Title: Experimental research on plasma plume and keyhole behaviour in laser deep-penetration welding of TC4

Biography:

Jiajun Xu is a PhD from the State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, China. He has published more than 10 papers about dynamic behaviour mechanism, deformation and residual stress prediction of laser welding. 

Abstract

Through laser welding experiment using high speed camera, the dynamics of plasma plume and keyhole could be observed simultaneously due to two image output modes of the camera. One showed the plasma plume and the other showed the keyhole. The keyhole area, plasma area and angle was extracted by image processing. To improve accuracy, a modified image processing algorithm named multiple binarization algorithm was proposed. It was found the areas of keyhole and plasma varied with changes in welding speeds and laser powers. Increased energy density led to an increase in their areas and a decrease in their stability. In addition, the plasma angle decreased with the decreased speed and has no relationship with the power.