Effect Of Activating Laser Welding On Porosity Of Aluminum Welding And Alloys Elements Burning

5A01aluminum alloy belongs to highly rust-proof aluminum alloys, which was researched by our country. Due to high Mg content and work hardening rate, the tensile strength is high. the It was mainly used as aluminum material of shipping and the structure of high corrosion resistance, good weldability, moderate intensity. due to low Absorption rate of laser welding,aluminum alloy has bad weld shaping and porosity is easy to occure. however, aluminum alloy activating laser welding not only can enhance absorption of laser and also improve weld shaping and reduce porosity of weld.5mm-5A01 aluminum was used as experimental material to operate activate laser welding. The activatings in experiment are single activating?SiO₂?NaF?CaF2?Cr2O3?Na3AlF6? and composite activating?SiO₂+ Cr2O3 ? Cr2O3+ CaF2 ? CaF2+Na3AlF6 ?Na3AlF6+ SiO₂?.Single activating to absolute alcohol rate is 1:1and composite activating elements to absolute alcohol rate is1:1.Laser welding experiment operates on aluminum of 290mm*80mm*5mm firstly with laser surfacing welding,then effect of weld shaping and improvement of laser absorption rate is analyzed. laser button welding experiment is operated on the aluminum of 150mm*70mm*5mm with SiO₂ activating flux,and effect of parameters on Mg element burning and weld zone hardness is studied.Results of experiment shows that different coating activating fluxes have different influence on welding surfaces. The welding surface coated with SiO₂ has better appearance and the surface is covered with even fish-scale metal. Activating fluxs can increase the weld depth and improve depth to width ratio obviously. Na3AlF6 and SiO₂ work most obviously among the single element activating flux. No new phase or activating elements occurred after coating activating flux. Weld pool changes to goblet-like shape with activating flux. Effect of various activating fluxes on on hardness is different. Coated with SiO₂ and Cr2O3+CaF2, hardness distribution of weld zone is homogeneous and higher than that with no activating flux.Activating laser butt welding was carried out on 5A01 aluminum alloy and the activating flux was SiO₂. It is found that weld porosity with activating flux is lower than that without activating flux. Power doesn't have a linear relation with porosity rate when the laser power is in the range from 4000 to 4200 W. When the welding speed is in the range from 1.5 to 2.4m/min, the trend of porosity change is consistent under the effect of welding speed in the two cases. When the speed increases, the porosity increases first and than decreases. However, the weld porosity with activating flux is lower than that without activating flux. With the defocus distance from-2 to +1mm, the weld porosity with activating flux was lower than that without activating flux. Weld porosity with negative defocus distance was higher than that with positive defocus distance. As the laser power, welding speed and defocus distance increase, containment of Mg decrease which indicate the burning of Mg element is increased. Mg burning of welding center is the most and it decreases in the zone away from welding center and Mg burning under activating flux is higher than it under no activating flux.