Effect of W Content in Flux‐Cored Wires on Microstructures and Properties of the Welding Interface in TiC Steel‐Bonded Cemented Carbide

This study investigates the effects of tungsten (W) on the microstructures and mechanical properties of the welding interface in TiC steel‐bonded cemented carbide (TiC‐SBCC) by depositing low‐alloy steel flux‐cored wires (FCWs) via arc welding. The research focuses on adjusting the W content (0–2.1 wt%) in the FCW, elemental diffusion across the TiC‐SBCC/weld metal interface. Results demonstrate that W addition undergoes reprecipitation and epitaxial growth in TiC surfaces, forming of (Ti, Mo, W)C solid solutions “core‐rim” particles in the fusion zone, which effectively inhibit TiC particle decomposition. The dissolved W atoms in the binder induce lattice distortion, elevating dislocation density to activate dislocation strengthening. These modifications drive a nonmonotonic shear strength response, peak shear strength reaching 816.3 MPa (0.7 wt% W), which is 1.7× higher than the base TiC‐SBCC (480 MPa). The hardness increases monotonically with W addition due to solid‐solution saturation. Optimized W content (0.7 wt%) establishes a crack‐resistant fusion zone through synergistic suppression of particle decomposition by rim phases and dislocation‐mediated strengthening, providing a pathway for high‐reliability carbide/steel joints in extreme service environments.