JPH09155523A - Sleeve of die casting machine and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a sleeve excellent in a heat retaining property in a low cost, in a molten metal pressurized pouring device of a die casting machine for injecting the molten metal poured into a sleeve by pressurizing with a plunger. SOLUTION: A cylindrical lost foam pattern 8 as the same as a cylindrical metal-made lining member 3 is arranged in a molding sand 7 and an iron alloy having <=20W/m.K thermal conductivity is melted and poured from a sprue 10. Then, the lost foam pattern 8 is replaced into the molten iron alloy to cast the sleeve body inserting the lining member 3. Since the sleeve body is composed of the iron alloy composed of the low thermal conductivity, the heat retaining property to molten light alloy for the die casting is excellent and further, since the lining member 3 can be inserted at the same time of casting the sleeve body, the following process of a shrinkage fitting, etc., is unnecessary, and the sleeve can be produced in the low cost.

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 molten metal pressure pouring device of a die casting machine and a method for manufacturing the same.

[0002]

2. Description of the Related Art As is well known, a die casting machine presses a molten metal of a light alloy for die casting by a molten metal pressure pouring device and injects it into a mold. This molten metal pressure pouring device includes a sleeve and a plunger that reciprocates in the sleeve, and the molten metal poured into the sleeve is pressurized by the plunger and injected into the mold through the sprue.

The sleeve of such a molten metal pressurizing and pouring apparatus is conventionally formed in a hollow cylindrical shape from an alloy tool steel, for example, SKD61, and in order to improve the erosion resistance to light alloys for die casting such as aluminum alloy and zinc alloy, In most cases, the peripheral surface is subjected to surface treatment such as nitriding treatment.

[0004]

[Problems to be Solved by the Invention] However, SKD
Since the 61-made sleeve has high thermal conductivity, the light alloy for molten die casting poured into the sleeve is instantly cooled and a solidified layer is formed at a portion in contact with the inner peripheral surface of the sleeve.
Then, the solidified layer is mixed with the light alloy for molten die casting and is injected into the mold, which causes a problem that the strength of the die cast product is reduced.

Therefore, in recent years, in order to improve the heat retaining property for the light alloy for molten die casting and prevent the solidified layer from being generated, for example, as disclosed in Japanese Utility Model Publication No. 7-1010, the inner circumference of the metal sleeve is shown. A composite sleeve in which a ceramic lining member is shrink-fitted on the surface is considered.

[0006] However, although ceramics can improve heat retention because of its low thermal conductivity, it has low toughness,
Under the present circumstances, composite sleeves using a ceramic lining member are not widely used, because they are liable to be cracked or chipped and are difficult to handle, and the manufacturing cost is high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture it at a low cost without using a ceramic member that is excellent in heat retention for a metal for molten die casting and that causes a high cockat. (EN) Provided are a die casting machine sleeve and a manufacturing method thereof.

[0008]

A sleeve of a die casting machine according to the present invention is a sleeve for supplying molten metal poured into a die of a die casting machine by pressurizing molten metal with a plunger and heating the molten metal in the range of room temperature to 400 ° C. Conductivity is 20 W / m
It comprises a tubular sleeve body made of an iron alloy of K or less, and a tubular metal lining member provided inside the sleeve body. In this sleeve, since the thermal conductivity of the sleeve body is low, the heat retaining property with respect to the metal for molten die casting is excellent.

Further, in the method for manufacturing the sleeve of the die casting machine of the present invention, the thermal conductivity is 20 outside the room temperature to 400 ° C. on the outside of the cylindrical metal lining member provided in the mold.
A sleeve in which the lining member is provided inside a tubular sleeve body formed of the iron alloy by pouring a molten metal made of an iron alloy of W / m · K or less and casting the lining member. Is manufactured.

According to this method, when the sleeve body is cast by pouring the molten metal to the outside of the lining member, the lining member is cast into the sleeve body at the same time, which is different from the conventional composite sleeve. Since it is not necessary to shrink-fit it, it is possible to easily manufacture a sleeve excellent in heat retention.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
Explanation will be given based on FIG. As shown in FIG. 2, the sleeve 1 of the molten metal pressure pouring device in the die casting machine according to the present invention has a tubular (cylindrical) shape inside a tubular (cylindrical) sleeve body 2 integrally having a flange 2a. ) Is provided, and a relatively thin walled lining member 3 is provided. The sleeve 1 is provided with a pouring port 4 for pouring a molten light alloy for die casting such as an aluminum alloy or a zinc alloy.

