高频调制电弧超声发射及其物理特性

由于传统的超声发射方法在实际焊接过程中的局限，提出了一种新的超声发生机构。利用高频功率电子开头逆变技术，在TIG焊接电弧回路中施加调制信号，对应着调制电流的上升沿和下降沿可分别激发出电弧超声。在调制度不大时，传声器接收到的声信号幅值和调制电流成正比。当调制脉宽超过一定值后，上升沿和下降沿激发出的超声信号可分开。试验表明，高频调制电弧的伏安特性更为无序。通过波动方程和对调制电弧物理特性的分析，解释了电弧超声产生的原因和声信号特征，电弧超声发射对于控制焊接过程、提高接头质量具有很高的工程价值。

High-frequency Modulated Arc as an Ultrasonic Generator and ItsPhysical Property

Since conventional ultrasonic is inconvenient for application during welding process, a new method to emit ultrasonic has been proposed. With the addition of modulating signal to the TIG welding loop by the high frequency power electronic switch inverting techniqUe, the arc ultrasonic has been excited corresponding to the rising edge and the descending edge of the modulating electronic current.The amplitude of the signal recorded by the microphone is linearly proportional to the current if the based current is modulated by a small amount. The signals corresponding to the rising edge and the descending edge of the modulating electronic current can be separated if the pulse width of the modulating signal is big enough. The experimental results show that the V/I character of the modulated are is much more disordered. The mechanism of the arcultrasonic generation and some characters of the arc ultrasonic are discussed by the wave eqUation and by the physical property of the modulated arc. The arc excited ultrasonic has more advantages of controlling welding process and improving the quality of the weld in engineering.