JPS63199060A - Metallic core for high pressure casting and its production - Google Patents

Abstract

PURPOSE:To supply a metallic core having smooth forming face after casting and enable easily production and its producing method by forming the core body by metal of pure zinc or zinc alloy and forming mica coating layer on the surface of the core body. CONSTITUTION:The core 1 for casting a die casting product 3 having bend hole 2 is constituted of the core body 11a and the coating layer 1b on the surface thereof. The core body 1a uses the pure Zn or Zn alloy having lower melting point than it of Al alloy for die casting and is formed by casting method of gravity casting, low pressure casting, die casting, etc. On the other hand, the coating layer 1b is formed by applying mica aqueous solution on the surface of the core body 1a, or the core body 1a is dipped into the mica aqueous solution and after that, drying it to form the coating layer 1b on the surface of the core body 1a. This core 1 and cast product 3 are heated in a furnace and the core 1 is melted out and the product 3 having smooth and beautiful inner face is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal core suitable for use in high-pressure casting such as die casting and squeeze casting, and a method for manufacturing the same.

[Prior art] The molding of gold filament products with undercuts, bent holes, etc. by die casting is limited to molding using a placed core, so there are considerable restrictions on the shapes of the undercuts and bent holes. Therefore, it was difficult to mold die-cast products with complicated undercuts and bent holes.

Water-soluble salt cores are known as an improvement over this, but such cores require high costs because wastewater treatment is difficult, and are difficult to put into practical use due to salt damage.

Also, Zn-based eluted cores are known, but when high-temperature A1 alloy molten metal is cast, they are melted and deformed by the heat and alloyed, resulting in a satisfactory A1 alloy casting. There are problems such as not having one.

In addition, there is a core disclosed in Japanese Utility Model Application Publication No. 60-46928 as the above-mentioned elution core, which has a core body made of a low melting point metal and coated with a high melting point metal (such as Cu) on the surface of the core body. It is provided by means such as plating, but since the total flexure coating itself has good thermal conductivity, when molten ^1 alloy is cast, the temperature of the metal core increases and it may become deformed. There are problems such as partially molten alloy formation.

Furthermore, ceramic coatings on the surface of the core body have problems such as being difficult to separate from the product after casting and not providing a smooth molding surface.

[Problem that the invention seeks to solve]

The present invention is an attempt to solve the above problems, and by providing a mica layer with excellent heat resistance and heat insulation on the surface of the low melting point metal core body, the core is deformed and the molten ^1 alloy The object of the present invention is to provide a metal core that does not react with other metals to form an alloy (and that provides a smooth molded surface and that can be manufactured easily) and a method for manufacturing the same.

[Means for solving the problem] That is, the present invention is constructed by providing a mica-based coating layer on the surface of the core body formed from pure Zn or Zn alloy metal, and also by providing a mica-based coating layer on the surface of the core body formed from pure Zn or Zn alloy metal. A process of casting the core body by a casting method such as gravity casting, low pressure casting, die casting, etc., and immersing the core body in a mica-based aqueous solution and then drying it to form a coating layer on the surface of the core body. The above problem was solved by the following steps.

[Example] Examples of the metal core of the present invention will be described in detail below based on the drawings.

Figures 1 and 2 show a hole 2 bent using the core 1 of the present invention.
As shown in the figure, the core 1 includes a core body 1a that constitutes the majority of the core, and a core body 1a that constitutes the majority of the core. It is composed of a coating layer 1b covering the surface of layer 1a.

The core body 1a is formed by a casting method such as gravity casting, low pressure casting, die casting, etc. using pure Zn or Zn alloy whose melting point is lower than that of the A1 alloy for die casting.

In addition, IJii [i2
In addition to n and zn alloys, Sn, Pb, and alloys thereof may also be used.

In addition, these metal cores are formed by gravity casting, low pressure casting, die casting, etc., and have better dimensional accuracy than other soluble cores and collapsible cores, and can be eluted in a short time.
Furthermore, there are many advantages in that the core material can be easily reused.

