JPH11342460A - Enveloped casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a casting, in which a material to be enveloped-cast is mounted under a normal condition by preventing erosion and dissolution of the enveloped-cast material. SOLUTION: A material 1 to be enveloped-cast, which is coated with a heat insulation material or on which an oxide film of 0.05-50 μm thickness is formed, is set inside a mold, and a molten metal to be an enveloped-casting material is poured in the mold. Nitride, oxide, boride, carbon dioxide salt, phosphoric salt, graphite, calcium carbonate, vermiculite, iron oxide, boric acid, mica, whiting, titanium oxide, kaolinite, glass fiber, silicon oxide, and the like, are used as a heat insulation material and can be applied on the material to be enveloped-cast by being mixed with a binder such as vermiculite, bentonite, water glass, sodium silicate, and boric acid. In this way, the enveloped-cast material is protected from high heat of the molten metal by means of the heat insulation material or the oxide film, resulting in restraint of erosion and dissolution. Since the heat insulation material and the oxide film are separated from the material to be enveloped-cast and floated before the re-molten metal obtained by recycling is solidified, they are not-left in recycled products.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recycle, corrosion-resistant material having no erosion, melting, etc.
The present invention relates to a method for producing a cast product having excellent oxidation resistance and the like.

[0002]

2. Description of the Related Art Products such as brakes having a fluid passage therein are also manufactured by drilling.
When providing a fluid passage having a complicated shape or a small inner diameter, a cast-in method is employed. In the cast-in method, when a product body is die-cast, a pipe made of the same material as the product body is integrally cast, and a small-diameter pipe is used as a fluid passage. When a pipe of the same material as the product body is cast, the pipe is heated by the heat of the molten metal which becomes the product body, and erosion and melting are likely to occur, which causes a problem in leak resistance of the fluid passage. Conventionally, various methods have been proposed to prevent erosion, dissolution, and the like of a member to be cast (hereinafter referred to as a cast-to-be-filled material). For example, Japanese Unexamined Patent Publication No.
In Japanese Patent No. 2058, after casting a metal having a high melting point on the outer peripheral surface of a material to be cast, the material is cast. Nickel plating, chromium plating, etc., are used as the metal having a high melting point to prevent the heat of the molten metal from being directly transmitted to the to-be-cast material, thereby suppressing erosion and melting of the to-be-cast material.

[0003]

However, the metal coating layer provided by plating, vapor deposition or the like is originally high in heat conductivity and is provided thinly, so that heat transfer from the molten metal cannot be sufficiently suppressed. Therefore, even when a metal coating layer having a high melting point is provided, it is not possible to completely prevent erosion or dissolution of the to-be-cast material. Moreover, by applying nickel plating, chromium plating, etc., the recyclability and corrosion resistance deteriorate. That is, even if the material to be cast and the material to be cast are the same kind of metal, Ni and Cr derived from the metal coating layer are mixed. Therefore, in the case where the waste is collected and used as a metal source, a special treatment is required for removing impurities. In addition, since a foreign metal is present at the contact interface between the to-be-cast material and the to-be-cast material, it becomes a starting point of corrosion or the like, and the corrosion resistance is apt to deteriorate. The present invention has been devised to solve such a problem. By covering the surface of the to-be-stuffed material with a heat insulating material, the erosion and dissolution of the to-be-stuffed material are suppressed, and the recyclability is improved. The purpose is to obtain a cast-in product having excellent corrosion resistance, oxidation resistance, and the like.

[0004]

SUMMARY OF THE INVENTION In order to achieve the object, according to the present invention, there is provided a method for setting a cast material to be covered with a heat-insulating substance in a mold, and forming a molten metal serving as the cast material into the mold. It is characterized by injection. Examples of heat insulating materials include nitrides, oxides, borides, carbonates, phosphates, graphite, calcium carbonate, vermiculite, iron oxide, boric acid, mica, chalk, titanium oxide, kaolinite, glass fiber, and silicon nitride. , Silicon oxide or one or more selected from silicon oxide. Further, when mixed with a binder such as vermiculite, bentonite, water glass, clay, sodium silicate, boric acid, resin, etc., application to a to-be-cast material becomes easy.
If the coating amount of the heat-insulating substance is too small, the heat-insulating properties will be insufficient. Therefore, it is desirable that the coating thickness is at least 15 μm or more (preferably 60 μm or more). However, if the coating is too thick, the adhesion between the cast-in and cast-in materials will be poor, so the coating thickness is preferably 120 μm or less. Further, it is more effective to form a coating layer with a multilayer structure of different heat insulating materials than to form a single coating layer.

