A study on the fluctuation behavior of molten pool and surface forming quality under different scanning speeds based on computational fluid dynamics

In order to enhance the surface quality of wire arc additive manufacturing components, this research examines the fluctuation behavior of the molten pool and the changes in forming quality for ER50-6 steel at process settings of 120A / 26V with speeds of 4, 5, and 6 mm/s, employing computational fluid dynamics (CFD) simulations and experimental techniques. Key findings indicate that a moderate scanning speed of 5-mm/s achieves optimal dynamic equilibrium, characterized by stable pool fluctuations (Standard deviation of fluctuation distance: 0.057 mm) and superior surface quality (Standard deviation of point cloud: 0.247 mm). Conversely, the slower speed of 4-mm/s results in significant molten pool oscillations (Standard deviation of fluctuation distance: 0.065 mm), while the faster speed of 6-mm/s condition leads to depression defects due to increased heat dissipation. This research elucidates the underlying mechanism where scanning speed influences thermal accumulation and molten pool fluidity, thereby determining dimensional accuracy and providing a scientific basis for optimizing process parameter in surface quality control.