Study On The Residual Stress Of 2219 Aluminum Alloy TIG And FSW Welding

2219 aluminum alloy is widely used in the manufacture of fuel tanks and combustion chambers for aerospace and rockets due to its high strength and fracture toughness.The residual stress of welded parts seriously affects the usability and structural safety of welded structures,especially the residual tensile stress,resulting in reducing size stability,stress corrosion cracking and other hazards.The heat source of induction heating technology is concentrated,and the heating efficiency is high and local heat-treatment can be realized,which makes it an effective means to reduce the welding stress.However,there are few studies on the induction heating of heat-treatment on the residual stress relief of aluminum alloy welding parts.In this paper,the finite element simulation and X-ray diffraction method were carried out for the research on the residual stress characterization of 2219 aluminum alloy welding and induction heating technology.For the X-ray stress measurement method,the influences of physical and chemical polishing methods and roughness on surface stress measurement were studied.The results show that the chemical polishing method is superior to the physical polishing method,and the surface topography of the treated sample is less serrated and does not generate additional surface deformation perturbation layers,while the sample surface roughness have a great impact on the X-ray stress measurement results.Experimental results show that when the sample surface roughness is reduced to a certain range,the measurement result is stable and close to the true value.Finite element simulation of residual stress in 2219 aluminum alloy by TIG welding and friction stir welding was carried out by MSC.Marc commercial finite element simulation software.The residual stress and its distribution characteristics of 2219 aluminum alloy under different welding methods were compared by simulation and X-ray stress method.Through the secondary development subroutine compilation,the simulation of residual stress in 2219 aluminum alloy friction stir welding based on stir heat source and thermo-mechanical coupled model was realized.At the same time,the effect of welding speed and spindle speed on welding temperature field and residual stress in the model was studied.The results show that the size of weld zone calculated by two different welding methods is consistent with the measured results.The results of X-ray stress test are in accordance with the finite element simulation results.It is proved that the rationality of welding heat source model and mechanics calculation.The results show that friction welding can achieve the welding with less residual stress.Through the design of the corresponding induction heating device to achieve the local heat treatment for the 2219 aluminum alloy welding zone.The results show that,in the aging temperature range,with the increase of induction heating temperature,the residual stress peak value decreases continuously,and the peak of tensile stress decreased significantly.The higher the heat-treatment temperature,the stress distribution becomes closer to uniform within a certain range.By means of the MSC.MARC subroutine,the simplified induction heating heat source model is compiled to achieve the induction heating heat treatment.The results of thermal cycling test and X-ray stress test agree well with the calculated results,which proves the rationality of the simplified induction heating model.