The Research Of Friction Stir Welding Of Aluminum Alloy And Applying Of Metro Vehicles Car Body

In this paper6082-T6aluminum alloy sheet and6005A-T6aluminum alloy commonlyused in city railway vehicle as the object of research, the best process parameters of frictionstir welding and mature MIG technology parameters of CSR Zhuzhou Electric LocomotiveCompany City Rail Division were selected and used. The6082-T6aluminum alloy sheet and6005A-T6aluminum alloy by MIG welding as the comparison object, microstructureanalysis,tensile property, bending properties, micro-hardness and fatigue strength and othermechanical properties of the FSW joint were analyzed, and the fracture morphology of fatiguespecimen were analyzed too. The main conclusions of this research are as follows:(1) The optimal friction stir welding process parameters of both6082-T6aluminum alloysheet and6005A-T6aluminum alloy rotation speed are1400rpm, and the their respectivewelding speed are400mm/min and600mm/min.(2) The strength of FSW6082aluminum alloy and6005A aluminum alloy joints isbetter than MIG welding joints. However, the bending property of joints is similar.(3) The micro-hardness distribution of FSW6082aluminum alloy joints show" W" typeand the hardness is lower than that of the base metal. The lowest value of hardness is in theheat affected zone; the hardness distribution of MIG welding is not obvious regularity, but theminimum value of the hardness is lower than that of friction stir welding.(4) The grain of the nugget zone of MIG joint is dendrite structure and the grain of heataffected zone is relatively coarse. But the grain is isometric crystal in the nugget zone of FSWjoint. However, the grains of HAZ of FSW alloy joint are similar base metal. In terms of thefatigue fractures, the fatigue source of FSW joint appears at the small range of the surface andmorphology is relatively bright and flat. However, MIG welding fatigue specimens havemultiple fatigue sources and the main source is from blowhole of melting welding. And thefracture surface is rough because of these fatigue sources connects the steps.(5) Compared to MIG welding process, FSW is much better in terms of the appearanceof weld quality, deformation, welding performance and field operating conditions.(6) The Friction Stir Welding, which is a new type of advanced welding technology, canbe successfully applied in manufacturing of the car body of metro vehicles by usingreasonable welding structure and suitable process parameter.