Chinese Journal of Lasers, Volume. 46, Issue 12, 1202004(2019)
Laser-Arc Hybrid Welding Process and Joint Performances of 6106-T6 Aluminum Alloy Profiles for High Speed Trains
The 6106-T6 aluminum alloy hollow extrusion profiles having a lock bottom structure were welded via fiber laser-cold metal transfer (CMT) arc hybrid welding, fiber laser-variable polarity tungsten inert gas (VPTIG) hybird welding, and fiber laser-melt inert gas (MIG) hybrid welding. Subsequently, a hybrid welding joint with good forming properties and without clear defects was obtained using optimized welding parameters. Furthermore, the joint microstructure, tensile, and fatigue properties were studied, and the fatigue fracture mechanism and fracture morphology were analyzed. The results denote that the sizes of equiaxed grains at the center of the laser-CMT and laser-VPTIG hybrid welding joints gradually decrease from the upper part of the bead to the bottom. However, the sizes of the coarse equiaxed grains in the upper and lower parts do not change considerably, and the sizes of grains at the center of the laser-MIG hybrid welding joint are large. Furthermore, the tensile strengths of the laser-CMT, laser-VPTIG, and laser-MIG hybrid welded joints are 213.0, 198.0, and 200.0 MPa, respectively. These values denote a certain degree of strength loss when compared with that of the base metal. The fatigue limits of the three hybrid welded joints are 105.00, 100.83, and 113.50 MPa, respectively. All the fatigue fracture positions are located in the columnar crystal zone at the fusion line of the welding joints. In addition, the fractures are dimpled, indicating a typical ductile fracture.
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Xiaohui Han, Shuaizhen Li, Zhendong Mao, Peng Wen, Zhongxiu Li, Shikai Wu. Laser-Arc Hybrid Welding Process and Joint Performances of 6106-T6 Aluminum Alloy Profiles for High Speed Trains[J]. Chinese Journal of Lasers, 2019, 46(12): 1202004
Category: laser manufacturing
Received: Jun. 20, 2019
Accepted: Aug. 7, 2019
Published Online: Dec. 2, 2019
The Author Email: Han Xiaohui (13793237339@139.com), Wu Shikai (wushikai@bjut.edu.cn)