CO_2激光焊接不锈钢光致等离子体动态特性分析

Dynamic behavior of plasma in CO_2 laser welding of stainless steel

光致等离子体是CO2激光焊接中一个重要的物理现象,它与焊接的稳定性、焊接质量及能量利用率等都有密切的关系。利用高速摄像及光信号监测两种手段对等离子体的动态变化过程及其对焊接稳定性的影响进行了深入的研究。提出了等离子体的变化每个周期内分为四个阶段,而影响焊接稳定性的根本原因是等离子体在穿透与未穿透之间的波动。

Laser induced plasma is an important physical phenomenon in laser deep penetration welding. It has stronger relationship to stability of process, quality of weld, and efficiency of laser energy. In this paper, two methods were used to study the dynamic behavior of plasma and the influences on stability of welding process. These methods were high-speed camera and optical signal monitoring. The results showed that the dynamic process of plasma can be divided into four steps, (1) material vaporing; (2) plasma increasing; (3) plasma bombing and separating; (4) plasma scattering. The main reason affected welding process stability is the fluctuation of plasma between non-penetration and penetration process.