Evaluation of fracture toughness and residual stress in AISI 316L electron beam welds

Mehdi Mokhtarishirazabad, Chris Simpson, Saurabh Kabra, Graeme Horne, Iain Palmer, Andrew Moffat, Christopher Truman, David Knowles, Mahmoud Mostafavi

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Weld residual stress and fracture behavior of 316L electron beam weldments, which are of particular interest in power generation industry, were investigated in this work. Two butt‐weld joints were manufactured in stainless steel 316L plates of 6 mm and 25.4 mm thicknesses. Three complementary methods were used to measure the three orthogonal components of the residual stress in the weld coupons, and fracture tests were conducted on single edge notched bending specimens extracted from different regions of the welds and parent metals.

The residual stress measurements showed a maximum value of 450 MPa in longitudinal direction, while it was less than 150 MPa in the other two orthogonal directions, revealing that in our material, and with the chosen weld parameters, the residual stresses were biaxial. The fracture resistance of the weldment and parent material was similar, with material microstructure differences being more significant than the measured residual stresses.

The study suggests that 316L electron beam weldments are not susceptible to fracture failure due to their high ductility and ability to relieve residual stresses through gross plasticity. Electron beam welding may therefore be suggested as a reliable manufacturing technology for safety critical 316L components.
Original languageEnglish
Pages (from-to)2015-2032
Number of pages18
JournalFatigue and Fracture of Engineering Materials and Structures
Volume44
Issue number8
Early online date12 Apr 2021
DOIs
Publication statusPublished - Aug 2021

Bibliographical note

Funding Information:
This work was support by the Department of Business, Energy and Industrial Strategy Nuclear Innovation Programme. The views expressed in the paper are those of the authors and should not be interpreted as BEIS or wider Government policy. The authors would like to acknowledge Royal Academy of Engineering funding through a senior research fellowship. EPSRC is thanked for partially funding the project through EP/R020108/1. Diamond Light Source is gratefully thanked for the allocation of beamtime SW21780. EnginX instrument, ISIS Neutron and Muon Source, is gratefully acknowledged for the allocation of beamtime RB1820199. NAMRC is thanked for manufacturing the weldments. The authors would like to thank Dr. Xander Warren, School of Physics, University of Bristol, for conducting the EBSD measurements in the Interface Analysis Centre. Dr. Abdullah Al Mamun, Bristol University, and Dr. Hokyeom Kim, Open University, are thanked for facilitating the acquisition of microhardness data. Dr. Ed Kingston, Veqter Ltd. is gratefully acknowledged for carrying out the Contour method.

Funding Information:
This work was support by the Department of Business, Energy and Industrial Strategy Nuclear Innovation Programme. The views expressed in the paper are those of the authors and should not be interpreted as BEIS or wider Government policy. The authors would like to acknowledge Royal Academy of Engineering funding through a senior research fellowship. EPSRC is thanked for partially funding the project through EP/R020108/1. Diamond Light Source is gratefully thanked for the allocation of beamtime SW21780. EnginX instrument, ISIS Neutron and Muon Source, is gratefully acknowledged for the allocation of beamtime RB1820199. NAMRC is thanked for manufacturing the weldments. The authors would like to thank Dr. Xander Warren, School of Physics, University of Bristol, for conducting the EBSD measurements in the Interface Analysis Centre. Dr. Abdullah Al Mamun, Bristol University, and Dr. Hokyeom Kim, Open University, are thanked for facilitating the acquisition of microhardness data. Dr. Ed Kingston, Veqter Ltd. is gratefully acknowledged for carrying out the Contour method.

Publisher Copyright:
© 2021 John Wiley & Sons, Ltd.

Keywords

  • austenitic stainless steel
  • electron beam weld
  • fracture toughness
  • residual stress

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