Flux cored wire for particle reinforced aluminum-based composite material fusion welding

Abstract

The invention relates to the field of novel welding materials, in particular to a flux cored wire for particle reinforced aluminum-based composite material fusion welding. The flux cored wire consists of an outer skin and core powder, wherein the outer skin is an aluminum foil which is prepared from aluminum silicon alloy; the mass of aluminum accounts for 85 to 95 percent of the total mass of the aluminum foil; the mass of silicon accounts for 5 to 15 percent of the total mass of the aluminum foil; the aluminum foil has thickness of between 0.15 and 0.55mm; the particle size of the core fluxpowder is 20nm to 200 mu m; the powder is prepared according to different proportions; the prepared powder is fully and uniformly mixed by applying a ball milling material mixer; the flux powder is held in the aluminum foil and coiled to form a cylindrical section; the flux powder is prepared into a soldering wire by rolling and drawing; and the diameter of the flux cored wire is 1.5 to 3.0mm. The flux cored wire is used for the fusion welding of the particle reinforced aluminum-based composite material; and the composition and the filling rate of the wrapped flux powder can be conveniently adjusted according to different welding requirements, so that the deposited metal can meet the requirements on mechanical property and process performance to the greatest extent.

Description

technical field [0001] The invention relates to the field of novel welding materials, in particular to a flux-cored welding wire used for fusion welding of particle-reinforced aluminum-based composite materials. Background technique [0002] The matrix of aluminum matrix composites is some metals with good plasticity and toughness, and its weldability is generally better; but the reinforcing phase is a non-metal with high strength, high elastic modulus, high melting point, and low linear expansion coefficient, and its weldability is very good. This feature makes it difficult to control the welding performance of aluminum matrix composites, thus hindering its industrial application. Fusion welding is the welding method with the strongest adaptability, the most mature technology and the widest application range among all welding methods. Therefore, the research direction of fusion welding of aluminum matrix composites has high research value. If a breakthrough is found in th...

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Problems solved by technology

[0004] ① The wettability between the reinforcement phase and the matrix is ​​poor. When filling elements are not used to improve the wettability between them, under the action of strong arc heat, Al is pushed from the center of the molten pool to the edge under the action of the arc force, which is not easy A stable weld pool is formed, and the performance of the welded joint decreases

② When welding composite materials with high volume fraction reinforced particles, due to the poor fluidity of the molten pool, segregation and pores are easy to form at the weld, which affects the mechanical properties of the welded joint

③The matrix Al in the composite material is a very active chemical element, and it is easy to react with the reinforcing material under high temperature conditions, forming needle-like brittle compounds at the interface, such as SiC p / Al will generate Al 4 C 3 , distributed at the SiC interface, which greatly weakens the effect of the reinforcing phase and reduces the strength of the joint near the seam

④ During the melting and crystallization process, due to the supercooling of the molten pool during solidification, the reinforcing phase (such as SiC or Al 2 o 3 Particles) are pushed to the fusion line or the front end of the molten pool, and cannot become the crystallization core, which can easily cause embrittlement and delamination of the weld structure, form crystallization cracks, and greatly reduce the strength of the joint

⑤ There are significant differences in physical properties such as thermal conductivity and thermal expansion coefficient between the composite material matrix and the reinforcement phase. After a strong welding thermal cycle, a large number of micro-region residual stresses are generated on the interface between the matrix and the reinforcement, which reduces the performance of the joint

However, due to the fact that the alloy sheet and the solid welding wire have undergone multiple high-temperature meltings from preparation to use, some elements have been severely burned, so it is difficult to control the amount of elements added to the inside of the welding pool, which is not conducive to the in-situ welding pool. The progress of the reaction

And when the alloy sheet or solid welding wire is directly added during the welding process, the weld shape is poor and the strength of the welded joint is low

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