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Title: Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting

Abstract

A high strength low alloy steel composition has been melted and processed by two different routes: simulated direct strip casting and slow cooled ingot casting. The microstructures were examined with scanning and transmission electron microscopy, atom probe tomography and small angle neutron scattering (SANS). The formation of cementite (Fe{sub 3}C), manganese sulphides (MnS) and niobium carbo-nitrides (Nb(C,N)) was investigated in both casting conditions. The sulphides were found to be significantly refined by the higher cooling rate, and developed an average diameter of only 100 nm for the fast cooled sample, and a diameter too large to be measured with SANS in the slow cooled condition (> 1.1 μm). Slow cooling resulted in the development of classical Nb(C,N) precipitation, with an average diameter of 7.2 nm. However, after rapid cooling both the SANS and atom probe tomography data indicated that the Nb was retained in the matrix as a random solid solution. There was also some evidence that O, N and S are also retained in solid solution in levels not found during conventional processing. - Highlights: • The influence of cooling rate on microstructure is investigated in a HSLA steel. • SANS, TEM and APT are used to characterise themore » sulphides and Nb(C,N) precipitates. • The slow cooling rate result in the formation of Nb(C,N) precipitates. • The fast cooling rate results in a microstructure supersaturated in Nb, C and N. • The sulphides are 100 nm in the fast cooled sample and > 1 μm in the slow cooled one.« less

Authors:
 [1];  [2]; ; ;  [1]
  1. Deakin University, Pigdons Road, Geelong, Victoria, 3216 (Australia)
  2. Australian Nuclear Science and Technology Organisation, Bragg Institute, New South Wales, 2234, Menai (Australia)
Publication Date:
OSTI Identifier:
22587107
Resource Type:
Journal Article
Journal Name:
Materials Characterization
Additional Journal Information:
Journal Volume: 112; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1044-5803
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; CASTING; CASTINGS; CEMENTITE; LOW ALLOY STEELS; MANGANESE; MANGANESE SULFIDES; MICROSTRUCTURE; NEUTRON DIFFRACTION; PRECIPITATION; SMALL ANGLE SCATTERING; SOLID SOLUTIONS; TRANSMISSION ELECTRON MICROSCOPY

Citation Formats

Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au, Wood, Kathleen, Taylor, Adam, Hodgson, Peter, and Stanford, Nicole. Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting. United States: N. p., 2016. Web. doi:10.1016/J.MATCHAR.2015.12.028.
Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au, Wood, Kathleen, Taylor, Adam, Hodgson, Peter, & Stanford, Nicole. Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting. United States. doi:10.1016/J.MATCHAR.2015.12.028.
Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au, Wood, Kathleen, Taylor, Adam, Hodgson, Peter, and Stanford, Nicole. Mon . "Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting". United States. doi:10.1016/J.MATCHAR.2015.12.028.
@article{osti_22587107,
title = {Quantitative examination of carbide and sulphide precipitates in chemically complex steels processed by direct strip casting},
author = {Dorin, Thomas, E-mail: thomas.dorin@deakin.edu.au and Wood, Kathleen and Taylor, Adam and Hodgson, Peter and Stanford, Nicole},
abstractNote = {A high strength low alloy steel composition has been melted and processed by two different routes: simulated direct strip casting and slow cooled ingot casting. The microstructures were examined with scanning and transmission electron microscopy, atom probe tomography and small angle neutron scattering (SANS). The formation of cementite (Fe{sub 3}C), manganese sulphides (MnS) and niobium carbo-nitrides (Nb(C,N)) was investigated in both casting conditions. The sulphides were found to be significantly refined by the higher cooling rate, and developed an average diameter of only 100 nm for the fast cooled sample, and a diameter too large to be measured with SANS in the slow cooled condition (> 1.1 μm). Slow cooling resulted in the development of classical Nb(C,N) precipitation, with an average diameter of 7.2 nm. However, after rapid cooling both the SANS and atom probe tomography data indicated that the Nb was retained in the matrix as a random solid solution. There was also some evidence that O, N and S are also retained in solid solution in levels not found during conventional processing. - Highlights: • The influence of cooling rate on microstructure is investigated in a HSLA steel. • SANS, TEM and APT are used to characterise the sulphides and Nb(C,N) precipitates. • The slow cooling rate result in the formation of Nb(C,N) precipitates. • The fast cooling rate results in a microstructure supersaturated in Nb, C and N. • The sulphides are 100 nm in the fast cooled sample and > 1 μm in the slow cooled one.},
doi = {10.1016/J.MATCHAR.2015.12.028},
journal = {Materials Characterization},
issn = {1044-5803},
number = ,
volume = 112,
place = {United States},
year = {2016},
month = {2}
}