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dc.contributor.authorBernås, Mia
dc.contributor.authorWestermann, Ida
dc.contributor.authorJohnsen, Roy
dc.contributor.authorTorres Rodriguez, Cristian
dc.contributor.authorJernberg, Anders
dc.contributor.authorQvale, Atle H
dc.contributor.authorIannuzzi, Manuela
dc.date.accessioned2019-02-27T13:24:15Z
dc.date.available2019-02-27T13:24:15Z
dc.date.created2018-12-20T17:21:30Z
dc.date.issued2018
dc.identifier.citationInternational Corrosion Conference Series. 2018, 2018-April 1-15.nb_NO
dc.identifier.issn0361-4409
dc.identifier.urihttp://hdl.handle.net/11250/2587840
dc.description.abstractAlthough extensively used in oil and gas production due to their excellent combination of mechanical properties and corrosion resistance, 25Cr super duplex stainless steels (SDSSs) are susceptible to the precipitation of deleterious phases during heat treatment and welding. Deleterious phases, in turn, affect both localized corrosion resistance and mechanical properties. Much debate still exists as to whether alloying elements such as tungsten accelerate or retard the formation of detrimental precipitates. In this work, the effect of W on the precipitation kinetics of three 25Cr SDSS grades, namely, UNS S32750 (W-free), S32760 (Low-W), and S39274 (High-W) was quantified in Time-Temperature-Transformation (TTT) diagrams. Optical microscopy, scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDS), and Electron backscatter diffraction (EBSD) were used to characterize the microstructure evolution and construct the TTT diagrams. The effect of intermetallic compounds (IMCs) and tertiary phases on localized corrosion resistance was investigated as a function of volume fraction and type of precipitate, with a focus on σ– and �–phase formation. The localized corrosion resistance of the various metallurgical stages was determined using open circuit potential measurements as a function of temperature during immersion in 6 wt% FeCl3 pH = 1.0. The σ–phase precipitation rate was slower in the High-W SDSS compared to the other alloys, possibly due to �–phase precipitation at grain boundaries. At 846°C, the isothermal heating time required to observe a drop in Critical Pitting Temperature (CPT) doubled for the High-W SDSS. The implications of these findings in materials selection for oil and gas production equipment are discussed. Key words: duplex stainless steels, seawater, critical pitting temperature, sigma phase, chi phase, chromium nitrides, time-temperature-transformation diagram.nb_NO
dc.language.isoengnb_NO
dc.publisherNACE Internationalnb_NO
dc.titleEffect of tungsten on the precipitation kinetics and localized corrosion resistance of super duplex stainless steelsnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.description.versionpublishedVersionnb_NO
dc.source.pagenumber1-15nb_NO
dc.source.volume2018-Aprilnb_NO
dc.source.journalInternational Corrosion Conference Seriesnb_NO
dc.identifier.cristin1646458
dc.description.localcodeThis article will not be available due to copyright restrictions (c) 2018 by NACE Internationalnb_NO
cristin.unitcode194,66,35,0
cristin.unitcode194,64,92,0
cristin.unitnameInstitutt for materialteknologi
cristin.unitnameInstitutt for maskinteknikk og produksjon
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode1


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