JP3126471B2 - Sleeve for die casting machine - Google Patents

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 (including alloys thereof) such as aluminum, zinc, tin and lead.

[0002]

2. Description of the Related Art In recent years, die casting technology capable of casting non-ferrous metals such as aluminum, zinc, tin and lead at a high precision and at a high speed has become an important means of producing various parts in the fields of automobiles, industrial machines and home electric appliances. It has become.

Conventionally, die steel such as JISSKD61 alloy is mainly used for a sleeve for a die casting machine (hereinafter, referred to as a sleeve). In addition, in order to increase the service life of the sleeve and improve the production yield, and to cope with the increase in the size of the cast product, an inner cylinder made of ceramic or a composite of titanium or a titanium alloy and ceramic is placed inside a steel outer cylinder. In some cases, a sleeve is used in which an inner cylinder made of a material is provided by shrink-fitting or casting.

[0004]

However, the above-mentioned conventional sleeve has the following problems. JIS SK
In the sleeve made of die steel such as D61 alloy, the non-ferrous metal alloy generally reacts easily with iron, so the bottom of the pouring port of the sleeve is significantly melted and the inner wall of the sleeve is also melted and worn. And will decrease. Therefore, it is necessary to replace the sleeve relatively complicatedly, and the life of the sleeve is short. Further, since the steel has good heat conduction, when the molten metal is injected into the sleeve, the temperature of the molten metal is significantly lowered. The decrease in the temperature of the molten metal at this time causes a decrease in the production yield of the cast product.

On the other hand, a sleeve in which a ceramic inner cylinder is shrink-fitted to a steel outer cylinder has excellent erosion resistance, but an extremely large impact is applied to the sleeve at the moment when the die casting machine injects the molten metal. As a result, the inner cylinder made of ceramics, which originally has brittle properties, may be broken. Then, the work must be interrupted, and the workability is poor.

Further, a sleeve in which an inner cylinder made of a composite material of titanium or a titanium alloy and ceramics is shrink-fitted to a steel outer cylinder is excellent in erosion resistance, impact resistance and heat retention of molten metal. Although a considerably long life is possible, there is a drawback that the adjustment of the ceramic content is extremely difficult. That is, when the ceramic content of the composite material is low, the erosion resistance of the sleeve is deteriorated, and in particular, a portion where the molten metal first hits when the molten non-ferrous metal is poured into the sleeve (hereinafter, referred to as a hot metal contact portion). ) Locally causes erosion. And, if you continue to use it, the melting of the hot metal will gradually expand, and the molten metal will solidify and accumulate there, and it will become the resistance of the chip, and the deposit will be caught and cast at the time of injection. , Which can cause product failure. Therefore, if erosion occurs, the operation must be interrupted. If the ceramic content is high, the impact resistance is deteriorated, the inner cylinder becomes brittle, and cracks occur during use, making it impossible to continue work.

The present invention has been made in view of the above problems, and has excellent erosion resistance, abrasion resistance, and heat retention properties of a molten metal at a contact portion of a molten metal, and excellent impact resistance. An object of the present invention is to provide a sleeve for a die casting machine having 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 in the outer cylinder and made of a composite material of titanium or a titanium alloy and ceramics. The ceramic content at the contact portion of the inner cylinder to which the molten metal is applied is higher than the remaining ceramic content.

[0009]

When the content of ceramics in a composite material of titanium or a titanium alloy and ceramics is high, there is a disadvantage that the wear resistance, the erosion 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 erosion resistance, abrasion resistance, and heat retention of the molten metal are low.

Therefore, in the present invention, a composite material of titanium or a titanium alloy and ceramics,
An inner cylinder having a different ceramic content in the hot water contact portion and the remaining portion is fitted into a steel outer cylinder to form a sleeve for a die casting machine. 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. Thereby, there is no occurrence of local melting damage due to the contact of the hot water at the hot water contact portion, and the inner cylinder does not become brittle at the remaining portion. Therefore, the sleeve for a die-casting machine according to the present invention has excellent erosion resistance, abrasion resistance and molten metal heat retention at the contact portion of the molten metal, and also has excellent impact resistance. In addition, the frequency of sleeve replacement can be reduced, and workability is improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below 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 flange at one end, and a hole penetrating from the outer surface to the inner surface is formed in a surface near the other end. 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 Composition B. Also, the inner cylinders 2a, 2b
Both have a cylindrical shape having an outer diameter that can be inserted into the outer cylinder 1, and a similar hole is drilled in the inner cylinder 2 a at a position matching the hole drilled in the outer cylinder 1. And the inner cylinder 2b
Is located inside the flanged end of the outer cylinder 1, and the inner cylinder 2 a is located inside the flangeless end of the outer cylinder 1, and the ends of the inner cylinders 2 a, 2 b are joined inside the outer cylinder 1. Are fitted into the outer cylinder 1 by shrink fitting.

