Effect of the metallurgical state of austenite on the microtexture properties of the bainitic transformation in a low alloy steel

Sophie Lubin (1) , Anne-Françoise Gourgues-Lorenzon (1) , Brigitte Bacroix (2) , Hélène Regle (3) , Frank Montheillet (4, 5)

1 CDM - Centre des Matériaux
2 PMTM - Propriétés mécaniques et thermodynamiques des matériaux
3 ICMMO - Institut de Chimie Moléculaire et des Matériaux d'Orsay
4 LCG-ENSMSE - UMR 5146 - Laboratoire Claude Goux
5 RMT-ENSMSE - Département Rhéologie, Microstructure, Thermomécanique

The effect of the metallurgical state of austenite (undeformed vs. deformed vs. deformed + recrystallised) on the properties of the austenite to bainite transformation were investigated thanks to thermal (Gleeble simulations) and thermomechanical (hot torsion) treatments. No obvious influence of the state of austenite was found, using electron backscatter diffraction, on the resulting microtexture. Advantages and drawbacks of using misorientation angle histograms vs. axis-angle pair distribution are discussed regarding investigations of local variant selection. For an austenite grain size higher than about 50 µm, a strong effect of the transformation temperature was evidenced, bainite formed at lower temperature (530°C) exhibiting a microtexture close to that of lath martensite in the same steel.

Mots clés: Bainite; steels; variant selection; electron backscatter diffraction; hot torsion

Domaines: Matériaux

Sophie Lubin, Anne-Françoise Gourgues-Lorenzon, Brigitte Bacroix, Hélène Regle, Frank Montheillet. Effect of the metallurgical state of austenite on the microtexture properties of the bainitic transformation in a low alloy steel. Solid-solid phase transformations in inorganic materials, Jun 2010, Avignon, France. pp.772-777, ⟨10.4028/www.scientific.net/SSP.172-174.772⟩. ⟨hal-00624009⟩