Improving the integrity and the microstructural features of electron beam welds of a creep-resistant martensitic steel by local (de-)alloying

Antonia Rabl, Florian Pixner, Bruno Duarte, Daniel Blatesic, Coline Beal, N Enzinger

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Martensitic 9–12% chromium steels present the most preferred material group for high-temperature components in thermal power plants. Previous investigations revealed that due to the use of a creep-resistant martensitic steel strengthened with boron and nitrogen (MarBN), the minimum creep rate can significantly be decreased. Furthermore, the formation of the fine-grained heat-affected zone (FGHAZ) due to welding can be suppressed. This FGHAZ is subject to the most dominant failure mode (type IV cracking) of welded joints during creep exposure. By using electron beam welding, the total width of the heat-affected zone (HAZ) can be reduced compared to conventional arc welding processes. Preceding investigation on electron beam welding of MarBN steel showed recurring difficulties with hot cracking within the fusion zone. Various approaches were tried to produce defect-free welds without the use of any filler metal, but no satisfactory results were achieved. In this investigation, the chemical composition of the fusion zone was modified by the addition of conventional 9% chromium creep-resistant steel as a filler material. By using the filler material, the fusion zone was locally (de-)alloyed and defect-free joints of MarBN steel were produced.

LanguageEnglish
Pages575-582
Number of pages8
JournalWelding in the world
Volume63
Issue number2
DOIs
StatusPublished - 8 Mar 2019

Fingerprint

Martensitic steel
Steel
Alloying
Electron beams
Creep
Welds
Heat affected zone
Electron beam welding
Fusion reactions
Chromium
Fillers
Defects
Filler metals
Boron
Electric arc welding
Failure modes
Power plants
Welding
Nitrogen
Chemical analysis

Keywords

  • 9–12% Cr steels
  • EBW
  • Focus wobbling
  • Local (de-)alloying
  • MarBN steel
  • Welding of large cross sections

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys

Fields of Expertise

  • Mobility & Production
  • Advanced Materials Science

Cite this

Improving the integrity and the microstructural features of electron beam welds of a creep-resistant martensitic steel by local (de-)alloying. / Rabl, Antonia; Pixner, Florian; Duarte, Bruno; Blatesic, Daniel; Beal, Coline; Enzinger, N.

In: Welding in the world, Vol. 63, No. 2, 08.03.2019, p. 575-582.

Research output: Contribution to journalArticleResearchpeer-review

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