[0013]

[Table 1]

The sleeve for a die-casting machine according to the present embodiment is constructed as described above, and a ceramic (Si
Since the inner cylinder 2a made of the composite material of the composition A having a content of 25% of C) is arranged, the erosion resistance, the abrasion resistance and the heat retention of the molten metal are excellent. In addition, the content of ceramics (SiC) was 10% in the portions other than
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 is actually manufactured,
The result of examining the performance will be described.

First, a titanium powder having an average particle diameter of 20 μm, silicon carbide having an average particle diameter of 5 μm, and nickel powder having an average particle diameter of 15 μm were mixed with the compositions shown in the above-mentioned Formulations A and B to form a raw material for a composite material. And This material is sealed in a rubber mold,
Cold isostatic press (CI) under the condition that the applied 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 degree of vacuum of 10 ⁻⁵ Torr and a temperature of 1350 ° C., the sintered body is lathe-processed to form an inner layer made of a composite material having the above-described composition. The cylinder 2a and the inner cylinder 2b were obtained. Next, an inner cylinder 2a made of a composite material having the composition shown in Formula A is disposed in a hot water contact portion 3 on a steel outer cylinder 1 having an inner diameter substantially the same as the outer diameter of the inner cylinders 2a and 2b. An inner cylinder 2b made of a composite material having the composition shown in Formulation B was disposed in the rest, and the ends of the cylinders were butted against each other and shrink-fitted to produce a sleeve according to the present example.

A sleeve made of a die steel (SKD 61) which has been conventionally used is used as a comparative example 1, and a sleeve in which an inner cylinder made of ceramics (silicon nitride) is shrink-fitted to an outer cylinder made of steel is used as a comparative example 2. And Furthermore, the formulation B of the above-described example was used.
Comparative Example 3 was a sleeve in which an inner cylinder made of a composite material having the same composition as in Example 1 was shrink-fitted to a steel outer cylinder.

Practical tests were carried out on the sleeves of the above-described examples and comparative examples, and their characteristics were examined. This practical test is a die casting machine for cold chamber (capability
(250 tonnes) with a sleeve attached, and an automobile engine cover was actually cast from a molten aluminum alloy (JIS ADC12). After 100,000 shots, the sleeve was removed, and the erosion and wear conditions were examined.

The results of these tests are shown in Table 2 below. In Table 2, the erosion wear condition is indicated by ◎ when the maximum erosion amount of the inner surface of the sleeve with respect to the dimensions before use is 0.1 mm or less, and indicated by を when the maximum erosion amount is more than 0.1 mm and 0.3 mm or less, A case exceeding 0.3 mm was indicated by △, and a case where work was interrupted halfway was indicated by ×.

[0020]

[Table 2]

As is apparent from Table 2, the sleeve according to the embodiment of the present invention was hardly melted even after 100,000 shots, and did not crack. On the other hand, the sleeve of Comparative Example 1 made of die steel had an extremely large amount of erosion. Further, the sleeve of Comparative Example 2 in which the ceramic inner cylinder was shrink-fitted was excellent in erosion resistance but inferior in impact resistance, and the ceramic part was cracked 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 was shrink-fitted has relatively excellent impact resistance and erosion resistance, the erosion resistance of the hot water contact portion is higher than that of this example. Was also inferior.

The ceramics that can be used in the above embodiments are not limited to the above-mentioned silicon carbide (SiC), but include Cr ₂ O ₃ , TiO ₂ , ZrO ₂ , and MgO.
And Y ₂ O ₃ oxide such, Si ₃ N _4, TiN, nitrides such BN and AlN, TiC, B ₄ C and CrC ₂ like carbide, ZrB ₂ and TiB ₂ and the like borides and sialon, etc. One or a mixture of two or more selected from ceramics may be used.

Although the present embodiment has been described for a horizontal sleeve, the present invention can be applied to a vertical sleeve, and the same effects can be obtained.

[0024]

As described above, according to the present invention, the outer cylinder made of steel and the 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 of the remaining portion of the inner cylinder, the erosion resistance at the hot water contact portion can be significantly improved. Therefore, the sleeve for a die-casting machine according to the present invention is excellent in erosion resistance, abrasion resistance, and heat retention property of the molten metal at the contact portion of the molten metal, and also has excellent impact resistance and obtains a sleeve with good workability. Can be.

[Brief description of the drawings]

FIG. 1 is a 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 made of blend A 2b; Inner cylinder made of blend B 3;

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22D 17/20 B22D 17/02

Claims (1)

(57) [Claims] 1. An outer cylinder made of steel, and an inner cylinder fitted in the outer cylinder and made of a composite material of titanium or a titanium alloy and ceramics. A sleeve for a die casting machine, wherein the content is higher than the remaining ceramic content.