The Novel Technique of Grain Refinement in the Aluminum-Free Ultrahigh Carbon Steel

In order to achieve high strength and toughness of the aluminum-free ultrahigh carbon steel (UHCS), the effect of a novel three-parameter combination technique including heating temperature, cooling rate, and isothermal eutectoid transformation time on the phase composition, grain morphology, and mechanical properties is investigated by X-ray diffraction analysis, optical microscopy, and mechanical tests. The result shows that when the steel is cooled from 860 °C to the eutectoid transformation temperature with the rate of 1.0 °C s−1 and held for 1.5 h, the excellent mechanical properties are obtained due to the grain refinement of carbide and matrix.