Numerical Simulation of Arc and Metal Transfer in Arc Welding Based Additive Manufacturing Assisted by External Longitudinal Static Magnetic Field

Abstract

The surface quality is one of important quality factors for arc welding based additive manufacturing (AWAM) parts. In this study, AWAM process assisted by an external longitudinal static magnetic field (ELSMF) is applied to improve surface quality of AWAM parts. In order to study the internal mechanism of AWAM process assisted by an external longitudinal magnetic field, a three-dimensional weak coupling model of the arc and metal transport is developed to simulate the arc, molten pool dynamic in AWAM assisted by ELSMF. The simulated results of single-bead deposition show that the ELSMF induces the asymmetrical tangential electromagnetic stirring in arc and molten pool, which can increase molten pool dynamics, drive the molten metal moving to the edge of the molten pool and reduce the temperature gradient. The simulated results of overlapping deposition show that the asymmetrical tangential electromagnetic stirring force can drive the molten metal moving to valley area between overlapping beads, which is beneficial to filling the valley area and improving the surface quality of the AWAM parts. The single-bead deposition experiment shows that the applying of ELSMF can reduce the height as well as increase the width of single weld bead. The multi-bead overlapping and the multi-layer multi-pass deposition experiments demonstrate that the external magnetic field can improve the surface quality of multi-layer part. The conclusions of the above study can provide the reference for AWAM process assisted by magnetic field.