超声-TIG复合焊枪变幅杆水冷装置的设计

Design of cooling system of horn in ultrasonic assisted tungsten inert gas welding torch

与常规TIG焊相比,超声-TIG复合焊可显著提高焊接效率、改善焊缝组织和力学性能,应用前景广泛.复合焊枪中超声振动系统对温度敏感,温度过高导致超声作用减弱甚至消失.为保证超声振动稳定输出,在变幅杆节点处加工环形槽通循环冷却水,对振动系统进行冷却.利用设计水冷后的复合焊枪进行定点焊接和变幅杆与换能器的测温试验,发现冷却后升温速度降低,峰值温度也分别从62℃和53℃降低到33℃,冷却效果明显.焊接电流为160 A的厚板铝合金堆焊试验结果表明,冷却变幅杆后复合焊枪连续稳定可焊时间从40 s增加到至少3 min.振动系统的温度始终低于37℃,且趋于恒值.复合焊枪焊接稳定性和大电流承载能力提高.

A new method named ultrasonic-assisted tungsten inert gas( U-TIG) welding was invented by connecting a TIG welding torch to an ultrasonic piezoelectric transducer. The ultrasonic wave was transferred through the welding arc. The welding penetration and depth to width ratio increased,the grain size reduced and the mechanical properties were improved. However,the ultrasonic vibration system was very sensitive to the temperature. The natural frequency of ultrasonic vibration system changed as the temperature went up. The amplitude,amplified from ultrasonic horn,would decrease and even disappear. In order to ensure that the ultrasonic vibration could be amplified stably by ultrasonic horn,an annular groove for circulating water was designed in horn to cool the ultrasonic vibration system. The temperature measurement show that after cooling,the temperature in ultrasonic transducer and horn decreased from 62 ℃ and53 ℃ to 33 ℃,respectively. The U-TIG welding of 8mm thick aluminum alloy sheet,without and with cooling,were carried out. The results show that the length of stable weld increased from 80 mm to almost 380 mm with cooling. The stability and carrying capacity for large current of U-TIG welding torch with cooling system was improved significantly.