On the other hand, the coating layer 1b is formed by applying a mica-based aqueous solution to the surface of the core body 1a, or by immersing the core body 1a in a mica-based aqueous solution to form a mica layer on the surface of the core body 1a. After that, it is dried and layered.
The film thickness can be freely changed within the range of L to 300 μm, and it can be formed uniformly.

The coating layer 1b may be applied to the entire surface of the core body 1a as shown in FIG.
The portion 1G fixed in the mold 4 as shown in the figure may be omitted.

Next, the method for manufacturing the metal core of the present invention will be described in detail.

[Example-1] A core body 1a was formed by die-casting using JIS, ZDC2 alloy (Zn-4% 8 alloy), and the core body 1a was degreased and placed in a mica aqueous solution shown in Table-1. After dipping to form a mica layer on the surface of the core body, it was soaked at 170℃ for 30 minutes.
The coating layer 1b was dried to form a coating layer 1b having a thickness of about 50 μm.

The core 1 manufactured in this way is placed in the squeeze mold 4 as shown in the figure, and the V 300T squeeze cast
Product 3 was cast using a JIS 5ADC10 alloy using a machine.

The casting conditions were molten metal temperature 720℃, casting pressure cuff 00'j
f/cM, injection plunger speed aos, "sec".

The core 1 and the molded product 3 were held in a furnace at 480° C. for 1 hour, and the core 1 was eluted.

The obtained product 3 had a smooth and clean inner surface with an undercut, and no washing or deformation caused by the molten metal alloy was observed.

Table-1 Mica aqueous solution [Example-2] Melting ln alloy (Zn-4%A1-1%Cu) by heating,
The mixture was cast into a mold for forming a core body that was preheated to 80°C to 120'C.

After degreasing this core body 1a and immersing it in the mica aqueous solution shown in Table 2, it was dried at 200"C for 30 minutes and
A coating layer 1b having a thickness of μm was formed.

This core 1 is placed in the die casting mold 2, and the DC50
Product 3 was cast using a JIS and ADC10 alloy using an 0T die-casting machine.

Casting conditions are molten metal temperature 670'C, casting pressure 500Kg.
f/cm s Injection plunger speed 0.5TrL/S
eC was torn.

Product 3 and core 1 thus cast were heated at 450'C for lH.
The core 1 was eluted by heating.

The obtained product 3 was a hollow product with a smooth inner surface showing no washing by the molten A1 alloy or thermal deformation.

Table-2 Metal powder mica-based water-soluble [Example-3] Zn(7) pure metal (melting point 419°C) 'Fr: 45
The core body 1a was formed by casting into a core mold preheated to 80°C to 120°C at 0'C.

This core body 1a was immersed in a slurry of mica aqueous solution shown in Table 3 mixed with zircon flour (1 μm), which is a finely powdered refractory, and then dried at 150'C for 18r.
A coating layer 1b of μ tiles was formed.

This core 1 is placed in a squeeze mold and cast to JIS with a V2O3T squeeze cast machine.

ADCIO alloy was also used for casting.

The casting conditions were a molten metal temperature of 700'C and a casting pressure of 500'.
l f /atr, injection plunger speed 50#/Se
C and F)).

The cast product 3 and the core 1 were held in a furnace at 500'C for 1 hour, and the core 1 was eluted.

The obtained product 3 is a hollow product with a smooth inner surface and a beautiful appearance.
No deformation or washing was found.

Table 3 Mica Aqueous Solution (Fine Powder Refractories) As explained above, the fine powder refractories such as zircon flour are effective in increasing heat resistance and preventing thermal deformation of the core body 1a. Further, the metal powder such as the fine stainless steel powder is effective in increasing the strength of the coating layer 1b, preventing penetration of the A1 molten metal, and increasing resistance to washing by the A1 molten metal.

In addition, as shown in FIG. 1, when the coating layer 1b is applied to the entire surface of the core body 1a, after molding the product 3,
By cutting a part of the coating layer 1b, for example, part a in the drawing, a part of the coating layer 1b is removed and a part of the core body 1a is brought out and held in the furnace. Good too.

