| In some industrial fields, resistance spot welding is a relatively common method ofwelding aluminum alloy material connections, it involves the spot welding of differentthickness of aluminum alloys, the nuggets offset in the direction of thick plank, surfacequality is poor and it makes the life of electrodes reduce, etc. And resistance spotwelding is a highly nonlinear, and there are lots of uncertain factors, for example theinvisibility of the nuggets and instantaneity of the welding process, controlling andmonitoring of welding quality are difficult. Therefore, this article used the finite elementsimulation software ANSYS to simulate the nucleation process of spot welding of thedifferent thickness of LY16aluminum alloys, it could improve the offsetting nuggets,and through experiment verification, that ensured the feasibility of the simulation.First of all, the paper set up the LY16aluminum alloys spot welding preloadingmodel, by observing the equivalent stress distribution cloud picture of the workpieceand the electrode, it got the state distributions of contact in order to determine thecontact area in the process of spot welding, laid the foundation for the analysis of heatand electricity; Also this paper studied preloading map of contact under differentelectrode pressures, through the analysis of curve variation in the process of thepreloading stress,it was known that the optimal electrode pressure was4KN.Secondly, it established a2-D model about the calculation of welding temperaturefield of heat and electricity. It considered the influence of the contact resistance,phase-change latent heat, the influence of electrode water-cooling and surface aircooling. By changing the surface size of cone shape electrodes, welding time andwelding current those were used for simulating the spot welding of different thicknessaluminum alloy, and finally it concluded that the process parameters were optimal whenwelding current was33KA, electrode pressure was4KN, welding time was2cyc and thetop electrode diameter was8mm, the bottom electrode diameter was8.6mm. And itused the same as the simulation of real welding process parameters by measuring thesample of the penetration rate, melt nuclear size and the shear strength to judge thequality of the spot welding; By comparing the simulation results and test results, whichis extremely similar. Under the optimal process parameters, the joint shear reached 4.125KN.Finally, during different thickness aluminum alloy spot welding, it was to improvethe molten nuclear migration by adding different thickness (0.1mm and0.2mm)stainless steel process gaskets, the effects of mechanical properties of welded joints onthe process parameters were investigated. And joint macro metallographic figure andmicrostructure were analyzed. The results showed that when adding0.1mm thickgasket, welding current was20KA, welding time was8cyc, welding pressure was3.3KN, the performance of joint was optimal and the shear reached4.031KN. |
PDF Full Text Request