Technical Research Of6082Aluminum Alloy Repairing Welding For High Speed Trains

6082aluminum alloy is the main material of the car body for China high speed trains, by its strongpoint of light weight and high intension. However, it may have defects of crack, air hole and no fusion when welding, repairing is necessary.6XXX aluminum alloy is the alloy that can been heat treatment for its high intension, the intension will down if the HAZ is heated by different times. Therefore, it is significative that deeply research of the influence for welding joint’s tissue and performance by different times welding repairing for improve the manufacturing level of the high speed trains and reduce the manufacturing cost.The welding process of the existing mature respectively6082aluminum alloy plate8mm thick plate butt welding, and welding1times,2times,3times and4times. The welding joints with different welding times were studied by nondestructive testing, tensile, bending, microstructure, hardness, pulsating tensile fatigue tests, comprehensive evaluation of the different effects of the number of welding joint microstructure and performance of6082aluminum alloy welding, the welding time and reasonable.The results show that, in nondestructive testing of all qualified circumstances, tensile test results all meet the standard requirements, have good tensile strength; when the number of welding is less than four, bending test can meet the standard requirements, but the bending properties of welding four welding joint does not meet the standard requirements, crack at greater than3mm softening zone face bend; metallographic results show that, the microstructure of the weld zone, fusion line, heat affected zone, the parent material of different welding times were not changed significantly; there is obvious softening zone of welded joints under different number of welding, change has little influence the number of welding on the softening zone width and hardness; not repair welding welding joint has good fatigue performance, welding and1,2,3,4times the relative lack of weld fatigue strength decreased significantly, the heat affected zone of weld four welded joint on fatigue fracture has occurred plastic deformation.For the test results, the reasonable times of welding for6082aluminum alloy up to3.