镀锌钢激光添粉焊接的等离子体监测机理

采用CO2激光器对1.6mm厚的B340/590DPD+Z镀锌钢板间添加不同量铜粉进行了激光搭接焊。基于光谱仪采集的焊接等离子体光信号,分析添加铜粉对焊接过程产生的等离子体光信号的影响,以及焊接气孔与等离子体光信号的关系。焊后采用扫描电子显微镜(SEM)及能谱仪(EDS)对焊缝截面扫描,检测铜元素的平均含量及气孔内壁主要元素的分布变化。研究结果表明,添加铜粉较未添加铜粉激光搭接焊时,等离子体温度振荡显著降低,平均温度下降约5000K;气孔内壁存在着铜锌固溶体合金,且焊缝中的气孔缺陷与CuI324.8nm谱线强度存在着关联。此结果为镀锌钢添加粉末激光焊接监测提供了理论依据,并为等离子体控制技术提供了一种新的方法。

Monitoring Mechanism of Plasma Generated by Laser Welding Galvanized Steel with Powder Feeding

Experiments of laser welding of 1.6 mm thick galvanized steel B340/590DPD+Z with different amounts of copper are performed by using a CO2 laser. Based on the light emission from the plasma plume acquired by spectrometer in the welding process, the effects of adding copper powder on the plasma optical signal and the relationship between the pores and the plasma optical signal is analyzed. Then the average content of copper element and the distribution of the main elements around the pores are detected by using a scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). The results show that compared to laser welding without adding copper powder, the oscillation of plasma temperature is significantly reduced and the average temperature drops about 5000 K. In addition the solid solution alloy of copper and zinc distributes around the pore wall and the porosity has a correlation with the intensity of spectrum at CuI324.8 nm as well. The researches provide a theoretical basis for monitoring on laser welding galvanized steel with powder feeding and a new method for the plasma control technology.