Applying electron backscattering diffraction to macroscopic residual stress characterisation in a dissimilar weld

K Abburi Venkata, C.E. Truman, H.E. Coules, A D Warren

Research output: Contribution to journalArticle (Academic Journal)

9 Citations (Scopus)
491 Downloads (Pure)

Abstract

Dissimilar metal welds are complicated in nature because of the complex microstructure characteristics in the weld fusion zone. It is often necessary to know the phase distribution in a dissimilar metal weld especially at the interface such as fusion zone and heat affected zone to be able to predict the behaviour of the joint and its fitness for service. In this paper, a dissimilar metal weld made between ferritic/martensitic modified 9Cr-1Mo steel (P91) and austenitic AISI 316LN stainless steel using autogenous electron beam (EB) welding was analysed. The weld fusion zone has a local segregation of bcc and fcc phases. The EBSD technique was applied to determine the volume fractions of each of these phases in the weld fusion zone. This information was incorporated into the analysis of neutron diffraction data from the weld zone, and the macro-scale residual stresses were calculated from phase-specific stresses arising from the welding process. The results indicate that the overall macroscopic residual stress distribution in the weld centre is predominantly compressive in nature driven by the solid-state phase transformation of the weld pool during rapid cooling, with tensile peaks pushed adjacent to the heat affected zone (HAZ)/Parent boundaries on both sides of the fusion zone.
Original languageEnglish
Pages (from-to)54-63
Number of pages10
JournalJournal of Materials Processing Technology
Volume241
Early online date6 Nov 2016
DOIs
Publication statusPublished - Mar 2017

Keywords

  • EBSD
  • dissimilar weld
  • phase volume fractions
  • phase dependent residual stresses
  • neutron diffraction

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