Effects of heat input on microstructure of tungsten inert gas welding used hastelloy X

Abstract

The present work provides a microstructure examination of the weld zone (WZ) and heat affected zone (HAZ) associated with the low and high heat input tungsten inert gas (TIG) welding condition of used hastelloy X (HX). For both welding conditions, the segregation of the elements during solidification led to the formation of second phases (σ and P phases). In low heat input condition, the heat from the WZ caused the dissolution of carbide in the HAZ, whereas in high heat input condition, there was no enough time for carbide to dissolve but simply melt in the grain boundaries. Liquid phase in the HAZ during welding decreased the tensile properties of this alloy. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) were used to evaluate the formation of phases and liquated product respectively. Additionally, the geometry analysis by using ANSYS software was introduced to ensure the different in stress concentration.