Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C

Oxidation tests using coupon specimens of alloy 625 and alloy 617, and four-point bending tests for a duration of 100 hrs were carried out in supercritical water (SCW) environment at a pressure of 24 MPa and in superheated steam (SHS) environments at 750°C. The noticeable difference between the oxid...

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Autores principales:	Tatsuya ISHIKAWA, Yuji OZAWA, Masashi SAITO, Susumu NAKANO, Yoichi TAKEDA
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2017
Materias:	a-usc alloy 625 alloy 617 supercritical water oxidation four-point bending test weight gain pitting aes Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/3377886b00704474b275813106429a4e
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spelling	oai:doaj.org-article:3377886b00704474b275813106429a4e2021-11-26T07:11:27ZAnalysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C2187-974510.1299/mej.17-00013https://doaj.org/article/3377886b00704474b275813106429a4e2017-10-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/4/5/4_17-00013/_pdf/-char/enhttps://doaj.org/toc/2187-9745Oxidation tests using coupon specimens of alloy 625 and alloy 617, and four-point bending tests for a duration of 100 hrs were carried out in supercritical water (SCW) environment at a pressure of 24 MPa and in superheated steam (SHS) environments at 750°C. The noticeable difference between the oxidation in two environments appeared in the oxidation behavior of primary precipitates like Nb rich MC carbide for alloy 625. In the SCW environment, a large number of pitting was observed. Those were thought to be made by electrochemical reactions, while in SHS most of the carbides were oxidized as Nb oxides with some extent of volume expansion. In the case of alloy 617, the pitting formation was also observed in both environments. It seemed to have a dependence on the oxidation behavior of the primary carbides similar to that of alloy 625. The effect of the applied stress was not apparent under current experimental conditions because permanent deformation was observed in all the specimens and stress relaxation subsequently occurred during the test. In addition, no cracks were observed on both alloys after four-point bending tests. In the outer layer of the oxide film formed in the SCW, the Cr content exhibit to have smaller in both alloys, and the oxide thicknesses were 0.53 to 0.88 times thinner than those in the SHS.Tatsuya ISHIKAWAYuji OZAWAMasashi SAITOSusumu NAKANOYoichi TAKEDAThe Japan Society of Mechanical Engineersarticlea-uscalloy 625alloy 617supercritical wateroxidationfour-point bending testweight gainpittingaesMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 4, Iss 5, Pp 17-00013-17-00013 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	a-usc alloy 625 alloy 617 supercritical water oxidation four-point bending test weight gain pitting aes Mechanical engineering and machinery TJ1-1570
spellingShingle	a-usc alloy 625 alloy 617 supercritical water oxidation four-point bending test weight gain pitting aes Mechanical engineering and machinery TJ1-1570 Tatsuya ISHIKAWA Yuji OZAWA Masashi SAITO Susumu NAKANO Yoichi TAKEDA Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
description	Oxidation tests using coupon specimens of alloy 625 and alloy 617, and four-point bending tests for a duration of 100 hrs were carried out in supercritical water (SCW) environment at a pressure of 24 MPa and in superheated steam (SHS) environments at 750°C. The noticeable difference between the oxidation in two environments appeared in the oxidation behavior of primary precipitates like Nb rich MC carbide for alloy 625. In the SCW environment, a large number of pitting was observed. Those were thought to be made by electrochemical reactions, while in SHS most of the carbides were oxidized as Nb oxides with some extent of volume expansion. In the case of alloy 617, the pitting formation was also observed in both environments. It seemed to have a dependence on the oxidation behavior of the primary carbides similar to that of alloy 625. The effect of the applied stress was not apparent under current experimental conditions because permanent deformation was observed in all the specimens and stress relaxation subsequently occurred during the test. In addition, no cracks were observed on both alloys after four-point bending tests. In the outer layer of the oxide film formed in the SCW, the Cr content exhibit to have smaller in both alloys, and the oxide thicknesses were 0.53 to 0.88 times thinner than those in the SHS.
format	article
author	Tatsuya ISHIKAWA Yuji OZAWA Masashi SAITO Susumu NAKANO Yoichi TAKEDA
author_facet	Tatsuya ISHIKAWA Yuji OZAWA Masashi SAITO Susumu NAKANO Yoichi TAKEDA
author_sort	Tatsuya ISHIKAWA
title	Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
title_short	Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
title_full	Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
title_fullStr	Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
title_full_unstemmed	Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C
title_sort	analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°c
publisher	The Japan Society of Mechanical Engineers
publishDate	2017
url	https://doaj.org/article/3377886b00704474b275813106429a4e
work_keys_str_mv	AT tatsuyaishikawa analysisoflocalizedoxidesandoxidefilmsformedonalloy625and617insupercriticalwaterandsuperheatedsteamenvironmentsat750c AT yujiozawa analysisoflocalizedoxidesandoxidefilmsformedonalloy625and617insupercriticalwaterandsuperheatedsteamenvironmentsat750c AT masashisaito analysisoflocalizedoxidesandoxidefilmsformedonalloy625and617insupercriticalwaterandsuperheatedsteamenvironmentsat750c AT susumunakano analysisoflocalizedoxidesandoxidefilmsformedonalloy625and617insupercriticalwaterandsuperheatedsteamenvironmentsat750c AT yoichitakeda analysisoflocalizedoxidesandoxidefilmsformedonalloy625and617insupercriticalwaterandsuperheatedsteamenvironmentsat750c
_version_	1718409710328086528

Analysis of localized oxides and oxide films formed on alloy 625 and 617 in supercritical water and superheated steam environments at 750°C

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