Effect of weaving frequency on pulsed laser weaving welding of thin 5052 aluminum alloy sheet

Laser weaving welding is considered to be a promising joining method for aluminum and titanium alloys, because it has a special advantage in solving the problem of welding porosity with a single heat source. Laser head with beam weaving module has been widely used in industrial lasers of various levels. Due to the regular weaving of the laser during welding, the convection in the weld pool is enhanced, so that the pores have more time to escape, thus reducing the pores in the weld. However, the more in-depth mechanism has not been well understood. In view of the great significance of weaving welding process for weld quality, the influence of laser weaving welding process parameters on porosity and the promotion of weld microstructure evolution are studied. The results show that with the increase of weaving frequency, the proportion of small angle grain boundary increases, grain refinement and porosity decrease. When the weaving frequency is 8 Hz, the tensile strength reaches the maximum of 176 MPa, which is about 85% of the base metal. The tensile strength of the weaving weld is 24.8% higher than that of the conventional weld. Based on the experimental results, the relationship between microstructure and weld performance was studied to optimize the welding strategy to meet the industrial needs.