Independent liquid level pressurization control system and method for multidigit parallel pressurization casting device

Abstract

The invention discloses an independent liquid level pressurization control system and method for a multidigit parallel pressurization casting device. The system comprises a platform for placing casting molds; the platform is provided with multiple liquid filling ports; multiple melt insulation furnaces are arranged under the platform; each liquid filling port communicates with one insulation furnace through a liquid rising pipe; and each melt insulation furnace is pressurized for mold filling through an independent pressure control system. The system performs the mold filling on melts in a molding cavity in a manner of similar to laminar currents, so that the local condensation feeding capacity is improved in a targeted manner, the dispersive shrinkage defect of castings is reduced or eliminated, and the pinhole degree and the looseness of large aluminum alloy castings can reach grade I.

Description

Technical field: [0001] The invention relates to a multi-position parallel pressurized casting device, in particular to a system and method for controlling the pressure of the holding furnace liquid level of the multi-position parallel pressurized casting device. Background technique: [0002] In the fields of aerospace, weapons, ships, automobiles, electronics, etc., the demand and application of large and complex castings, especially large and complex aluminum alloy frames, plate shapes, and cabin castings are becoming more and more extensive. This type of casting has structural characteristics such as large contour size (maximum about 2500mm), variable wall thickness (5mm~100mm), long process, and scattered heat nodes, which lead to many problems in the casting molding process: First, the wall thickness of the casting has a large differential pressure , the rising liquid is unstable, and the liquid level is not synchronized, which is easy to generate turbulent flow and ai...

AI Technical Summary

Problems solved by technology

This type of casting has structural characteristics such as large contour size (maximum about 2500mm), variable wall thickness (5mm~100mm), long process, and scattered heat nodes, which lead to many problems in the casting molding process: First, the wall thickness of the casting has a large differential pressure , the rising liquid is unstable, and the liquid level is not synchronized, which is easy to generate turbulent flow and air entrainment; second, the long process, the surface tension of the melt is high, and the casting is prone to large-area cold shuts and insufficient pouring; the third is that there are multiple scattered heat nodes in the casting, Insufficient feeding capacity of the casting process, resulting in excessive pinholes and porosity; fourth, the temperature difference between the solid and liquid intervals of the paste solidification alloy is large, and the hot cracking tendency is serious; fifth, the Al-Mg alloy casting is filled in the atmosphere, and the oxidation of the Mg element , severe burning

[0004] The above-mentioned patents only mention the simultaneous lifting of liquid by multiple tubes, but in essence, the smooth filling of the mold cannot be achieved only by the simultaneous lifting of multiple tubes, especially for complex, large-scale castings with large wall thickness changes , even if multiple tubes are raised at the same time, it cannot solve the internal quality problems caused by filling, such as cold insulation, insufficient pouring, turbulent flow and other defects

Even if the liquid is filled synchronously by controlling the melt in the riser, due to the complexity of the casting, when the melt enters the cavity, there will still be large fluctuations in the filling liquid level, which will cause the above problems

[0005] In addition, during the process of pressurizing the liquid surface, the problem of the metal liquid surface being out of sync in the mold is likely to occur, and it is very likely that multiple holding furnaces will pour back into each other, which will pose a threat to the quality of the casting.

At present, domestic studies have been carried out on the process control of anti-gravity casting liquid surface pressurization, including multi-level PID parametric control, parameter fuzzy control, and PID output fuzzy control, but these control algorithms are difficult to apply to large-volume anti-gravity casting equipment.

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