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Title: Variation of carbon concentration in proeutectoid ferrite during austenitization in hypoeutectoid steel

Abstract

The variation of the C concentration in proeutectoid ferrite (α{sub PF}) during austenitization in hypoeutectoid steels was quantitatively investigated using the massive transformation start temperature (T{sub m}) of α{sub PF} to austenite (γ) measured by high-temperature confocal laser scanning microscopy and hardness of α{sub PF}. The C concentration in α{sub PF} at T{sub m} in hypoeutectoid steels increased with increasing total C concentration up to approximately 0.2 wt.% during heating. The hardness of α{sub PF} with isothermal holding time at 775 °C in S20C steel revealed C enrichment in α{sub PF} at the early stage of isothermal holding and its reduction with further holding. These results explain the redistribution of the C in α{sub PF} during austenitization as follows: free C atoms released from cementite during pearlite decomposition diffuse excessively into neighboring α{sub PF} as well as pearlitic ferrite. The supersaturated C concentration in α{sub PF} is reduced during the long-range diffusive transformation of α{sub PF} to γ. However, some of the excess C atoms still remain in α{sub PF} until α{sub PF} starts to massively transform to γ. - Highlights: • Massive transformation of αPF to γ in hypoeutectoid steels was observed using CLSM. • C content in αPFmore » during austenitization was analyzed by measured Tm and hardness. • Tm decreases and C content in αPF at Tm increases with increasing total C. • C atoms released from θ during formation of P to γ diffuse excessively into αPF. • Supersaturated C content in αPF is reduced during transformation of αPF to γ.« less

Authors:
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Publication Date:
OSTI Identifier:
22403528
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 94; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AUGMENTATION; AUSTENITE; CARBON; CEMENTITE; CONCENTRATION RATIO; FERRITE; HARDNESS; LASER RADIATION; MICROSCOPY; PHASE TRANSFORMATIONS; STEELS; VARIATIONS; VICKERS HARDNESS

Citation Formats

Jung, Minsu, Cho, Wontae, Park, Jihye, Jung, Jae-Gil, and Lee, Young-Kook, E-mail: yklee@yonsei.ac.kr. Variation of carbon concentration in proeutectoid ferrite during austenitization in hypoeutectoid steel. United States: N. p., 2014. Web. doi:10.1016/J.MATCHAR.2014.05.009.
Jung, Minsu, Cho, Wontae, Park, Jihye, Jung, Jae-Gil, & Lee, Young-Kook, E-mail: yklee@yonsei.ac.kr. Variation of carbon concentration in proeutectoid ferrite during austenitization in hypoeutectoid steel. United States. doi:10.1016/J.MATCHAR.2014.05.009.
Jung, Minsu, Cho, Wontae, Park, Jihye, Jung, Jae-Gil, and Lee, Young-Kook, E-mail: yklee@yonsei.ac.kr. Fri . "Variation of carbon concentration in proeutectoid ferrite during austenitization in hypoeutectoid steel". United States. doi:10.1016/J.MATCHAR.2014.05.009.
@article{osti_22403528,
title = {Variation of carbon concentration in proeutectoid ferrite during austenitization in hypoeutectoid steel},
author = {Jung, Minsu and Cho, Wontae and Park, Jihye and Jung, Jae-Gil and Lee, Young-Kook, E-mail: yklee@yonsei.ac.kr},
abstractNote = {The variation of the C concentration in proeutectoid ferrite (α{sub PF}) during austenitization in hypoeutectoid steels was quantitatively investigated using the massive transformation start temperature (T{sub m}) of α{sub PF} to austenite (γ) measured by high-temperature confocal laser scanning microscopy and hardness of α{sub PF}. The C concentration in α{sub PF} at T{sub m} in hypoeutectoid steels increased with increasing total C concentration up to approximately 0.2 wt.% during heating. The hardness of α{sub PF} with isothermal holding time at 775 °C in S20C steel revealed C enrichment in α{sub PF} at the early stage of isothermal holding and its reduction with further holding. These results explain the redistribution of the C in α{sub PF} during austenitization as follows: free C atoms released from cementite during pearlite decomposition diffuse excessively into neighboring α{sub PF} as well as pearlitic ferrite. The supersaturated C concentration in α{sub PF} is reduced during the long-range diffusive transformation of α{sub PF} to γ. However, some of the excess C atoms still remain in α{sub PF} until α{sub PF} starts to massively transform to γ. - Highlights: • Massive transformation of αPF to γ in hypoeutectoid steels was observed using CLSM. • C content in αPF during austenitization was analyzed by measured Tm and hardness. • Tm decreases and C content in αPF at Tm increases with increasing total C. • C atoms released from θ during formation of P to γ diffuse excessively into αPF. • Supersaturated C content in αPF is reduced during transformation of αPF to γ.},
doi = {10.1016/J.MATCHAR.2014.05.009},
journal = {Materials Characterization},
number = ,
volume = 94,
place = {United States},
year = {Fri Aug 15 00:00:00 EDT 2014},
month = {Fri Aug 15 00:00:00 EDT 2014}
}