Ultrasonic The Casting Vibration System Thermal Modal And Broadband Frequency Tracking The Realization Of Its Pilot Study

The practice and the fundamental research have indicated that exerting power ultrasonic in the process of casting metals can improve solidification mechanical properties, reduce the hot tearing and enhance the properties of metals effectively. In view of the special environment of the ultrasonic casting process, it's very important to investigate the properties of the ultrasonic vibration system and the electrical control system under high temperature and develop relative equipments. The main content of the paper can be summarized as follows:1. The temperature-modal coupled model of the 20kHz ultrasonic vibration system was built based on the finite element soft ANSYS and the rule of resonance frequency of the ultrasonic vibration system was found in the casting process. The simulation result showed that the resonance frequency dropped linearly along with the increasing of temperature. At the same time, it was found that the panel surface of the ultrasonic vibration system hardly changed in the casting circumstance by analyzing vibration amplitude cloud chart.2. The characteristics of common tracking patterns were elaborated, and the shortcomings of phase tracking patterns were analyzed and the electric current tracking pattern was adopted as the frequency tracking pattern. Effective proposals were put forward unifying harmony response curve of the ultrasonic vibration system in view of the establishment scope of two key parameters STEP and RANGE in the tracking pattern.3. The ultrasonic cast experiment was carried out. The result showed that the resonance frequency dropped linearly, which consisted with the result of theoretical analysis. At the same time, it was effective and reliable to select the electric current track method and related software for ultrasonic generator, which definitely satisfied the special operating mode request under the ultrasonic casting condition.