CN-122007378-A - Low-pressure casting device and method for high-pressure GIS aluminum alloy mechanism chamber

CN122007378ACN 122007378 ACN122007378 ACN 122007378ACN-122007378-A

Abstract

The invention belongs to the technical field of low-pressure casting, and particularly relates to a low-pressure casting device and method of a high-pressure GIS aluminum alloy mechanism chamber, wherein the high-pressure GIS aluminum alloy mechanism chamber comprises a base flange, a hemispherical first shell, a left chamber and a right chamber, the low-pressure casting device comprises a die system, a sand core system, a pouring system, a chill system and a stripping system, and the pouring system is as follows: the pouring gate is arranged below the flange surface of the high-pressure GIS aluminum alloy mechanism chamber, the cross gate is arranged between the pouring gate and the flange surface, aluminum liquid is injected from the bottom pouring gate and enters the cavity through the cross gate, the area of the cross gate is designed based on the height of a casting, the maximum length of the horizontal direction, the maximum width of the horizontal direction and the average wall thickness, the internal defect of the casting is eliminated, the consistency of the product is ensured, the compactness of the casting and the process yield are improved, a stable casting cycle beat is formed, the production efficiency and the product percent of pass are improved, and the production cost is reduced.

Inventors

GUI JING
ZHOU LIWEI
XU GONGJIE
WANG HONGWEI
ZHANG HUARUI

Assignees

诸城航大新材料技术有限公司

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. A low-pressure casting device of a high-pressure GIS aluminum alloy mechanism chamber is characterized in that, The high-voltage GIS aluminum alloy mechanism chamber comprises a base flange, a hemispherical shell, a left chamber and a right chamber, The base flange is in a truncated cone shape, the thickness is 25-35 mm, the outer diameter is not less than 450mm, and the inner diameter is not less than 320mm; the wall thickness of the hemispherical shell is not more than 25mm, the outer diameter is not less than 190mm, and the inner diameter is not less than 175mm; The wall thickness of the left chamber and the right chamber is 10-15 mm, and the height of the high-pressure GIS aluminum alloy mechanism chamber is not less than 500mm; the low-pressure casting device comprises a mould system, a pouring system, a follow-up aluminum alloy chill and a mould stripping system, wherein the pouring system is structurally characterized in that a pouring gate is arranged below a flange surface of a base flange, a runner is arranged between the pouring gate and the flange surface, aluminum liquid rises under the pressure of compressed air, is injected from the pouring gate through a liquid lifting channel and enters a cavity through the runner; the demolding system comprises a first riser, a second riser and a demolding groove which are arranged at the top of a high-pressure GIS aluminum alloy mechanism chamber, after a casting is solidified, a side mold of the mold system is opened, a top mold of the mold system is lifted upwards by a certain height by a main oil cylinder group, the casting is driven to ascend by the holding force of the demolding system and the casting, a runner is separated from a bottom mold of the mold system, and then the casting on the top mold is ejected by an ejection oil cylinder to enable the casting to fall to the bottom mold.
2. The low pressure casting device of the high pressure GIS aluminum alloy housing of claim 1, wherein the runner area is designed based on the height of the casting, the maximum length in the horizontal direction, the maximum width in the horizontal direction, and the average wall thickness.
3. The low-pressure casting device of the high-pressure GIS aluminum alloy mechanism chamber according to claim 2, wherein the outer sides of the cross runners are staggered from the outer sides of the base flange, the width of the two sides of the cross runner is 0.8 times that of the base flange, the width of the central part of the cross runner is 1.5 times that of the base flange, and the cross runners are symmetrically arranged on two sides with the pouring gate as the center.
4. The low-pressure casting device of the high-pressure GIS aluminum alloy mechanism chamber according to claim 3, wherein the mold system comprises a bottom mold, a side mold, a top mold and a sand core, wherein the bottom mold is used for fixing a pouring cup and a vacuum cup, supporting and positioning the sand core and forming a pouring gate and a runner, the side mold is used for integrally forming the outer side of the high-pressure GIS aluminum alloy mechanism chamber and providing supporting and positioning for the sand core, and the top mold is used for forming the top surface of the high-pressure GIS aluminum alloy mechanism chamber.
5. The low-pressure casting device of the high-pressure GIS aluminum alloy mechanism chamber according to claim 4, wherein the sand core is used for forming an inner cavity of the high-pressure GIS aluminum alloy mechanism chamber, the bottom surface of the sand core is matched with the bottom die, and the side surface of the sand core is matched with the side die, so that the sand core is fixed, prevented from rotating and prevented from floating.
6. The low pressure casting device of the high pressure GIS aluminum alloy mechanism room according to claim 5, wherein a side riser is arranged at the side mold position for feeding the thick and large position of the high pressure GIS aluminum alloy mechanism room.
7. The low pressure casting device of the high pressure GIS aluminum alloy housing of claim 6, wherein the side riser draft angle is 2 ° -3 ° and the top riser draft angle is 1 °.
8. The low pressure casting apparatus of the high pressure GIS aluminum alloy housing as claimed in claim 7, wherein the die cavity depth is 40mm.
9. The low pressure casting device of the high pressure GIS aluminum alloy mechanism chamber according to claim 8, wherein the follow-up aluminum alloy chill is arranged on the sand core, the thickness of the follow-up aluminum alloy chill is 20mm, and a cooling system is arranged in the mold system.
10. A method for low-pressure casting of a high-pressure GIS aluminum alloy facility chamber by using the low-pressure casting apparatus as claimed in claim 9, comprising the steps of: 1) In the liquid lifting stage, aluminum liquid in the heat preservation furnace enters the pouring gate through the liquid lifting channel under the pressure of compressed air; 2) Continuously increasing the pressure of compressed air to fill the cavity with aluminum liquid, and dynamically adjusting the rising speed of the filling pressure according to the liquid level of the aluminum liquid to finish the cavity filling; 3) A crust boosting stage, namely after the mold filling stage is finished, continuously increasing a certain compressed air pressure to complete crust formation of the casting in a certain time; 4) A crystallization pressure maintaining stage, namely maintaining the pressure of compressed air in a crust pressurizing stage until all aluminum liquid in the cavity is solidified; 5) And the pressure relief stage is to discharge the compressed gas in the heat preservation furnace to realize pressure relief, so that the non-solidified aluminum liquid in the pouring gate and the liquid lifting channel flows back into the heat preservation furnace.

