JPH02280953A - Injecting parts for die casting machine - Google Patents

Abstract

PURPOSE:To suppress erosion and wear of parts to low by forming a part of suction in contact with molten metal of a composite material containing the specific quantity of Co and the balance of Ti (alloy) and ceramic particles with inevitable impurities. CONSTITUTION:At least a part in contact with the molten metal is made of the composite material containing 0.1-20wt.% Co and the balance Ti (Alloy) and the ceramic particles with the inevitable impurities. This composite material is made by adding the ceramics particles having high strength and high hardness to the Ti (alloy) having excellent erosion resistance to molten non-ferrous metal and excellent impact resistance and possesses the erosion resistance, impact resistance and wear resistance at the same time. By this method, as the part in contact with the molten metal is formed with this composite material, the injecting parts for die casting machine having long service life and excellent workability can be obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has excellent erosion resistance and impact resistance, and is suitable for use in die casting machines for casting nonferrous metal alloys such as aluminum, zinc, tin, and lead. Regarding parts.

[Prior art] In recent years, die-casting technology, which allows non-ferrous metals such as aluminum, zinc, tin, and lead to be cast with high precision and high speed, has become an increasingly important production method in fields such as automobiles, industrial machinery, and home appliances. There is.

Conventionally, JIS 5 was used for injection part parts of die-casting machines.
Cold or hot die steels such as KDII or 5KD81 are used. In addition, in recent years, parts such as sleeves and plungers have also been used in which ceramic members are cast in the parts that come into contact with the molten metal, such as sleeves and plungers.

[Problems to be Solved by the Invention] However, the injection parts of the die-casting machine described above have the following drawbacks.

First, in injection parts using die steel, the nonferrous metal alloy in the film tends to react with iron, so significant erosion occurs in the parts that come into contact with the molten metal of the die casting machine. For this reason, parts of the injection part must be replaced frequently, resulting in a short lifespan.

In addition, parts in which the surface of die steel is nitrided are also used in order to suppress melting damage. However, in this case as well, the thickness of the nitride layer is at most several μm, so even if nitriding is applied to sliding parts such as sleeves and plungers, the nitride film will easily wear out and the base metal will be damaged. be exposed. Therefore, the effect of extending the life of the parts of the injection part is small.

Furthermore, although injection parts in which ceramics are placed in contact with the molten metal have excellent corrosion resistance, the material is inherently brittle because an extremely large impact is applied to the entire die-casting machine at the moment the die-casting machine injects the molten metal. Ceramic parts may be destroyed. In this case, it is necessary to interrupt the work, resulting in poor work efficiency.

The present invention has been made in view of such problems, and includes:
It has excellent corrosion resistance against molten non-ferrous metals, and
The purpose of the present invention is to provide an injection part for a die-casting machine that has excellent impact resistance and good workability.

[Means for Solving the Problems] In the injection part for a die-casting machine according to the present invention, at least a part of the part that comes into contact with the molten metal contains 0.1 to 20% by weight.
It is characterized in that it is formed of a composite material containing Co, with the remainder consisting of titanium or titanium alloy, ceramic particles, and inevitable impurities.

[Function] In the present invention, at least a portion of the portion that comes into contact with the molten metal is formed of a composite material of titanium or a titanium alloy containing a predetermined amount of Go and ceramic particles. This composite material is made by adding ceramic particles with high strength and hardness to titanium or titanium alloy, which has excellent corrosion resistance against molten nonferrous metals and has excellent impact resistance. It has excellent strength, impact resistance, and abrasion resistance. Therefore, by forming the molten metal contact portion with this composite material, an injection part for a die-casting machine with a long life and excellent workability can be obtained.

Next, the reasons for limiting the composition of each component of this composite material will be explained.

Mono-positive Co has the effect of improving the wettability between the matrix made of metallic titanium or titanium alloy and ceramic particles, and improving the bonding properties between the two, and adding Co to the composite material improves the resistance of the composite material. Impact resistance can be improved. This CO may be added by mixing CO powder into the raw material powder of the composite material, or may be incorporated into the composite material as Ti-Co alloy powder.

In this case, the CO content Wffi in the composite material is 0
．． It is necessary that the content is 1% by weight or more. CO content
If the 'ffi is 0.1% by weight without grooves, the above-mentioned effect of improving wettability cannot be obtained. For this reason, the raw material powder is not sufficiently sintered during the production of the composite material, resulting in low hardness and elongation of the composite material.

On the other hand, when the content of co exceeds 20% by weight, CO and Ti
Intermetallic compounds between the metal and the metal precipitate in excess of the required amount, making the composite material brittle. Therefore, the content of Go in the composite material is set to 0.1 to 20% by weight.

The volume content of ceramic particles in the composite material is 0.1%.
Without grooves, the hardness and wear resistance of the composite material will be extremely low. On the other hand, the volume content of ceramic particles is 5
If it exceeds 0%, the composite material becomes brittle, resulting in decreased impact resistance and easy cracking. Therefore, the volume content of ceramic particles in the composite material is preferably 0.1 to 50%.

- The average particle size of the ceramic particles in the composite material is 0.
If the diameter is less than 0.01 μm, it is difficult to uniformly disperse the ceramic particles in the titanium or titanium alloy matrix, and it is difficult to obtain a composite material with stable characteristics. On the other hand, the average particle size of the ceramic particles is 50
If it exceeds 0 μm, the distance between ceramic particles increases, resulting in a decrease in the hardness of the composite material. Therefore, the wear resistance of the composite material is also reduced. Therefore, the average particle size of the ceramic particles in the composite material is 0. It is preferable that the thickness is 01 to 500 μm.

[Example] Next, an example of the present invention will be described in comparison with a comparative example.

