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Effect of Thermal Aging on Fracture Mechanical Properties and Crack Propagation Behavior of Alloy 52 Narrow-Gap Dissimilar Metal Weld

  • Matias AhonenEmail author
  • Sebastian Lindqvist
  • Teemu Sarikka
  • Jari Lydman
  • Roman Mouginot
  • Ulla Ehrnstén
  • Pekka Nevasmaa
  • Hannu Hänninen
Conference paper
Part of the The Minerals, Metals & Materials Series book series (MMMS)

Abstract

Determination of the fracture toughness properties and thermal aging behavior of dissimilar metal weld (DMW) joints is of utmost importance for successful structural integrity and lifetime analyses. This paper presents results from fracture resistance (J-R), fracture toughness (T0) and Charpy-V impact toughness tests as well as fractography performed for an industrially manufactured narrow-gap DMW mock-up (SA508-Alloy 52-AISI 316L). Tests were performed on post-weld heat treated, 5000 h aged and 10,000 h aged material. The results show that this DMW is tough at the SA 508-Alloy 52 interface, which typically is the weakest zone of a DMW. The DMW joint maintains its high fracture resistance also after thermal aging. Crack propagates for a large part in the carbon-depleted zone (CDZ) of SA 508 but deflects occasionally to the Alloy 52 side due to small weld defects in µm scale. Ductile-to-brittle transition temperature determined from Charpy-V impact toughness tests increases due to thermal aging, but only to a minor extent. No significant change is observed for the T0 transition temperature due to aging.

Keywords

Dissimilar metal weld Ni-base alloy Microstructural characterization Aging 

Notes

Acknowledgements

This study has been made in collaboration between VTT Technical Research Centre of Finland Ltd and Aalto University School of Engineering within the Nickel-base Alloy Welding Forum (NIWEL) research project funded by TEKES, Finnish (Teollisuuden Voima Oyj and Fortum Oyj) and Swedish (Ringhals AB and OKG AB) energy industry. The authors wish to express their gratitude for the funding and participation of all the participants of the project.

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Copyright information

© The Minerals, Metals & Materials Society 2019

Authors and Affiliations

  • Matias Ahonen
    • 1
    Email author
  • Sebastian Lindqvist
    • 1
  • Teemu Sarikka
    • 2
  • Jari Lydman
    • 1
  • Roman Mouginot
    • 2
  • Ulla Ehrnstén
    • 1
  • Pekka Nevasmaa
    • 1
  • Hannu Hänninen
    • 2
  1. 1.VTT Technical Research Centre of Finland Ltd.EspooFinland
  2. 2.Aalto University School of EngineeringAaltoFinland

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