Friction Welding of ETP-Cu Plate to SS304L Round Bar: An Experimental Study on Asymmetrical Dissimilar Metal Joints

This article outlines the development and examination of the properties of an asymmetrical dissimilar metal joint produced using friction welding (FW). Friction welding involving dissimilar materials, specifically a 50 mm (length) × 45 mm (width) × 20-mm (thickness) electrolytic tough pitch copper (ETP-Cu) plate and a 12.5-mm-diameter SS304L rod, was carried out. The assessment of the asymmetrically welded components encompassed ultrasonic testing, high-pressure helium gas testing, leak testing, tensile testing, scanning electron microscopy, optical microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, hardness measurements, and elemental mapping via X-ray. Significantly, there was an observed increase in tensile strength, resulting in a joint efficiency of 86.50% compared to the ETP-Cu base material, following FW between an asymmetric ETP-Cu plate and SS304L rod. The study unveiled notable variations in the microstructure near the joint interface on the ETP-Cu material side. Intermetallic compounds, such as FeCu₄ and Cu₉Si phases, were detected within the reaction layer at the interface between ETP-Cu and SS304L, exhibiting a variable thickness ranging from 30 to 50 μm.