JPH06198413A - Die casting method in solid-liquid coexistent range - Google Patents

Abstract

PURPOSE:To improve the cost and the workability of a die casting in solid-liquid coexistent range by heating a vessel incorporating raw material in one time of the injection to the solid-liquid coexistent temp. range and inserting this raw material into an injection sleeve. CONSTITUTION:The raw material 2 is charged into the vessel body 3 sealing the upper opening part with a cover 1, and heated to the solid-liquid coexistent temp. range of the raw material 2 by an electric resistant heating furnace, etc. By turning over the vessel body 3, the raw material 2 is laid on the end surface of an injection rod 5. By lowering the injection rod 5, the raw material 2 is inserted into the sleeve 6. Therefore, in comparison with the die casting using the molten metal, entrapment of foreign matter is eliminated, and the excellent quality of a product, such as dimensional precision and the excellent yield, etc., are obtd. As the heating in the sleeve as the ordinary method is unnecessary as expensive and brittle ceramic-made sleeve may be not used, and the cost and the workability can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention proposes a solid-liquid coexisting die casting method suitable for improving die casting product quality, economy and workability.

[0002]

2. Description of the Related Art In a normal molten metal die casting method, a material is evenly inserted into a sleeve and injected. In this method, the amount of molten metal required for the injection is drawn out from the melting furnace with a ladle and inserted into the sleeve every injection.

As a solid-liquid coexistence region die casting method, for example, there is a method disclosed in JP-A-4-052059 (die casting method and die casting machine for solid-liquid coexisting metal).

According to this method, a part of the raw material is melted and the solid phases are connected in a net-like manner during heating or during transfer, and the whole behaves like a solid. The phase is broken, and the broken solid phase particles are suspended in the liquid and heated to a temperature at which the liquid phase is similar to that of the liquid (for example, the temperature at which the liquid phase becomes about 0.4 of the whole). Then, the heated material is transferred in a solid state to the mold gate portion and injected into the mold cavity. It should be noted that, at the time of injection, the net-like solid phase is broken and becomes fluid like a liquid, so that the material can be filled in the mold cavity.

The insertion of the material into the sleeve in this method is to insert a lump material preheated to room temperature or a temperature below the solidus into the sleeve, and thereafter, electrically or electromagnetically, such as by induction heating in the sleeve. Heat to the solid-liquid coexistence temperature range. Therefore, the material of the sleeve is Si ₃
A non-electrically conductive material having excellent heat resistance such as N ₄ is used.

Further, there is also a method in which the material is wrapped in ceramic paper, heated in a heating furnace, and the ceramic paper is inserted into a sleeve and injected.

[0007]

In the method of inserting the molten metal into the drawing-out sleeve with a ladle or the like, it is difficult to draw out an accurate amount of the molten metal, and the yield is lowered.
There is a problem that the product quality is deteriorated due to the increase in gas entrapment and the inclusion of foreign matter.

Further, in the solid-liquid coexistence region die casting method, a product of excellent quality with less entrainment of gas and foreign matter can be obtained, but a material having a temperature below the solidus is inserted into the sleeve. Since the sleeve is electrically or electromagnetically heated to a solid-liquid coexistence temperature range, the sleeve needs to have excellent heat resistance and non-electrical conductivity, so expensive and fragile materials such as ceramics are used. There is no choice but to handle it with great care, and there is the problem of poor economy and workability.

Further, in the method in which the material is wrapped in ceramics paper and heated and inserted into the sleeve, the fragments of the ceramics paper are left in the biscuit and are not mixed into the product at the time of injection, but completely prevented from being mixed into the product. It is difficult to do this, and it is also difficult to completely remove the pieces of ceramic paper when this biscuit is used repeatedly.

Therefore, the present invention is intended to advantageously solve the above-mentioned problems, and is economical in a solid-liquid coexisting region die casting having advantages such as reduction of entrainment of gas and foreign matter and improvement of yield. The purpose of the present invention is to propose a solid-liquid coexistence zone die casting method that can improve workability.

[0011]

The summary of the present invention is as follows. In the process of inserting the material for one injection into the sleeve of the die casting machine and injecting it into the mold cavity in a semi-molten state by the injection rod, put the block material for one injection into the container and heat the container together. After raising the temperature to the solid-liquid coexistence temperature range of the material, the container containing the material is transferred to the material insertion port of the sleeve, and the container is inverted to insert the material from the material insertion port of the sleeve into the sleeve. And a solid-liquid coexisting region die casting method (first invention). In the first invention, the material contained in the container is heated in an inert atmosphere or a non-oxidizing atmosphere of a reducing atmosphere (second invention), and the container containing the material is provided with a lid, and the container is placed in the atmosphere. It is for heating (third invention). The material in the first invention is a container made of Al-based alloy made of stainless steel (fourth invention), and the material in the third invention is made of stainless steel for both and / or one of the container body and the lid made of Al-based alloy. (Fifth invention).

