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In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process
The relationships between initial microstructures, process parameters, and grain evolutions in isothermal holdings have drawn wide attention in recent years, but the grain growth behaviors of 300M steel were not well understood, resulting in a failure in precise microstructure controlling in heat tr...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2018
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213102/ https://www.ncbi.nlm.nih.gov/pubmed/30274356 http://dx.doi.org/10.3390/ma11101862 |
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author | Chen, Rongchuang Zheng, Zhizhen Li, Jianjun Li, Ning Feng, Fei |
author_facet | Chen, Rongchuang Zheng, Zhizhen Li, Jianjun Li, Ning Feng, Fei |
author_sort | Chen, Rongchuang |
collection | PubMed |
description | The relationships between initial microstructures, process parameters, and grain evolutions in isothermal holdings have drawn wide attention in recent years, but the grain growth behaviors of 300M steel were not well understood, resulting in a failure in precise microstructure controlling in heat treatment. In this work, in situ observations were carried out to characterize the grain evolutions of 300M steel with varying holding time, holding temperatures, and initial microstructures. The intriguing finding was that the grain refinement by austenization of 300M steel was followed by a dramatic grain growth in the initial stage of holding (≤~600 s), and with increasing time (~600–7200 s), the average grain size appeared to have a limit value at specific temperatures. The austenization process accelerated the grain growth by generating large quantity of grain boundaries at the initial stage of holdings, and the growth rate gradually slowed down after holding for ~600 s because the driven force was weakened due to the reduction of grain boundary energy. The initial structure and the initial grain size of 300M steel had no obvious influences on the grain size evolutions. The mechanisms of grain growth were analyzed based on in situ observations and transmission electron microscope (TEM) characterizations. A grain evolution model considering the grain boundary migration of 300M steel was established for the isothermal holding process. Good agreement was obtained between the in situ observation results and the model calculation results. This investigation aimed to understand fundamentally the grain evolutions of 300M steel in the isothermal holding process. |
format | Online Article Text |
id | pubmed-6213102 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2018 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-62131022018-11-14 In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process Chen, Rongchuang Zheng, Zhizhen Li, Jianjun Li, Ning Feng, Fei Materials (Basel) Article The relationships between initial microstructures, process parameters, and grain evolutions in isothermal holdings have drawn wide attention in recent years, but the grain growth behaviors of 300M steel were not well understood, resulting in a failure in precise microstructure controlling in heat treatment. In this work, in situ observations were carried out to characterize the grain evolutions of 300M steel with varying holding time, holding temperatures, and initial microstructures. The intriguing finding was that the grain refinement by austenization of 300M steel was followed by a dramatic grain growth in the initial stage of holding (≤~600 s), and with increasing time (~600–7200 s), the average grain size appeared to have a limit value at specific temperatures. The austenization process accelerated the grain growth by generating large quantity of grain boundaries at the initial stage of holdings, and the growth rate gradually slowed down after holding for ~600 s because the driven force was weakened due to the reduction of grain boundary energy. The initial structure and the initial grain size of 300M steel had no obvious influences on the grain size evolutions. The mechanisms of grain growth were analyzed based on in situ observations and transmission electron microscope (TEM) characterizations. A grain evolution model considering the grain boundary migration of 300M steel was established for the isothermal holding process. Good agreement was obtained between the in situ observation results and the model calculation results. This investigation aimed to understand fundamentally the grain evolutions of 300M steel in the isothermal holding process. MDPI 2018-09-30 /pmc/articles/PMC6213102/ /pubmed/30274356 http://dx.doi.org/10.3390/ma11101862 Text en © 2018 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 (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Chen, Rongchuang Zheng, Zhizhen Li, Jianjun Li, Ning Feng, Fei In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title | In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title_full | In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title_fullStr | In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title_full_unstemmed | In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title_short | In Situ Investigation of Grain Evolution of 300M Steel in Isothermal Holding Process |
title_sort | in situ investigation of grain evolution of 300m steel in isothermal holding process |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213102/ https://www.ncbi.nlm.nih.gov/pubmed/30274356 http://dx.doi.org/10.3390/ma11101862 |
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