Title: Effects of the austenite grain size on transformation plasticity in a 35 NCD 16 steel

Authors: Achraf Boudiaf, Lakhdar Taleb, Mohamed El Amine Belouchrani

Addresses: Laboratoire Genie des Materiaux, Ecole Militaire Polytechnique, BP 17 – 16111 Bordj El-Bahri Alger, Algerie; Groupe de Physique des Materiaux, UMR CNRS 6634, INSA Rouen, BP 08, Avenue de l'universite 76800, St Etienne du Rouvray, France. ' Groupe de Physique des Materiaux, UMR CNRS 6634, INSA Rouen, BP 08, Avenue de l'universite 76800, St Etienne du Rouvray, France. ' Laboratoire Genie des Materiaux, Ecole Militaire Polytechnique, BP 17 – 16111 Bordj El-Bahri Alger, Algerie

Abstract: In this work, the influence of the austenitic grain size (AGS) on the transformation induced plasticity (TRIP) was experimentally studied. The study was undertaken in the case of the martensitic transformation of a 35NCD16 steel. Transformation induced plasticity tests (TRIP tests) were carried out under various conditions of austenitisation leading to different grain sizes of austenite. Two studies have been performed leading to different observations. In the first study, where the heating rate during austenitisation was relatively fast (50°C/s), the results seem indicate that the transformation induced plasticity is higher when the austenitic grain size is smaller (Boudiaf et al., 2008). In the second study we have considered a slower heating rate during austenitisation (0.5°C/s) on specimens manufactured from another batch of the same steel. Different results were then obtained where TRIP increases slightly with the grain size. However, the uncertainties pointed out in assessing TRIP incite to be more careful. The work is still in progress in order to clarify the observed difference evaluating in particular the role of the heating rate during the austenitic transformation.

Keywords: transformation plasticity; austenite grain size; martensitic transformation; ferritic steel; heating rate.

DOI: 10.1504/IJMMP.2010.037611

International Journal of Microstructure and Materials Properties, 2010 Vol.5 No.4/5, pp.338 - 353

Published online: 20 Dec 2010 *

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