The Spectral Analysis of Laser-Induced Plasma in Laser Welding with Various Protecting Conditions
DU Xiao1, YANG Li-jun1, 2*, LIU Tong1, JIAO Jiao1, WANG Hui-chao1
1. School of Material Science and Engineering, Tianjin University, Tianjin 300072, China 2. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin University, Tianjin 300072, China
Abstract：The shielding gas plays an important role in the laser welding process and the variation of the protecting conditions has an obvious effect on the welding quality. This paper studied the influence of the change of protecting conditions on the parameters of laser-induced plasma such as electron temperature and electron density during the laser welding process by designing some experiments of reducing the shielding gas flow rate step by step and simulating the adverse conditions possibly occurring in the actual Nd∶YAG laser welding process. The laser-induced plasma was detected by a fiber spectrometer to get the spectral data. So the electron temperature of laser-induced plasma was calculated by using the method of relative spectral intensity and the electron density by the Stark Broadening. The results indicated that the variation of protecting conditions had an important effect on the electron temperature and the electron density in the laser welding. When the protecting conditions were changed, the average electron temperature and the average electron density of the laser-induced plasma would change, so did their fluctuation range. When the weld was in a good protecting condition, the electron temperature, the electron density and their fluctuation were all low. Otherwise, the values would be high. These characteristics would have contribution to monitoring the process of laser welding.
Key words：Laser welding;Laser-induced plasma;Spectrum diagnosis;Electron temperature;Electron density
杜 笑1，杨立军1, 2*，刘 桐1，焦 娇1，王会超1 . 保护条件变化的激光焊接等离子体光谱分析 [J]. 光谱学与光谱分析, 2016, 36(01): 15-19.
DU Xiao1, YANG Li-jun1, 2*, LIU Tong1, JIAO Jiao1, WANG Hui-chao1 . The Spectral Analysis of Laser-Induced Plasma in Laser Welding with Various Protecting Conditions. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2016, 36(01): 15-19.
[1] Chen Genyu, Zhang Mingjun, Zhao Zhi, et al. Optics & Laser Technology, 2013，(45): 551. [2] Kong F R, Ma J J, Carlson B, et al. Optics & Laser Technology, 2012, 44(7): 2186. [3] Ma J J, Kong F R, Carlson B, et al. Journal of Materials Processing Technology, 2013, 213(3): 495. [4] Sibillano T, Ancona A, Rizzi D, et al. Physics Procedia, 2010, 5: 429. [5] Sibillano T, Rizzi D, Ancona A, et al. Journal of Materials Processing Technology, 2012, 212(4): 910. [6] Konuk A R, Aarts R, Veld A J, et al. Physics Procedia, 2011, 12: 744. [7] Griem H R. Principle of Plasma Spectroscopy. Cambridge Monographs on Plasma Physics. Cambridge: Cambridge University Press, 1997. [8] Griem H R. Plasma Spectroscopy. New York, USA: McGraw-Hill publishing, 1964. [9] Lacroix D, Jeandel G, Boudot C. Journal of Physics D: Applied Physics, 1997, 81(10): 6599.