[0012]

The operation of the present invention and its operation will be described below. This invention puts the material in a metal container, heats the container to a solid-liquid coexistence temperature range of the material in an electric resistance heating furnace, a gas heating furnace, etc., and then transfers the container containing the material to the sleeve insertion port. Only the material in the solid-liquid coexisting temperature range is inserted into the sleeve and injected into the mold sleeve. By doing so, the above-mentioned various conventional problems can be solved. In other words, it becomes unnecessary to use an expensive and fragile sleeve made of ceramics, which is a weak point of the solid-liquid coexistence region die casting method, which is excellent in product quality and yield.
Economic efficiency and workability can be improved. Hereinafter, it will be described in more detail based on specific examples. The raw material may be a round bar material obtained by continuously casting a molten metal or a semi-molten or semi-solid metal material or a round bar material manufactured by extrusion, forging or the like. This round bar is cut into a length that will weigh one injection. The cut material is placed in a cylindrical metal container having a bottom.

Here, in order to prevent seizure between the metal container and the material, a release material made of non-metal powder is usually applied to the inner surface of the metal container. However, when the material is an Al-based alloy, if the mold release material is applied when the stainless steel container is first used, seizure does not occur even if the mold release material is not applied during repeated use thereafter. The material is A
When heating with a lidded container with an l-based alloy, both the container body and the lid may be made of stainless steel, but when the stainless steel container is expensive, the number of products of the same size manufactured is small. In order to reduce the initial investment, the steel may be made of inexpensive steel, and in this case, it is appropriate to apply a mold release agent after each heating. In addition, when transferring the heated material into the sleeve without applying shocking force, the material may be moved from the top of the lid to the end surface of the injection rod. In this case, a release material made of ceramic is not required at all. By doing so, the possibility of contamination of the material by the release material can be eliminated.

Next, the material contained in this container is heated to a solid-liquid coexisting temperature range of the material in an electric resistance heating furnace or the like. During this heating, in order to prevent the material from being oxidized, the material is heated in an inert atmosphere or a non-oxidizing atmosphere such as a reducing atmosphere. It is preferable to use the optimum atmosphere for these atmospheres in consideration of the reaction between the material and the atmosphere gas. For example, when the material is an Al-based alloy, the absorption of hydrogen adversely affects the material, but it does not react with nitrogen, so a nitrogen atmosphere is preferable.

After the material is heated to the solid-liquid coexistence region temperature where it has a predetermined solid phase ratio, the container containing the material is taken out of the furnace, transferred to the sleeve insertion port, and the container is tumbled to put only the material in the sleeve. Then, the heated material is injected into the mold cavity. It is desirable that a non-oxidizing atmosphere is provided between the furnace and the sleeve as in the above case, but the time between the materials is short, so that it may be in the atmosphere. Also, if the container is capped with a small difference between the internal dimensions and the dimensions of the material, that is, if a container with a lid is used, the amount of air in the container is small and the invasion of air from the outside air is small, so it is not necessarily non-oxidizing. There is no need to use an atmosphere furnace without heating in a neutral atmosphere. Further, the advantages of using the lidded container will be described below. If the material collapses when the material in the solid-liquid coexisting temperature range is dropped into the sleeve,
Make the depth of the container approximately equal to the length of the material, and invert the container with the material removed from the furnace with the lid on. The material in the solid-liquid coexistence temperature range remains on the lid when the container body that has been tumbled is lifted directly above. If the end surface of the injection rod is raised to the position of the upper end of the sleeve in advance and the material on the lid is moved onto the end surface of the injection rod and the injection rod is gently lowered, the material will not be subject to shocking force, and it will easily collapse. Even a material having a solid phase ratio can be inserted into the sleeve without breaking the material, and injection into the mold cavity can be performed without any trouble.

The above procedure will be described with reference to the drawings. FIGS. 1 (a), (b), (c), (d), and (e) show a procedure of transferring and inserting a heated material into a sleeve without applying an impacting force to the heated material. FIG. In these figures, 1 is a lid, 2 is a material, 3
Is a container body, 4 is a guide, 5 is an injection rod, and 6 is a sleeve.

Each of the figures will be described in order below. (A) is an explanatory view of a heated state, and the material 2 is placed inside the container body 3.
And the upper opening of the container body 3 is closed by the lid 1. (B) is an explanatory view showing a state in which (a) is tumbled, and the central axis direction of the material 2 when tumbled is made parallel to the central axis direction of the injection rod 5. (C) is an explanatory view showing a state where the container body 3 is removed, and the lid 1
Material 2 is on top of it. (D) is an explanatory view showing a state in which the material 2 is placed on the end surface of the injection rod 5, the material 2 is moved to the guide 4 together with the lid 1, and only the material 2 is slid on the guide 4 to make the injection rod 5
Place it on the end face of. (E) An explanatory view showing a state in which the material 2 is inserted into the sleeve 6, and the injection rod 5 is lowered by lowering the injection rod 5.
The material 2 placed on the end face of is inserted into the sleeve 6.

