<p>Oscillating laser technology demonstrates effectively effective improvement in coating formability and microstructure refinement. This study fabricates tungsten carbide (WC)/Stellite 6 composite coatings on high-chromium cast iron BTMCr20 using circular oscillating laser cladding to examine the effects of WC content (0–30 wt.%) on the microstructure and mechanical properties. Results indicate that laser oscillation induces mechanical stirring that enhances molten pool convection, effectively inhibiting WC particle settling and maintaining uniform distribution even at 30 wt.% WC. In addition to the inherent grain refinement effect of the oscillating laser, the increasing WC content provides additional heterogeneous nucleation sites, leading to further microstructural refinement. This resulted in a reduction of the average grain size by approximately 40% compared to the coating without WC, which is attributed to the presence of reinforcing phases such as W₂C, Fe₇W₆, and Cr₇C₃. Microhardness and wear resistance improve linearly with WC content, reaching 613 HV_0.2 and 2.17 × 10⁻⁴ mm³ wear volume at 30 wt.% WC. The wear mechanism transitions from mixed abrasive-adhesive to predominantly abrasive wear. Impact toughness peaks at 10.59&#xa0;J/cm² with 20 wt.% WC, attributed to synergistic grain refinement, dispersed carbides, and ductile γ-Co phase. These findings provide valuable guidance for microstructural control in particle-reinforced laser-clad coatings.</p>