Hot top casting process for phi 784-mm 7xxx-series superhard aluminum alloy round bar

Abstract

The invention discloses a hot top casting process for a phi 784-mm 7xxx-series superhard aluminum alloy round bar. The aluminum alloy round bar is composed of, by mass, 0.25% of Si, 0.4% of Fe, 1.55-1.65% of Cu, 0.25% of Mn, 2.55-2.65% of Mg, 0.19-0.25% of Cr, 5.6-5.7% of Zn, 0.15% of Ti, 0.03% of Zr and the balance Al. The manufacturing process comprises the steps of a, material preparation; b, smelting; c, stirring; d, refining; e, slagging-off; f, heat preservation and standing; g, online thinning; h, online degassing; i, filtration; j, casting; k, homogenizing. Through the process, the defects, such as cracks, component segregation, bright grains, thick grains and loose pores, which often appear when a direct condensation casting technology is adopted for large-diameter superhard aluminum alloy are overcome, and by the adoption of hot top casting, the defects of surface segregation tumors, thick coarse-grain layers and the like are overcome.

Description

technical field [0001] The invention belongs to the field of metal material forming, and relates to an aluminum alloy casting method, in particular to a hot-top casting process for a 7xxx series superhard aluminum alloy round bar with a diameter of 784 mm. Background technique [0002] 7xxx series aluminum alloys have the advantages of high specific strength and hardness, good thermal processing performance, excellent welding performance, good corrosion resistance and high toughness, etc., and should be made into structural materials with greater bearing capacity and widely used In the aerospace industry and other civil industrial fields. [0003] Although the strength of 7xxx series aluminum alloys is superior to that of 6XXX series aluminum alloys, the tensile strength and yield strength of some alloys can reach more than 400MPa, but the tensile strength and yield strength of 7xxx series aluminum alloys both reach 400MPa or more, after anodic oxidation, the surface The qu...

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Problems solved by technology

[0004] In view of this, the object of the present invention is to provide a hot-top casting process for 7xxx series superhard aluminum alloy round rods with a diameter of 784 mm. cracks, composition segregation, bright crystal grains, coarse grains, loose pores and other defects, and the use of hot top casting solves the defects of surface segregation, coarse grain layer thickness, etc., greatly improving the yield and production efficiency, and reducing casting costs

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