JP3245338B2 - Hot chamber die casting machine for low aluminum zinc base alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-chamber die-casting machine for casting a zinc-based alloy having an aluminum content of less than 0.3%, and more particularly to a hot-chamber die-casting machine in contact with a molten metal of the zinc-based alloy. The present invention relates to a low-aluminum zinc-base alloy hot chamber die casting machine in which at least a specific portion of a member to be formed is made of a specific material.

[0002]

2. Description of the Related Art At present, ZDC2 and ZDC1 shown in JIS H 5301 are mainly used as a die-casting zinc alloy. These zinc based alloy die casts contain 3.5-4.3% aluminum,
This aluminum has the effect of improving the fluidity of the alloy melt and reducing the erosion of melting equipment and molds by the alloy melt. Therefore, these aluminum-containing zinc-based alloy die casts are capable of converting aluminum to 3.9-4.3.
It is cast by a hot chamber casting method by using one type of zinc alloy lump for die casting or two types of zinc alloy lump for die casting shown in JIS H 2201 containing%.

[0003] It is known that iron hardly dissolves in a zinc-based alloy melt containing 0.3% or more of aluminum (H. Grubitsch et al .: Korrosion u. Metallsch.,
14, 345, 1938). Meanwhile, Ilzulo (I
LZRO) 14 alloy, Ilzulo 16 alloy,
Zinc-based alloy die-cast products using Zn-Cu-Ti-based alloys with extremely low aluminum content are available in ZDC2 and ZDC2.
Compared with DC1, it has the characteristic of being superior in creep strength and thermal stability. Because it is less than 0.3%,
The hot-chamber casting method has a drawback that a part made of an iron-based alloy in a portion that comes into contact with the molten metal of the alloy is eroded and corroded, and a trouble caused by these causes a problem that a product cannot be continuously cast for a long time. there were. For example, when a high-pressure casting of ILLUSLO 14 alloy is performed on a sleeve and a plunger tip of a hot chamber die casting machine using an alloy tool steel SKD61 generally used for these members, eroded or formed Fe
-Only a few thousand shots could be cast at most due to malfunctions due to Zn intermetallics. For this reason, in conventional high pressure casting of Ilzulo 14 alloy and Ilzulo 16 alloy,
A cold chamber system that has a short contact area and a short contact time with the molten metal of the alloy has been used. However, this cold chamber method has disadvantages in that the production speed is inferior, the cost is high, and small articles such as precision zinc-based alloy die-cast products cannot be produced.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an Irzuro 14 alloy having excellent creep strength and thermal stability.
An object of the present invention is to provide a low-aluminum zinc-base alloy hot chamber die-casting machine capable of high-pressure casting of a zinc-based alloy having a low aluminum content typified by Ilzuro 16 alloy with high productivity.

[0005]

Means for Solving the Problems The present inventors have made intensive studies on the above-mentioned problems, and as a result, have formed at least a surface layer portion of a member that comes into contact with the molten aluminum-zinc base alloy of a hot chamber die casting machine from a specific material. As a result, the present inventors have found that the above objects can be achieved, and have completed the present invention. That is, the hot chamber die casting machine for a low aluminum zinc based alloy of the present invention is a hot chamber die casting machine for casting a zinc based alloy having an aluminum content of less than 0.3%. At least the plunger tip and / or the member that comes into contact with the molten metal of the base alloy
Alternatively, at least the surface layer portion of the sleeve is made of a material having a contact angle (hereinafter, simply referred to as a contact angle) with a droplet of the zinc-based alloy melt measured in a non-oxidizing gas atmosphere of 100 degrees or more. It is characterized by.

