An integrated computer model with applications for austenite-to-ferrite transformation during hot deformation of Nb-microalloyed steels
Abstract
This work presents an austenite decomposition model, based on the thermodynamics of the system and diffusion-controlled nucleation theory, to predict the evolution of microstructure during hot working of niobium-microalloyed steels. The differences in microstructural development of hotdeformed microalloyed steel in the single-phase austenite and two-phase (austenite + ferrite) regions have been effectively described using an integrated computer modeling process. The complete model presented here takes into account the kinetics of recrystallization, recrystallized austenite grain size, precipitation, phase transformation, and the resulting ferrite structure. After considering existing austenite decomposition models, we decided that the method adopted in the present work relies on isothermal transformation kinetics and the principle-of-additivity rule. The thermomechanical part of the modeling process was carried out using the finite-element method. Experimental results at different temperatures, strain rates, and strain levels were obtained using a Gleeble thermomechanical simulator. A comparison of results of the model with experiments shows good agreement.
- Publication:
-
Metallurgical and Materials Transactions A
- Pub Date:
- May 2002
- DOI:
- 10.1007/s11661-002-0073-x
- Bibcode:
- 2002MMTA...33.1509M
- Keywords:
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- Ferrite;
- Austenite;
- Material Transaction;
- Iron Steel Inst;
- Transformation Kinetic