Here, the sleeve body 2 is kept at room temperature to 40 degrees.
Iron alloy with a thermal conductivity of 20 W / mK or less in the range of 0 ° C,
For example, it is formed of an iron alloy containing 5% or more and 50% or less of Ni and 7% or less of Si. The lining member 3 is made of alloy tool steel such as SKD61.

The sleeve body 2 is manufactured by casting with the lining member 3 as a cast-in member. In this embodiment, the vanishing model casting method is adopted, and the mold used therefor is shown in FIG. In FIG. 1, the mold 5 is placed on a vibrator 6, and the mold 5 is filled with molding sand 7. A state in which the lining member 3 and the vanishing model 8 formed in a comparatively thick cylindrical shape of, for example, expanded polystyrene in the molding sand 7 are in close contact with the outside of the lining member 3 It is embedded in.

In this case, as shown in FIG. 3, the outer peripheral surface of the lining member 3 is for preventing oxidation and for the lining member 3.
In order to promote a melting / diffusion reaction between the iron alloy and the above-mentioned iron alloy for casting the sleeve body 2, a metal coating 9 is previously formed.
Are formed. The metal coating 9 is a nickel or tin coating deposited on the outer peripheral surface of the sleeve body 2 by plating, or a metal coating deposited on the outer peripheral surface of the sleeve body 2 by thermal spraying. A metal, specifically, an MSFNiB alloy containing Ni-Cr-Si-B as a main component is used.

The casting sand 7 is provided with a spout 10 for pouring the iron alloy (hereinafter referred to as molten iron alloy) melted in the disappearance model 8 and is replaced with the disappearance model 8. A molten metal 11 is provided to prevent the cast product (sleeve main body 2) from shrinking when the molten iron alloy is solidified.

In order to cast the sleeve body 2, the molten iron alloy is poured from the sprue 10 while driving the vibrator 6 to apply vibration to the form 5. Then, the molten iron alloy reaches the disappearance model 8, and the disappearance model 8 is gasified by the heat of the molten iron alloy and disappears. As a result, the molten iron alloy is replaced with the vanishing model 8 and is poured into the outer periphery of the lining member 3, and eventually solidifies and is cast into the sleeve body 2 encapsulating the lining member 3.

Here, on the outer peripheral surface of the inner lining member 3, that is, on the surface that comes into contact with the molten iron alloy poured outside, a metal coating 9 made of nickel, tin, or the self-fluxing metal described above is used.
Thus, the molten iron alloy can firmly encase the lining member 3.

That is, when the outer peripheral surface of the lining member 3 is oxidized, the oxide film deteriorates the wettability between the outer peripheral surface of the lining member 3 and the molten iron alloy, and it becomes impossible to secure a strong bond between the two. However, in the present embodiment, since the outer peripheral surface of the lining member 3 is prevented from being oxidized by the metal coating 9 formed by plating or thermal spraying, good wettability of the molten iron alloy to the outer peripheral surface of the lining member 3 is ensured. Moreover, in this embodiment, in particular, since vibration is applied to the form 5 from the vibrator 6, the adhesion between the molten iron alloy and the lining member 3 is enhanced by the vibration, so that the vibration is applied to the outer peripheral surface of the lining member 3. The wettability of the molten iron alloy becomes better.

Further, under this good wettability, the metal film 9 promotes a melting / diffusion reaction between the molten iron alloy and the lining member 3 (diffusion of the iron alloy component into the lining member 3). Since an alloy layer (layer thickness of 20 to 100 μm) is formed on the boundary surface of the molten iron alloy, the molten iron alloy is in a state in which the lining member 3 is firmly cast.

In addition, since the molten iron alloy contracts when it solidifies, the contraction causes the lining member 3 to be shrink-fitted in the sleeve body 2 to more firmly bond the two. . Moreover, since vibration is imparted to the molten iron alloy from the vibrator 6 during the casting, the gas generated in the solidification process of the molten iron alloy can be discharged more easily, and the gas is accumulated in the sleeve body 2. The dense sleeve body 2 can be cast by effectively preventing the formation of a nest.

