Abstract
The formation of austenite during intercritical annealing at temperatures between 740 and 900 °C was studied in a series of 1.5 pct manganese steels containing 0.06 to 0.20 pct carbon and with a ferrite-pearlite starting microstructure, typical of most dual-phase steels.
Austenite formation was separated into three stages: (1) very rapid growth of austenite into pearlite until pearlite dissolution is complete; (2) slower growth of austenite into ferrite at a rate that is controlled by carbon diffusion in austenite at high temperatures (~85O °C), and by manganese diffusion in ferrite (or along grain boundaries) at low temperatures
(~750 °C); and (3) very slow final equilibration of ferrite and austenite at a rate that is controlled by manganese diffusion in austenite. Diffusion models for the various steps were analyzed and compared with experimental results.
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Speich, G.R., Demarest, V.A. & Miller, R.L. Formation of Austenite During Intercritical Annealing of Dual-Phase Steels. Metall Trans A 12, 1419–1428 (1981). https://doi.org/10.1007/BF02643686
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DOI: https://doi.org/10.1007/BF02643686