Kinetics of ferrite to Widmanstatten austenite transformation in high strength low alloy steels

The growth kinetics of ferrite to Widmanstatten austenite transformation ha s been studied in two compositions of HSLA steels, one containing Nb and th e other Ti and V. The Widmanstatten structure is observed late during the f errite to austenite transformation in both steels when the carbon diffusion field has diminished. Whereas distinct plate morphology of the Widmanstatt en austenite is observed above 1073 K, both plate and needles are observed at intermediate transformation temperature and only needles at low temperat ure. The data have been analysed using theoretical models developed by Triv edi.