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 °C and then quenched to holding temperatures between 890 °C and 750 °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.