| The main content of this paper is the research on the application of high frequency coupling TIG welding technology in spaceflight products structure(project number ZDGY2013-48,Task Number GY-172).Aiming at the problem of low comprehensive properties of welded joints in welding process of aerospace high-strength aluminum alloy,the electrical signal parameters,heat input,thermal cycle,mechanical properties and metallographic structure analysis of welding process are synthesised.The optimization mechanism of aluminum alloy TIG welding process is put forward,and the range of welding parameters is determined,so as to promote the practical engineering application and popularization of the new process.In this paper,the coupling high frequency pulse current on main current of TIG welding is developed,and the parameters of high frequency TIG device is optimized,taking the 2A14 aluminum alloy storage box as the research object,and the coupling technology of high frequency pulse current and main current of TIG welding is developed.In order to improve the welding performance and meet the requirements of high reliability of aerospace products,the effect of TIG welding pool stirring is enhanced,grain refinement,welding porosity reduction,and so on.The main research contents are as follows:(1)the coupling technology of high frequency pulse current and main current of TIG welding as well as its system integration are studied to realize the precise quantization control of three kinds of energy waveforms.(2)Optimization of the coupling high frequency TIG welding process parameters.The effect of coupling effect on different TIG parameters and high frequency parameters on the porosity and grain size in weld seam were observed,and the correlation was determined,so as to establish a reasonable process method and improve the comprehensive properties of welded joints.The effects of different modulation pulse parameters,AC pulse parameters,welding current and other welding parameters on the welding pool stirring and weld quality are studied.The control rules of the above parameters on the welding porosity and weld quality are determined.By optimizing TIG welding parameters and high frequency parameters,the control of welding metallurgical defects is realized,and the engineering application research of the structural parts of welding products is further studied,such as reducing porosity,refining grains,controlling defects and analyzing the comprehensive properties of joints.(3)According to the product of the tank,the system integration and process implementation scheme are optimized,the welding of test piece is completed,the production adaptability of this technology in different structures such as tank longitudinal joint and circumferential joint are verified,and the process is optimized according to the structure characteristics.Promote the application of technology in product production. |
