Microstructural Analysis of Friction Welded Dissimilar Steel Joints

Abstract

This study investigates the microstructural changes and energy-dispersive X-ray (EDX) spectra of ASTM A106 Grade B steel and EN 19 steel during friction welding, with an additional focus on the heat treatment of EN 19 steel. Friction welding, a solid-state welding process, was employed to join these two distinct steel grades, known for their differences in chemical composition and mechanical properties. The EN 19 steel underwent heat treatment prior to welding to enhance the joint's performance. Microstructural analysis is conducted using scanning electron microscopy (SEM) to observe the fusion zone, heat-affected zone (HAZ), and base material interfaces. Results indicated significant changes in grain structure and phase transformations at the weld interface, with the EN 19 steel exhibiting more pronounced refinement in the microstructure after heat treatment. EDX spectra were recorded from various regions of the welded joint to analyse the elemental distribution and identify any intermetallic phases formed due to diffusion across the interface. The analysis revealed elemental diffusion primarily in the weld region, contributing to the formation of a mixed microstructure.