JPH04361850A - Casting apparatus - Google Patents

Abstract

PURPOSE:To improve the productivity and the casting quality by arranging a preheating means for controlling temp. at a sprue part to execute temp. control and controlling the temp. there so that solidification of molten metal at each runner part completes at the almost same time. CONSTITUTION:The molten metal 5 is poured into a crucible 3 in a holding furnace 2, and gas is supplied from a gas passage 6 and pressurized. The molten metal 5 is filled up into cavity 9 in a metallic mold 8 through a stokes 7. Plural runner parts 10 are communicated with lower part of the cavity 9. The pre- heating means is arranged at outer peripheral part of the sprue part 16 communicated with the runner part 10. While measuring the temps. in plural runner parts 10, preheating with the pre-heating means is controlled so that all runner parts 10 solidify at the same time. The productivity is improved and also, passing pressure to the molten metal is uniformized till completing the solidification and the casting quality is improved.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates, for example, to a casting device in which melt is poured from a plurality of runners, in which the solidification of each runner is completed at the same time, thereby improving mold releasability. .

0002

BACKGROUND OF THE INVENTION In recent years, with the advancement of casting technology, large-sized castings have come to be cast, and it is common for such large-sized castings to have a plurality of runners. In other words, the molten metal injected into the mold cavity begins to solidify as the mold cools, but if there is a single runner, the casting time will be longer, resulting in uneven solidification as a whole. This is because if there is only one runner, a sufficient riser effect cannot be obtained, and such problems can be prevented by providing a plurality of runners. On the other hand, in the case of a low-pressure caster, for example, a sprue is usually provided between the runner and the lower stoke, through which the molten metal is poured.

0003

[Problem to be solved by the invention] However, in the conventional case,
Since the sprues mentioned above are provided at the same height in the vertical direction, for example, in a casting machine that has multiple runners with different flow path diameters or lengths, the solidification rate of each runner will be different. However, there was a problem in that the mold could not be opened until the final runner had completely solidified. Moreover, due to the difference in the solidification speed of each runner, while waiting for solidification at the final runner, solidification progressed downward in the runner where it solidified first, and the pressurized gas pressure for the feeder was released. At times, problems such as coagulated material being mixed into the molten metal flowing back into the crucible were caused.

0004

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a casting apparatus in which a plurality of runners below a casting cavity are communicated with a sprue section below, and a height direction of each sprue section is provided. Preheating means for controlling the temperature of each runner section was provided at different positions and on the outer periphery thereof. Moreover, by this preheating means, the solidification of the molten metal in each runner is completed almost simultaneously.

[0005]

[Operation] If the temperatures of the plurality of sprues are independently controlled by the preheating means and the solidification of the molten metal in each sprue is completed almost simultaneously, release from the mold will be smooth. Furthermore, since the solidification rate in each runner is kept constant, the feeder effect is uniform throughout, improving casting quality. Furthermore, it is possible to prevent the problem of solidified foreign matter being mixed into the molten metal that flows back into the crucible after casting.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a casting apparatus according to the present invention will be explained based on the attached drawings. FIG. 1 is a longitudinal cross-sectional view of the entire low-pressure casting machine, FIG. 2 is an enlarged view of the main parts around the sprue, and FIG. 3 is a further enlarged view of a part thereof. The casting apparatus of the present invention is applied, for example, as a low-pressure casting machine 1 as shown in FIG. 1, and this low-pressure casting machine 1 is equipped with a crucible 3 in a holding furnace 2, as is well known. Then, the molten metal 5 of aluminum alloy or the like injected from the supply port 4 of the crucible 3 is pressurized by compressed air or inert gas fed from the gas path 6, and is poured into the cavity 9 of the mold 8 via the stoke 7. Fill it. Furthermore, cavity 9
A plurality of runners 10, which will be described later, are in communication below.

On the other hand, the mold 8 includes an upper mold 11 and a lower mold 12, and a hydraulic cylinder unit 13 is connected to the upper mold 11 to open and close the mold vertically. Then, the above-mentioned cavity 9 is formed with the mold closed. Further, an intermediate stalk 14 is provided on the aforementioned stalk 7. This intermediate stoke 14 has a wide upper side in order to distribute and supply molten metal 5 to a plurality of sprues 16 described below, and a stoke lid 15 is provided on this intermediate stoke 14. ing. A plurality of sleeve-shaped sprues 16 are provided on the upper part of the stoke lid 15, and these sprues 16 communicate with the runner 10.

