Finite element analyses were carried out to investigate the effect of ultrasonic vibration on drawing force in large diameter tube drawing. Ultrasonic vibration was imposed to a drawing die using ultrasonic vibration horns. The horn was designed to have desired amplification ratio and natural frequency using a wave equation. The drawing forces obtained with and without ultrasonic vibration were compared. The effect of vibration amplitude and phase delay of two horns located in opposite side on drawing force was investigated. Results showed that the drawing force could be reduced about 11% by using ultrasonic vibration of 20 μm amplitude and that the phase shift of two opposite horns had a great effect on the drawing force.

CP (Commercially Pure) titanium has been widely used in various industries such as in energy plants and bio-materials because of an excellent corrosion resistance and its non-toxicity to the human body. But there are limitations for usage as structural materials due to low strength. The tensile properties of CP titanium could be improved by microstructure refinement such as in a SPD (Severe Plastic Deformation) process. However, high strengthening of CP titanium wire is impossible by SPD processes like ECAP (Equal Channel Angular Pressing), HPT (High-Pressure Torsion), and the ARB (Accumulative Roll Bonding) process. The study purposes are to increase the strength of CP titanium wire by optimization of the cold drawing process and the harmonization with mechanical properties by heat treatments for the next forming process. The optimization process was investigated with regard to the design of drawing dies and the reduction ratio of cross sections. The elongations of high strength CP titanium were controlled by heat treatment.