Simulation And Mechanism Research On The Titanium And Titanium Alloy Wire Drawing With Longitudinal-torsional Composite Ultrasonic Vibration

Titanium and titanium alloy have a great number of excellent characteristics,such as high strength, low density, corrosiveness resistance, high temperatureresistance, excellent conduction and so on. And due to these properties, titaniumand titanium alloy has been regarded as a significant strategic metal, which hasalready been widely used in many fields. However, titanium, especially fortitanium alloy, is quite difficult to manufacture. Titanium wire is generallyproduced by rolling, extrusion and drawing, which all must be pretreated bycomplicated heat preparation, surface treatment and multiple vacuum annealing.Besides, conventional wire drawing needs large drawing force and friction force,which leads to high energy consumption. In this case, a novel method andtechnology, with economical and high efficient, is urged to be put forward toenhance the finish quality. Fortunately, through long term research, ultrasonicvibration with high power has been found that it has advantageous impacts on theplastic deformation of titanium and titanium alloy, such as improve the plasticity,decrease the yield stress, reduce friction and power consumption.In this thesis, uniformly distributed slanting slots are adopted in the horn,which transforms the longitudinal vibration of piezoelectric transducer to thelongitudinal-torsional composite vibration in the mould, and the influences of thecomposite vibration on drawing progress will be discussed. This paper mainlyincludes the following works:Firstly, the impacts of ultrasonic vibration parameters (including vibrationfrequency, the amplitude of longitudinal and torsional vibration, drawing velocity,section shrinkage rate) on the drawing progress were analyzed in ANSYS. And thevariation of longitudinal drawing stress, contact stress in reducing and maintainingarea were mainly discussed. And then, the ultrasonic vibration parameters whichare beneficial to drawing progress were determined.Secondly, the longitudinal vibration transducer and horn were designed withfour-terminal network method. And then uniformly distributed slanting slots werecut down at the end part of the horn to produce longitudinal and torsional vibration.Next, the effects of slanting slots’ parameters (including length, width, depth,inclined angle, number of slots and the distance between slots’ center and the frontend of horn) on the resonance frequency, amplitudes of longitudinal and torsionalvibration were analyzed through ANSYS. And then, based on the above analysis,three kinds of vibrators were designed which met the advantageous vibrationalcondition, including longitudinal vibration and longitudinal-torsional composite vibration.Thirdly, the drawing progress simulation of the above three vibrators wasperformed through ANSYS. Their differences on longitudinal drawing stress,contact and frictional stress in reducing and maintaining area were analyzed. Itshows that both longitudinal vibration and longitudinal-torsional compositevibration are beneficial to the plastic deformation of wires, especially for thelongitudinal-torsional composite vibration. In the meantime, the variation offrictional coefficient under longitudinal-torsional composite vibration wasdiscussed in terms of mechanics and tribology.Lastly, combined with electrical match, a wire drawing platform wasestablished to verify the influences of longitudinal vibration, longitudinal-torsionalcomposite vibration, the section shrinkage rate on the plastic deformation of wires.The experimental results were in good agreement with the above simulation.