CN211803763U

CN211803763U - Low-pressure filling type gravity compensation casting mould

Info

Publication number: CN211803763U
Application number: CN202020187011.6U
Authority: CN
Inventors: 钱德双; 吴素坤; 周信宝; 王盼; 廖飞虎; 王芳; 林罗友
Original assignee: Wenzhou Ruiming Industrial Co ltd
Current assignee: Wenzhou Ruiming Industrial Co ltd
Priority date: 2020-02-02
Filing date: 2020-02-02
Publication date: 2020-10-30
Anticipated expiration: 2030-02-02

Abstract

The invention discloses a low-pressure filling gravity feeding type casting mold, which is characterized in that an upper mold, a lower mold, a left end mold, a right end mold, a front mold and a rear mold are combined to form a mold cavity, the bottom of the lower mold is provided with an inner pouring gate and a pouring gate opening which are communicated, and the pouring gate opening is sequentially connected with a transition sleeve and a riser tube. And a heating resistance wire is arranged in the upper part of the upper die. The liquid lifting pipe is arranged on the heat preservation furnace, aluminum liquid in the heat preservation furnace sequentially enters a mold cavity through the liquid lifting pipe, the transition sleeve, the pouring gate opening and the ingate to fill the mold, a casting top dead head can be formed at the upper part of the upper mold, the casting top dead head automatically feeds the metal casting under the action of self gravity, so that gas in the mold cavity has enough discharge time, the casting defects of air holes, gas blocking and the like of the metal casting are prevented, and the metal casting with good quality is obtained, and the mechanical property of the metal casting is that the tensile strength is more than or equal to 250MPa, the yield strength is more than or equal to 190MPa, and the elongation is.

Description

Low-pressure filling type gravity compensation casting mould

Technical Field

The invention relates to a casting mold which is filled with low pressure by a low-pressure machine.

Background

At present, with the increasing progress of automobile technology, new energy automobiles gradually take the leadership of the automobile industry, and traditional automobiles are also developed and innovated to achieve the best performance standard by using the least energy consumption. Under the premise, the designed parts are increasingly complex, and the parts are particularly applied to a power system. Most of the parts are formed by casting. The invention mainly aims at aluminum parts needing casting forming, and the casting of the aluminum alloy parts mainly comprises three types of casting processes of high-pressure casting, low-pressure casting and gravity casting. Each casting process has certain limitation, a complex casting is cast by adopting a low-pressure process in China, the basic principle of low-pressure casting is that low-pressure gas is used for driving metal melt in a crucible or a heat preservation furnace to rise through a liquid lifting pipe and enter a mold cavity, and after mold filling is finished, the low-pressure gas is used for enabling the metal melt in the mold cavity to finish solidification and feeding under the action of pressure through the crucible or the heat preservation furnace. The low pressure casting process may be reflected by the pressure-time curve acting on the surface of the molten metal. The pressure-time curve of the typical sand mold low-pressure casting comprises seven stages of liquid lifting, mold filling, incrustation pressurization, incrustation pressure maintaining, crystallization pressurization, crystallization pressure maintaining and pressure relief. Because of different casting materials, the metal mold low-pressure casting and the sand mold low-pressure casting generally omit the crusting stage, and the casting mold is filled with the molten metal as stably as possible in the mold filling stage so as to avoid the defects of air holes and impurities caused by turbulent air entrainment; after the filling is completed, it is desirable to increase the pressure in the mold to the maximum extent possible to avoid or reduce casting defects such as shrinkage porosity due to shrinkage of the molten metal. The internal structure of the automobile part is more and more complex, and the traditional low-pressure process cannot meet the requirement of product quality. If the parts are cast by adopting the traditional low-pressure casting process, the pressure of the die must be increased to a certain value (0.0025-0.075 MPa) to ensure that the parts with qualified performance and structure are obtained. Most of the parts are provided with fine thin-wall sand cores, and casting defects such as core breakage, sand adhesion and the like are easily caused by pressure in the casting process; if the casting defects need to be overcome, the pressure needs to be reduced, but the pressure is reduced, so that the casting cannot be effectively fed and solidified under low pressure, and the defects of shrinkage porosity, shrinkage cavity and the like of the casting can be caused.

