Investigation Of Pinless Stir Friction Welding Method For Aluminum Alloy/PC Dissimilar Materials

With the rapid development of the times,green,energy saving,lightweight has become an important indicator of human sustainable development,the development of connection technology is also inseparable from these indicators,today’s connection technology mainly has mechanical connection,gluing and welding and other methods.As a new type of solid phase welding technology,friction stir welding has the main advantages of green environmental protection,no dust splash pollution,low welding temperature and no need to consume additional materials,etc.Therefore,friction stirred welding is gradually favored by all walks of life in the field of connection technology.Conventional pinless stir friction welding is difficult to complete the lap welding of dissimilar materials,so this paper uses two ways to pretreat the aluminum alloy sheet by opening the groove and opening the hole,and uses the pinless stirred friction welding technology to carry out the overlapping self-riveting welding test of the dissimilar material.The ABAQUS software is used to simulate the welding process for preliminary thermodynamic coupling,and the temperature field and the stress-strain situation are simulated and predicted,and the temperature field results show that the maximum temperature can reach 378 °C;the deformation simulation results show that the deformation of the two long sides of the plate is more serious,and the overall deformation trend is consistent with the test results.Taking 6061-T6 aluminum alloy and PC as the experimental research object,the pinless lap welding test is carried out,and the test results show that the connection of aluminum alloy and PC dissimilar material can be realized by opening the groove and opening the hole,and the open hole self-riveting welding test has a better macroscopic morphology of the weld seam than the slotted self-riveting welding test,and the strength of the weld is higher,under the optimal process parameters.The tensile strength of the slotted self-riveting welding test can reach 68.6% of the base metal PC,and the tensile strength of the open-hole self-riveting welding test is far better than the slotted self-riveting welding test,which can reach 189.8% of the PC strength of the base metal,and the tensile strength of the slotted self-riveting welding test is greatly improved;in the hardness test test,the average hardness of the weld section of the weld section obtained by the open-hole self-riveting welding test can reach 87.3HV.Metallographic microstructure observation of the weldment obtained from the good process parameters of the open hole self-riveting welding test,the observations show that the upper aluminum alloy has undergone obvious plastic flow in the weld position,and the aluminum alloy and the PC can be mixed well in the prefabricated hole,which improves the overall quality of the weld;through the SEM electron microscopy observation experiment,the obvious PC flow layer can be seen,indicating that the PC reaches the melting state at high temperature and flows upward with the aluminum alloy under the pressure of the shaft shoulder,and the agitation and mixing occurs.Form an effective connection.