Semi-automatic MIG Welding Technology Research Of Aluminum Radiator End Enclosure

As an important part of automobile engine cooling system,radiator’heat dissipatingperformance is related to the security and reliability of cars running,at the same time,the development of car is moving toward lightweight, high power.It puts forward newrequirements on the selection of materials, processing technology and productionefficiency of the radiator. The main materials of the radiator is3003aluminum, the mainprocessing technic is welding on the radiator core body and end enclosure.The radiatorcore body is using furnace brazing and the end enclosure is using argon arc welding.This topic is entrusted by a radiator manufacturers in Chongqing,on the bad basis of theoriginal manual wire filling TIG welding which has a low production efficiency,a nothigh qualified rate and need a lot of repair welding,puts forward a MIG semi-automaticwelding technology for the end enclosure of radiator. It improves the welding qualityand production efficiency, and has a great practical significance for production.In this paper, considering the three factors：welding current, welding speed andprotection gas flow,design a three factors, four levels testing scheme under theprinciple of orthogonal test,analysis the impact of different process parameters on theappearance of welding line,microstructure of weld metal,joint microhardness andwelding residual stress distribution.According to the results,increasing welding current and welding speed would resultin weld width and Weld width increasing,and vice versa.A overlarge welding currentwill lead to burn through and too small will cause defects such as lack of fusion.Smallprotective gas flow will lead to weld showed severe oxidation,affects the weldappearance,we Should adopt the protection of large gas flow in the production.At thesame time,increasing welding current or welding speed will make the weld area stayinghigh temperature for a longer time and grain coarsening.High current or low speed canalso lead to welding heat affected zone width increased,the existence of the HAZsoftening phenomenon has a great influence on the mechanical properties of weldingjoint, should be reasonable control welding current and welding speed in the actualproduction.Welding residual stress well reduce with the reduction of the weldingcurrent welding speed,but the overall change is not obvious.From the joint performancetest,the technological parameter of radiator end enclosure MIG semi-automatic weldingcan be:Shielding gas flow16L/min,welding current is100a or110a, the welding speed is15mm/s or20mm/s.On this basis,Welding some radiator according to the above several groups ofparameters,then do quality inspection and heat dissipation performance test,including:weld appearance quality, water pressure test, air tightness test, SWAAT test, vibrationtest and wind tunnel test.The results show that the quality and heat dissipationperformance of the technological parameter:Current is110A, the welding speed is15mm/s, protective gas flow is16l/min is significantly better than others,inspectionqualified rate reached98%,can be used as guide the vendor production processparameters.Through the study,provides a set of welding process parameters of good qualityand high production efficiency for the all aluminum radiator,eventually applied topractical production.