The Study Of 6082 Al-Mg-Si Alloy Joints' Mechanical Properties And Microstructure By Ar Arc Welding

6082 Al-Mg-Si alloy is high-quality aluminum alloy after heat treatment and pre-drawing process, and has a broad range of applications. The main connecting method of aluminum alloy is welding. Welded joint is the weakest parts of structure.This study is based on the key project of the Central South University of Forestry and Technology's Youth Fund. This paper took 6082 Al-Mg-Si alloys as object of research by using TIG welding and MIG welding. And it studied the influence of welded joint after two different welding on microstructure, mechanical properties and burning loss of alloy element, by testing the hardness, mechanical properties, bending test, optical microscopy(OM), and scanning electron microscopy(SEM). The main research methods were as follows:The first, we looked the microstructure of the weld joint such as organizing shape and grain size by the Leica DMI 5000M optical microscope, and analyzed the differences in the causes of Microstructure.The second, using THV-5 type of micro-Vickers, we measured the hardness in different regions of welded joints. After that, combining with microstructure we analyzed the reasons for the differences in hardness.The third, in the CSS-44100 electronic universal material testing machine, we test such as the tensile, bending mechanical properties.The fourth, using KYKY-Amray 2800 scanning electron microscopy, we observed the tensile fracture surface, and analyzed the difference in fracture morphology of the two welding methods.The fifth, after various experiment, we arranged the types, distribution and shapes of pore, summarized the characteristics of pore, analyzed the causes.Finally, through the testing of alloy composition in different regions, we could drew alloying elements burning in welded joints, and investigated the influence between alloying elements burning and structure property.In summary, this research on mechanical properties and microstructure of 6082 Al-Mg-Si alloy's welded joints by TIG and MIG welding, have some theoretical significance and wide range of practical guiding significance.