激光诱导等离子体辅助脉冲电弧导电的机制研究

Study on Mechanism of Laser Induced Plasma Assisted Pulsed Arc Welding

利用汉诺威弧焊质量分析仪、高速摄像机、光谱仪实现对激光-电弧复合焊接过程的焊接电信号、电弧形态图像、等离子体发射光谱等信号的同步采集。研究了激光-电弧两脉冲热源复合焊接过程中电弧形态变化、等离子体的电子温度和电子密度变化规律。结果表明,电弧燃弧初期在激光匙孔和焊丝端部形成明显的抛物线形的白亮带,白亮带成为电弧与熔池实现能量交换的主要通道,随着电弧燃烧的进行白亮带逐渐消失。等离子体的电阻率的计算结果表明,激光等离子体具有更低的电阻率,是导电通道形成的始点。随着激光脉冲作用时间的增加,等离子体辐射光谱的强度增加,等离子体电子密度升高,电子温度降低。

The electrical signals,arc shape images and the plasma spectrum signals of laser-arc hybrid welding is acquired synchronously,using the Hanover welding quality analyzer,high-speed cameras,spectrometer.The change of the arc shape and the change law of the plasma electron temperature and electron density is studied in the process of the both pulsed laser-arc hybrid welding.Results showed that,the beginning of the arc in laser keyhole and the wire end formed obvious parabolic white band,the band become the main channels of energy exchange between arc and molten pool.As the arc burning,white band gradually disappear.The calculation results of plasma resistivity show that the laser plasma has lower resistivity,which is conductive channel formation of the starting point.With the increase of the laser pulse duration,the plasma radiation spectrum enhanced,the electron density increased,electron temperature decrease.