Paper Title:

The Formation of Ultrafine Ferrite and Low Temperature Bainite through Thermomechanical Processing

Periodical Materials Science Forum (Volumes 706 - 709)
Main Theme THERMEC 2011
Chapter Chapter 18: Steels
Edited by T. Chandra, M. Ionescu and D. Mantovani
Pages 2047-2052
DOI 10.4028/
Citation Hossein Beladi et al., 2012, Materials Science Forum, 706-709, 2047
Online since January 2012
Authors Hossein Beladi, Ilana B. Timokhina, Peter D. Hodgson
Keywords Low Temperature Bainite, Thermomechanical Processing (TMP), Ultra Fine Ferrite, Warm Deformation
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In the current study, a novel approach was employed to produce a unique combination of ultrafine ferrite grains and low temperature bainite in a low carbon steel with a high hardenability. The thermomechanical route included warm deformation of supercooled austenite followed by reheating in the ferrite region and then cooling to bainitic transformation regime (i.e. 400-250°C). The resultant microstructure was ultrafine ferrite grains (i.e. <4μm) and very fine bainite consisting of bainitic ferrite laths with high dislocation density and retained austenite films. This microstructure offers a unique combination of ultimate tensile strength and elongation due to the presence of ductile fine ferrite grains and hard low temperature bainitic ferrite laths with retained austenite films. The microstructural characteristics of bainite were studied using optical microscopy in conjunction with scanning and transmission electron microscopy techniques.