Advertisement

Welding in the World

, Volume 60, Issue 3, pp 459–473 | Cite as

Low heat input gas metal arc welding for dissimilar metal weld overlays part I: the heat-affected zone

  • Julian Frei
  • Boian T. Alexandrov
  • Michael Rethmeier
Research Paper

Abstract

Dissimilar metal weld overlays of nickel base alloys on low alloy steel components are commonly used in the oil and gas, petro-chemical, and power generation industries to provide corrosion and oxidation resistance in a wide range of service environments and temperatures. Traditionally, weld overlays are produced using cold or hot wire gas tungsten arc welding (GTAW). Potential advantages of cold metal transfer (CMT) welding, a low heat input gas metal arc welding process, over the conventional GTAW in production of weld overlays were evaluated. Metallurgical characterization was performed on CMT overlays of Alloy 625 filler metal on Grade 11 and Grade 22 steels. Significant grain refinement was found in the high temperature HAZ compared to the traditional coarse-grained HAZ in arc welding. Evidences of incomplete carbide dissolution, limited carbon diffusion, and incomplete transformation to austenite were also found. These phenomena were related to high heating and cooling rates and short dwell times of the high-temperature HAZ in austenitic state. Tempering effects in the steel HAZ were identified, showing a potential for development of CMT temperbead procedures. Based on the results of this study, the steel HAZ regions in CMT overlays were classified as high-temperature HAZ and intercritical HAZ.

Keywords (IIW Thesaurus)

Nickel alloys Low alloy steels GMA Surfacing DIP Transfer Coarse-grained heat-affected zone Microstructure Clad steels 

Notes

Acknowledgments

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

References

  1. 1.
    M.F. Dodge, H.B. Dong, M. Millititsky, R.P. Barnett, V.F. Marques, M.F. Gittos: Environment-induced cracking in weld joints in subsea oil and gas systems—part 1. 31st International Conference on Ocean, Offshore and Arctic Engineering (OMAE2013).Google Scholar
  2. 2.
    M.F. Gittos and T.G. Gooch: The interface below stainless steel and nickel-alloy claddings, 1992.Google Scholar
  3. 3.
    V. Olden, P.E. Kvaale, P.A. Simensen, S. Aaldstedt, J.K. Solberg: The effect of PWHT on the material properties and micro structure in Inconel 625 and Inconel 725 buttered joints. Canun, Mexico, OMAE, 2003. OMAE 2003–37196.Google Scholar
  4. 4.
    Alexandrov BT, Lippold JC, Sowards JW, Hope AT, Saltzmann DR (2012) Fusion boundary microstructure evolution associated with embrittlement of Ni–base alloy overlays applied to carbon steel. Weld World. doi: 10.1007/s40194-012-0007-1 Google Scholar
  5. 5.
    B.T. Alexandrov, J.M. Rodelas, Shu Shi, J.C. Lippold: A new test for evaluation of susceptibility to hydrogen assisted cracking in dissimilar metal welds. NACE International Corrosion Conference and Expo, 51312-01602-SG (2012).AST14 ASTM International: A182/A182M–14: Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service, 2014.Google Scholar
  6. 6.
    N. McVicker, T. Daniels, B.T. Alexandrov, J.C. Lippold (2014) Application of CMT for dissimilar metal structural weld overlays in nuclear power repair. 11th International EPRI Conference Welding and Repair Technology for Power Plants, Naples, FL, June 2014.Google Scholar
  7. 7.
    Fronius International, Pettenbach, Austria: Weld and Vision, Welding technology magazine No. 13, 09/2004.Google Scholar
  8. 8.
    C.F. von Dueren: Formulae for calculating the maximum hardness in the heat affected zone of welded joints, IIW-Doc. IX-1437-86, IIW, 1986.Google Scholar
  9. 9.
    Easterling K (1992) ‘Introduction to the physical metallurgy of welding’, Butterworth/ Heinemann, Second EditionGoogle Scholar
  10. 10.
    Beaugrand VCM, Smith LS,Gittos MF (2009) Subsea dissimilar joints: failure mechanisms and opportunities for mitigation. NACE International Corrosion Conference and Expo, Paper No. 09305Google Scholar

Copyright information

© International Institute of Welding 2016

Authors and Affiliations

  • Julian Frei
    • 1
  • Boian T. Alexandrov
    • 2
  • Michael Rethmeier
    • 3
  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.Fraunhofer Institute for Production Systems and Design Technology IPK | BAM - Federal Institute for Materials Research and TestingBerlinGermany

Personalised recommendations