As described above, the present invention further improves the solid-liquid coexistence region die-casting, which is superior to the die-casting of the molten metal in product quality such as gas, entrapment of foreign matter, dimensional accuracy and yield, and

Since the container containing the material is heated outside the sleeve and not inside the sleeve, the expensive and fragile ceramic sleeve, which has been a weak point of the conventional solid-liquid coexisting liquid die casting method, is not used. Well, therefore, the economy and workability can be improved,

In addition, the oxidation of the material during heating is suppressed to prevent the inclusion of oxides in the product, and by using a container with a lid, the heated material is easily broken (for example, low solid fraction). Even if there is, it can be inserted into the sleeve without losing its shape, and injection into the mold cavity can be performed without any problems.

[0021]

Example: Dimensions of Al-4 mass% Si alloy: 60 mmφ ×
Using a 70 mm round bar piece as a material, the material was heated to 622 ° C. (solid phase ratio: 0.4) in a mesh belt furnace, inserted into the sleeve of a vertical die casting machine, and then injected into a mold cavity. . Applicable examples and comparative examples of the present invention with the above as basic conditions are listed below.

Matching Example 1 The material is put in a cylindrical container made of SUS304 having a bottom,
It was heated in a nitrogen atmosphere, grabbed the container with fire chopsticks and transferred, and the container was inverted to insert the heated material into the sleeve and ejected. As a result, normal injection was possible, and no harmful oxide was caught in the product.

Conformity Example 2 The material was placed in a cylindrical container with a lid made of SUS304 having a bottom, the lid was closed, and after heating in the atmosphere, the container was grabbed with the fire chopsticks and the material heated by the procedure shown in FIG. It was inserted into the sleeve and injected. As a result, normal injection was possible, and no harmful oxide was caught in the product.

Comparative Example 1 The material was heated in a nitrogen atmosphere and tried to be caught with fire chopsticks.
The material collapsed and could not be inserted into the sleeve.

Comparative Example 2 A material was placed in a cylindrical container having a bottom and made of SUS304, heated in the atmosphere, grasped and transferred with a chopstick, and the container was turned over to insert the heated material into a sleeve. And then fired. As a result, normal injection was possible, but harmful oxides were found in the product.

[0026]

Industrial Applicability The present invention is a solid-liquid coexistence zone die-casting method in which a material is put in a container and the whole container is heated to the solid-liquid coexistence temperature range of the material outside the sleeve, and then only the material is inserted into the sleeve for injection molding. According to the present invention, it is not necessary to use an expensive and fragile ceramic sleeve, which was a weak point of the solid-liquid coexistence zone die casting method, which is excellent in product quality, and it is possible to improve economical efficiency and workability, and to reduce quality at low cost. We can supply excellent die casting products.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a procedure of transferring a heated material into a sleeve using a container with a lid without giving a shocking force. (A) is an explanatory view of a heated state. (B) is explanatory drawing which shows the state which turned down (a). (C) is explanatory drawing which shows the state which removed the container main body. (D) is an explanatory view showing a state in which the material is placed on the end surface of the injection rod. (E) is explanatory drawing which shows the state which inserted the raw material in the sleeve.

[Explanation of symbols]

 1 Lid 2 Material 3 Container Body 4 Guide 5 Injection Rod 6 Sleeve

Front page continuation (72) Inventor Yuichi Ando 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Stock company Leotech

Claims (5)

[Claims] 1. A step of inserting a material for one injection into a sleeve of a die casting machine and injecting the material for one injection into a mold cavity in a semi-molten state by an injection rod. After heating the entire container to raise the temperature to the solid-liquid coexistence temperature range of the material, transfer the container containing the material to the material insertion port of the sleeve and invert the container to transfer the material from the material insertion port of the sleeve into the sleeve. A solid-liquid coexistence zone die casting method characterized by insertion. 2. The solid-liquid coexisting zone die casting method according to claim 1, wherein the material contained in the container is heated in a non-oxidizing atmosphere such as an inert atmosphere or a reducing atmosphere. 3. The solid-liquid coexistence die-casting method according to claim 1, wherein the container containing the material is provided with a lid and heated in an air atmosphere. 4. The solid-liquid coexistence region die casting method according to claim 1, wherein the container made of an Al alloy is made of stainless steel. 5. The solid-liquid coexistence zone die-casting method according to claim 3, wherein both or either of the container main body and the lid made of an Al-based alloy are made of stainless steel.