Study On Resistance Spot Welding Of Vehicle

In this paper, the subject of vehicle resistance spot welding is studied. At the very beginning, the shunt solder joint arrangement and nugget size eligibility criteria are discussed. Based on the B410LA expansion experiment of the resistance spot welding of high strength steel, the welding parameters have been well adjusted for1.4mm B410LA plate welding.The influences of tempering electrification on the joints’microstructures and mechanical performance have been researched and the welding parameters of the first and the second tempering electrification have been attained. Moreover, it shows from the experiments that the maximum allowable tensile shearstress for the sample of the joint without tempering is at the same order of the samples of with first and twice temperings.Experimental study on resistance spot welding for three pieces of high strength steel sheets are made by using specific sheets with Zn coating. The first electrification parameters, the curve of Nugget size vs. current of second electrification of the welding process are got by the experiments. Further, the second electrification parameters could also be deduced.The topic of Zinc inclusions in the zinc-coated steel sheets resistance spot welding is researched. Three main conclusions have been obtained by comparing the welding procedure with one electric current and with twice-electric currents.According to the changes of the electrode and the electrode grinding frequency in the zinc-coated steel sheets resistance spot welding, it has obtained the relation curve among the electrode surface size,nugget size and the number of welding points and has determined the grinding frequency in gived parameters.Based on the typical defects in resistance spot welding process which are specifically discussed in this paper, the solutions for overcome or minimization of these defects are propo-sed in this paper.This paper builds up a process specification and an expert system based on daily automo-bile production. It designs the welding performance test specification,welding parameters det-ermination specification,current step increasing and electrode Grinding specification under continuous welding processes. At the end of this paper, it preliminarily designs a spot welding expert system with detailed discussion for both its disadvantages and improvement directions.