Microstructural evolution and wear mechanism analysis in hot-rolled high-chromium cast iron/carbon steel laminates

This study investigates the effects of hot rolling deformation on the microstructural evolution and wear mechanisms of laminated high-chromium cast iron (HCCI)/low-carbon steel composites. Vacuum-assisted hot rolling at 1200 °C with 30–60 % reduction produced pronounced refinement and dispersion of primary carbides, enhanced interfacial bonding, and transformation of the martensitic matrix to austenite. SEM and EBSD analyses revealed reduced carbide size and increased fractions of small-angle grain boundaries. Nanoindentation confirmed hardening of M 7 C 3 carbides and concurrent matrix softening, whereas hardness and impact toughness increased by 40–65 %. Tribological tests demonstrated a 48 % reduction in wear track depth and a shift in the dominant wear mechanism from oxidative–abrasive to oxidative–fatigue modes. The superior performance is attributed to the synergistic effects of carbide strengthening, matrix plasticity, and stable tribofilm formation. These findings demonstrate that thermomechanical processing offers a viable route for improving both wear resistance and toughness in HCCI-based laminates.