Al-Cu series aluminum alloy fired mold precision casting deformation control method for severe transition of wall thickness of C-shaped opening

Abstract

The invention provides an Al-Cu series aluminum alloy fired mold precision casting deformation control method for severe transition of the wall thickness of a C-shaped opening. The method comprises the steps that firstly, according to the structural features of a casting, a pouring system is designed, a cross gate in the shape of a half Chinese character 'mi' is designed, an anti-deformation rib is arranged at the opening of the thick wall portion, a wax mold is pressed, and module combining is carried out; then, the size of the anti-deformation rib is adjusted till the size of the C-shaped opening is qualified, and after the wax mold is fixed, the anti-deformation rib is removed; and finally, according to the fired mold casting technological process, shell making and pouring of the casting are carried out, the cross gate with the direction the same as that of the C-shaped opening of the casting is kept, the casting is subjected to heat treatment according to the technological requirements, and after heat treatment, the cross gate is removed. The casting is subjected to X-ray detection, fluorescence detection and size inspection. After combining, the anti-deformation rib of the waxmold is removed, and the situation that the wax mold deforms in the module combining process, and consequently finally the size of the casting is unqualified is avoided; and the cross gate is removedafter heat treatment, and the situation that the casting deforms in the heat treatment process, and consequently the size of the casting is unqualified is avoided.

Description

technical field [0001] The invention relates to a method for controlling the deformation of an Al-Cu series aluminum alloy investment precision casting with severe transition of "C"-shaped opening wall thickness. Background technique [0002] With the rapid development of my country's aerospace industry, aerospace castings are gradually becoming integrated and lightweight, so aluminum alloy investment castings are widely used. [0003] Al-Cu series aluminum alloys have been widely used due to their excellent mechanical properties, but the Al-Cu series crystallization temperature range is wide, it is a typical paste solidification, the casting process is poor, and defects such as shrinkage cavities and cracks are prone to occur. Especially when the casting structure has severe wall thickness transition, the wall thickness transition of each size is severe, and the overall shape of the casting is a "C"-shaped opening, the casting is more likely to have defects such as opening ...

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Problems solved by technology

[0003] Al-Cu series aluminum alloys have been widely used due to their excellent mechanical properties, but the Al-Cu series has a wide crystallization temperature range, which is a typical paste solidification, poor casting process, and prone to defects such as shrinkage cavities and cracks.

Especially when the casting structure has severe wall thickness transition, the wall thickness transition of each size is severe, and the overall shape of the casting is a "C"-shaped opening, the casting is more prone to defects such as opening deformation and cracks

[0004] At present, the qualification rate of such parts produced by domestic foundry manufacturers is generally low. The main reason for scrapping is that the C-shaped opening is offset 2mm-4mm inward (outward) on one side, or the C-shaped opening is offset 2mm-4mm to one side as a whole. As a result, the qualified rate of castings is less than 20%, resulting in serious waste of production costs and prolongation of production cycle

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