CAJ | 학술논문

超声复合电弧作为一种新的焊接热源，在电弧焊接过程中可利用超声实现对熔融金属的深度处理，但是超声与电弧等离子体间相互作用机理还不清晰，这成为阻碍该技术工程应用的关键问题。本文通过实验与相应理论针对外加超声场对焊接电弧调控特性进行了研究。为说明电弧特性，针对试验中高速摄像采集的电弧图片进行了处理。对比未加超声情况，超声复合电弧受内外声场共同作用等离子体拘束程度明显提高，电弧亮度增强，弧柱高温区范围扩展至阳极，中间粒子出现团聚并以一定频率上下抖动。通过改变超声激励电流大小和声发射端高度，电弧结构产生显著变化，在谐振点附近，电弧挺直度最强，脉动频率最大。试验结果显示通过外加超声可以达到对焊接电弧热等离子体调控的目的。最后结合波动方程和二维声边界元模型，分析了电弧内部声传播过程以及声场结构对等离子体粒子的作用规律，这为进一步理解超声对电弧的调控机理打下良好基础。
초성복합전호작위일충신적한접열원，재전호한접과정중가이용초성실현대용융금속적심도처리，단시초성여전호등리자체간상호작용궤리환불청석，저성위조애해기술공정응용적관건문제。본문통과실험여상응이론침대외가초성장대한접전호조공특성진행료연구。위설명전호특성，침대시험중고속섭상채집적전호도편진행료처리。대비미가초성정황，초성복합전호수내외성장공동작용등리자체구속정도명현제고，전호량도증강，호주고온구범위확전지양겁，중간입자출현단취병이일정빈솔상하두동。통과개변초성격려전류대소화성발사단고도，전호결구산생현저변화，재해진점부근，전호정직도최강，맥동빈솔최대。시험결과현시통과외가초성가이체도대한접전호열등리자체조공적목적。최후결합파동방정화이유성변계원모형，분석료전호내부성전파과정이급성장결구대등리자체입자적작용규률，저위진일보리해초성대전호적조공궤리타하량호기출。
As a new welding method, ultrasound has been successfully introduced into the pool during ultrasonic wave-assisted arc welding process. However, the interaction mechanism between the ultrasound and the arc plasma is not clear, thus preventing the new technique from engineering applications. In this paper, the characteristic of arc regulation by external ultrasonic field is investigated based on the experimental data and the corresponding theory. In order to figure out the characteristics of arc, the arc images obtained by high-speed camera are processed. Compared with the conventional welding arc, ultrasonic wave-assisted arc is more contracted and becomes brighter, the high-temperature region in an arc column greatly expands, and there are internal particle agglomerations shaking up and down at a constant frequency. The arc shape varies with ultrasound excitation current and the height of ultrasonic radiator. In the vicinity of the resonance point, the straight-degree of the arc is the strongest and the ripple frequency is also the largest. Results show that the purpose of using external ultrasound field to regulate the thermal plasma has basically achieved. Analyzing the acoustic pressure wave equation for the neutral component shows that the spatial distribution of acoustic wave can be generated in the arc and its intensity is proportional to the local amplitude of acoustic waves. Acoustic pressure field can be calculated based on the dependence of the electron temperature and density on time and space. In addition to the action of acoustic field within the arc, the arc plasma is also controlled by the acoustic field structure. A two-cylinder model incorporating boundary element method is developed, establishing a relationship between the binding capability and the geometric parameters of an ultrasonic radiator with reference to wavelength. This model is successful in predicting resonant modes of the acoustic field and explaining the influences of the ultrasonic radiator height on welding arc. Variation of arc shape is the result of the combined effect of axial and radial acoustic radiation forces on particles (electron, ion and neutral). The thermal e?ciency will be significantly enhanced since the particle density increases in the ultrasonic wave-assisted arc. The acoustic propagation in the arc is the interacting process between acoustic and thermal plasmas. The mechanism of ultrasound acting on the arc can be reasonably explained in this study. And the results may provide a reference for plasma engineering applications. However, it also needs further research on the impact of an arc on the acoustic field.