Effects of heat input on metallurgical behavior in HAZ of multi-pass and multi-layer welded IN-939 superalloy


Mashhuriazar A., GÜR C. H. , Sajuri Z., Omidvar H.

Journal of Materials Research and Technology, vol.15, pp.1590-1603, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 15
  • Publication Date: 2021
  • Doi Number: 10.1016/j.jmrt.2021.08.113
  • Journal Name: Journal of Materials Research and Technology
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, Directory of Open Access Journals
  • Page Numbers: pp.1590-1603
  • Keywords: Iran, Welding, Nickel-based superalloy, IN-939, Heat treatment, Crack, Heat input, AFFECTED ZONE, MECHANICAL-PROPERTIES, LIQUATION CRACKING, INCONEL 738, MICROSTRUCTURE, WELDABILITY, ALLOY, PHASE, EVOLUTION, M23C6
  • Middle East Technical University Affiliated: Yes

Abstract

© 2021 The Author(s)The hot components of a gas turbine are susceptible to damage in the high-temperature environment of turbine engine operation. Given that these components are relatively costly to manufacture, they are often repaired than replaced when damaged. Fusion welding is an economical method for repairing the damaged components of a gas turbine. This research examines the roles of heat input, pass number and layer number on the intergranular liquation cracking of the Inconel-939 (IN-939) precipitate nickel base superalloy during tungsten arc welding. Several specimens were welded with IN-625 filler alloy under argon gas by following the Taguchi method and an L8 array. These specimens were then characterized via metallographic investigations and hardness measurements. Results show that, during welding, the IN-939 heat-affected zone (HAZ) is acutely prone to cracks that propagate along the grain boundaries. Moreover, layer number, heat input and pass number significantly influence the microstructure and liquation cracking of HAZs with impact percentages of 72.37%, 22.17% and 4.84%, respectively.