When aluminum or an aluminum alloy is used as the material to be cast, an artificial oxide film formed by anodizing, high-temperature oxidation or the like may be used as the heat insulating layer instead of coating with a heat insulating material. The oxide film prevents high heat immediately after pouring the melt of the cast-in material into the cast-filled material, similarly to the coating of the heat insulating material. In order to secure such an effect, it is preferable to adjust the thickness of the oxide film to 0.05 to 50 μm in a normal casting method. In addition, in the casting method in which the high-temperature molten metal is prevented from directly hitting the stuffed material during casting, 0.05 μm is used.
Even if the film thickness is more than m, it works as a heat insulating layer. The effect of the oxide film is saturated at a film thickness of 50 μm, and even if the film thickness is further increased, the production cost increases. The oxide film is formed by subjecting the material to be cast to an oxidation treatment such as anodizing or high-temperature oxidation prior to the casting. Alternatively, when aluminum or an aluminum alloy on which an oxide film has already been formed is used as a material to be cast, it can be set as it is in a mold.

When a hollow pipe is used as a material to be cast, a molten metal as a material to be cast can be injected into the mold while supplying a coolant to the hollow pipe set in the mold. The same or different metals or alloys can be used for the cast-to-fill material and the cast-to-fill material. Even if the melting point of the cast-to-fill material is the same as or lower than the melting point of the cast-to-fill material, the heat-insulating powder can be used. As it is protected, it can be cast-in. For example, a cast caliper material and a cast body material can be made of an aluminum alloy, and a brake caliper can be manufactured.
It is also possible to cast a magnesium material and an aluminum material.

[0007]

[Function] When a cast-filled material covered with a heat-insulating material is placed in a mold and a molten metal serving as the cast-in material is poured, the heat-insulating material is interposed between the cast-filled material and the molten metal. In addition, the high heat immediately after pouring is not directly transmitted to the cast-through material. Therefore, the cast-filled material is not directly exposed to high heat immediately after pouring, and erosion and dissolution are suppressed. When re-melting the cast-in product at the time of recycling, the heat-insulating substance floats and separates on the surface of the molten metal and does not enter the recycled product. Similarly, the oxide film formed on the surface of the aluminum material also prevents high heat from being directly transmitted to the material to be cast, and floats and separates on the surface of the molten metal in the remelting process during recycling. Just by coating with an insulating material or forming an oxide film in this way, the material to be cast is protected from the high heat of the molten metal,
As compared with the case where a metal coating layer having a high melting point is provided by conventional nickel plating, chromium plating, or the like, manufacturing is simplified, and a low-cost, high-quality cast-in product is obtained.

[0008]

EXAMPLE 1 An example in which a brake caliper is manufactured by using a 6063 aluminum alloy as an insert material and an AC4C aluminum alloy as an insert material will be described. However, the present invention is not limited to this. Of course, other cast-in products can be provided as well. As shown in Table 1, a heat insulating powder was applied to the surface of a pipe made of 6063 aluminum alloy having an outer diameter of 6 mm and a wall thickness of 1.5 mm. In Test No. 3, two types of heat insulating powders were applied repeatedly. The both ends of the pipe 1 coated with the heat insulating powder are supported by the lower mold 2 as shown in FIG.
Cavity 5 formed between lower mold 2 and upper mold 4
Faced. Then, an AC4C aluminum alloy was injected into the cavity 5 at a pouring temperature of 710 ° C., and the pipe 1 was cast. In the present embodiment, the casting was performed under the condition that the molten metal injection flow from the basin was in direct contact with the pipe 1 which was the material to be cast.

[0009]

Each of the manufactured brake calipers was subjected to an air communication test, and erosion and dissolution of the pipe 1 were examined. For comparison, a brake caliper (Test No. 4) in which a pipe to which no heat insulating powder was applied was similarly cast was also subjected to an air communication test. In the air communication test, air was blown from one end of a pipe, which is a material to be cast, and the air communication was examined by checking whether air came out from the other end of the pipe. In the brake caliper of Comparative Example 1, the pipe was eroded by the injection of the molten metal as the cast-in material, and the original shape was hardly retained. Therefore, in the air communication test, as shown in Table 2, there was no air communication in all the units. On the other hand, in Test Nos. 2 and 3 in which the heat insulating powder was applied with a thickness of 60 μm, it was found that all the units had air communication and all the cast units could be used as brake calipers. Also,
Even in Test No. 1 in which the heat insulating powder was applied relatively thinly, a product having no harmful defect near the hollow pipe was obtained, although a defective product occurred.

