JPH10113755A - Sleeve for die casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the melt-sticking of an aluminum alloy and to drastically extend the service life by preventing heat crack. SOLUTION: A sleeve 10 is constituted with an inner layer sleeve 12, two layer outer sleeves 13, 14 and a sleeve body 15 as multi-complex structure. The inner layer sleeve 12 is formed with a ceramic of zirconia, etc. Both outer layer sleeves 13, 14 and the sleeve body 15 are formed with a hot-worked steel of KSD61, etc. Each sleeve 12, 13, 14 and the sleeve body 15 are integrated with cooling fitting or shrinkage fitting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die-casting sleeve used as an injection sleeve in a die-casting machine, and more particularly to a die-casting sleeve which achieves an improved life by adopting a multilayer structure.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional die casting sleeve used for an injection sleeve in a cold chamber type die casting machine. This sleeve 1
The material is formed of tool steel (SKD61), and a nitrided layer is formed on the inner peripheral surface 2 of the inner peripheral surface 2 by a nitriding treatment to strengthen the strength. A gate 3 for pouring the molten aluminum alloy is formed so as to penetrate in the radial direction.

[0003]

In the above-mentioned conventional die-casting sleeve, the SKD which is the material of the sleeve 1 is used.
61 is excellent in hardness and toughness, but has a poor thermal conductivity of about 1/2 to 1/3 that of a normal steel material. Further, since the sleeve 1 has a single-layer structure and a large layer thickness, molten aluminum alloy is used. When the molten metal is poured, the temperature difference between the lower part 4 of the pouring port 3 and the outer surface part 5 becomes large, and as shown in an exaggerated manner in FIG. 4, thermal deformation occurs and excessive thermal stress is generated. Will be. By this repetition, minute heat cracks enter the inner peripheral surface of the sleeve 1, and the molten metal penetrates into the cracks to cause volume expansion. It is said that this type of conventional sleeve 1 has a short service life of 25,000 to 50,000 times in a casting cycle.

Recently, ceramics or sintered alloys which do not react with the molten aluminum alloy have been developed.
It is being used as a material for the sleeve 1.

[0005] These materials are resistant to thermal shock and have excellent resistance to molten metal welding, but are poor in impact resistance. For example, when burrs are caught between the sleeve 1 and the plunger 6, In addition, there are many practical problems such as the life of the sleeve 1 being unpredictable, such as cracks caused by excessive stress acting on the sleeve 1.

In order to compensate for the disadvantages of ceramics,
Although a structure in which the outside of the ceramic is wrapped with a low thermal expansion material and a compressive stress is constantly applied to the ceramic has been developed, there is a problem that the manufacturing cost is high and the ceramic is not practical.

In view of the above situation, the present invention has been made to solve the problems of the above-mentioned prior art, and includes heat cracks due to thermal shock, adhesion of molten aluminum alloy, deformation due to temperature difference during pouring, and the like. More effectively prevent
It is an object of the present invention to provide a low-cost die-casting sleeve capable of greatly extending the life.

[0008]

In order to achieve the above object, the present invention provides an inner sleeve made of a material having resistance to molten metal welding, and an outer layer formed of an iron-based material disposed on the outer peripheral side of the inner sleeve. And a sleeve, wherein each of the sleeves is integrated by cooling or shrinking. Further, the inner layer sleeve can improve the molten metal welding resistance to the aluminum alloy. Further, by cooling and integrating the sleeves by shrinking or shrinking, only the inner sleeve is uniformly heated when the molten aluminum alloy is poured, thereby preventing the occurrence of thermal shock cracking. In addition, since the production is easy, the cost can be reduced.

According to a preferred embodiment of the present invention, the inner sleeve is preferably formed of ceramics such as zirconia, alumina and silicon nitride. Thus, it becomes possible to further improve the resistance to molten metal welding to the aluminum alloy.

According to the present invention, the inner sleeve may be formed of an iron-based material whose inner peripheral surface has been subjected to a surface treatment with aluminum alloy resistance such as nitriding treatment or boring treatment.
Thus, it is possible to improve the mechanical impact resistance of the inner sleeve.

The outer sleeve is preferably made of a hot tool steel such as SKD61, and by this, the heat conduction from the inner sleeve can be suppressed to prevent the occurrence of thermal shock cracking, and the production cost is also reduced. Become cheap.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sleeve for die casting according to the present invention. FIG. 1 is a sectional view showing a sleeve for die casting according to an embodiment of the present invention. This sleeve 10
Has, in order from the inside, a four-layer composite structure of an inner sleeve 12, two outer sleeves 13 and 14 outside the inner sleeve 12, and an outermost sleeve body 15; The sleeves 13 and 14 and the sleeve main body 15 are integrated by cooling or shrinking. A pouring port 3 into which the molten aluminum alloy is poured is provided in the sleeve 10 in a radial direction.
2, 13, 14 and the sleeve main body 15 are penetrated and provided.

