JPH05261507A - Sleeve for die casting machine - Google Patents

Abstract

PURPOSE:To provide a sleeve for a die casting machine which is excellent in the erosion resistance, the molten metal heat retaining property, the shock resistance and the wear resistance at a part in contact with the molten metal. CONSTITUTION:A sleeve for a die casting machine consists of an outer cylinder 1 made of steel and inner cylinders 2a, 2b made of titanium or a composite material of titanium alloy and ceramics. The inner cylinders are divided into the inner cylinder 2a and the inner cylinder 2b, and the inner cylinder 2a is arranged at a part 3 in contact with the molten metal, while the inner cylinder 2b is arranged at the part other than the part 3 in contact with the molten metal. The ceramics content of this inner cylinder 2a is higher than that of the inner cylinder 2b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sleeve for a die casting machine suitable for casting non-ferrous metals such as aluminum, zinc, tin and lead (including alloys thereof).

[0002]

2. Description of the Related Art Recently, die-casting technology capable of casting non-ferrous metals such as aluminum, zinc, tin and lead with high precision and high speed is an important means for producing various parts in the fields of automobiles, industrial machines and home appliances. Has become.

Conventionally, die steel such as JIS SKD61 alloy has been mainly used for sleeves for die casting machines (hereinafter referred to as sleeves). In addition, in order to extend the life of the sleeve, improve the manufacturing yield, and cope with the increase in the size of cast products, the inner cylinder made of ceramics or the composite of titanium or titanium alloy and ceramics is provided inside the steel outer cylinder. A sleeve provided with an inner cylinder made of material by shrink fitting or cast molding may be used.

[0004]

However, the above-mentioned conventional sleeve has the following problems. JIS SK
In a sleeve made of die steel such as D61 alloy, the non-ferrous metal alloy and iron are generally prone to react with each other, so that the bottom of the spout of the sleeve is significantly melted and the inner wall of the sleeve is also melted and worn. Will decrease. Therefore, it is necessary to replace the sleeve relatively complicatedly, and the life of the sleeve is short. Further, since steel has good thermal conductivity, the molten metal temperature is significantly lowered when the molten metal is injected into the sleeve. The decrease in the molten metal temperature at this time leads to a decrease in the production yield of the cast product.

On the other hand, a sleeve obtained by shrink-fitting an inner cylinder made of ceramics into an outer cylinder made of steel is excellent in erosion resistance, but an extremely large impact is applied to the sleeve at the moment when the die casting machine injects the molten metal. Therefore, the inner cylinder made of ceramics, which is inherently brittle, may be destroyed. Then, the work has to be interrupted and the workability is poor.

A sleeve obtained by shrink-fitting an inner cylinder made of a composite material of titanium or a titanium alloy and ceramics into an outer cylinder made of steel is excellent in melting resistance, impact resistance and heat retention of molten metal. Although it enables a considerably long life, it has a drawback that it is extremely difficult to adjust the ceramic content. That is, when the ceramic content of the composite material is low, the melting resistance of the sleeve is deteriorated, and particularly, when the molten metal of the non-ferrous metal is poured into the sleeve, the portion where the molten metal first comes into contact (hereinafter, referred to as a hot water contact portion). ) Locally melts. Then, if it continues to be used as it is, the melting loss of the molten metal gradually expands, the molten metal solidifies and accumulates there, and becomes the resistance of the chip, and the deposit is caught and cast during injection. It also causes product defects. Therefore, if melting damage occurs, the work must be interrupted. In addition, when the ceramic content is high, the impact resistance deteriorates, the inner cylinder becomes brittle, and cracks occur during use, making it impossible to continue the work.

The present invention has been made in view of the above problems, and is excellent in melt damage resistance, wear resistance, and heat retention of the molten metal in the hot water contact portion, and is also excellent in impact resistance. An object of the present invention is to provide a sleeve for a die casting machine, which has a long life and good workability.