First, titanium powder with an average particle size of 20 μm and a purity of 99.7% by weight or more and tungsten carbide (WC) powder with an average particle size of 5 μm were mixed at a volume ratio of 5:1. Then, Co powder having an average particle size of 0 μm was uniformly mixed into this mixed powder at the ratio shown in Table 1 below to obtain a raw material.

Table 1 This raw material was sealed in a rubber mold and subjected to cold isostatic pressing (CIP) at a pressure of 1 ton/cJ to obtain a cylindrical green compact. And the degree of vacuum is 10-'orr1
After sintering the green compact in a vacuum furnace at a temperature of 1300°C, the sintered body was lathe-processed to produce a sleeve for a cold chamber made of a composite material. These sleeves were designated as Examples 1 to 3 and Comparative Examples 1 to 3.

Next, titanium alloy powder containing 5% by weight of Co, with the balance being titanium and unavoidable impurities, with an average particle size of 35 μm, and silicon carbide (S i C) with an average particle size of 15 μm.
The raw materials were uniformly mixed with powder in the proportions shown in Table 2 below.

Table 2 Next, Al2O3 powder with the average particle size shown in Table 3 below, titanium powder with an average particle size of 20 μm and a purity of 99.7% by weight, and Co powder with an average particle size of 10 μm were mixed. It was used as a raw material. In this case, the mixing ratio of titanium powder, Co powder, and Al2O3 powder is 80:2:18 in weight ratio %.

Table 3 This raw material was used in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 3.
Similarly, a cylindrical composite material was obtained by cold isostatic pressing and sintering in vacuum. This composite material is used in conventional cold chamber sleeves (material: SKD [
A sleeve for a cold chamber was manufactured by casting the composite material on the inner surface of the molten metal.

These sleeves were used in Examples 4 to 7 and Comparative Examples 4 to 6.
And so.

This raw material was used in the above-mentioned Examples 4 to 7 and Comparative Examples 4 to 6.
Similarly, after cold isostatic pressing, vacuum sintering was performed to obtain a cylindrical composite material. By casting this composite material on the inner surface of a conventional cold chamber sleeve,
A sleeve for a cold chamber was manufactured in which the composite material was disposed in the portion that came into contact with the molten metal. This was designated as Examples 8 to 12 and Comparative Example 7.

In addition, as shown in Table 4 below, as conventional examples 1 and 2, sleeves for cold chambers made of 5KD61 alloy (hardness HRCGO) with nitrided surfaces and sleeves cast with ceramics (silicon nitride) were used. Prepared.

Table 4 - Hardness Test The micro Vickers hardness of each sleeve of the Example, Comparative Example and Conventional Example was measured.

■Tensile test Elongation was measured using a tensile tester.

(4) Practical Test The sleeves of Examples, Comparative Examples, and Conventional Examples were attached to a cold chamber die-casting machine (capacity: 2 sets), and an automobile engine cover was actually cast from molten aluminum alloy CADC12. And 1000 times
After the sleeve was removed, the wear caused by melting was examined.

The results of these tests are summarized in Table 5. However, regarding the corrosion damage condition, if the maximum amount of corrosion damage on the inner wall of the sleeve is 0.1 + n or less, it is ◎, and if it exceeds iffim and is 0.3 dragon or less, it is 0.
Cases exceeding 10.311II are indicated by △.

The sleeves of the above-mentioned Examples, Comparative Examples, and Conventional Examples were subjected to the following tests to examine their performance.

Table 5 (Part 1) Table 5 (Part 2) As is clear from Table 5, the amount of erosion loss in Examples 1 to 12 was 0. jam or less, and no cracking occurred. On the other hand, Comparative Example 3.6 and Conventional Example 2 had an elongation of 0.
It was extremely low, less than 4%, and cracking occurred. Other Comparative Examples 1, 2, 4.5.7, and Conventional Example 1 all had a loss amount exceeding 0.1++ m, and had poor resistance to loss.

Note that the ceramics that can be used in the present invention are not limited to the above-mentioned WC, SiC, and Azz Oa, but include oxide ceramics such as Cr 20a , T 102 , ZrO□, MgO, and Y2O3, and S ta N
4, TiN% B Various materials can be used, such as nitride ceramics such as N and AfN, carbide ceramics such as TiC1B4C and CrCz, boride ceramics such as ZrB2 and TiBz, and sialon.

Moreover, two or more types of these ceramics can be mixed and used.

In addition, although the above-mentioned embodiments relate to sleeves for cold chambers, other parts include plunger tips and sleeve bushings for cold chambers, sleeves for hot chambers, plunger rings, plunger tips and nozzles, and molten metal transport pipes. Also, a composite material of titanium or titanium alloy containing CO and ceramic particles can be used.

[Effects of the Invention] As explained above, in the injection part for die casting mines according to the present invention, at least a part of the part that comes into contact with the molten metal is made of a composite material of titanium or a titanium alloy containing a predetermined amount of Go and ceramic particles. Because of this, it is possible to suppress erosion and wear of these parts to an extremely low level. Also,
It also has excellent impact resistance, which prevents parts from cracking.
It is possible to work continuously and has excellent workability.

Claims (3)

[Claims] (1) At least a part of the part that comes into contact with the molten metal is 0.1
An injection part for a die-casting machine, characterized in that the injection part is made of a composite material containing 20% by weight of Co, with the remainder being made of titanium or a titanium alloy, ceramic particles, and inevitable impurities. (2) The injection part for a die-casting machine according to claim 1, wherein the volume content of ceramic particles in the composite material is 0.1 to 50%. (3) The injection part for a die-casting machine according to claim 1, wherein the ceramic particles have an average particle size of 0.01 to 500 μm.