| Lightweight is one of the central topics that the transport unit development. Using aluminum structure for railway vehicles will be not only energy efficiency, but also reduce the body's weight. With more and more extensive application of aluminum alloy, the welding technology has become particularly important. Currently, aluminum is welded by MIG widely internal. However, the joint surface is oxidized easily and there are many welding defect occured due to chemical active and good thermal conductivity of aluminum. All walks of life have payed more attention on FSW owing to its obvious advantage since 1991. But it is not widespread application of the railway industry in our country.The topics to CRH body materials for the research background. Microstructures and properties of 6082 aluminum alloy weld joints by MIG and FSW are investigated by room-temperature tensile, bending, fatigue, impact, hardness test and metallographic analyse respectively.The microstructure of the welded seam center is equiaxed grain of MIG welded joint. The organization grain of FSW welded joint is smaller than MIG welded joint , and HAZ is more narrow. The face bending angle is of up to 90°of FSW joint. But both face and back bending angle are not exceed 90°of MIG welded joint . So FSW joint bending performance is better than MIG welded joint. In the 107 cycles, FSW joint fatigue strength is 108MPa, and MIG welded joint fatigue strength is 97MPa. The impact energy of WN,TMAZ and HAZ is higher than the BM of FSW joint at room temperature.MIG and FSW joints both have softening areas in HAZ. FSW joint soften on the advancing side is more serious than the back. MIG welded joint of thickness 8mm and 4mm extension is of base material were 5.83% and 2.92%. And FSW joints is of base material were 1.67% and 1.16%.MIG welded joint of thickness 8mm and 4mm tensile strength is of the base materials were 77.8%and 73%. And FSW joint is of the base materials were 77.23%and 78.86%.
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