University of Oulu

Pashangeh, S., Somani, M. C., Ghasemi Banadkouki, S. S., Karimi Zarchi, H. R., Kaikkonen, P., & Porter, D. A. (2020). On the decomposition of austenite in a high-silicon medium-carbon steel during quenching and isothermal holding above and below the Ms temperature. Materials Characterization, 162, 110224. https://doi.org/10.1016/j.matchar.2020.110224

On the decomposition of austenite in a high-silicon medium-carbon steel during quenching and isothermal holding above and below the Mₛ temperature

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Author: Pashangeh, Shima1,2; Somani, Mahesh Chandra1; Ghasemi Banadkouki, S.S.2;
Organizations: 1University of Oulu, Materials and Mechanical Engineering, Centre for Advanced Steels Research, Post Box 4200, 90014 Oulu, Finland
2Mining Technologies Research Center, Department of Mining and Metallurgical Engineering, Yazd University, University Blvd, Safayieh, Yazd, PO Box: 98195-741, Iran
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.1 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2020041618912
Language: English
Published: Elsevier, 2020
Publish Date: 2020-04-16
Description:

Abstract

The microstructural mechanisms operating during the decomposition of austenite in a high-Si, medium‑carbon steel (Fe-0.53C-1.67Si-0.72Mn-0.12Cr) subjected to quenching and isothermal holding at temperatures above and below the martensite start (Mₛ) temperature for times up to 1 h have been investigated using a Gleeble 3800 thermomechanical simulator. Dilatometry and metallography using laser scanning microscopy, transmission electron microscopy, scanning electron microscopy together with X-ray diffraction and hardness measurements have been employed. Treatment with the quench stop and isothermal hold both above and below Ms lead to the formation of both martensite and bainite. In the case of isothermal treatment above Mₛ, at 350 and 300 °C, high‑carbon martensite is formed during the final cooling to room temperature. In the case of isothermal treatment at temperatures below Mₛ, at 250 and 200 °C, the initial martensite formation and subsequent carbon partitioning to austenite is followed by the formation of bainite containing carbides and high‑carbon martensite that forms during the final cooling to room temperature. Despite the presence of the high silicon content, carbides are able to form even at the lowest temperature studied (200 °C). All treatments led to the presence of carbon enriched retained austenite, which ranged from 4 to 18 vol%. The variation of room temperature hardness as a function of isothermal holding time at the various temperatures is rationalized in terms of the microstructural development.

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Series: Materials characterization
ISSN: 1044-5803
ISSN-E: 1873-4189
ISSN-L: 1044-5803
Volume: 162
Article number: 110224
DOI: 10.1016/j.matchar.2020.110224
OADOI: https://oadoi.org/10.1016/j.matchar.2020.110224
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Subjects:
Funding: The funding of this research activity under the auspices of the Genome of Steel (Profi3) by the Academy of Finland through project #311934 is gratefully acknowledged. S. Pashangeh expresses her gratitude to the Ministry of Science Research and Technology in Iran for funding a research visit to the University of Oulu, Finland to conduct this research work.
Academy of Finland Grant Number: 311934
Detailed Information: 311934 (Academy of Finland Funding decision)
Copyright information: © 2020 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/).
  https://creativecommons.org/licenses/by-nc-nd/4.0/