Corrosion Behaviour of Alloy 800H in Low Density Superheated Steam

Bsat, Suzan; Huang, Xiao

doi:10.2355/isijinternational.isijint-2015-651

Cited by 12 publications

(4 citation statements)

References 25 publications

(30 reference statements)

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“…were compared to values provided by Bsat & Huang [2016] and Sanchez et al [2018]. The oxide phase composition values calculated in this study show excellent correspondence with those provided by Bsat & Huang [2016]. Except for (Ni,Fe)Cr2O4 and Fe2CrO4, excellent correspondence was also observed between the oxide phase composition values calculated in this study and those provided by Sanchez et al [2018].…”

Section: A2 Corroborating the Oxide Phase Compositionssupporting

confidence: 70%

Section: A2 Corroborating the Oxide Phase Compositionssupporting

confidence: 60%

“…5.2). After 1,000 hours of exposing 800H to SHS (800 o C, 0.1 MPa), Bsat & Huang [2016] also observed Cr2O3 and MnCr2O4, in addition to Fe2O3, NiO, and (Ni,Fe)Cr2O3. Bsat et al [2018-2], in their study into 800H exposed to SCW (700 o C, 25 MPa, 150 ppb O2, pH 7, 7 mL/min) for 1,000 hours, also observed Cr2O3, in addition to Fe2O3/Fe3O4 and Fe-rich spinel.…”

Section: Bs Specimensmentioning

confidence: 85%

“…Considering that the typical 800H dual-layered oxide contains Fe-rich oxide in the outer layer and Cr-rich oxide in the inner layer [Tan et al, 2006;Choudhry et al, 2016], the implication was that the expected Fe-rich outer layer has apparently spalled for the BS specimens being studied in SHS and SCW. Other researchers have also noted a Cr-rich single oxide layer having formed over Incoloy 800/H when exposed to high-temperature air (1,000 -1,200 o C) [Khalid et al, 1999], SHS [Bsat & Huang, 2016] and SCW [Bsat et al, 2018-2], all of whom cited spallation of the outer oxide layer as the cause for the observance of a single-layer oxide scale.…”

Section: (A) and (D))mentioning

confidence: 97%

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Oxidation Study of Incoloy 800H Tubes Exposed to Super-Heated Steam and Supercritical Water

Nazarali

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Incoloy 800H, a high-nickel austenitic alloy, has great merit for use in Supercritical Water (SCW). The development of the CANada Deuterium Uranium (CANDU) nuclear Supercritical Water Reactor (SCWR) was the driving force behind this research to investigate the oxidation performance of Incoloy 800H for use as fuel cladding.The oxidation behaviour of Incoloy 800H was investigated in Super-Heated Steam (SHS) (625 o C, 0.1 MPa) for a duration of 500 hours and, again, for 1,000 hours, and in SCW (625 o C, 26.14 MPa) for 500 hours using novel tube specimens. Four specimen configurations were prepared to have a combination of Open-Ends (OE) or Closed-Ends (CE) with either a Bare Surface (BS) or a NiCrAlY Coated Surface (CS). The OE and CE specimens experienced different through-thickness stress distributions due to their testing environment, which allowed comparison and characterization of their performance with regard to oxidation and stress.Standard mass and dimension change measurements performed on the test specimens were observed to be unreliable for characterizing the relative oxidation between different test environments and specimen configurations. Detailed metallographic studies were made with the aid of optical microscopy, Scanning Electron Microscopy (SEM), Energy Dispersion Spectrometry (EDS), and X-Ray Diffraction (XRD), in addition to mass and dimensional measurements. Finite Element Analysis (FEA) was performed to determine the effect that specimen configuration and testing environment have on the stress distributions within the specimens.Testing showed that BS specimens in SHS and SCW produced sufficiently similar oxidation behaviours and oxide scales; spallation of the outer Fe-rich oxide layer was believed to have occurred. The CS specimens formed a thin and discontinuous oxide under both SHS and SCW. The CE/BS tube yielded and collapsed when exposed to SCW with iv cracks and 'folds' vulnerable to oxidation forming on the collapsed surfaces. The NiCrAlY coating provided sufficient strength to reinforce the CE/CS tube preventing its collapse in SCW conditions.From the perspective of oxidation performance, it has been determined that SHS (625 o C, 0.1 MPa) is a suitable medium for investigating the oxidation behaviour of Incoloy 800H in SCW (625 o C, 26.14 MPa) and would provide comparatively conservative results.The coating affords the tube additional protection from both oxidation and stress, providing the potential of extending the operating life of the Incoloy 800H tubes. v I am grateful for the support and expertise of

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