JPH09314281A - Casting method and mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the development of metal penetration and shrinkage cavity. SOLUTION: An aluminum foil 15 is stuck on recessed parts 10, 11 of an upper die 2 and a lower die 11 and also on sand core surface positions 12, 13 faced to the recessed parts 10, 11 with adhesives. At the time of pouring molten aluminum 16 into a cavity 7 in a mold 5, the molten aluminum 16 filled up into the cavity thick parts 8a, 8b is uniformly and rapidly cooled and solidified with the aluminum foil 15 stuck to the recessed parts 10, 11 and the sand core surface positions 12, 13 and the shrinkage cavity is not developed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method and a mold in which shrinkage cavities and insertions do not occur.

[0002]

2. Description of the Related Art As a method of preventing shrinkage cavities, a fine metal powder for cooling which accelerates cooling of molten metal is applied to a predetermined portion of a mold surface which forms a cavity, and the molten metal poured into the mold is cooled. In order to increase the cooling rate of the molten metal by bringing it into contact with the fine metal powder for use, for example, a method of applying fine chromium powder to the inner surface of the cavity during casting of a cast iron casting (Japanese Patent Laid-Open No. Hei 4)
No. 118164), and a method of applying fine aluminum powder to the inner surface of the cavity when casting an aluminum casting. Further, as another method for preventing the occurrence of shrinkage cavities, a method of burying a cooled metal in a desired portion of a mold and rapidly cooling the molten metal by pouring the molten metal in the mold into contact with the cooled metal is known. (For example, the prior art disclosed in Japanese Patent Laid-Open No. 7-1074).

[0003]

However, in the conventional method using the cooling metal fine powder, a thin coating portion is generated when the cooling metal fine powder is applied to a predetermined portion of the mold surface, and the thin coating portion There is a problem that shrinkage cavities are likely to occur in the engaged casting parts. Further, the method using a chill does not easily cause shrinkage cavities in the casting, but when casting a casting having a complicated shape, the work of burying the chill becomes complicated. Therefore, the present invention has been made to solve the above problems, and an object of the present invention is to provide a casting method and a mold that can easily prevent the occurrence of shrinkage cavities.

[0004]

A casting method according to claim 1 is characterized in that a metal foil is attached to a predetermined portion of a mold surface forming a mold cavity, and then a molten metal is poured into the cavity. To do. A casting method according to a second aspect is the casting method according to the first aspect, characterized in that a predetermined portion of the mold surface is a portion facing a thick portion of the cavity. The mold according to claim 3 is the mold according to claim 1 or 2, characterized in that a predetermined portion of the surface of the mold to which the metal foil is attached is formed of refractory sand. The mold according to claim 4 is the mold according to claim 3, characterized in that the mold surface is formed from a mold body surface and / or a sand core surface.

The metal foil attached to a predetermined portion of the mold surface cools the molten metal in contact with the metal foil uniformly and rapidly and does not cause shrinkage cavities. Further, the metal foil prevents the molten metal from entering the mold surface and does not cause insertion.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As a casting method of the present invention, a gravity casting method, a local pressure casting method, a reduced pressure casting method, a low pressure casting method and the like are used. Aluminum foil, copper foil, zinc foil, and iron foil are used as the metal foil, and the thickness thereof is 0.01 to 0.5 mm.
Are preferred. A release agent may be applied to the surface of the metal foil. In the mold according to claims 3 to 4, the mold surface part may be made of refractory sand as the part to which the metal foil is attached, and other parts, for example, parts around the part to which the metal foil is attached may be made of metal. Good.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. The mold 1 is formed of a mold body 4 composed of an upper mold 2 and a lower mold 3 made of refractory sand, and a sand core 5 interposed between the upper mold 2 and the lower mold 3. Between the core 5
A runner portion 6 and a cavity 7 which communicate with a sprue (not shown) are formed. The cavity 7 is composed of cavity thick parts 8a and 8b forming a thick part of the casting and a cavity thin part 8c forming a thin part of the casting. The recessed portion 1 formed
0 and the sand core surface portion 12 facing the concave portion 10, and the cavity thick portion 8b is the mold body surface 3 of the lower mold 3.
It is formed between the recess 11 formed in a and the sand core surface portion 13 facing the recess 11. An aluminum foil 14 having a thickness of 0.05 mm is attached to the recesses 10 and 11 with an adhesive so as to cover the recesses 10 and 11.
An aluminum foil 15 having a thickness of 0.05 mm is attached to the Nos. 2 and 13 by an adhesive so as to cover the sand core surface regions 12 and 13.

