| Compared with conventional engineering materials, magnesium alloy islightweight, high strength, and easy recovery characteristics with broadapplication prospects. With the increasingly applications of magnesium alloys,the welding quality of it is required higher and higher. The welding quality ofmagnesium alloy can't be met because of the existence of welding residualstress. Thus, it is very necessary to study welding residual stress. Cryogenictreatment can improve the life of the parts, and increase the uniformity of thematerial organization to a certain extent as the extension of cold treatment. Cancryogenic treatment eliminate the welding residual stress and deformationeffectively, thereby enhancing the quality of welding?TlG welding process test of AZ31magnesium alloy sheet with7mm thickis done first in certain welding parameters. The cryogenic treatment of buttwelding magnesium alloy plate is completed using liquid method. Then measurewelding residual stress of the butt plate by taking specimen point and comparedwith the welding residual stress before deep cold treatment. A suitable heatsource model is selected, and three-dimensional finite element model of thenumerical simulation of AZ3l magnesium alloy TIG welded butt joints isestablished using finite element software ANSYS. The temperature field andresidual stress field of AZ3l magnesium alloy plate that is welded by TIGwelding before and after cryogenic treatment is simulated. The impact of deepcryogenic treatment on the welding residual stress is obtained by combining thevalue of simulation and the experimental data.By comparing and analyzing the welding residual stress of selected nodeson the weldment before and after cryogenic treatment, longitudinal andtransverse residual stress throughout the welding plate is reduced in differentdegrees. The overall decrease is up to about20%. At the same time, there is littleeffect on the distribution of residual stress. |
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