Study Of5×××Aluminum Alloy Welding Wire

With the rapid development of high-speed railway in China, the amount of manufacture of trains is also growing. The skin of the carriage of high speed trains with the speed of over200km/h is mostly made of welded aluminium alloy plates and large-type profiles. At present, the welding wires imported are used in high speed trains with the speed of300km/h below. So with the increment of the speed (above300km/h), the welding wires with better welding property are needed to ensure the safety of high speed trains.In this study,13kinds of welding wires are maded and welded to2.8mm thick5083-O aluminum alloy plates with TIG AC. Microstructures and mechanical properties during the process of the preparation of welding wires are studied by using metallographic microscope, tensile test and SEM. The effects of materials, coats of crucible, content of Mg, content of Zr with different content of Mn and content of Mn with different content of Fe on properties of welding wires are studied. The main results are as follows:(1)Purity of raw materials have a significant effect on welding properties of welding wires, and bttter properties of welding wires are obtained with the improvement of the purity. Moreover, when the melting tools are coated with TiO2, the pollution during the process of alloy melting can be avoided so that the high purity of alloy are guaranteed.(2)When the content of Mg varies from4.5%to5.5%, the mechanical properties of welded joint, which is welded with the welding wires of5.5%Mg content, are developed. And the strengh of welded joint will be287.0MPa that reaches above90%that of the base material and the elongation will be14.0%.(3)In the condition of different Mn content, the mechanical properties of welded joint are better when5083plates are welded with aluminum alloy welding wires with Zr addition. In the condition of high Mn content, the strengh of welded joint with Zr addition will be295.7MPa that reaches above93%that of the base material and the elongation will be16.4%and the strengh of welded joint without Zr addition will be286.0MPa that reaches above90%that of the base material and the elongation will be14.5%.(4) In the condition of different Fe content, the mechanical properties of welded joint are better when5083plates are welded with aluminum alloy welding wires with high Mn content. In the condition of high Fe content, the strengh of welded joint of high Mn content will be293.4MPa that reaches above92%that of the base material and the elongation will be15.9%and the strengh of welded joint of low Mn content will be285.9MPa that reaches above90%that of the base material and the elongation will be13.8%.