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Low heat input gas metal arc welding for dissimilar metal weld overlays part III: hydrogen-assisted cracking susceptibility

  • Julian FreiEmail author
  • Boian T. Alexandrov
  • Michael Rethmeier
Research Paper
  • 78 Downloads

Abstract

Dissimilar metal weld overlays of nickel-base alloys on low-alloy steel components are commonly used in the oil and gas, petrochemical, and power generation industries to provide corrosion and oxidation resistance in a wide range of service environments and temperatures. Traditionally, dissimilar weld overlays are produced using cold or hot wire gas tungsten arc welding. This study aims to identify and evaluate potential advantages of low heat input gas metal arc welding processes over the conventional gas tungsten arc welding in the production of such overlays. Parts I and II of this publication series described characteristics of the heat-affected zone and the transition zone region of alloy 625 on grade 22 steel overlays. These results indicate a good resistance against hydrogen-assisted cracking, which is being verified within this third part of the publication series. To determine the hydrogen-assisted cracking susceptibility, welded samples are tested using the delayed hydrogen-assisted cracking test. Fractography is performed using scanning electron microscopy along with energy dispersive spectroscopy. The results confirm the suitability and efficiency of low heat input gas metal arc welding for dissimilar weld overlays. Variation of the postweld heat treatment procedure bears potential for improvement in this respect.

Keywords

Low heat input GMA welding Dissimilar metal weld overlays Coarse-grained heat-affected zone Grain size Microstructure Fusion zone Nickel alloys 

Notes

Acknowledgements

This study was supported by ExxonMobil and Fronius International through provision of materials, welding equipment, and technical support and was performed at the Welding Engineering Laboratory of the Ohio State University.

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Copyright information

© International Institute of Welding 2019

Authors and Affiliations

  1. 1.Department of Joining and Coating TechnologyFraunhofer Institute for Production Systems and Design Technology IPKBerlinGermany
  2. 2.Welding Engineering Program, Department of Material Science and EngineeringThe Ohio State UniversityColumbusUSA
  3. 3.BAM - Federal Institute for Materials Research and TestingBerlinGermany
  4. 4.Institute of Machine Tools and Factory ManagementTechnical University of BerlinBerlinGermany

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