Novel Friction-Assisted Tube Forming Methods: A Comparison of Microstructure and Mechanical Properties

Abstract

Expanding performance of friction power in material processing techniques, considerably improves the process efficiency while decreases required load and increases imposed strain by the localized material softening. This paper proposes friction-assisted tube forming (FATF) and friction-assisted tube extrusion (FATE) to deform cylindrical tubes for desirable radius and thickness. These methods were successfully examined on commercially pure copper tubes. Finite element (FE) analyses were executed to simulate heat generation, temperature, and strain fields. Using friction power in the presented methods significantly reduced processing force and enhanced imposed strain. Therefore, FATF and FATE show a great capability to forming and extrusion of the cylindrical tubes with minimum processing power. Mechanical properties of the processed tubes showed considerable changes in which yield strength and ultimate tensile strength increased 4.6 and 1.6 times greater than those from the initial values. Dynamically recrystallized fine grains with mean size of 8.3 μm were obtained compared with 60 μm for the annealed sample.