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The Correlation of Hardness to Toughness and the Superior Impact Properties of Martensite in Pressure Vessel Steels applied to Temper Bead Qualification

Smith, Mackenzie Boeing J
http://rave.ohiolink.edu/etdc/view?acc_num=osu1609939800037596

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Welding Engineering.
Temper bead (TB) welding is often used as an alternative to PWHT when welding hardenable steels in the fabrication and repair process, commonly employed in the nuclear industry. Historically, qualification of TB welding techniques have employed Charpy V-notch testing to ensure acceptable HAZ fracture toughness; however, ASME Section IX (QW-290) included a provision, in 2004, that allows temper bead qualification through tensile, bend, and peak hardness without impact testing requirements. Previous work shows that for SA508, a common pressure vessel steel, tempered Martensite has the highest toughness of the microstructures present in the heat affected zone. This work looks to find a quantitative correlation between instrumented indentation, the newly found hardness drop parameter, and critical brittle volume fraction of the overall microstructure with impact toughness. These correlations will be the foundation for creating an alternative TB qualification criterion from just hardness indents but based on impact toughness properties, which supports the formation of tough Martensitic microstructures for pressure vessel steels, mainly SA508 but also SA387 Gr.22 Cl.2 (commonly referred to as F22). The idea of shifting these practices toward producing more Martensitic microstructures to improve impact toughness is a paradox when thinking about general steel metallurgy. Carbon partitioning to Austenite which is transformed to Martensite upon cooling can occur in heterogeneous structures embrittling the Martensite. However, in a fully Martensitic microstructure carbon partitioning does not occur and autotempering, tempering upon cooling, can be a toughening mechanism for untempered Martensite in pressure vessel steels. An investigation into carbon partitioning and autotempering was conducted which will further the field’s fundamental knowledge on the impact properties of Martensite in pressure vessel steels.
Antonio Ramirez (Advisor)
Boian Alexandrov (Committee Chair)
Desmond Bourgeois (Committee Chair)
324 p.
Engineering; Materials Science; Nuclear Engineering
Hardness, Impact Toughness, Microstructure, Martensite, Autotempering, Carbon Partitioning, Instrumented Indentation, Temper Bead, SA508, SA387, F22, HAZ, Weld, pressure vessel

Recommended Citations

Citations

  • Smith, M. B. J. (2021). The Correlation of Hardness to Toughness and the Superior Impact Properties of Martensite in Pressure Vessel Steels applied to Temper Bead Qualification [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1609939800037596

    APA Style (7th edition)

  • Smith, Mackenzie Boeing. The Correlation of Hardness to Toughness and the Superior Impact Properties of Martensite in Pressure Vessel Steels applied to Temper Bead Qualification. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1609939800037596.

    MLA Style (8th edition)

  • Smith, Mackenzie Boeing. "The Correlation of Hardness to Toughness and the Superior Impact Properties of Martensite in Pressure Vessel Steels applied to Temper Bead Qualification." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1609939800037596

    Chicago Manual of Style (17th edition)

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© 2021, some rights reserved.Creative Commons License The Correlation of Hardness to Toughness and the Superior Impact Properties of Martensite in Pressure Vessel Steels applied to Temper Bead Qualification by Mackenzie Boeing J Smith is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by The Ohio State University and OhioLINK.
Release 3.2.12