Disclosure of Invention

The invention aims to overcome the defects and provide a low-pressure filling type gravity feeding type casting mold, which solves the problems that the prior low-pressure casting cannot ensure good feeding of a casting and the casting cannot obtain good performance.

The purpose of the invention is realized by the following technical scheme: low pressure fills type gravity benefit shrink formula casting mould, including last mould, lower mould, left end mould, right-hand member mould, front mould, back mould, go up mould, lower mould, left end mould, right-hand member mould, front mould, back mould combination back formation mould die cavity, it installs under the cope match-plate pattern to go up the mould, the lower mould is installed on the lower bolster, the upper portion of going up the mould can form foundry goods top rising head, the bottom of lower mould has communicating interior water, the gate mouth meets with transition cover, stalk in proper order.

And a heating resistance wire is arranged in the upper part of the upper die, and the upper part of the upper die is connected with a temperature display through a thermocouple.

The invention can make the metal casting obtain good feeding and obtain good mechanical property, when the aluminum liquid flows through the lift tube to enter the die cavity of the casting die under the action of the low-pressure machine, the pressurizing mechanism and the pressurizing driving device, the pressure is selected to be less than 0.004 Mpa. After the mold cavity is filled with the aluminum liquid under lower pressure, the pressure in the heat preservation furnace is exhausted, the metal casting and the casting top riser thereof are formed in the casting mold, and the metal casting is automatically gravity-fed by the casting top riser by utilizing the gravity principle. Because the opening and closing stroke of the upper die is large, the heat dissipation is fast, and the position of a riser at the top of a casting of a metal casting cannot keep the effective feeding temperature, a casting riser heating and heat preservation mode is added at the upper part of the upper die and the position of the riser feeding, so that the temperature of the feeding position of the riser is kept between 380 ℃ and 420 ℃. Thereby leading the casting top dead head to play a full feeding role during feeding. Compared with the prior art, the invention can ensure that the casting can obtain good feeding, and the mechanical property of the casting can reach that the tensile strength is more than or equal to 250MPa, the yield strength is more than or equal to 190MPa, and the elongation is more than or equal to 2 percent. When the low-pressure casting process is used for casting parts, better performance and structure can be obtained, the shrinkage porosity of the casting is reduced by 90%, and the mechanical performance is improved by 50%.

Drawings

Fig. 1 is an exploded view of the low-pressure filling gravity-compensated casting mold according to the present invention.

FIG. 2 shows a process diagram of the casting method (forming metal casting, removing transition sleeve) used in the present invention.

Fig. 3 is a schematic structural diagram of a casting riser heating and heat preserving device adopted by the invention.

Detailed Description

The invention is further described with reference to the following detailed description and accompanying drawings.

Referring to fig. 1 and 2, the low-pressure filling gravity feeding type casting mold using a low-pressure machine comprises an upper mold 1, a lower mold 4, a left end mold 3, a right end mold 8, a front mold 7 and a rear mold 2, wherein the upper mold 1, the lower mold 4, the left end mold 3, the right end mold 8, the front mold 7 and the rear mold 2 are combined to form a mold cavity 13, the upper mold 1 is installed below an upper mold plate 9, the lower mold 4 (i.e., a bottom mold) is installed on a lower mold plate 10, a casting top riser 14 can be formed at the upper part of the upper mold 1, an inner pouring gate 12 and a pouring gate 11 which are communicated with each other are arranged at the bottom of the lower mold 4, the pouring gate 11 is sequentially connected with a transition sleeve 5 and a riser pipe 6, and is connected with the riser pipe 6 through the transition sleeve 5 below the. Wherein, the upper template 9 and the lower template 10 can be arranged on the corresponding positions of the low-pressure machine.

