Rotary friction welding of Inconel 718 – AISI 304 stainless steel dissimilar joint

Abstract

Nickel-based superalloy Inconel 718 and austenitic stainless steel AISI 304 are joined by rotary friction welding. The changes in microstructure and mechanical properties of the dissimilar joint for solutionising, solutionising + aging, and post-weld aging treatment, with a prior solution heat treatment, are studied. Two distinct microstructural zones, the FDZ (fully deformed zone) and the TMAZ (thermo-mechanically affected zone) are observed in all weldments. The post-weld aged joint sample shows the highest tensile strength and hardness due to the precipitation of γ′ (Ni₃(Ti, Al)) and γ^″ (Ni₃Nb) strengthening precipitates. The solution-treated sample shows the highest yield strength, while the solutionising + aging treatment is found to deteriorate the mechanical properties of the dissimilar joint. The observed changes in the mechanical properties are investigated based on microstructure and electron dispersive spectroscopy.

KEYWORDS:

• Rotary friction welding
• Inconel 718
• post-weld heat treatment
• dissimilar welding

Disclosure statement

No potential conflict of interest was reported by the author(s).