Next, the details of the structure of the sprue portion 16 will be explained based on FIGS. 2 and 3. Sleeve-shaped sprue part 16
is made of FC, for example, and has a cavity 9.
Considering the shape, wall thickness, positional relationship with the gas venting part, etc.
Its position is determined, and the height position differs depending on the location. Further, a preheating means 17 is provided around each sprue portion 16. That is, a heater groove is provided all around the outer periphery of the sprue portion 16, and a heater wire 20 having a small diameter of, for example, about 3 mm is wound around the heater groove. Then, thermal spraying is applied from above the heater wire 20 to form a thermal spray layer 21, which covers the heater wire 20. As such a thermal spray material, molybdenum, which is a high melting point metal, is used, for example. Therefore, the adhesion between the heater wire 20 and the sprue portion 16 is improved, and the temperature raising effect can be improved.

On the other hand, a temperature sensor 22 is embedded adjacent to this heater groove. And this temperature sensor 22
The terminals are respectively connected to separate program temperature controllers to control preheating by the heater wire 20. The area around the preheating means 17 of the sprue 16 constructed in this way is as shown in FIG.
A cover 23 as shown in the figure is attached to the preheating means 17.
protect. A runner collar 24 having a different diameter or length depending on the location is provided above the sprue 16, and the interior of the runner collar 24 forms the runner 10 described above. The preheating of the preheating means 17 is carried out by the plurality of runners 1.
The solidification of the molten metal in each of the molten metals is controlled separately so that the solidification is completed almost simultaneously.

The effects of the casting apparatus constructed as described above are as follows. When the molten metal 5 is injected into the crucible 3 and pressurized by the gas pressure from the gas path 6, the molten metal 5 rises up the stoke 7 and passes through the runners 10 through the plurality of sprues 16. and flows into the cavity 9 all at once. Molten metal 5
When filled into the cavity 9, the gas pressure is maintained while waiting for solidification. In other words, solidification starting from the end of the cavity 9 gradually progresses toward the runner 10. During this time, sprue section 1
The preheating by the preheating means 7 of 6 is controlled separately, and as described above, prevents solidification of the portion below the runner 10 and prevents delay in solidification around the runner 10 due to excessive preheating. do. In other words, the timing of solidification of all sprues 16 is balanced. For this reason, cavity 9
The molten metal inside can receive static pressure and molten metal replenishment from each runner section 10 until solidification is completed, making it possible to cast with good quality.

[0011] Furthermore, during this temperature control, the preheating structure with improved adhesion by the sprayed layer 21 is effective for precise temperature control. In other words, it is possible to control the temperature in a high temperature range, which was previously impossible. When the desired solidification is achieved, pressurization is stopped, and the molten metal below the sprue 16 falls and refluxes into the crucible 3. At this time, since solidification has not progressed to the bottom, solidified lumps are mixed into the molten metal 5. There is no problem with doing so. Furthermore, since the solidification in each sprue portion 16 is almost simultaneous, it is possible to accelerate the timing of mold release, contributing to improved productivity.

0012

As described above, the casting apparatus of the present invention allows the solidification of a plurality of runners to be completed almost simultaneously, so that mold release is smooth and productivity can be improved. Additionally, the feeder pressure applied through the runner is uniform throughout, improving casting quality. Furthermore, since the parting line between the solidified portion and the unsolidified portion can be appropriately controlled, problems such as contamination of solidified material into the molten metal can be prevented, and the quality of the cast product will not be impaired.

[Brief explanation of the drawing]

[Figure 1] Longitudinal cross-sectional view of the entire low-pressure casting machine

[Figure 2] Enlarged view of the sprue area

[Figure 3] Partially enlarged view of Figure 2

[Explanation of symbols]

(1) Low pressure casting machine (9)
Cavity (10) runner part
(16) Sprue part (17) Preheating means

Claims (2)

[Claims] 1. A casting device in which a plurality of runners below a casting cavity are communicated with a sprue portion below, in which the height positions of the sprue portions are different, and each sprue has a 1. A casting device characterized by being provided with preheating means for controlling the temperature of a runner. 2. The casting apparatus according to claim 1, wherein the temperature control by the preheating means is controlled so that solidification of the melt fields in each runner is completed almost simultaneously.