7 C 3 (M=Fe, Cr), and Fe 3 W 3 C carbides from WC decomposition, which contribute to solid solution strengthening and second‐phase strengthening, thus increasing the hardness and wear resistance of the coatings. The wear mechanisms are mainly abrasive and oxidative wear, and fatigue rupture of the WC particles is also observed. During the wear process, the hard phase WC serves as a structural backbone, reducing cutting actions, interrupting scratches, and retaining fragmented wear debris.