[0006] In this specification, all percentages are weight%, and the contact angle in the present invention means, as shown in FIG. 1, a droplet of a zinc-based alloy melt on a substrate having a smooth surface. The angle θ between the tangential direction of the droplet surface and the substrate surface at one point of the contact circumferential end, and the following Young's equation holds between the surface tension γ: γ _s = γ _sl + γ _l cos θ (where γ _s is the surface tension of the solid, γ _sl is the interfacial tension at the solid-liquid interface, and γ _l is the surface tension of the liquid). When measuring the contact angle θ, the member to be tested should be a substrate with a smooth surface, and if the measurement is performed in an oxidizing atmosphere such as air, the object to be measured will be oxidized and a system containing a large amount of oxide Therefore, the measurement was performed by placing the substrate and the molten zinc-based alloy in a non-oxidizing gas atmosphere such as argon, nitrogen gas, or hydrogen gas. Is the temperature at which the droplets of the zinc-based alloy are maintained in the molten state, for example, 450 to 500.
After taking a predetermined time, for example, 120 hours at a temperature of ° C., the photograph was taken and read. Since the surface tension and the interfacial tension change under the influence of temperature, atmospheric gas, progress of alloying at the solid-liquid interface, etc., the contact angle θ also changes. In the present invention, even after the above change, the contact angle is 100 degrees or more,
Preferably, a material that is always at least 120 degrees is used. It is particularly preferable to use a material in which the alloying reaction at the solid-liquid interface does not progress or progresses very slowly and the contact angle θ hardly changes.

[0007] Materials that have a contact angle of 100 ° or more and do not progress or are extremely slow to react with a zinc-based alloy having a highly corrosive aluminum content of less than 0.3% include tungsten and molybdenum. Refractory metals, nitrides such as silicon nitride and aluminum nitride, oxides such as alumina and zirconia, oxynitrides such as sialon, carbides such as chromium carbide and tungsten carbide, graphite, C / C composite (carbon fiber reinforced carbon) Etc. In order to avoid problems such as cracks and chipping due to thermal shock, mechanical shock or differences in the coefficient of thermal expansion from the iron-based alloy constituting other members, and to perform continuous production, titanium carbide, titanium nitride It is preferable to use a composite of titanium carbide and titanium nitride, or sialon.

In a hot chamber die casting machine, members that come into contact with molten zinc-based alloy include a melting pot, an injection member (plunger tip and sleeve), a high-pressure molten metal passage member (gooseneck, gooseneck tip, nozzle), a mold, and the like. Therefore, it is desirable that all of these members are made of a material having a contact angle of 100 degrees or more. However, considering the production cost, ease of production, strength, etc. of the entire hot chamber die casting machine, among these members, the injection member, that is, the plunger tip and the sleeve are particularly susceptible to erosion. It is essential that at least the surface layer of the member is made of a material having a contact angle of 100 degrees or more, and at least the surface layer of the plunger tip, sleeve, gooseneck, nozzle and mold has a contact angle of 100 degrees or more. It is preferred to be composed of the following material. Although the entirety of these members may be made of a material having a contact angle of 100 degrees or more, only the surface layer of these members has a contact angle of 100 in consideration of production cost, ease of production, strength, and the like. It is preferable to use a material that is at least degree. Such a surface layer can be formed by a known method such as a CVD method, a vacuum evaporation method, an ion plating method, and a sputtering method.

The aluminum content suitable for casting in the hot chamber die casting machine of the present invention is 0.3
% Of the zinc-based alloy is 0.01-0.03% of aluminum, 1.0-1.5% of copper, 0.25-0.
Ilzulo 1 containing 30% titanium and the balance being zinc
4 alloy, 0.01-0.04% aluminum, 1.0
-1.5% copper, 0.15-0.25% titanium,
There is an Irzuro 16 alloy containing 10 to 0.20% chromium, the total amount of titanium and chromium being 0.30 to 0.40%, and the balance being zinc. The contact angles of various materials measured as described above, and the casting that can be performed when the surface layer of the member that comes into contact with the molten zinc alloy is manufactured using those materials and cast using a hot chamber die casting machine. As is clear from FIG. 2 showing the correlation with the number of shots, the number of casting shots that can be performed at a contact angle of about 90 degrees has been greatly increased. Especially contact angle 12
At 0 degrees or more, the number of castable shots is significantly increased.
This is due to the malfunction of the injection unit and the decrease in sealing performance.
This is probably because troubles caused by formation of e-Zn intermetallic compounds and erosion of members were able to be suppressed.

