Tilting pouring method and device for low pressure casting

Abstract

A tilting pouring method and device for low-pressure casting, which uses a clamp to clamp the cavity so that the liquid filling channel of the cavity cooperates with the riser; by pressurizing the crucible furnace, the molten metal rises from the riser through the liquid filling channel and enters the cavity to fill the mold; the characteristic is that a gate is set on the liquid filling channel of the cavity, and when filling the mold, the gate is opened, and when the filling is completed, the gate is closed and the cavity is immediately clamped by a clamp to rotate so that the opening of the liquid filling channel is located at the upper part of the cavity, and the part is taken out after cooling and solidification. The present invention realizes the sequential solidification of the casting from bottom to top through the rotation of the cavity, so that the pressure holding or boosting process in the traditional process is not required, the process control is convenient, the production efficiency is high, and the volume of the riser can be greatly reduced; the cavity can use materials with a relatively low iron sand content, saving costs.

Description

Technical Field

[0001] The invention relates to a metal low-pressure casting method, in particular to a tilting pouring method used in low-pressure casting. Background Art

[0002] In metal casting, especially in the field of core assembly low-pressure casting, a filling channel is usually opened at the bottom of the cavity to connect with the liquid riser in the furnace. After the mold is closed, bottom pouring is achieved by pressurization. For example, Chinese invention patent application CN107297484A discloses a low-pressure casting method for aluminum alloy, including the following steps: S1 metal liquid preparation; S2 device detection and preparation; S3 pressurization, placing the metal liquid in a holding furnace, adding a certain amount of aluminum powder to the holding furnace, stirring it thoroughly for 1-2 hours, and then passing a gas 0.01-0.05Mpa higher than the atmospheric pressure into the holding furnace for 2-8 minutes. When the mold is filled to the top of the mold, the pressure should be increased rapidly immediately; S4 solidification and forming, the metal liquid is pressed into the mold through the liquid riser under pressurized conditions, the mold opening temperature is between 350-450℃, and the mold closing time is 4-6 minutes; S5 cooling and taking out the parts.

[0003] In the low-pressure casting process, the mold is filled from the bottom to the top through the riser. Generally, at the end of the filling, in order to compensate for the shrinkage of the casting, a "pressure holding" process is required, which has low production efficiency. In the above technical solution, in order to solve the shrinkage compensation problem, when the mold is filled to the top of the mold, a rapid pressure increase is used to compensate for the shrinkage. On the one hand, it increases the difficulty of process control, and on the other hand, the cavity needs to withstand greater pressure. Therefore, when making the cavity, it is necessary to increase the iron sand ratio, resulting in an increase in the cost of the cavity material.

[0004] Therefore, in order to improve production efficiency, reduce costs and process difficulty, it is necessary to improve the pouring and filling method during low-pressure casting. Summary of the invention

[0005] The object of the present invention is to provide a tilting pouring method for low-pressure casting to solve the production efficiency problem caused by shrinkage compensation and reduce production costs.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention is: a tilting pouring method for low-pressure casting, which adopts a clamp to clamp the mold cavity so that the liquid filling channel of the mold cavity cooperates with the riser; by pressurizing the crucible furnace, the molten metal rises from the riser tube and enters the mold cavity through the liquid filling channel to fill the mold; a gate plate is arranged on the liquid filling channel of the mold cavity, and the gate plate is opened during filling, and when the filling is completed, the gate plate is closed and the mold cavity is immediately clamped by a clamp to rotate, so that the opening of the liquid filling channel is located at the upper part of the mold cavity, and the part is taken out after cooling and solidification.

[0007] In the above technical scheme, the pressure maintaining or boosting process during low-pressure casting in the prior art is eliminated. By arranging a gate plate on the liquid filling channel, the gate plate is used to seal the filling channel after the filling is completed. The mold cavity is creatively rotated so that the filling channel is located at the upper part, thereby making the bottom of the mold cavity with the highest temperature become the upper part, and the casting gradually cools and solidifies from bottom to top, which is conducive to realizing the shrinkage compensation of the casting.

[0008] A further technical solution is to set a level sensor on the upper part of the cavity during filling. When the level sensor detects molten metal, it will give a signal that filling is completed, controlling the closing of the gate and the rotation of the cavity.

[0009] Preferably, after the gate is closed, the cavity is rotated 90° and placed on a platform for natural cooling.

[0010] In order to realize the above-mentioned pouring method, the present invention provides a tilting pouring device for low-pressure casting, comprising a mold cavity and a crucible furnace. The crucible furnace is provided with a riser, a heating device and a pressurizing device. The mold cavity has a liquid filling channel cooperating with the riser, and the liquid filling channel is provided with a gate that can be opened and closed; the mold cavity is clamped by a clamp, and the clamp is provided with a rotating mechanism. When the rotating mechanism rotates to make the mold cavity in a first position, the liquid filling channel of the mold cavity is in the same position as the riser and is in a filling position. When the rotating mechanism rotates to make the mold cavity in a second position, the liquid filling channel of the mold cavity is located at the upper part of the mold cavity and is in a cooling position.

