Research On The Weld Performance Of 5A03 Aluminum Alloy With Variable Gas TIG Welding

Aluminum alloys are widely used in traditional manufacturing industries.Because of their excellent weldability and corrosion resistance,they are mainly used in the automotive and shipbuilding industries.As industrial development has put forward higher and higher requirements for the properties of aluminum alloys,aluminum alloy welding technology as an important processing method has become a research focus in this field.In the traditional TIG welding process of aluminum alloy,the weld is prone to problems of low strength and coarse grains.At present,pulse and external ultrasonic methods are usually used to improve the weld quality,and there are few ways to improve the weld quality by using variable air supply.This article takes 5A03 aluminum alloy as the object to study the welding seam of 1Hz fluctuating gas fed TIG welding.This article first studied the forming quality of the 5A03 aluminum alloy variable aeration TIG welded joint.Comparing the surface quality of the weld and the macro cross-section of the weld,it is found that the surface of the variable aeration weld is fish-scale,while the surface of the traditional TIG weld is smooth and uniform without fish-scale.Compared with the traditional welding seam,the welding seam adopting the variable gas supply welding parameters has deeper penetration and narrower penetration width,and no pores are found in the weld,and the internal quality of the variable gas welding seam is better.The study on the structure of the two welds found that by comparing the same areas of the two welds,it was found that the grain size of the variable gas weld zone was23?m,while the grain size of the traditional weld weld zone was 30?m.Significant changes have taken place.The variable air supply method can achieve the purpose of refining the grain in the weld zone.Through the analysis of the weld tensile test data,it is found that the tensile strength of the variable aeration weld is higher than that of the traditional TIG weld,and the yield ratio is lower,indicating that the mechanical properties of the variable aeration weld are better.Analyzing the SEM photos of the weld fracture surface,it is found that the size of the dimples on the fracture surface of the fluctuating gas welded seam is smaller and the number is larger.Through EDS analysis of the ?-phase particles in the dimples,the composition of the phase is determined to be Al8Mg5.Strengthening phase in aluminum alloy.Analysis of the electrochemical data of the two types of welds found that: traditional welds have lower self-corrosion potential,lower self-corrosion current density and smaller capacitive arc resistance,so the corrosion resistance of traditional welds is slightly better.This is due to the grain refinement of the variable gas supply weld,which results in the increase of the number of grain boundaries and the increase of the number of primary cells due to gas shock.In this paper,the welding seam of the variable gas TIG welding method is studied,and the relationship between the structure and properties of the 3mm thick 5A03 aluminum alloy plate weld and the variable gas is analyzed.After analysis and testing,it is found that the variable gas TIG weld is compared with the traditional TIG welding The grain size of the seam weld zone is refined,the tensile strength is improved,and the corrosion resistance is slightly reduced.Overall,the weld performance is improved.