Occurrence of dynamic ferrite transformation in low-carbon steel above Ae3

Dynamic ferrite transformation behavior was investigated over a wide temperature range using a 6Ni–0.1C steel. Softening in flow stress due to dynamic transformation was observed at temperatures above Ae3, the ortho-equilibrium austenite-to-ferrite transformation temperature. Microstructural observation revealed that ferrite grains formed at temperatures above Ae3 showed deformation microstructures, and those grains were reversely transformed to austenite during subsequent holding at the same temperature. Therefore, we concluded that dynamic ferrite transformation could certainly occur even above Ae3.