Optimization of the solidification conditions by means of beam oscillation during laser beam welding of aluminum

Abstract

Aluminum (AA6016) sheets were welded in overlap configuration to investigate the influence of different beam oscillation patterns on the resulting temperature gradient, the local solidification rate and the resulting grain structure and to compare the results with those obtained with the conventional rectilinear welding. Two pyrometers were used to experimentally determine the temperature gradient. The weld pool boundaries on the surface plane of the work piece were determined by image processing of high speed videos, in order to evaluate the local solidification rates. Metallographic analysis of the weld seams proved that laser beam oscillation during welding can be used to reliably form an equiaxed dendritic grain structure, which reduces the susceptibility to the formation of hot cracks.