Comparative study on CCTIG welding and PCTIG welding of GH4169 under the same heat input

Abstract

GH4169 is a nickel-based superalloy, but high welding heat input and the harmful precipitates of the Laves phase seriously affect the mechanical properties of the welding joint. In this study, constant current tungsten inert gas welding (CCTIG) and pulsed current tungsten inert gas welding (PCTIG) were used to weld the GH4169 alloy sheet under the same heat input. After welding, the relationship between microstructure and comprehensive mechanical properties was analyzed. According to the results, under the same heat input: (1) The PCTIG welded joint has narrower weld and denser microstructure. (2) The pulse current improved the segregation of Nb element at the weld, and then reduced the precipitation of the Laves phase. (3) Pulse current improved the comprehensive mechanical properties of weld metal. The tensile strength and elongation were increased by 18% and 79% respectively.