| In recent years, with requirements of high efficient and quality on welding technology, many kinds of new method has been widely used in welding industry. Now A-TIG welding (activating TIG welding) has been widely applied in welding process for stainless steel, aluminum alloys and nonferrous metal. The results show that the qualified joint weld is obtained by the A-TIG welding method which can meet the requirements of nugget dimension and mechanical properties. Many foundational experimental studies are made to improve penetration and productivity. Activating flux-TIG spot welding process for stainless steel was proposed. The new method experiment was researched with arc of argon tungsten-arc welding as the heat source. A-TIG spot welding is coated on surface of plate by activating flux. The results show that the weld penetration can be greatly improved with the same welding specification.The welding base metal is the SUS304 stainless steel, the thickness of which is 2 mm. The effects of the A-TIG spot welding process parameters on the shape welding spot and the shear tensile strength were investigated. From a series of technology experiments, the best welding criteria meeting requirements were obtained. The Ar-CO2 mixed gas TIG spot welding for 304 stainless steel plate was carried out. This work reviewed the effect on the shape of molten pool by adding different composition of CO2 in Ar shielding gas, and summarized the optimization of additive amount for active gas. The perfect welding penetration can be obtained under this welding parameter.The influences of activating flux and CO2 gas on micro structure of TIG weld spot have been studied. The mechanical properties of the welded joints were measured and the tensile strength, micro-hardness and the fracture mechanism of soldered joints were tested. The result showed that the welded joint meet requirements under the optimum parameter condition. Ar-CO2 mixed gas shield welding technology is helpful for improving the welding performance, but the welded joint can not meet requirement.An experimental collection system is established in order to collect the signals of welded joints. In welding process voltage signal and video image signal are collected. The rule of voltage and welding arc of TIG spot welding, A-TIG spot welding and mixed gas shield TIG spot welding can be obtained from the analysis of data.The voltage and the arc images collected data were analyzed by its changes in morphology. Two different TIG spot welding of increase in penetration theory were studied. A pool of surface tension gradient changed played a major role in A-TIG welding. Under the role of active gas, the arc contraction and changes in surface tension gradient have played a complementary role in making solder joints increased penetration.A-TIG spot welding method is simple, low cost and widely used, can be widely used in the welding of stainless steel sheet and get a good solder joint size and mechanical properties. At the same time in the welding process with real-time acquisition, the A-TIG spot welding for automatic production can have a good reference. A-TIG spot welding is one of a kind with the potential for the development and application of new welding technology.
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