[0011]

Example 2: Casting made of an AC4C aluminum alloy under the same conditions as in Example 1 except that a 6063 aluminum alloy having various thicknesses of anodized film formed thereon is used as a to-be-cast material, and a brake caliper. Was manufactured. The obtained brake caliper was subjected to the same air communication test as in Example 1 to investigate the effect of the thickness of the anodic oxide film on the yield of non-defective products. The yield rate of non-defective products was represented by the number of non-defective products when ten cast-in products were manufactured. As can be seen from the test results in Table 3, when the thickness of the anodic oxide film was in the range of 5 to 50 μm specified in the present invention, a high yield of good products was obtained. Further, in Test No. 9 in which a relatively thick anodic oxide film was formed, all good cast-in products were obtained even when the casting temperature was increased. On the other hand, in Test No. 11 (Comparative Example) having no anodized film, the to-be-cast material was significantly eroded, and air leakage occurred in all of the obtained as-cast products. In Test No. 12 (Comparative Example) where the anodic oxide film was thin, only two good products were obtained because the heat insulating effect of the anodic oxide film was insufficient.

[0013]

Example 3 Casting of an AC4C aluminum alloy under the same conditions as in Example 1 except that a 6063 aluminum alloy having an anodized film or a high-temperature oxide film formed in various thicknesses is used as a cast material. As a whole, brake calipers were manufactured. In this embodiment, the surface of the molten metal poured into the mold from the pool was gradually raised in the mold cavity, and was cast so as to cover the material to be cast. The obtained brake caliper was subjected to the same air communication test as in Example 1 to investigate the effect of the thickness of the oxide film on the yield of non-defective products. The yield rate of non-defective products was represented by the number of non-defective products when ten cast-in products were manufactured. As can be seen from the test results in Table 4, when the thickness of the oxide film was in the range of 0.05 to 50 μm specified in the present invention, a high yield rate of good products was obtained. In particular, 0.5 μm, 0.05 μm or 5 μm
It has been found that even when an oxide film having a relatively small thickness of m is formed, by employing a casting method in which the molten metal from the puddle does not directly contact the material to be cast, erosion of the material to be cast can be suppressed. On the other hand, Test No. 29 to No.
In 31 (comparative example), the cast toy material was significantly eroded,
Air leakage occurred in all of the obtained cast-in products.

[0015]

[0016]

As described above, in the present invention, the high heat of the injected molten metal is prevented from being directly transmitted.
Since the cast material covered with the heat insulating material or the oxide film is set in the mold, and the molten metal serving as the cast material is injected, the erosion or melting of the cast material by the molten metal is suppressed. . As a result, even when a material having substantially the same melting point is used as a cast-in place material or a cast-in place material, a cast product in which the cast-in place material is installed in a sound form can be obtained. The heat insulating material and the oxide film of the coating layer are separated from the material to be cast and float when the molten metal obtained by re-melting by recycling is solidified, and therefore do not remain in the recycled product. Therefore, the deterioration of the recyclability, corrosion resistance, oxidation resistance, and the like due to the mixing of the heat insulating material and the oxide film can be prevented.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment for manufacturing a brake caliper.

[Explanation of symbols]

1: Hollow pipe coated with heat insulating powder 2: Lower mold
3: Core 4: Upper die 5: Mold cavity

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahide Hamada 1-1-1, Koyokita-Kita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Seisakusho (72) Inventor Yoshiki Matsuzaki 1-chome, Koyokita, Itami-shi, Hyogo No. 1, No. 1 Sumitomo Electric Industries, Ltd. Itami Works

Claims (7)

[Claims] 1. A method according to claim 1, wherein a material to be cast coated with a heat insulating material is set in a mold, and a molten metal as a material to be cast is injected into the mold. 2. Nitride, oxide, boride, carbonate, phosphate, graphite, calcium carbonate, feldspar, iron oxide, boric acid,
Mica, chalk, titanium oxide, kaolinite, glass fiber,
2. The method according to claim 1, wherein one or more selected from silicon nitride and silicon oxide are used as the heat insulating material. 3. Mixing one or more binders selected from vermiculite, bentonite, water glass, clay, resin, sodium silicate and boric acid with a heat insulating material, and forming a material to be cast. The method according to claim 1 or 2, wherein the coating is performed. 4. The method according to claim 1, wherein the material to be cast and the material to be cast are both aluminum or an aluminum alloy. 5. An aluminum or aluminum alloy on which an oxide film having a thickness of 0.05 to 50 μm is formed is set in a mold as a cast material, and a molten metal of the cast material is injected into the mold. Cast-in method. 6. A hollow pipe is used as a material to be cast,
The method according to any one of claims 1 to 5, wherein a molten metal serving as a cast-in material is injected into the mold while supplying a coolant to a hollow pipe set in the mold. 7. A brake caliper manufactured by the method according to claim 1.