3 Ton Melting with CaO Desulfurization of Ni-Base Single Crystal Superalloy TMS-1700, Simulating a Recycling of Used Turbine Blades

Tadaharu Yokokawa, Hiroshi Harada, Kyoko Kawagishi, Masao Sakamoto, Makoto Osawa, Yuji Takata, Michinari Yuyama, Toshiharu Kobayashi, Takuya Sugiyama, Shinsuke Suzuki

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In order to investigate the applicability of a direct and complete recycling method to commercial-scale ingot production, 3 tons of a Ni-base single crystal (SC) superalloy, TMS-1700(MGA1700) was melted and desulfurized by CaO during the melting. Sulfur content in the molten alloy was reduced from about 23 ppm to about 2 ppm within 60 min after adding granular CaO to the molten alloy. Microstructural observations using SEM and EPMA showed no presence of inclusions caused by CaO addition. Creep rupture lives of the recycle-simulated TMS-1700 were equivalent to that of the standard TMS-1700 under the conditions from 800 °C/735 MPa to 1100 °C/137 MPa. The recycle-simulated TMS-1700 exhibits even better oxidation resistance compared with the standard TMS-1700, which has better oxidation resistance than CMSX-4TM. Thus, it became clear that the CaO desulfurization improves the oxidation resistance of Ni-base superalloys. High cycle fatigue (HCF) properties of the standard and the recycle-simulated TMS-1700 were equivalent. From the results described above, it has been suggested that the application of direct and complete recycling method to commercial-scale ingot production is feasible.

Original languageEnglish
Title of host publicationSuperalloys 2020 - Proceedings of the 14th International Symposium on Superalloys
EditorsSammy Tin, Mark Hardy, Justin Clews, Jonathan Cormier, Qiang Feng, John Marcin, Chris O'Brien, Akane Suzuki
PublisherSpringer Science and Business Media Deutschland GmbH
Pages400-407
Number of pages8
ISBN (Print)9783030518332
DOIs
Publication statusPublished - 2020
Event14th International Symposium on Superalloys, Superalloys 2021 - Seven Springs, United States
Duration: 2021 Sep 122021 Sep 16

Publication series

NameMinerals, Metals and Materials Series
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Conference

Conference14th International Symposium on Superalloys, Superalloys 2021
CountryUnited States
CitySeven Springs
Period21/9/1221/9/16

Keywords

  • CaO desulfurization
  • Creep
  • Ni-base single crystal superalloys
  • Oxidation resistance
  • Recycle

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy Engineering and Power Technology
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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