Effect of ultrasonic-assisted laser melting on the coating organization and properties of the central trough of scraper conveyor

To refine the grain organization of the coating and improve the quality of the fused coating, ultrasound-assisted laser cladding technology was used to prepare WC-Fe60 composite coating on the surface of 16Mn steel. With the help of a metallurgical microscope, microhardness tester, scanning electron microscope, energy spectrum analyzer, ray diffractometer, friction and wear testing machine, and other means of characterization, the physical composition of the coating, macroscopic morphology, microstructure, hardness distribution, friction factor, and other parameters were analyzed and tested. The results indicate that the surface of the cladding layer prepared with ultrasonic vibration became smoother, and the slag reduced in size and quantity. The cavitation effect and acoustic streaming generated by ultrasonic vibration refine the coating grains, primarily composed of small equiaxed crystals with a minor amount of dendrites. There was a significant reduction in pores and cracks within the coating, and the intense high-frequency vibration homogenized the distribution of coating elements. The coating phase consists of α-Fe, γ-Fe, M23C6 (M: Cr, W, or Fe), and WC. Following the application of ultrasonic vibration, the average microhardness of the coating reached 1150HV0.5, marking a 30% increase compared to the coating without ultrasonic vibration. The friction coefficient stood at 0.60, a decrease of ∼14%, resulting in improved wear resistance. Ultrasound-assisted laser cladding notably enhances the quality of the prepared coating, densifies the microstructure, and boosts hardness and wear resistance. This study offers a theoretical foundation for the advancement of wear-resistant materials and the refinement of surface hardening techniques.