University of Oulu

Pashangeh, S.; Ghasemi Banadkouki, S.S.; Somani, M.; Kömi, J. Characteristics and Kinetics of Bainite Transformation Behaviour in a High-Silicon Medium-Carbon Steel above and below the Ms Temperature. Materials 2022, 15, 539. https://doi.org/10.3390/ma15020539

Characteristics and kinetics of bainite transformation behaviour in a high-silicon medium-carbon steel above and below the Mₛ temperature

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Author: Pashangeh, Shima1; Banadkouki, Seyed Sadegh Ghasemi1; Somani, Mahesh2;
Organizations: 1Department of Mining and Metallurgical Engineering, Yazd University, University Blvd, Safayieh, Yazd P.O. Box 98195-741, Iran
2Materials and Mechanical Engineering, Centre for Advanced Steels Research, University of Oulu, P.O. Box 4200, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.5 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2022041128056
Language: English
Published: Multidisciplinary Digital Publishing Institute, 2022
Publish Date: 2022-04-11
Description:

Abstract

This work deals with the kinetic aspects of bainite formation during isothermal holding above and below the martensite start (Mₛ~275 °C) temperature using a low-alloy, high-silicon DIN 1.5025 steel in a range suitable for achieving ultrafine/nanostructured bainite. Dilatation measurements were conducted to study transformation behaviour and kinetics, while the microstructural features were examined using laser scanning confocal microscopy and electron backscatter diffraction (EBSD) techniques combined with hardness measurements. The results showed that for isothermal holding above the Mₛ temperature, the maximum bainitic transformation rate decreased with the decrease in isothermal holding temperature between 450 and 300 °C. On the other hand, for isothermal holding below the Mₛ temperature at 250 and 200 °C, the maximum rate of transformation was achieved corresponding to region I due to the partitioning of carbon and also possibly because of the ledged growth of isothermal martensite soon after the start of isothermal holding. In addition, a second peak was obvious at about 100 and 500 s, respectively, during holding at 250 and 200 °C due to the occurrence of bainitic transformation, marking the beginning of region II.

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Series: Materials
ISSN: 1996-1944
ISSN-E: 1996-1944
ISSN-L: 1996-1944
Volume: 15
Issue: 2
Article number: 539
DOI: 10.3390/ma15020539
OADOI: https://oadoi.org/10.3390/ma15020539
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: This research was funded by the Genome of Steel (Profi3) by the Academy of Finland, grant number 311934.
Copyright information: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
  https://creativecommons.org/licenses/by/4.0/