When a zinc-based alloy having an aluminum content of less than 0.3% is subjected to high-pressure casting, in the case of a conventionally used material, at most several thousand shots are cast by a hot chamber method due to a trouble caused by erosion or the like. could not. However, as in the present invention, at least the surface layer of the member in contact with the molten zinc bath has a contact angle of 100%.
By using a material that is higher than or equal to the degree, it is possible to suppress problems such as malfunction of the injection part and deterioration of the sealing property, and the zinc-based alloy, which could be cast at high pressure only by the conventional cold chamber method, is economically advantageous. It has become possible to cast by the hot chamber method which is excellent in quality.

[0011]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. Example 1 In a hot chamber die casting machine for casting ZDC1 or ZDC2, a surface coating of titanium carbide was coated on a flat plate manufactured using alloy tool steel SKD61 which is generally used as a member of a portion that comes into contact with molten metal. Ilzulo 1 on this coated plate
4 alloy (composition Zn-1.44% Cu-0.03% Al-
A droplet of a 0.3% Ti-0.001% Fe) molten metal was placed and held at 450 ° C. in a nitrogen gas atmosphere, and the contact angle measured 120 hours later was 165 °. An injection member such as a sleeve or a plunger tip is made of such a material in which titanium carbide is coated on SKD61,
A passage member such as a gooseneck and a nozzle through which high-pressure molten zinc passes, and a mold were configured. Using a hot-chamber die-casting machine of 5 tons in die-casting power, casting was performed using an Illusro 14 alloy having the same composition as that in which the above-mentioned contact angle was measured. As a result, about 125,000 shots could be cast. The contact angle was measured at 600 ° C. in a nitrogen gas atmosphere separately at 450 ° C. and found to be 162 °.

Examples 2 to 4 In place of the surface-coated flat plate of Example 1, a tungsten sintered plate, a sialon flat plate, or a steam-treated Fe-4% Ni-based alloy sintered plate was used.
The contact angle was measured at 450 ° C. for 120 hours in a nitrogen gas atmosphere in the same manner as described above. Further, a sleeve and a plunger tip of a hot chamber die casting machine are manufactured using a sintered sintered body of Fe-4% Ni-based alloy which has been subjected to a tungsten sintered body, sialon, or steam, and other members that come into contact with the molten metal are described. The number of shots that can be cast and practicable was determined in the same manner as in Example 1 using a die casting machine configured using the material No. 1. The results are shown in Table 1 together with the results of Example 1.

Comparative Example 1 On the flat plate prepared by using the SKD61 used in Example 1, the same Illus 14 alloy as in Example 1 was placed, and kept at 450 ° C. in nitrogen gas, and the contact angle after 120 hours was measured. It was 62 degrees when measured. The contact angle after 600 hours was 51 degrees, and it is considered that zinc and iron reacted with the lapse of time and the interfacial tension changed, resulting in a decrease in the value of the contact angle. A sleeve and a plunger tip were manufactured from this material, and an ILLUSLO 14 alloy was cast using a die casting machine having a mold clamping force of 5 tons. As a result, only about 3,000 shots could be cast.

Comparative Example 2 Ni-based Hastelloy X alloy used as a heat-resistant alloy (Ni-22% Cr-9% Mo-0.6% W-18% F
e-1.5% Co-1.0% Si-1.0% Mn-0.
The same Illeslot 14 alloy as in Example 1 was placed on a flat plate made using 1% C), and the contact angle was measured at 120 ° C. in nitrogen gas at 450 ° C., and the contact angle was found to be 22 °. A plunger tip was manufactured from this material, and using an SKD61 for the sleeve, an Illusro 14 alloy was cast using a die casting machine with a mold clamping force of 5 tons. As a result, only about 2,000 shots could be cast. Separately, when 100 shots were cast in the same manner, the casting was interrupted as it was, and when it was attempted to restart it 12 hours later, the plunger and the sleeve adhered to each other and did not operate, and could not be restarted.

