JPH0313260A - Structure of metallic mold for half melt molding - Google Patents

Abstract

PURPOSE:To obtain a molding having good mechanical properties by forming the communicating part to a stock holding chamber of a passage connecting between the stock holding chamber and a forming mold to the sectional area smaller than the sectional area in the outlet of the holding chamber and forming the communicating part of this passage to a forming mold to the sectional area larger than the sectional area in the outlet of the forming mold. CONSTITUTION:The forming mold 11 and an upper mold 12 are kept at the half melting temp. of the stock by a heater 15. After the stock is heated to the half melting temp. in a separately prepd. furnace, the stock is put into the stock holding chamber 12b. An upper punch 13 is lowered to push the stock 14 through the passage 12a into a recess 11a. While drawing is executed in two stages in the above-mentioned embodiment, the drawing in >=3 steps is equally good alternative and the adoption of the structure to decrease the sectional area of the passage gradually toward the forming mold is equally satisfactory. The drawing rate at the time of extrusion during the molding of the stock is increased in this way while the molding pressure is kept low. The molding having the good mechanical properties, such as tensile strength, is thus obtd.

Description

Detailed Description of the Invention <Industrial Application> The present invention relates to a mold structure for semi-molten molding. Casting is known as one of the methods. Casting is a processing method in which molten metal is poured into a mold and shaped, and has the characteristic that even relatively complex shapes can be manufactured easily and at low cost. However, casting tends to cause product defects such as shrinkage cavities, and there are also problems in that a product with excellent mechanical properties such as tensile strength and yield strength cannot be obtained.

On the other hand, forging is a processing method that compresses a metal material between a pair of tools or dies by bringing the tools or dies close together, but at the same time it can form the material into the desired shape and improve the mechanical properties of the material. is known to be something that can be improved.

However, since forging requires a large amount of pressure to compress the mold, etc., there is a problem that it is difficult to mold some materials.

Therefore, the semi-molten forming method, which is a method for forming metals in a coexistence of solid and liquid states, has recently been studied as a method to reduce the deformation resistance during forming and improve the mechanical properties of molded products. ing.

An object of the present invention is to provide a mold structure for use in such a semi-molten molding method.

Means for Solving the Problems> A semi-molten molding mold structure according to the present invention that achieves the above-mentioned object has a mold and a material holding chamber communicating with the mold, and the material is held in the material holding chamber. A mold for stamping a molded material into a mold, the mold having a passageway connecting the material holding chamber and the molding die, and a cross-sectional area of a communicating portion of the passageway with the material storage chamber. It is characterized by being smaller than the cross-sectional area of the outlet of the holding chamber and larger than the cross-sectional area of the communication portion of the passageway with the mold.

Function When the material in a semi-molten state is pressed, it is pushed out from the material holding chamber into a passage and squeezed, and further extruded from the outlet of the passage into a mold and squeezed. Since the material is squeezed by extrusion at least twice in this way, mechanical properties such as tensile strength and stiffness are improved.

Example of implementation Hereinafter, the present invention will be explained based on examples.

FIG. 1 shows a cross section of a semi-molten mold according to this embodiment. As shown in the figure, this mold has a recess 1 for molding the product.
1a, a passage 12a communicating with the recess 11a, and a material holding chamber 1 communicating with the passage 12a.
2b is formed on the upper die 12. And upper mold 12
An upper punch 13 that fits into the material holding chamber 12b is provided above so as to be movable in the vertical direction, and the upper punch 13 allows the material 14 held in the material holding chamber 12b to pass through the recess 12a. It is designed to be pushed into 11a and embossed. In addition, the mold 11
A heater 15 is provided around the upper mold 12 to maintain the material 14 in a semi-molten state.

Here, the cross-sectional area of the passage 12a is smaller than the cross-sectional area of the material holding chamber 12b, and the cross-sectional area of the entrance of the recess 11m is smaller than the cross-sectional area of the passage 12a.
It is set smaller than the cross-sectional area of . Therefore, material 1
4 is narrowed down when pushed from the material holding chamber 12b into the passage 12a, and narrowed down when pushed from the passage 12a into the recessed part. By performing the narrowing in two stages in this way (and without increasing the molding pressure of the upper punch 13 too much), a large drawing ratio (cross-sectional area ratio) can be obtained.

For example, as shown in FIG. 2, if only the material holding chamber 12a' is provided in the upper mold 12', if an attempt is made to increase the drawing ratio, the molding pressure will increase (increase). With this mold structure, it was difficult to increase the drawing ratio while maintaining the effect of reducing the molding pressure by adopting semi-molten molding.However, with the mold structure of the present invention, the molding pressure You can increase the aperture and rate while keeping it low.

By increasing the drawing ratio in this way, mechanical properties such as tensile strength and yield strength can be improved, perhaps due to metallographic modification, and for example, products similar to forged products can be obtained. .

For example, when high-strength aluminum is to be formed by forging, it is carried out at 420 to 430°C, but since the elongation is small, a forming pressure of Kana 9 is required. On the other hand, when semi-molten molding is performed using the mold of the present invention, molding can be performed at low molding pressure without losing the characteristics of the material such as elongation.

Needless to say, if the material is molded from a solid state to a semi-molten state, defects such as shrinkage cavities due to air entrainment, etc., which occur during casting, will not occur.

Next, a process of semi-molten molding using the mold of the above embodiment (see FIG. 1') will be described.

First, when aluminum is used as the material, the mold 11 and the upper mold 12 are heated to a half-melting temperature of 5 by the heater 15.
The temperature is maintained at 80-630°C, for example 600°C. Although not shown, the mold is provided with a thermocouple as a sensor for the concentration ygwn.

Then, after heating the material to, for example, 600° C. in a separately prepared furnace, put it into the material holding chamber 12b. Then,
Lower the upper punch 13 and pass the material 15 through #112.
a and push it into the recess 11a. As a result, the material 15 is squeezed in a semi-molten state and then molded.

In the above embodiment, the narrowing down is performed in two stages, but it goes without saying that a structure in which the narrowing down is performed in three or more stages is also possible. Alternatively, the cross-sectional area of the passage may be configured to gradually decrease toward the mold.

<Effects of the Invention> As explained above, according to the semi-molten molding die according to the present invention, the drawing ratio during extrusion during molding of the material can be increased while keeping the molding pressure low. The effect is that it is possible to easily obtain a formed amount that improves mechanical properties.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semi-molten mold according to an embodiment of the present invention, and FIG. 2 is a sectional view of a mold for comparison. In the drawings, 11 is a mold, 11a is a recess, 12 is an upper mold, 12a is a passage, 12b is a material holding chamber, 13 is an upper punch, 14 is a material, and 15 is a heater.

Claims (1)

[Claims] A mold that has a mold and a material holding chamber communicating with the mold, and presses a material held in the material holding chamber into the mold, the material holding chamber and the mold being connected to each other. The passage has a connecting passage, and the cross-sectional area of the passage with the material holding chamber is smaller than the exit cross-sectional area of the material holding chamber, and the cross-sectional area of the passage with the forming mold is smaller than the entrance of the mold. A semi-molten mold structure characterized by a larger cross-sectional area.