Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels
Autor(a) principal: | |
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Data de Publicação: | 2020 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Materials research (São Carlos. Online) |
Texto Completo: | http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500208 |
Resumo: | Abstract Duplex stainless steels (DSS) are used in off-shore platforms due to their good properties resulting from the combination of two phases, namely austenite and ferrite. Secondary intermetallic phases, such as alpha prime (α´) and sigma (σ), which are harmful, can be formed at temperatures above 400 °C, or by a casting process. This study investigates the formation of sigma phase by thermal cycles running in a dilatometer (800 °C, 850 °C, 900 °C and 1,000 °C) for 1h, and at 850 °C for 3h and 7h. The optical microscopy of the DSS microstructure subjected to 800, 850 and 900 °C for one hour revealed a small fraction of σ phase with nucleation in the contour of ferrite/austenite phases, and tests by ferritoscope indicated a decrease (~4%) in a magnetic fraction (ferrite). However, samples subjected to dilatometric cycles at 850 °C for 3 hours showed an 18% decrease in the magnetic phase and quantitative metallography revealed a 33% fraction of σ phase precipitated in the ferrite phase. Tests conducted at 850 ºC for 7 hours indicated a high fraction of σ phase precipitated (approximately 50%), starting in the grain boundary, austenite/ferrite, and advancing in ferrite grain. |
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Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless SteelsDuplex Stainless Steel (DSS)DilatometerSigma PhaseQuantitative MetallographyFerristoscopeIntermetallic PhasesAbstract Duplex stainless steels (DSS) are used in off-shore platforms due to their good properties resulting from the combination of two phases, namely austenite and ferrite. Secondary intermetallic phases, such as alpha prime (α´) and sigma (σ), which are harmful, can be formed at temperatures above 400 °C, or by a casting process. This study investigates the formation of sigma phase by thermal cycles running in a dilatometer (800 °C, 850 °C, 900 °C and 1,000 °C) for 1h, and at 850 °C for 3h and 7h. The optical microscopy of the DSS microstructure subjected to 800, 850 and 900 °C for one hour revealed a small fraction of σ phase with nucleation in the contour of ferrite/austenite phases, and tests by ferritoscope indicated a decrease (~4%) in a magnetic fraction (ferrite). However, samples subjected to dilatometric cycles at 850 °C for 3 hours showed an 18% decrease in the magnetic phase and quantitative metallography revealed a 33% fraction of σ phase precipitated in the ferrite phase. Tests conducted at 850 ºC for 7 hours indicated a high fraction of σ phase precipitated (approximately 50%), starting in the grain boundary, austenite/ferrite, and advancing in ferrite grain.ABM, ABC, ABPol2020-01-01info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersiontext/htmlhttp://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500208Materials Research v.23 n.5 2020reponame:Materials research (São Carlos. Online)instname:Universidade Federal de São Carlos (UFSCAR)instacron:ABM ABC ABPOL10.1590/1980-5373-mr-2020-0252info:eu-repo/semantics/openAccessSouza,Elki C.Bueno,Raiched F.Fortulan,Carlos A.Rollo,João M. D. A.eng2020-10-22T00:00:00Zoai:scielo:S1516-14392020000500208Revistahttp://www.scielo.br/mrPUBhttps://old.scielo.br/oai/scielo-oai.phpdedz@power.ufscar.br1980-53731516-1439opendoar:2020-10-22T00:00Materials research (São Carlos. Online) - Universidade Federal de São Carlos (UFSCAR)false |
dc.title.none.fl_str_mv |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
title |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
spellingShingle |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels Souza,Elki C. Duplex Stainless Steel (DSS) Dilatometer Sigma Phase Quantitative Metallography Ferristoscope Intermetallic Phases |
title_short |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
title_full |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
title_fullStr |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
title_full_unstemmed |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
title_sort |
Dilatometric Cycles in the Study of Precipitation of Intermetallic Phases in Duplex Stainless Steels |
author |
Souza,Elki C. |
author_facet |
Souza,Elki C. Bueno,Raiched F. Fortulan,Carlos A. Rollo,João M. D. A. |
author_role |
author |
author2 |
Bueno,Raiched F. Fortulan,Carlos A. Rollo,João M. D. A. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Souza,Elki C. Bueno,Raiched F. Fortulan,Carlos A. Rollo,João M. D. A. |
dc.subject.por.fl_str_mv |
Duplex Stainless Steel (DSS) Dilatometer Sigma Phase Quantitative Metallography Ferristoscope Intermetallic Phases |
topic |
Duplex Stainless Steel (DSS) Dilatometer Sigma Phase Quantitative Metallography Ferristoscope Intermetallic Phases |
description |
Abstract Duplex stainless steels (DSS) are used in off-shore platforms due to their good properties resulting from the combination of two phases, namely austenite and ferrite. Secondary intermetallic phases, such as alpha prime (α´) and sigma (σ), which are harmful, can be formed at temperatures above 400 °C, or by a casting process. This study investigates the formation of sigma phase by thermal cycles running in a dilatometer (800 °C, 850 °C, 900 °C and 1,000 °C) for 1h, and at 850 °C for 3h and 7h. The optical microscopy of the DSS microstructure subjected to 800, 850 and 900 °C for one hour revealed a small fraction of σ phase with nucleation in the contour of ferrite/austenite phases, and tests by ferritoscope indicated a decrease (~4%) in a magnetic fraction (ferrite). However, samples subjected to dilatometric cycles at 850 °C for 3 hours showed an 18% decrease in the magnetic phase and quantitative metallography revealed a 33% fraction of σ phase precipitated in the ferrite phase. Tests conducted at 850 ºC for 7 hours indicated a high fraction of σ phase precipitated (approximately 50%), starting in the grain boundary, austenite/ferrite, and advancing in ferrite grain. |
publishDate |
2020 |
dc.date.none.fl_str_mv |
2020-01-01 |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500208 |
url |
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-14392020000500208 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
10.1590/1980-5373-mr-2020-0252 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.format.none.fl_str_mv |
text/html |
dc.publisher.none.fl_str_mv |
ABM, ABC, ABPol |
publisher.none.fl_str_mv |
ABM, ABC, ABPol |
dc.source.none.fl_str_mv |
Materials Research v.23 n.5 2020 reponame:Materials research (São Carlos. Online) instname:Universidade Federal de São Carlos (UFSCAR) instacron:ABM ABC ABPOL |
instname_str |
Universidade Federal de São Carlos (UFSCAR) |
instacron_str |
ABM ABC ABPOL |
institution |
ABM ABC ABPOL |
reponame_str |
Materials research (São Carlos. Online) |
collection |
Materials research (São Carlos. Online) |
repository.name.fl_str_mv |
Materials research (São Carlos. Online) - Universidade Federal de São Carlos (UFSCAR) |
repository.mail.fl_str_mv |
dedz@power.ufscar.br |
_version_ |
1754212677790466048 |