3 is a microscopic photograph showing a cross section of a part of a core 1 manufactured according to the present invention and a product 3 molded using the same core 1.

As is clear from the figure, the coating layer 1b is uniformly adhered to the surface of the core body 1a, and even after the product is molded,
It can be seen that core 1 was not washed by the A1 molten metal.

In FIGS. 1 and 2, 5 indicates a cavity and 6 indicates a runner.

[Effects of the Invention] As explained above, the surface of the metal core for high-pressure casting according to the present invention is covered with a mica-based coating A1b having excellent heat resistance and heat insulation properties, so that A1 alloy can be used during product molding. It can prevent deformation due to the temperature of the molten metal, being washed and scraped by the flow of the molten A1 alloy, and being alloyed by reacting with the molten A1 alloy, making it possible to produce products 3 with undercuts and holes with high precision. It can be molded to high quality with a smooth and beautiful inner surface.

Further, according to the core manufacturing method of the present invention, the core body 1a formed of a low melting point metal is immersed in a mica-based aqueous solution, or the surface of the core body 1a is coated with the aqueous solution. It is simple and easy to manufacture.

[Brief explanation of the drawing]

1 and 2 show a metal core for high pressure casting according to the present invention,
FIG. 3 is a longitudinal cross-sectional view showing the state in which the core is placed in a mold and a product is molded. FIG. 3 shows the metal core of the present invention and a product molded using the same core and mold. It is a micrograph showing a cross section of a part of. 1... Core 1a... Core body 1b... Mica-based coating layer It! /ff1 1: Medium Chi 1a; Koshi Δ Jun lb: Mica-based coating I# Diagram 2 Procedures Amendment Written by the Commissioner of the Japan Patent Office December 23, 1982, Sumi 1, Indication of the case, 1988 Patent Application No. 221525 No. 2, Name of the invention Metal core for high-pressure casting and its manufacturing method 3, Relationship with the case of the person making the amendment Patent applicant address 762 Mezaki-cho, Fuchu-shi, Hiroshima Prefecture Voluntary amendment 5, Contents of the amendment subject to the amendment ( 1) The column "Detailed Description of the Invention" in the specification is amended as follows. 1) In the 12th line of page 4, "A die-cast product 3" is corrected to "FAI die-cast product 3." 2) In the 3rd line of page 6, replace the text ``rZn-4% 8 alloy'' with ``
Zn-4%A1 alloy”. 3) The word "mica" in the fifth line of page 6, the sixth line of the same page, and the third line of page 9 is corrected to "mica." 4) On page 6, line 19, "He Alloy" is corrected to "A1 Alloy." 5) In the 5th line of page 7, "sodium water" should be corrected to "sodium aqueous solution." 6) In the 6th line of page 7, "lubricant" should be corrected to "wetting agent". 7) In the 16th line of page 7, "Die-casting mold 2" is corrected to "Die-casting mold 4." 8) Correct the phrase "sodium water" on page 8, line 14 and page 10, line 4 to read "sodium aqueous solution." 9) On page 8, line 16, "stainless steel powder" should be corrected to "stainless steel powder." 10) Correct "1b:" in the 6th line of page 9 to "1b". 11) Change rJIs, J on page 9, line 9 to “JIS
Correct with J. 12) On page 9, line 10, the phrase “alloys too” should be corrected to “alloys.”

Claims (3)

[Claims] (1) A metal core for high-pressure casting, characterized in that a mica-based coating layer is provided on the surface of a core body molded from pure zinc or zinc alloy metal. (2) A process of casting a core body using pure zinc or zinc alloy metal by a casting method such as gravity casting, low pressure casting, or die casting, and immersing the core body in a mica-based aqueous solution and then drying it. A method for producing a metal core for high-pressure casting, comprising the step of: forming a coating layer on the surface of the core body. (3) The method for producing a metal core for high-pressure casting according to claim 2, wherein the mica-based aqueous solution contains a metal powder or a finely powdered refractory.