Numerical simulation of periodic fluctuation in electron beam welding pool

Abstract

In order to further explore the mechanism during electron beam welding, electron beam welding was carried out on a 10mm 2219 aluminum alloy. A three-dimensional electron beam welding model in which volume of fluid (VOF) was combined with dynamic heat source was established using numerical software Fluent to simulate the coupling between keyhole and molten pool. The process and formation of vortex in molten pool were analyzed, the interaction between electron beam and keyhole was also identified and discussed. The results show that the molten pool is divided into three parts through the analysis of liquid metals. The liquid metal in zone Ⅰ maintains the stability of the volume of the molten pool. The surface of the molten pool is enlarged by vortex in zone Ⅱ. Vortex in zone Ⅲ plays an important role in causing the keyhole to collapse. The coupling analysis of electron beam and keyhole wall shows that the electron beam is not uniformly distributed on the keyhole wall,which results in a certain hysteresis at the bottom of keyhole.

Keywords

• electron beam welding
• molten pool behaviour
• vortex
• periodic fluctuation
• heat source-keyhole coupling