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Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles

Inclusion-induced acicular ferrite (AF) nucleation has been used for microstructure refinement in steel. Austenitization conditions have a significant influence on AF nucleation ability. In this paper, the effects of austenitization temperature and holding time on the transformation behaviors of low...

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Autores principales: Wang, Chao, Wang, Xin, Kang, Jian, Yuan, Guo, Wang, Guodong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480536/
https://www.ncbi.nlm.nih.gov/pubmed/30939817
http://dx.doi.org/10.3390/ma12071070
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author Wang, Chao
Wang, Xin
Kang, Jian
Yuan, Guo
Wang, Guodong
author_facet Wang, Chao
Wang, Xin
Kang, Jian
Yuan, Guo
Wang, Guodong
author_sort Wang, Chao
collection PubMed
description Inclusion-induced acicular ferrite (AF) nucleation has been used for microstructure refinement in steel. Austenitization conditions have a significant influence on AF nucleation ability. In this paper, the effects of austenitization temperature and holding time on the transformation behaviors of low carbon steel containing Ti–Ca oxide particles were studied. A thermal treatment experiment, high temperature in situ observation, and calculation of Mn diffusion were carried out. The results indicate that small austenite grain size under low austenitizing temperature promoted grain boundary reaction products. With an increase in austenitizing temperature, the nucleation sites transferred to intragranular particles and AF transformation was improved. The inclusion particles in the Ti–Ca deoxidized steel were featured by an oxide core rich in Ti and a lesser amount of Ca and with MnS precipitation on the local surface, which showed a strong ability to promote AF nucleation. At a low austenitizing temperature, Mn diffusion was limited and the development of Mn-depleted zones (MDZs) around inclusions was not sufficient. The higher diffusion capacity of Mn at a high austenitizing temperature promoted the formation of MDZs to a larger degree and increased the AF nucleation ability. Boron segregation at large-sized austenite grain boundaries played an important role in AF transformation. Austenite grain size, Mn-depleted zone development, and boron segregation at grain boundaries were the decisive factors influencing the transformation behaviors under different austenitization conditions for the test steel.
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spelling pubmed-64805362019-04-29 Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles Wang, Chao Wang, Xin Kang, Jian Yuan, Guo Wang, Guodong Materials (Basel) Article Inclusion-induced acicular ferrite (AF) nucleation has been used for microstructure refinement in steel. Austenitization conditions have a significant influence on AF nucleation ability. In this paper, the effects of austenitization temperature and holding time on the transformation behaviors of low carbon steel containing Ti–Ca oxide particles were studied. A thermal treatment experiment, high temperature in situ observation, and calculation of Mn diffusion were carried out. The results indicate that small austenite grain size under low austenitizing temperature promoted grain boundary reaction products. With an increase in austenitizing temperature, the nucleation sites transferred to intragranular particles and AF transformation was improved. The inclusion particles in the Ti–Ca deoxidized steel were featured by an oxide core rich in Ti and a lesser amount of Ca and with MnS precipitation on the local surface, which showed a strong ability to promote AF nucleation. At a low austenitizing temperature, Mn diffusion was limited and the development of Mn-depleted zones (MDZs) around inclusions was not sufficient. The higher diffusion capacity of Mn at a high austenitizing temperature promoted the formation of MDZs to a larger degree and increased the AF nucleation ability. Boron segregation at large-sized austenite grain boundaries played an important role in AF transformation. Austenite grain size, Mn-depleted zone development, and boron segregation at grain boundaries were the decisive factors influencing the transformation behaviors under different austenitization conditions for the test steel. MDPI 2019-04-01 /pmc/articles/PMC6480536/ /pubmed/30939817 http://dx.doi.org/10.3390/ma12071070 Text en © 2019 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
Wang, Chao
Wang, Xin
Kang, Jian
Yuan, Guo
Wang, Guodong
Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title_full Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title_fullStr Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title_full_unstemmed Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title_short Effect of Austenitization Conditions on the Transformation Behavior of Low Carbon Steel Containing Ti–Ca Oxide Particles
title_sort effect of austenitization conditions on the transformation behavior of low carbon steel containing ti–ca oxide particles
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6480536/
https://www.ncbi.nlm.nih.gov/pubmed/30939817
http://dx.doi.org/10.3390/ma12071070
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