Research On Method And Procedure Of TIG-Arc Stud Welding Of High Strength Aluminum Alloy Stud

To solve technical issues such as easy burning loss, incomplete fusion, many pores and easy oxidation existing in welding of large-diameter high-strength aluminum alloy stud, this paper mainly focus on 5A06 high-strength aluminum alloy stud with diameter of Φ18mm, adopts TIG-arcing composite heat source stud welding as basic welding method, and researches on the design of protection devices and protection types and composite technology specification of stud welding. And it carries out comprehensive assessment, analysis and optimization for the composite technology of high-strength aluminum alloy stud welding according to the mechanical properties and microstructure morphology of stud connectors.The gas protection device designed in this paper mainly consists of protective gas hood body, which is coupled with stud welding gun, head cover of gas hood, which is coupled with different sizes of stud jackets, and bottom cover of gas hood that coupled with ceramic ring. Independent air chamber is designed in the protective device for inert gas atmosphere at welds, which effectively improve the oxidation at weld crater during the welding and the device can be applicable to studs of different diameters. One set of protective device can accommodate full-size studs, which solve the problem of poor adaptability of gas protection device in engineering applications.This paper analyzes the impacts on formation of weld of various technological parameters using single factor way, and determines the select range of three main technological parameters, finds the optimal technological parameters using orthogonal experiment, and optimizes the test results through range analysis and variance analysis. The shear strength of optimized joint reaches 176.4Mpa, which is increased by 5% compared with the group with best orthogonal result. It is determined that the optimized technological parameters are optimal technological specifications, and use it as a reference to determine the optimal technological specification of 5A06 aluminum sheet and obtained stud connectors with shear strength reached 184MPa.This paper studies the combined procedure of welding of high-strength aluminum alloy stud based on optimized technological specification of orthogonal test, analyzes the protective effect of mixed inert gases and vaporized brazing flux for welds, and finds that the composite protection by mixing helium and argon by 2:8 has a better preventive effect to high-strength aluminum alloy stud welds, because the arc energy is more concentrated under helium atmosphere, which can prevent the oxidation film and secondary oxidation completely and enhance the liquidity of weld crater. Combined with the initiative clean of vaporized brazing flux for weld crater, the structure property of welds is improved. The shear strength of weld under this composite technology increased by more than 10% compared with that under pure argon protection.