As a material of the inner layer sleeve 12, ceramics such as zirconia, alumina, silicon nitride, etc., which are in direct contact with the poured aluminum alloy molten metal, are less likely to react with the aluminum alloy and have excellent molten metal welding resistance. preferable. Instead of these ceramics, hot work tool steel such as KSD61 having a surface treatment for imparting aluminum alloy resistance such as nitriding treatment or boring treatment to the inner peripheral surface thereof may be used as the material. Such an inner sleeve 12
Is set to about 2.5 mm at the maximum thickness in consideration of deformation during processing. The inner layer sleeve 12 can greatly improve the resistance to molten aluminum alloy fusion.

The outer sleeves 13 and 14 are
It is formed of a material having a low thermal conductivity, such as hot tool steel such as KSD61, and the thickness thereof is preferably as thin as possible, but at most 2.5 mm in consideration of deformation during processing. Set to about. The number of layers of each of the outer layer sleeves 13 and 14 is adjusted according to the required thickness of the entire sleeve 10.

The sleeve body 15 is made of a hot tool steel having a low thermal conductivity, for example, SKD61. The thinner the better, the better. As described above, the distance is set to about 2.5 mm in consideration of deformation during processing.

Next, the operation of the present embodiment will be described. The sleeve 10 is formed by fitting and integrating the inner sleeve 12, the two outer sleeves 13, 14 and the sleeve body 15 by cooling or shrink fitting. For this reason, as shown in an exaggerated manner in FIG. 2, a large number of air gaps 16 due to processing accuracy exist between the respective layers, and the air gaps 16 extremely reduce the heat conduction between the layers. Thus, when the molten aluminum alloy is poured from the pouring port 3, only the inner sleeve 12 is uniformly heated at the molten metal drop point 4, and the thermal shock applied to the outer sleeves 13 and 14 is reduced. It is possible to keep it small. For this reason, it is possible to prevent the occurrence of thermal shock cracking, which is a drawback of the conventional sleeve made of tool steel. Moreover, in combination with the performance that is resistant to thermal shock cracking, the inner layer sleeve 12 is made of zirconia, alumina,
When a ceramic material such as silicon nitride is used as a material, the material has excellent resistance to molten metal welding, and thus exhibits sufficient durability.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors manufactured a sleeve 10 having a four-layer structure shown in FIG. The inner sleeve 12 is made of silicon nitride, and both outer sleeves 13 and 14 and the sleeve body 15 are made of SK.
D61. Further, the thickness of the entire sleeve 10 is set to 10
mm, the layer thickness of each of the sleeves 12, 13, 14 and the sleeve body 15 was 2.5 mm.

The sleeve 10 manufactured as described above
Is attached to a cold chamber type die casting machine.
The melt of ADC12 maintained at 80 ° C. was poured.
This pouring was repeated 200,000 times, but no damage such as heat check and welding occurred, and the sleeve 10
It has been confirmed that the life of the device can be greatly extended.

The present inventors also conducted the same experiment as described above, using the inner sleeve 12 made of nitrided steel. As a result, although pouring was repeated 100,000 times, damages such as heat cracks and welding did not occur, and even if the inner sleeve 12 was manufactured using nitrided steel, the life of the sleeve 10 could be greatly extended. It was confirmed that it was possible.

[0020]

As described above, the present invention provides a multi-layered structure including an inner sleeve made of a material having a resistance to molten metal welding, and an outer sleeve formed of an iron-based material and disposed on the outer peripheral side of the inner sleeve. Since it is composed of a composite structure and each of the sleeves is integrated by cooling or shrinking,
The thermal shock can be alleviated and the welding of the molten metal can be prevented, so that the life can be greatly extended.

In the present invention, since the inner layer sleeve is formed of ceramics such as zirconia, alumina, silicon nitride, etc., the molten metal welding resistance to the aluminum alloy can be further improved and the life can be greatly extended. .

In the present invention, the outer sleeve is made of SKD
If it is formed of hot tool steel such as 61, heat conduction from the inner sleeve can be suppressed, so that it is possible to prevent the occurrence of thermal shock cracking, which is a drawback of tool steel, and to reduce the production cost. Reduction can be achieved.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a sectional view showing a conventional die-casting sleeve.

FIG. 4 is an explanatory view showing a state of thermal deformation in a conventional die casting sleeve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Sleeve 12 Inner layer sleeve 13 and 14 Outer layer sleeve 15 Sleeve body 16 Air gap

Claims (4)

[Claims] 1. A multi-composite structure including an inner sleeve made of a material having a resistance to molten metal welding, and an outer sleeve formed of an iron-based material and disposed on an outer peripheral side of the inner sleeve. A die-casting sleeve, which is integrated by cooling or baking. 2. The die casting sleeve according to claim 1, wherein said inner layer sleeve is formed of a ceramic material such as zirconia, alumina, silicon nitride or the like. 3. The inner layer sleeve according to claim 1, wherein the inner peripheral surface is formed of an iron-based material whose inner peripheral surface has been subjected to a surface treatment such as nitriding treatment or boring treatment which is resistant to molten metal welding. Die casting sleeve. 4. The die-casting sleeve according to claim 2, wherein the thickness of each sleeve does not exceed 2.5 mm.