The influences of welding parameters on the metal vapor plume in fiber laser welding based on 3D reconstruction

Fiber laser has significant advantages in the welding of moderately thick stainless steel plates. However, the influences of welding parameters on interaction behavior are still not fully understood. The metal vapor, as process product of fiber laser welding, carries abundant information of interaction behavior. A novel three-dimensional reconstruction technique was used to establish spatial structure of metal vapor during fiber laser welding. The spatial field of temperature and electron density were computed based on the 3D distribution of radiation intensity, as well as the relative spectral intensity method. Experimental results showed that the temperature of the metal vapor was generally at about 4000-5500 K. Defocusing amount had a significant influence on metal vapor and its energy interaction process in fiber laser welding.