High-Speed Quenching Dilatometer Investigation of the Austenite-to-Ferrite Transformation in a Low to Ultralow Carbon Steel

摘要

The austenite-to-ferrite transformation is investigated in two Fe-C alloys with carbon mass fractions w_C of 0.007 and 0.15 pct using a high-speed quenching dilatometer. The specimens are austenitized at 925 deg C and then quenched to holding temperatures between 890 deg C and 750 deg C. In the alloy with lowest carbon content, two stages of phase transformation can be identified. The first stage is extremely fast. The second stage is slower and can be clearly distinguished from the first stage. The nature of the two-stage transformation is explored.