[0011] According to a further technical solution, a level gauge is provided in the mold cavity, and the level gauge is located at the upper part of the mold cavity when it is in the filling position.

[0012] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0013] 1. The present invention realizes the sequential solidification of the casting from bottom to top by rotating the cavity, thereby eliminating the need for the pressure holding or pressure boosting process in the traditional process, making the process control convenient, the production efficiency high, and the riser volume greatly reduced;

[0014] 2. The present invention provides a gate plate so that the cavity can rotate before solidification;

[0015] 3. Since there is no need for pressure boost, the cavity of the present invention can be made of materials with relatively low iron sand content, thus saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic diagram of a filling process of an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of the embodiment of the present invention during cooling.

[0018] In the figure: 1. Cavity; 2. Level indicator; 3. Gate; 4. Rising tube; 5. Crucible furnace; 6. Liquid filling channel. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0020] Embodiment 1: A tilting pouring device for low pressure casting, see attached Figure 1 , including a cavity 1 and a crucible furnace 5, wherein a riser 4, a heating device and a pressurizing device (not shown in the figure) are provided in the crucible furnace, wherein the cavity 1 has a liquid filling channel 6 cooperating with the riser 4, and a gate 3 which can be opened and closed is provided on the liquid filling channel 6; the cavity is clamped by a fixture (not shown in the figure), and the fixture is provided with a rotating mechanism, when the rotating mechanism rotates to make the cavity in the first position, the liquid filling channel of the cavity is in the same position as the riser, and is in the filling position, and when the rotating mechanism rotates to make the cavity in the second position, the liquid filling channel of the cavity is located at the upper part of the cavity, and is in the cooling position. A level gauge 2 is provided in the cavity 1, and the level gauge 2 is located at the upper part of the cavity 1 when it is in the filling position.

[0021] See also Figure 1 The figure shows the filling process. At this time, the liquid filling channel of the cavity cooperates with the liquid riser. By pressurizing the crucible furnace, the molten metal rises from the liquid riser and enters the cavity through the liquid filling channel to fill the mold.

[0022] When the level sensor detects the metal liquid and gives a signal that the filling is completed, the gate is controlled to move in the "P" direction to close the filling channel. At this time, the pressure in the crucible furnace is released and there is no need to continue "maintaining pressure".

[0023] See also Figure 2 After the filling process is completed and the metal liquid is "blocked", there is no need to wait, and then the fixture clamps the cavity and tilts it to finally Figure 2 As shown in the figure, the metal liquid temperature at the top of the cavity is the highest, and the casting gradually cools and solidifies from bottom to top, which is conducive to realizing the shrinkage compensation of the casting.

Claims

1. A tilting pouring method for low-pressure casting, wherein a fixture is used to clamp the mold cavity, so that the liquid filling channel of the mold cavity cooperates with the liquid riser; by pressurizing the crucible furnace, the molten metal rises from the liquid riser through the liquid filling channel and enters the mold cavity for filling; characterized in that: A gate is arranged on the liquid filling channel of the cavity. When filling, the gate is opened. When filling is finished, the gate is closed and the cavity is immediately clamped and rotated by a clamp so that the opening of the liquid filling channel is located at the upper part of the cavity. After cooling and solidification, the part is taken out. Among them, a level meter is set on the upper part of the cavity during filling. When the level meter detects the molten metal, it gives a signal that the filling is completed, controls the closing of the gate and the rotation of the cavity.

2. The tilting pouring method for low pressure casting according to claim 1, characterized in that: After the gate is closed, the cavity is rotated 90° and placed on a platform for natural cooling.

3. A tilting pouring device for low-pressure casting, comprising a mold cavity and a crucible furnace, wherein a liquid riser, a heating device and a pressurizing device are arranged in the crucible furnace, and the mold cavity has a liquid filling channel cooperating with the liquid riser, characterized in that: The liquid filling channel is provided with a gate that can be opened and closed; the cavity is clamped by a clamp, and the clamp is provided with a rotating mechanism. When the rotating mechanism rotates to make the cavity in the first position, the liquid filling channel of the cavity and the riser are in the filling position; when the rotating mechanism rotates to make the cavity in the second position, the liquid filling channel of the cavity is located at the upper part of the cavity and is in the cooling position.

4. The tilting pouring device for low pressure casting according to claim 3, characterized in that: A material level indicator is arranged in the mold cavity, and the material level indicator is located at the upper part of the mold cavity when it is in the filling position.

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