As shown in fig. 3, the casting top riser feeding technology also needs a matched casting riser heating and heat insulating device, which includes an upper die 1 (mounted on an upper die plate 9), a heating resistance wire 21 is mounted in the upper portion of the upper die 1 (capable of forming a casting top riser), the upper portion of the upper die 1 is connected with a temperature display 23 (displaying the temperature of the casting top riser) through a thermocouple 22, so as to heat and insulate the casting top riser formed on the upper portion of the upper die, and the casting top riser can realize effective feeding of the metal casting (when the metal casting is still in a molten state). The thermocouple 22 is located at the side of the heating resistance wire 21, and the two are not in contact.

The casting method adopted by the low-pressure filling type gravity compensation casting mold comprises the following steps: first, a mold cavity 13 (each of which is divided according to a metal casting structure) is formed by a combination of an upper mold 1 (mounted below an upper mold plate 9), a lower mold 4 (mounted on a lower mold plate 10), a left end mold 3, a right end mold 8, a front mold 7, and a rear mold 2 of a casting mold, as shown in fig. 1; in the process layout of the casting method, the bottom of the lower die 4 is provided with an ingate 12 and a sprue gate 11 which are communicated, the sprue gate 11 is connected with a riser tube 6, the ingate 12 is positioned at the bottom of the lower die (between the lower die and a lower die plate) of a casting die, and the upper part of the upper die 1 can form a casting top riser 14 (used for gravity feeding of metal castings); the lift pipe is installed on the holding furnace, and then pressurized by the driving of the low-pressure machine, the pressurizing mechanism and the pressurizing driving device, so that the aluminum liquid in the holding furnace (crucible type) smoothly enters the mold cavity 13 through the lift pipe 6, the transition sleeve 5, the pouring gate 11 and the inner pouring gate 12 in sequence to fill the mold (the mold cavity is filled with a laminar flow to form a metal casting), as shown in fig. 2, the adopted process steps (and parameters) are as follows in sequence: low-pressure mold filling, pressure maintaining, pressure relief, riser feeding at the top of the casting and solidification of the metal casting; the temperature of the aluminum liquid is 710 +/-5 ℃, the liquid-raising pressure is 20Kpa, the mold-filling pressure is 35Kpa, the mold-filling time is 27S, and the pressure-maintaining time is 60S; after the pressure maintaining is finished, cutting off the pressure in the heat preservation furnace for pressure relief, so that the top dead head 14 of the casting automatically feeds the metal casting (when the metal casting is still in a molten state) under the action of the self gravity (the solidification time is 300S), the gas in the cavity of the mold has enough discharge time, the metal casting is prevented from casting defects such as air holes, gas blocking and the like, and the metal casting with good performance quality is obtained through the gravity feeding technology of the top dead head of the casting on the metal casting (after the casting product is formed, the top dead head 14 of the casting, the inner pouring gate 12 and the pouring gate 11 are machined and cut).

Claims

1. Low pressure fills type gravity benefit shrink formula casting mould, including last mould, lower mould, left end mould, right end mould, front mould, back mould, its characterized in that: the upper die, the lower die, the left end die, the right end die, the front die and the rear die form a die cavity after being combined, the upper die is installed below the upper die plate, the lower die is installed on the lower die plate, a casting top dead head can be formed on the upper portion of the upper die, a communicating inner pouring gate and a pouring gate opening are formed in the bottom of the lower die, and the pouring gate opening is sequentially connected with the transition sleeve and the liquid lifting pipe.

2. The low pressure charged gravity fed casting mold of claim 1, wherein: and a heating resistance wire is arranged in the upper part of the upper die, and the upper part of the upper die is connected with a temperature display through a thermocouple.