Study On The Process And Simulation Of Automatic Welding Of Thick Aluminum Alloy6063Motor Housing

As an important component of electric car motors--self-circulating water coolingaluminum motor housing, its weight, heat resistance and corrosion resistance are the keyfactor of the electric vehicle development. In this paper, aluminum alloy6063electric carscirculating water cooling of the motor housing has some defects of manual welding includinglow efficiency, quality varies, poor sealing, not high strength. We study the automatic weldingprocess of new energy electric vehicles from circulating water cooling aluminum motorhousing. In order to ensure the quality of Shell shaped plate6063welded joints, theconnection of the motor housing is backing welding with the TIG welding, MIG welding forfilling, capping. For thick plate6063shell welding joint, we adopt optical microscopy,scanning electron microscopy, micro hardness tester, universal tensile testing machinemicrostructure and impact testing machine testing mechanical properties for welded joints.For further numerical simulation study temperature field, stress field numerical dynamicsimulation during welding. The results of this research are to achieve stable quality, reliablysealing, high strength, and to meet the requirements of actual production enterprises. Theexperiment results show that:1、The welding technology program is reasonable, In view of the special structure of thestudied shell, it requires its tightness, reliably sealing, high strength during the course. wedetermine that the use of TIG welding backing weld welding, MIG welding and automaticwelding for filling and capping through research, literature, laboratory analysis; whilecomparative analysis by grouping experiments to optimize the welding parameters (security).2、 Analysis on microstructure shows that, The base metal matrix is completelyrecrystallized microstructure, weld heating affected zone is the dendrite, the weld is equiaxedgrains; micro-hardness test results show that the area near the center of the weld themicro-hardness is greater, hardness value69.7HV, about12mm from the center of the weldexists softening zone, the minimum hardness is58.2HV.3、Tensile test analysis shows that, the base metal tensile strength is212MPa, tensilestrength of6063aluminum motor housing manual and automatic welding of welded jointswere approximately73MPa and135MPa, respectively. It is obvious automatic welding isbetter than manual welding. The strength of welded joints increase approximately doubled;the tensile fracture SEM analysis showed that the fracture surface also distributed a largenumber of dimples, which show good ductile fracture characteristics. Automatic welding hasmore dimples on the fracture surface than manual welding, which is more uniform and deeperthan manual welding, On a macro level, strength and elongation automatic welding seen to behigher than the manual welding.4、By analysis of the impact test, impact strength of the aluminum alloy6063weldingweld joint motor housing is about60J, welding strength of the welded joint can be seen to meet the requirements of actual production.5、During welding process, the numerical dynamic simulation of6063aluminum motorhousing temperature field results show that, the weld pool move with the movement of theheat source in welding process, the distribution of temperature changes occur gradually. Thehighest temperature point concentrated in the center of the weld, is approximately720~755oC,the temperature around the weld about595oC and decrease to both sides, temperature gradientappears to gradually change over time, tend to room temperature. During MIG weldingprocess, the of distribution temperature field simulation is consistent with the TIG weldingsimulation.6、The6063aluminum motor housing stress field numerical simulation during weldingresults show that, the heat-affected zone has the maximum stress and more concentratedduring the simulation process, and move with the movement of the heat source, the maximumstress is about149~220MPa. Stress field distribution around the heat affected zone isgradually decreasing, with the cooling of the weld joint; the stress distribution tends to thevalue of0.16MPa. Stress field simulation results of MIG welding process show that themaximum stress value of67MPa which is located in the heat affected zone, and duringcooling stage Maximum stress is located in the center of weld. The dynamic simulated resultprovides experimental and theoretical foundation for predicted and controlled residual stressof weldment.