[0008]

A sleeve for a die casting machine according to the present invention has an outer cylinder made of steel and an inner cylinder fitted into the outer cylinder and made of a composite material of titanium or titanium alloy and ceramics. The ceramic content in the molten metal contact portion of the inner cylinder against which the injected molten metal hits is higher than the ceramic content in the remaining portion.

[0009]

In the composite material of titanium or titanium alloy and ceramics, when the ceramic content is high, there is a drawback that the abrasion resistance, the melt damage resistance and the heat retention of the molten metal are good, but the impact resistance is low. On the other hand, when the ceramic content is low, the impact resistance is good, but there is a drawback that the melting resistance, abrasion resistance and molten metal heat retention are low.

Therefore, in the present invention, in addition to the composite material of titanium or titanium alloy and ceramics,
A sleeve for a die casting machine is constructed by inserting an inner cylinder having a ceramic content different between the hot water contact portion and the rest thereof into a steel outer cylinder. That is, in the inner cylinder, the ceramic content in the hot water contact portion is higher than the ceramic content in the remaining portion. As a result, the molten metal does not locally melt due to the molten metal, and the inner cylinder does not become brittle in the remaining portion. Therefore, the sleeve for a die casting machine according to the present invention has excellent melt damage resistance, wear resistance, and molten metal heat retention in the hot water contact portion, and also has excellent impact resistance. In addition, the frequency of sleeve replacement can be reduced and workability is improved.

[0011]

Embodiments of the present invention will now be described with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a sleeve for a die casting machine according to an embodiment of the present invention. The outer cylinder 1 has a cylindrical shape with a collar at one end, and a hole near the other end has one hole penetrating from the outer surface to the inner surface. The inner cylinder is composed of an inner cylinder 2a made of a composite material having a composition shown in Table 1 below and an inner cylinder 2b made of a composite material having a composition shown in Table B below. Also, the inner cylinders 2a and 2b
Both have a cylindrical shape having an outer diameter that can be inserted into the outer cylinder 1, and the inner cylinder 2a is provided with a similar hole at a position aligned with the hole formed in the outer cylinder 1. And the inner cylinder 2b
Is arranged inside the flanged end of the outer cylinder 1, and the inner cylinder 2a is arranged inside the flangeless end of the outer cylinder 1. Inside the outer cylinder 1, the ends of the inner cylinders 2a and 2b are Are butted and fitted into the outer cylinder 1 by shrink fit.

[0013]

[Table 1]

The sleeve for a die casting machine according to the present embodiment is constructed as described above, and the ceramic (Si
Since the inner cylinder 2a made of the composite material according to the composition A having the content rate of C) of 25% is arranged, the melt loss resistance, the wear resistance and the heat retention property of the molten metal are excellent. In addition, the content of ceramics (SiC) is 10% and the composition A
Since the inner cylinder 2b made of a composite material having a lower formulation B is arranged, the impact resistance is also excellent.

Next, the sleeve of this embodiment was actually manufactured,
The results of examining the performance will be described.

First, titanium powder having an average particle size of 20 μm, silicon carbide having an average particle size of 5 μm, and nickel powder having an average particle size of 15 μm are mixed in the compositions shown in Formula A and Formula B in Table 1 above to prepare a raw material for a composite material. And This raw material is sealed in a rubber mold,
Cold isostatic pressing (CI under conditions of pressure is 1 ton / cm ²
P) processing was performed to obtain a cylindrical green compact. Next, after sintering the green compact in a vacuum furnace having a vacuum degree of 10 ⁻⁵ Torr and a temperature of 1350 ° C., the sintered body is subjected to lathe processing to obtain an internal composite material having the above composition. A cylinder 2a and an inner cylinder 2b were obtained. Next, a steel outer cylinder 1 having an inner diameter substantially the same as the outer diameter of these inner cylinders 2a and 2b is provided with an inner cylinder 2a made of the composite material having the composition shown in Formula A in the hot water contact portion 3. The inner cylinder 2b made of the composite material having the composition shown in Formulation B was placed in the balance, the ends of the cylinders were butted against each other, and shrink-fitted to manufacture a sleeve according to this example.

