Numerical Simulation And Key Technology Research Of The Auto Front Longeron Of Laser Welding With Filling Wire

Body in white laser welding has become one of the advancedmanufacturing technologies in recent years to promote the automotiveweight lighting.This technology has been widely used in the automotiveindustry. Laser welding technology used in automotive BIW welding,especially the butt joints welding, greatly improved the strength andstiffness of the car body, increased the security of the car body andreduced the lap width of the lap joints, saved more materials, effectivelyreduced the body weight.It’s very good for lightweight the BIW.In the laser butt welding,the assembly gap between the workpiece isvery stringent, existing research results showed that, the allowed maximungap is about18%of the thickness of the workpieces.It greatly limits theapplication of laser welding in car body manufacturing. Laser weldingwith filling wire just make up this shortcoming,by adding the wire, on onehand can reduce the assembly requirements, and reduce the machiningprograms before welding; on the other hand, can adjust the metallurgycomponents of the weld by adding a wire to meet the performance require-ements, and some materials difficult to be weld such as high strengthaluminum alloy can be connected.An auto front longeron is selected to be the special object of the study.The simulation of the laser welding with filling wire of the auto frontlongeron used SYSWELD was carried out, and the technology experim-ents was also carried.And the over burning accured at the corner of thethree-dimensional structure in the laser welding was studied,and at thesame time,some methods to avoid the over burning were put forward.At first, the simulation of the laser welding with filling wire on theauto front longeron was carried using the professional software SYSWE-LD.This work includes modeling, meshing, selecting the heat source andverification, pre-processing, calculation and post-processing program, theresults of the temperature and stress fields at different speeds and differentpower conditions were obtained. The simulation results can make a certainguidance for the subsequent process experiments. Next, According to the results of the simulation, the over burning atthe corner of the three-dimensional in the laser welding process wasstudied.Four key nodes of the model around the corner were selected toanalyze.The preliminary programs to solve the over burning wasobtained, and the experiment by changing the laser incident angles wascarried, the good range of the incident angles was achived.It can be agood guidance to the laser welding on the three-dimensional structure.At last, the technology experiments on the auto front longeron werecarried using the process parameters with reference to the simulationresults and the orthogonal test. And the appearance, the hardness, and themetallographic of the weld were tested by samping. And through the crashtest,the weld quality of the laser welding and the arc welding werecompared. And the results showed that the auto front longeron welded bythe laser welding with filling wire was better than that welded by the arc.