Distribution and Variation Characteristics of Temperature in Inertia Friction Welded Inconel 718 Joint

Abstract

The temperature evolution in inertia friction welded Inconel 718 joint was measured by means of embedding thermocouples in specimens. The spatial distributions of temperature in the axial and radial directions of weldments were obtained and the varying characteristics of the temperature distributions were analyzed. The results indicate that the heating rate during the inertia welding process decreases gradually. The temperature distribution in the radial direction of weldment is uneven and the temperature rises gradually with the increase of distance from the center. But the relation between the temperature and distance is nonlinear. In the axial direction, the shorter the distance from the initial friction surface is, the bigger the rate of temperature increment becomes and the higher the peak temperature and the temperature gradient are. Meanwhile, the longer the distance from the initial friction surface is, the later the peak temperature appears and the longer the delay time gets. Moreover, the results of microhardness testing in a welded joint prove that the measurement of temperature in this study is reliable.

Microstructure and mechanical properties of friction welded alloy 718

“…Mary and Jahazi reported that higher friction pressure leads to structural degradation, very high temperature at the weld interface and narrow thermo-mechanically affected zone (TMAZ) in case of linear friction welds of IN 718 [15]. Bu et al [16] reported that with increasing friction time, the temperature gradient in the axial direction decreases mainly due to very high energy given in the initial stage and low heat conduction of alloy 718. Kim et al [17] have observed that an aging treatment after friction welding improves hardness and tensile properties of friction welded alloy 718 and SNCrW stainless steel (chemical composition (in wt.…”