Optimization On Welding Paremeters In Resistance Spot And Establishment Of Quality Prediction Model

With the development of science and technology, the quality of human’s life hasbeen improved so that attention is highly paid to the quality of articles for daily life andengineering material. As is known to all, the weld plays the important part on theproduction, and resistance spot welding is usually adopted in the soldering. Therefore,it is improving the material of resistance spot welding that will ameliorate the quality ofproduction. This thesis mainly does the research on the optimization of weldingparemeters in the resistance spot and Establishment of the quality prediction model.Firstly, this thesis adopts single factor alternate method, aims at five weldingparameters such as welding current, pre-machining time, welding pressure, weldingtime and time in the material of spot welding (DX51D+Z). Meanwhile, testing thetensile cut load of welding spot and handling and analysing the diameter of nugget, wecan ensure the best welding parameters of DX51D+Z with1mm thick. That is: weldingcurrent—11.18KA, pre-machining time—39cycles, electrode force—0.25MPa,welding time—18cycles and time of maintainance—10cycles.The next, On the basis of single factor alternate method, the effect of differentoptimum match--welding current, pre-machining time, welding pressure, welding timeand time of maintainance in resistance spot welding process for DX51D+Z on thequality of welding spot was studied by orthogonal design method. According to resultsof tensile test and tear test, welding current, exerts the most important impact upon thequality of welding spot. And welding pressure, welding time, as well as pre-machiningtime, play a less important role. Meanwhile, time of maintainance, is the least importantfactor. The best welding parameters are welding current—11.18KA, pre-machiningtime—40cycles, electrode force—0.25MPa, welding time—9cycles and time ofmaintainance—9cycles. The welding spot has good appearance forming and higherstrength at this time.Lastly, this thesis will adopt the method of mathematical statistics,use the steelplate given in the experiment by operating Matlab,and establish the mathematical modelbetween tensile cut load and diameter of nugget.And we will take advantage of thismodel to predict tensile cut load and diameter of nugget. The result does indicate thatthe forecast error of the tensile cut load in welding spot is within7percent and thediameter of nugget in welding spot is within9percent， showing the higher forecastaccuracy. What’ s more, this research method is not only adapt to other material exceptDX51D+Z cold rolling galvanized steel, but also other productions in factories.