Investigation of ultrasonic vibration effects on the microstructure and hardness of aluminum alloy 2024 tube spinning parts

Tube spinning process, also known as flow forming, is one of the manufacturing methods in production of seamless tubes. During the tube spinning process, the workpiece was excited by ultrasonic vibrations. The authors' last research was focused on variation of forming forces and surface effects of tube spinning parts under ultrasonic vibrations. In the present study, the effects of ultrasonic vibrations on mechanical and metallurgical properties of AA 2024 workpieces were investigated. In fact, different characteristics of the workpiece in the presence and absence of ultrasonic vibrations were evaluated. The results of microstructure and microhardness tests revealed that in the presence of ultrasonic vibrations, precipitate formation was reduced. Also, precipitate shape and distribution through microstructure, particularly near the outer surface up to 2 mm depth, was changed. In addition, applying ultrasonic vibrations not only increased the hardness and the depth of hardened layers but also improved the uniformity of hardness profile across the thickness.