方波交流GTAW电弧再引燃机理的研究

STUDY ON MECHANISM OF ARC RE-IGNITION IN SQUARE-WAVE ALTERNATING-CURRENT GTAW

交流电弧再引燃主要影响因素是电流换向瞬间的电压、电弧空间的电离度和电极发射电子的能力。方波交流电源以其高的电流换向速率提高了交流焊接电弧再引燃的可靠性。但用交流钨极氩弧焊接铝时，由于铝工件熔点和沸点低，电子发射能力弱，在钨极接负变为工件接负时，电弧再引燃困难，仍须采用附加的稳弧措施。在双逆变式交流方波电源中，在利用前级高频逆变恒流电源的快速响应特性的基础上改进了后级的电路结构，克服了传统的高压脉冲或高频高压稳弧的缺点，可靠实现了交流钨极氩弧焊铝的电弧再引燃。

：The voltage and gas ignization with current zero-crossing and the electron emission ability of the electrode are the principal factors of re-ignition of alternating-current welding arc．Square-wave Alternating-current power source rapidly zero-crossing to assure reliable arc re-ignition．The emission ability of aluminum and its alloys are lower．When welding aluminum，arc re-ignition is difficult at the time when the current is changing from DCEN(direct current electrode negative)to DCEP(direct current electrode positive)．Even though auxiliary circuit can be used to provide a high ionizing voltage，such as superimposed high-frequency energy．In this paper，square-wave alternation-current power source is to use two inverter circuits．Circuit topology of the second stage is improved based on rapid response characteristic of primary constant current using high-frequency conversion technique．This power source avoids traditional arc re-ignition circuit，in which high-voltage pulse or high-frequency high-voltage energy is employed．The arc re-ignition of the alternating-current welding aluminum is realized simply and reliably．