激光辅助引燃TIG电弧机理分析

Analysis on mechanism of laser-assisted TIG arc ignition

采用1 000 W半导体激光器实现了激光辅助引燃TIG电弧,并运用发射光谱分析方法观测了电弧引燃过程中不同时刻的光谱信息,同时运用Stark展宽法得到了电子密度在各瞬态的特征值,为研究激光辅助引弧的物理过程提供了科学的依据.结果表明,在电弧引燃过程中,不同元素贡献电子的程度明显不同,在起弧初期,是由金属元素发生电离贡献电子,随着时间的递增,气体成分贡献电子能力逐渐增强,并由于电极间电场的存在,高温气体很快形成了串级电离而使电弧建立.

Laser-assisted TIG arc ignition was applied by 1000W semiconductor laser.Using emission spectroscopy method,the arc ignition process of the spectral information at different moments was observed,while the transient characteristics of electron density were obtained by Stark broadening method.The results show that,in the arc ignition process,the contribution of electron from different elements is obviously different.In the beginning of arc ignition,the contribution of electron was from the ionizing metallic element,as time increasing,the contribution of electron from gas was gradually increased,and for the existence of the electric field between electrodes,high-temperature gas quickly formed a cascade of ionizing and finally arc was established.