Further, a sleeve made of conventionally used die steel (SKD 61) is used as Comparative Example 1, and a sleeve obtained by shrink fitting a ceramic (silicon nitride) inner cylinder to a steel outer cylinder is used as Comparative Example 2. And Furthermore, the formulation B of the above-mentioned example
A sleeve obtained by shrink-fitting an inner cylinder made of a composite material having the same composition as that of a steel outer cylinder was used as Comparative Example 3.

Practical tests were carried out on the sleeves of the above-mentioned examples and comparative examples to examine their characteristics. This practical test is based on the die casting machine for cold chamber
A sleeve was attached to 250 tons and an automobile engine cover was actually cast from a molten aluminum alloy (JIS ADC12). Then, after 100,000 shots, the sleeve was removed, and the erosion wear state was examined.

The results of these tests are shown in Table 2 below. In Table 2, the erosion wear state is indicated by ◎ when the maximum amount of erosion on the inner surface of the sleeve with respect to the dimension before use is 0.1 mm or less, and by ○ when it is more than 0.1 mm and 0.3 mm or less. When it exceeds 0.3 mm, it is shown by △, and when work is interrupted on the way, it is shown by ×.

[0020]

[Table 2]

As is clear from Table 2, the sleeves according to the examples of the present invention were hardly melted even after 100,000 shots, and cracks did not occur. On the other hand, the sleeve of Comparative Example 1 made of die steel had an extremely large amount of melt loss. In addition, the sleeve of Comparative Example 2 in which the inner cylinder made of ceramics was shrink-fitted was excellent in melting resistance but inferior in impact resistance, and cracks occurred in the ceramics part after 200 shots, and the work was interrupted. .. Furthermore, although the sleeve of Comparative Example 3 in which the inner cylinder made of the composite material shown in Formulation B is shrink-fitted is relatively excellent in impact resistance and erosion resistance, the erosion resistance in the hot water contact part is better than that of this embodiment. Was also inferior.

The ceramics usable in the above-mentioned embodiments are not limited to the above-mentioned silicon carbide (SiC), but Cr ₂ O ₃ , TiO ₂ , ZrO ₂ , MgO.
And oxides such as Y ₂ O ₃ , nitrides such as Si ₃ N ₄ , TiN, BN and AlN, carbides such as TiC, B ₄ C and CrC ₂ , borides such as ZrB ₂ and TiB ₂ and sialon. One or a mixture of two or more selected from ceramics may be used.

Further, although the horizontal sleeve has been described in this embodiment, the present invention can be applied to a vertical sleeve and the same effect can be obtained.

[0024]

As described above, according to the present invention, an outer cylinder made of steel and an inner cylinder made of a composite material of titanium or a titanium alloy and ceramics are used. Since the ratio is higher than the ceramic content in the remaining part of the inner cylinder, the melt damage resistance in the molten metal contact part can be significantly improved. Therefore, the sleeve for a die casting machine according to the present invention is excellent in melting resistance, wear resistance, and heat retention of molten metal in a hot water contact portion, and is also excellent in impact resistance and workability. You can

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a sleeve for a die casting machine according to an embodiment of the present invention.

[Explanation of symbols]

 1; Outer cylinder 2a; Inner cylinder 2b made of mix A; Inner cylinder made of mix B 3; Hot water contact part

Claims (1)

[Claims] 1. A ceramic in a hot water contact portion of the inner cylinder having a steel outer cylinder and an inner cylinder fitted into the outer cylinder and made of a composite material of titanium or a titanium alloy and ceramics. A sleeve for a die casting machine, which has a higher content rate than the remaining ceramic content.