Research on the welding metallurgical property and weld joint mechanical property of SAl 5183 welding wire for ship building

The study focuses on the newly developed SAl 5183 marine aluminum alloy welding wire, with the base material selected as 5083-H116 aluminum alloy. The TIG/MIG welding techniques were employed to conduct vertical up, overhead, and flat welding to investigate the metallurgical properties and reliability of this welding wire. The research includes tests on the properties of the deposited metal, chemical composition analysis, mechanical performance testing of the welded joints, and microstructural analysis. The results indicate that the tensile strength of the deposited metal reaches 291 MPa with an elongation of 30%, and its chemical composition meets the requirements of CCS material and welding specifications. Tensile tests on the joints show that the tensile strength of the MIG welded joints is slightly higher than that of the TIG welded joints, while the mechanical properties of the vertical up, overhead, and flat welded joints under the same welding technique are similar, with tensile strengths reaching 90% of the base material's tensile strength. Microstructural examination reveals the presence of white dispersed phase Al₆(Fe, Mn) compounds in the weld zone under different welding processes. Notably, when using MIG flat welding and vertical up welding processes, the size of precipitate phase in the welded joints is relatively larger, resulting in better dispersion strengthening effects. Additionally, the weld zone exhibits the solid solution strengthening effect of Mg elements, with a more uniform distribution of Mg in the joints produced by MIG vertical up welding, TIG vertical up welding, and TIG overhead welding, leading to enhanced solid solution strengthening effects. These two strengthening effects ensure the welded joints possess good tensile strength.