Research On Three-layer Resistance Spot Welding Process For Unequal Thickness Aluminium Alloy

As one of the main joining methods of automobile body in white,the joining integrity of resistance spot welding has always been valued by the automobile manufacturers.The joining object of resistance spot welding process is normally uesd for lightweight metal sheet,joining may occur in the process of joining is not successful,may arise after the joining and joining point(joint)strength is insufficient,some problems such as weld defects.This paper mainly uses simulation and experiment to study how to reduce the occurrence of the above defects so as to optimize the joining process and improve the quality of aluminum alloy resistance spot welding.First of all,this paper studies and expatiates on aluminum alloy resistance spot welding.The resistance spot welding technology is mainly summarized and classified,and its forming mechanism is described.After the analysis and classification of the joint invalidation form,the direct and indirect indexes of the quality of the joint are put forward,and the technological parameters and their relationship are preliminarily expounded.Secondly,the preloading process of aluminum alloy with unequal thickness is studied by Finite element simulation.Mainly elaborated the process of simulation model construction,The arrangement of the simulation and the notices in the simulation,and then to analyze the results of the simulation,The contact situation of four contact surfaces and the distribution of stress and strain inside the three plate workpiece are analyzed in detail with the use of two kinds of electrodes.Then three layer of aluminum alloy plate of the investigation on the influence of welding parameters on weld quality,using orthogonal test and extreme difference analysis and variance analysis to explore the relevant welding parameters,it is concluded that the various parameters on the molten nuclear forming joint quality,mechanical properties and the influence law of indentation depth,and select the best parameter combination.Finally,the paper compares the process of three-layer spot welding process with adhesive and non-adhesive,and analyzes the causes and laws of defects in the process of adhesive welding by means of test method.