Effects of vanadium on the microstructures and mechanical properties of microalloyed steel for the forged wheels

In this study, the microstructure and mechanical properties of vanadium (V) microalloyed wheel steel were investigated to elucidate the strengthening mechanisms and microstructural evolution. The incorporation of 0.13 wt% V not only refined the austenite grain size but also promoted the formation of an increased ferrite content and reduced pearlite lamellar spacing. Compared to plain carbon (C) wheel steels without vanadium, the 0.13 wt% V alloy exhibited superior yield strength, tensile strength, and hardness while maintaining comparable fracture toughness. The addition of 0.13 wt% V enhanced the precipitation of vanadium-rich particles in pro-eutectoid ferrite, contributing significantly to strengthening. The primary mechanisms responsible for the improved strength and refined microstructure were identified as precipitation strengthening and grain refinement. Interphase precipitation was observed in the vanadium-microalloyed wheel steel, with high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS) confirming the presence of nanosized VC carbides.