The Procedure Optimization Of Twin-Wire Mag Welding And Numerical Simulation For Wheel

The synthesis of various types of wheel rim and spoke is mostly used weldingmethods about production of steel wheels in the domestic. Traditional single wire MAGwelding have some deficiencies, for example, low productivity, large welding distortion.Twin-wire MAG welding has the advantages of high welding speed, high depositionrate and is widly used for welding of thick plates in the vehicle and constructionmachinery field. Based on procedure test and finite numerical simulation, steel wheelwas studied to optimize the two-wire MAG welding procedure in this paper.T-joint of welding procedure with twin-wire pulsed MAG was studied above all.Welding parameters such as different pulse mode, welding speed, wire feed rate ofleading wire and peak pulse voltage of trailing wire can affect the appearance of weld.And then optimal welding procedure was determined to meet business requirements:mean of communication is synchronization, welding speed is0.96m/min, wire feed rateof leading wire is24m/min and12m/min respectively, peak pulse voltage of trailingwire is36V and38V respectively. Finally, this paper studied the microstructure of theheat affected zone and weld zone and the hardness of welded joint on the basis ofoptimal parameters.Based on MSC.MARC, finite element model of T-joint was established.Superimposition and motion of heat source model was completed. This paper advancedfive kinds of welding sequences and then respectively calculated the weldingtemperature field, residual stress and welding distortion. A comparison between theexperimental and simulation results showed a good agreement, which verified theaccuracy of the finite element model. Weld pool of twin-wire welding obtained throughthe analysis of the temperature field was narrow and long.The maximum of equivalentvon mises stress of five welding sequences exceeded the material yield strength. Thedirection of welding distortion under five welding sequences was concave. Through thecomparison, the lowest welding distortion was a kind of welding sequence that theinside welded joint was firstly welded and the outer one secondly. The value was0.57mm. A mathematical model for calculating the mounting surface flatness of spokewas established. The smallest value was0.39mm and it was less than the automotiveindustry standards.Diversification of displacemnet about nodes on the spoke was studied. The reasonof three kinds of welding sequences produced concave distortion was that the synthesiswelding position of the spoke and rim was an asymmetric structure and the spoke moreeasily produced angular distortion. Therefore, the welding distortion state of insidewelded joint directly determined the distortion of the entire welding process. Through experimental about appearance of weld and finite element numericalsimulation of welding distortion, the optimal welding parameters and welding sequencewas finally obtained. The study result can be used to guide the steel wheel of thesynthesis of the welding process and it can also provide a theoretical basis for theproduction of other models of wheels.