Effects of Submerged Arc Weld (SAW) Parameters on Bead Geometry and Notch-Toughness for X70 and X80 Linepipe Steels

• Author / Creator

  Pepin, Joel

• For the manufacture of higher strength pipelines to be feasible, a better understanding of the effects of welding on toughness is necessary. Bevel submerged arc welds were performed on X80 grade steel. The subsequent Charpy V-notch (CVN) test results indicated that the notch placement in the various heat affected zone regions, and hence the bead geometry, affected the test results. A series of bead-on-plate (BOP) submerged arc welds then were performed on X70 grade steel plate to determine the effects of current, voltage, heat input, polarity, and waveform manipulation (i.e., balance, offset, and frequency) on both single and tandem weld bead geometry. A new bead profile characteristic, the SP ratio, is proposed to describe weld bead geometry, and its relationship with welding parameters is discussed. Sub-size CVN specimens, pulled from many of the BOP weld coupons, were then tested. The greatest subsize CVN fracture energies were achieved when the bead was produced using lower heat input, and when the bead profile possessed a greater SP ratio.

• Subjects / Keywords

  • Charpy V-notch
  • Linepipe steel
  • X80
  • HAZ
  • Fracture energy
  • SAW
  • Bead-on-plate weld
  • Toughness
  • Heat affected zone
  • Submerged arc weld
  • CVN
  • X70
  • Bevel weld

• Graduation date

  Fall 2009

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3N061

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.