Comparative Example 3 SUS304L steam-treated in place of SKD61
Using a sintered body, the contact angle after 120 hours at 450 ° C. in a nitrogen gas atmosphere was measured in the same manner as in Comparative Example 1, and using a die-casting machine made of the same material as in Comparative Example 1. The number of shots that can be cast and practicable was determined in the same manner as in Comparative Example 1. Table 1 shows the results together with the results of Comparative Examples 1 and 2.

[0016]

The data shown in Table 1 are plotted with the contact angle θ as the horizontal axis.
FIG. 2 is a plot of the number of practicable casting shots on the vertical axis. As is clear from FIG. 2, the number of shots that can be cast is greatly increased at a contact angle of about 90 degrees.

[0018]

According to the present invention, Zn having an aluminum content of less than 0.3% is used.
-When casting a Cu-Ti base alloy at high pressure, due to troubles caused by erosion and the like, at most only several thousand shots could be cast by the hot chamber method. By configuring at least the surface layer with a material having a contact angle of 100 degrees or more, it is possible to particularly suppress problems such as malfunction of the injection portion and deterioration of sealing performance, and high-pressure casting can be performed only by the conventional cold chamber method. It has become possible to cast a zinc-based alloy having a low aluminum content by a hot chamber method which is excellent in economy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a contact angle θ.

FIG. 2 is a graph showing a correlation between a contact angle between various materials and an alloy 14 after 120 hours and the number of casting shots.

[Explanation of symbols]

θ Contact angle γ _s Surface tension of solid γ _sl Interfacial tension at solid-liquid interface γ _l Surface tension of liquid

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) B22D 17/02 B22D 21/00 C22C 18/02

Claims (5)

(57) [Claims] 1. A hot-chamber die-casting machine for casting a zinc-based alloy having an aluminum content of less than 0.3%, wherein at least one of members of the hot-chamber die-casting machine that comes into contact with a molten metal of the zinc-based alloy. At least the surface layer portion of the plunger tip or the sleeve is made of a material having a contact angle with the droplet of the molten zinc-based alloy measured in a non-oxidizing gas atmosphere of 100 degrees or more. Hot chamber die casting machine for aluminum zinc base alloy. 2. A hot-chamber die-casting machine for casting a zinc-based alloy having an aluminum content of less than 0.3%, wherein at least one of the members of the hot-chamber die-casting machine that comes into contact with the molten zinc-based alloy. At least the surface layers of the plunger tip, sleeve, gooseneck, nozzle and mold have a contact angle with the zinc-based alloy melt droplet of 100 measured in a non-oxidizing gas atmosphere.
A hot-chamber die-casting machine for low-aluminum zinc-based alloys, characterized by being made of a material having a degree of heat treatment. 3. A zinc-based alloy having an aluminum content of less than 0.3% is cast from 0.01 to 0.03% aluminum, 1.0 to 1.5% copper, 0.25 to 0.30%. The hot chamber die casting machine for a low aluminum zinc-based alloy according to claim 1, wherein the hot chamber die casting machine is an Irzuro 14 alloy containing 0.1% titanium and the balance being zinc. 4. A zinc-based alloy having an aluminum content of less than 0.3% is cast from 0.01 to 0.04% aluminum, 1.0 to 1.5% copper, 0.15 to 0.25%. % Of titanium, 0.10 to 0.20% of chromium, the total amount of titanium and chromium is 0.30 to 0.40%, and the balance is zinc. 2. A hot chamber die casting machine for a low aluminum zinc base alloy according to 2. 5. The method according to claim 1, wherein the material having a contact angle of 100 degrees or more is titanium carbide, titanium nitride, a composite of titanium carbide and titanium nitride, or sialon. A hot chamber die casting machine for a low aluminum zinc-based alloy according to the present invention.