Zhao, H. and Palmiere, E.J. orcid.org/0000-0002-4048-8536 (2018) Effect of austenite grain size on acicular ferrite transformation in a HSLA steel. Materials Characterization, 145. pp. 479-489. ISSN 1044-5803
Abstract
Austenite grain size is well known to have a significant influence on various phase transformations in steels. Although the effects of many thermomechanical processing parameters on acicular ferrite (AF) transformation in HSLA steels have been investigated, little attention has been paid to the influence of austenite grain size. Therefore, in this research, different parameters of solid-solution heat treatment and rough deformation were adopted to generate austenite with different grain sizes and the effects of austenite grain size before deformation on the AF transformation and grain refinement were investigated. It was found that the reduction of prior-austenite grain size (PAGS) from 62.8 μm to 37.0 μm before austenite deformation promotes the AF transformation and simultaneously refines and homogenises the transformed microstructures. A reciprocally increased density of deformation induced dislocations with the reduction of PAGS was proposed to account for these results, which not only increase the nucleation sites of AF but also suppress the lengthening of BF laths. Further reducing PAGS from 37.0 μm to 22.3 μm, the fraction of AF is not increased and the transformed microstructure is not refined. Possible differences in the type, distribution, and density of austenite deformation substructures between austenite with PAGSs of 37.0 μm and 22.3 μm were argued to be responsible for the cease of grain refinement. The relationship between effective grain sizes and the Sv parameter was investigated and an equation relating effective grain sizes with processing parameters was also proposed.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 Elsevier. This is an author produced version of a paper subsequently published in Materials Characterization. Uploaded in accordance with the publisher's self-archiving policy. Article available under the terms of the CC-BY-NC-ND licence (https://creativecommons.org/licenses/by-nc-nd/4.0/). |
Keywords: | Austenite grain size; Acicular ferrite; Effective grain size; Bainitic ferrite; Austenite deformation |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 21 Jun 2019 14:33 |
Last Modified: | 13 Sep 2019 00:38 |
Status: | Published |
Publisher: | Elsevier |
Refereed: | Yes |
Identification Number: | 10.1016/j.matchar.2018.09.013 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:147656 |