Casting of a casting using the mold 1 will be described. A molten aluminum 16 is injected from a spout (not shown) of the matched mold 1, and the cavity 7 is filled with the molten aluminum 16 through the runner portion 6. The molten aluminum 16 filled in the cavity thick portions 8a, 8b is recessed 1
0 and 11 and the aluminum foils 14 and 15 attached to the sand core surface portions 12 and 13 uniformly and rapidly solidify, so that shrinkage cavities do not occur. Metal foil 14,1 attached to a casting
No. 5 is removed when sand core sand attached to the casting is removed.

Next, a second embodiment of the present invention will be described with reference to FIG. The mold 21 includes an upper mold 22 and a lower mold 2 made of iron.
It is formed from a mold body 24 composed of 3 and a sand core 25 interposed between the upper mold 22 and the lower mold 23, and a sprue (not shown) is provided between the mold body 24 and the sand core 25. ) And a cavity 27 are formed to communicate with each other. The cavity 27 is the thick wall portion 2 of the cavity forming the thick wall portion of the casting.
8a, 28b and a cavity thin portion 28c forming a thin portion of the casting, and the cavity thick portion 28a is a funnel-shaped through hole 3 formed in the mold body surface 22a of the upper mold 22.
The cavity thick portion 28b is formed between the second umbrella-shaped portion 32a and the sand core surface portion 30 facing the umbrella-shaped portion 32a.
A funnel-shaped through hole 3 formed in the mold surface 23a of the lower mold 23.
It is formed between the umbrella-shaped portion 33a of No. 3 and the sand core surface portion 31 facing the umbrella-shaped portion 33a. Cylindrical portion 32b of through hole 32
And the cylindrical portion 33b of the through hole 33 has a pressure piston 3
4, 35 are arranged so that they can move forward and backward, and the pressure piston 3
4, 35 are connected to a drive device (not shown) via piston rods 36, 37. An aluminum foil 38 having a thickness of 0.05 mm is attached to the sand core surface portions 30, 31 of the sand core 25 with an adhesive so as to cover the sand core surface portions 30, 31.

Casting of a casting using the mold 25 will be described. The molten aluminum 39 is poured from a sprue (not shown) of the matched mold 21, and the cavity 27 is filled with the molten aluminum 39 through the runner 26. Cavity thick part 28a, 28b
And molten aluminum 39 in the cavity thin portion 28c
When is solidified, the pressure pistons 34 and 35 are moved forward (in the direction of the center of the paper surface in FIG. 2) to pressurize the unmelted or semi-solidified molten aluminum 39. Cavity thick part 2
The molten aluminum 39 filled in 8a, 28b is uniformly quenched and solidified by the aluminum foil 38 attached to the sand core surface portions 30, 31, and the pressure piston 3
It is pressurized by the forward movement of 4,35 and does not generate shrinkage cavities. In addition, the pressurized aluminum melt 39 is pressed against the sand core surface portions 30 and 31.
Since 8 prevents the molten aluminum 39 from entering the mold 25, the insertion does not occur. The aluminum foil 38 attached to the casting is removed when the core sand attached to the casting is removed.

[0011]

According to the present invention, since the metal foil is attached to a predetermined portion of the mold surface forming the cavity of the mold, the molten metal is cooled uniformly and rapidly so that shrinkage cavities do not occur and the molten metal is Since it does not invade, it does not occur and a sound casting can be easily cast. Since the insertion does not occur, the step of removing the casting burr can be omitted, and since the casting portion in contact with the metal foil forms a dense metal structure, a casting without pressure leakage defects can be easily cast.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a mold according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of a mold according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Mold 2a Mold body surface 3a Mold body surface 4 Mold body 5 Sand core 7 Cavity 8a Cavity thick part 8b Cavity thick part 12 Sand core surface part 13 Sand core surface part 14 Aluminum foil 15 Aluminum foil 16 Aluminum molten metal 21 mold 24 mold body 25 sand core 27 cavity 28a cavity thick part 28b cavity thick part 34 sand core surface part 35 sand core surface part 38 aluminum foil 39 aluminum molten metal

Claims (4)

[Claims] 1. A casting method, which comprises applying a metal foil to a predetermined portion of a mold surface forming a mold cavity, and then pouring a molten metal into the cavity. 2. The casting method according to claim 1, wherein a predetermined portion of the mold surface is a portion facing the thick portion of the cavity. 3. The mold according to claim 1 or 2, wherein a predetermined portion of the surface of the mold to which the metal foil is attached is made of refractory sand. 4. The mold according to claim 3, wherein the mold surface is formed of a mold body surface and / or a sand core surface.