【摘要】 针对微TIG小电流电弧不稳定的问题，研发了一种高频脉冲复合直流的微TIG焊接电源。通过测试输出电流波形，结合高速摄影采集电弧形貌，研究小电流电弧形态特征及高频脉冲复合直流对极限小电流电弧、6 mm间隙微电弧的影响，探讨微TIG电弧形态形成的原因及高频脉冲作用效果。结果表明，该电源输出的高频脉冲电流可实现快速变换，且具有精度高、输出稳定的特点；随着电流减小，电弧形态发生变化，并非保持“钟罩状”，高频脉冲电流可提高微TIG电弧稳定性，使电弧在平均电流低至2 A时也能维持稳定燃烧；6 mm间隙时，8 A微TIG电弧在燃烧过程中会发生大幅度形态变化，复合高频脉冲可以降低其变化幅度，提高挺度。更多还原

【Abstract】 Aiming at the improvement of arc stability in low current TIG, a power supply which could supply direct current superposed highfrequency pulse current was developed. By testing waveform of output current and collecting arc morphology with a high-speed photography system, small current arc characteristics and influence of DC superposed high-frequency pulse on extremely small current arc and 6 mm gap micro-arc were studied. Forming causes of micro-TIG arc characteristics and high-frequency pulse effect were discussed. The results showed that the power supply could rapidly transform, and it had characteristics of high accuracy and stable output. As the current decreased, arc morphology changed and did not remain “bell-shaped”. High-frequency pulse current could improve stability of micro-TIG arc, so that the arc could maintain stable combustion when the average current was as low as 2 A. When the arc length reached 6 mm, 8 A micro-TIG arc would experience a large morphology variation, and high-frequency pulse could reduce its amplitude of variation and improve arc stiffness.更多还原