Investigation On Laser Welding Of Aluminum Alloy With Different Thickness Of Welding Process And Temperature Field

Tailor-welded Blanks is a way that welded different materials or thickness of sheet metal into blanks, and prepared for the press molding.Now this process is mainly used in the manufacture of automobile body, and get a great success.CO₂ laser welding of aluminum alloy 5A05 sheet with different thickness was perfomed, every main factors of affecting welding process affecting weld shape and weld quality were investigated. Welding parameters of the were determined. The results indicate that:the influence of with or without the addition of filler metal powder for welding aluminum alloy 5A05 was not obviously,the weld with the addition of filler metal powder increased the absorption of laser,so the welding process reaction intense and blast slightly.Furthermore, using optical microscope, electron probe(EPMA), scanning electron microscopy(SEM), micro-hardness tests, the microstructure and mechanical characteristics of the welded joints were evaluated. The results indicate that:the microstructure of the welds center is cellular dendrite structure, the composition in the center of the welding line wereα(Al) +β(Mg₂Al₃) with little FeAl₃, (FeMn)AI₆ and SiMg₂. The hardness of weld center was the highest,near the fusion line the hardness was the lowest,the hardness of thin, thick base metal which was annealed state before welding was change slightly.Finally, using ANSYS soft, a 3D temperature field of aluminum alloy for different thickness with laser welding was simulated. In order to improve solution accuracy, thermal analysis unit SOLID90 was used. Elliptical distribution function heat source model was choosed. ANSYS' APDL to compile program to apply load of moving heat source was used. The effects of temperature-dependence material parameters and potential heat, boundary conditions, plasma, melting pool convection and characteristics of different thickness are considered in the model. By using high-temperature thermocouple, the temperature was measured. It is shown that the simulation results are in accordance with the experimental results.