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The role of Ti carbonitride precipitates on fusion zone strength-toughness in submerged arc welded linepipe joints

  • L. Aucott
  • , S. W. Wen
  • , H. Dong*
  • *Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

The role of micro-alloying in the submerged arc welding (SAW) of high strength low alloy steel linepipe is paramount in facilitating the high strength properties of the linepipe. In this study, transmission electron microscopy analysis revealed the presence of large (0.85. μm) Ti (C,N) precipitates within the predominantly acicular ferrite SAW joint. Cross-weld Vickers hardness and Charpy impact tests revealed that the fusion zone has high hardness and low toughness properties in relation to the base metal and heat affected zone. Fractography observations made on the ductile fracture surface of the fusion zone revealed a high number of the large Ti (C,N) precipitates to be located within the microvoids - suggesting their role in nucleating microvoids. Finally, fracture micro-mechanics are used to evaluate the relationship between the coarse precipitates and reduced strength-toughness properties in the SAW weld of the API-5L grade X65 linepipe steel.

Original languageEnglish
Pages (from-to)194-203
Number of pages10
JournalMaterials Science and Engineering: A
Volume622
DOIs
Publication statusPublished - 2 Jan 2015

Bibliographical note

Publisher Copyright:
© 2014 Elsevier B.V.

Keywords

  • Carbonitrides
  • Mechanical characterization
  • Precipitation
  • Steel
  • Submerged arc welding

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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