Study On Laser-TIG Both-Side Synchronization Welding For T-Joint Of Aluminum Alloys

Today, light metal alloys and thin-walled lightweight structure are increasingly used in manufacturing industries such as aircraft, automobile and rolling stock in order to reduce vehicle weight and improve carrying capacity. It is prominent to reduce weight that using welding crafts replace traditional rivet bond especially in the manufacturing of the aircraft skin, panel, etc... However, due to the properties of aluminum alloy and the structural characteristics of T-joint, whether traditional TIG welding or advanced laser welding has to face with some problems in formation of weld, such as pores, cracks, deformation, which are difficult to solve by single way. In this paper, the fillet weld for T-joint of 3.0 mm thick 6061 aluminum alloy has been completed through Laser–TIG Both-Side Synchronization Welding (LTBSW), which provides many advantages which are not found in either.First of all, the positioning device, arc torch and fixture which offer the equipment condition for craft investigation have been designed and optimized according to requirements of LTBLW experiments and structural characteristics of T-joint.In addition, we have studied with the LTBSW horizontal welding in vertical board on different welding parameters which effect formation of weld, obtained good parameter range, and lay the groundwork for welding of T-joint. The results show that the key of LTBSW is to realize the linking up of the molten pool on both sides each other in T-joint. When the laser and arc energies on both sides are properly matched, both molten pools can be integrated, and the interaction of laser-arc is strengthened, such as melting into organic whole, smaller differences on welding width. In this case, a stable welding process and good formations of the welds are achieved.Finally, the effects of weld parameters for 6061 aluminum alloy of T-joint and forms of weld joints on the welding seam have been studied. Then, microstructure and mechanical properties of weld have been studied and analyzed as well. The results show that right process parameters of LTBSW in T-joint can complete good formations of weld which has similar organizations on both sides and has properties of grain-based and transitional uniform. Tensile strength for welding joints which has been broken in the parent material is up to 247.7Mpa. Bending angle has reached more than 15°and the crackle has taken the form of saw tooth.The research results can help to understand the interaction between laser and arc hybrid processing, reduce porosity deformation in T-joint, as well as improve the stability of weld process and energy utilization. This research helps to improve welding technology of the high-strength aluminum alloy and applications in the fields of Aero-Space, fast trains, ships and automobiles, etc...