Description

Low-pressure casting device and method for high-pressure GIS aluminum alloy mechanism chamber Technical Field The invention belongs to the technical field of low-pressure casting of large-size aluminum alloy structural parts, and particularly relates to a low-pressure casting device and method of a high-pressure GIS aluminum alloy mechanism chamber. Background The large-size aluminum alloy shell structural member is widely applied to the fields of aerospace, ship manufacturing, power equipment and the like due to light weight, high strength and toughness and good corrosion resistance. The mechanism chamber or commonly called crank arm box in high-voltage switch equipment (such as a breaker and a disconnecting switch) in the field of electric equipment is a key mechanical transmission component for connecting an operating mechanism (spring, hydraulic, pneumatic and electric) and a switch body (an arc extinguishing chamber and a contact system). The key function of the device is to accurately and reliably convert the linear or rotary motion output by the operating mechanism into the specific motion (usually rotary or linear motion) required by the switching operation of driving the switch moving contact to switch on or off. The mechanism chamber/crank arm box of the high-voltage switch is a key structural member integrating high strength, high rigidity, precise transmission, reliable sealing, long-term lubrication and excellent environmental tolerance. Under the conditions of extreme mechanical stress and severe environment, the motion conversion and position maintenance tasks must be completed reliably and accurately for a long time, and the performance of the motion conversion and position maintenance tasks is directly related to the safe and stable operation of the whole high-voltage switch equipment and even a power grid. Very high levels of expertise are required for design, manufacture and maintenance. The sealing characteristics of the mechanism chamber are critical, so that external dust, moisture, salt mist and corrosive gas are prevented from intruding, internal precise moving parts and lubricating grease are protected, and internal lubricating grease is prevented from leaking, and in a GIS (gas insulated metal enclosed switchgear), a dynamic sealing structure (such as a penetration part of an operating rod) between the mechanism chamber and a gas chamber filled with SF6 gas is required to bear gas pressure or vacuum, so that extremely high sealing reliability is required to prevent insulation failure of equipment caused by insulation gas leakage. The mechanism room made of aluminum alloy is usually formed by full sand casting or metal mold gravity casting due to the complex structure and the requirement of various small batches. The casting head systems of the two casting modes are complex, the casting systems are designed by experience, the mechanism chamber belongs to casting types with thin walls and large cavities, the height and the transverse distance are large, the flow of molten metal is extremely long, the design difficulty is great, and the problems of low process yield, qualification rate and low production efficiency caused by unreasonable design are easy to occur. And under sand casting or metal mold gravity casting technology, the aluminum alloy is solidified in the atmospheric environment, the casting structure is not compact enough, and the failure risk of the mechanism room under SF6 gas pressure is increased. In addition, for the castings of the structural members of the mechanism chamber, the height is large, in the demolding process of the traditional casting process, the stroke of the main oil cylinder is required to completely cover more than 2.5 times of the height of the castings (namely, the stroke S is more than or equal to 2.5H), so that the axial deflection tolerance of the oil cylinder under the continuous high-pressure working condition is generally exceeded, the manufacturing cost is high, the mold closing precision is easily deteriorated due to the dynamic sagging risk of the oil cylinder, the error modulus is large, the defects of the castings are increased, the stroke of the main oil cylinder is reduced through a demolding mode with reasonable design, and the problem to be solved in the production of large-size castings is also solved. Disclosure of Invention The invention designs a low-pressure casting process and a die for matching an inner sand core and a local chill of a metal outer die with an aluminum alloy mechanism chamber structural member of a high-pressure GIS aluminum alloy mechanism chamber, and through reasonable design of a pouring system and an auxiliary demoulding structure of a casting, the internal defect of the casting is eliminated, the consistency of the product is ensured, meanwhile, the compactness of the casting and the process yield are improved, and a stable casting cycle beat is formed under the matching of low-pressure casting equipment