The sleeve body 2 is cast by the vanishing model casting method as described above, and at the same time as the casting of the sleeve body 2, the lining member 3 is cast in the sleeve body 2 and manufactured as the sleeve 1. It is something. Then, after taking out from the mold, the sprue 10 and the riser 1
1 is removed, and after being surface-treated by cutting or the like, nitriding is performed on the inner peripheral surface of the lining member 3 in order to enhance the melt damage resistance to the metal for molten die casting, for example, the light alloy for molten die casting such as aluminum alloy and zinc alloy. Perform surface treatment such as treatment.

The sleeve 1 manufactured in this manner is intended to secure the heat retaining property to the light alloy for molten die casting by the sleeve body 3 made of an iron alloy having a low thermal conductivity. Therefore, it is not necessary to form the lining member 2 from a material having low thermal conductivity such as ceramics,
It can be formed of a metal such as alloy tool steel. Therefore, unlike conventional composite sleeves that have a structure that enhances heat retention with a ceramic lining member, it is not necessary to use a ceramic material, so there is no need to take care not to crack or chip, and it has excellent handleability. Will be things.

By the way, in this embodiment, the sleeve body 2
As a metal for casting, an iron alloy having a thermal conductivity of 20 W / m · K or less in the range of room temperature to 400 ° C. is used, and the iron alloy contains 5% or more and 50% or less of Ni and 7%.
The following high Ni-Si iron alloys containing Si were adopted. The content of each element is a weight percentage (hereinafter the same).

The reason why the Ni content is set to 5% or more and 50% or less and the Si content is set to 7% or less is as follows. First, in the high Ni-Si iron alloy of the present example, clarified spheroidized graphite is deposited on an austenite matrix that also contains C (carbon) and partially contains martensite in order to improve castability, as will be apparent from the following. First, the relationship between the amount of Ni and the thermal conductivity of the Fe-Ni alloy is shown in FIG.

As is clear from FIG. 4, the Ni content is 5 to 65.
%, The thermal conductivity is about 33 W / m · K or less, and when Si is added to the Fe—Ni alloy having the Ni content in this range, the Ni content is 5% or more and 50% or less. Is
The thermal conductivity was as low as 20 W / m · K or less, but when the Ni content exceeds 50%, a Ni-Si intermetallic compound having high thermal conductivity is formed when Si is contained, and the thermal conductivity increases. The conductivity exceeds 20 W / mK.

Further, when the Ni content is 10% or more and 40% or less, the austenite base partially contains martensite, so that the thermal conductivity is about 26 W / mK or less, as is apparent from FIG. (At a minimum of about 11 W / mK), and when Si was added to this, the thermal conductivity further decreased. Further, when the Ni content was 13% or less and 25% or more, the thermal conductivity was 20 W / m · K or less, and when Si was added to this, the thermal conductivity further decreased.

From the above, the thermal conductivity is 20 W / m.
To make K or less, the content ratio of Ni is 5% or more and 5
Must be 0% or less, and within this range 10% or more 4
The Ni content is preferably 13% or less and 25% or more. On the other hand, when Si is 7% or more, Si and Ni form an intermetallic compound, resulting in high thermal conductivity. Therefore, Si is preferably 7% or less.

Here, in this embodiment, as shown in FIG. 5, C1.3%, Si4.5%, Mn0.6%, Ni1
5%, Mg0.05%, Sample 1 with the balance substantially Fe, C1.5%, Si5.0%, Mn0.6%, Ni1
6%, Mg0.05%, sample 2 with the balance substantially Fe, C2.0%, Si5.0%, Mn0.6%, Ni1
An experiment was conducted to obtain the thermal conductivity at 400 ° C. for Sample 3 containing 8%, Mg0.05%, and the balance being substantially Fe. As a result, Sample 1 was 18.0 W / m · K, and Sample 2 was 18 The low thermal conductivity of 0.5 W / m · K and Sample 3 was 20.0 W / m · K.

Therefore, in order to compare the heat retaining properties of the sleeve 1 according to the present invention and the conventional SKD61 sleeve, the temperature drop of the light alloy for molten die casting which is poured into the sleeve using both sleeves is compared. The result of the experiment is shown in FIG. For the sleeve 1 of the present invention used in this experiment, an iron alloy having the composition shown in the following Table 1 was used for casting the sleeve main body 2, which was melted in a high-frequency induction electric furnace to a temperature of about 1500 ° C. It is manufactured by pouring molten metal into the mold 5 at a temperature.

[0030]

[Table 1]

The experimental conditions are shown in Table 2 below. Here, the molten metal is a light alloy for molten die casting that is poured into the sleeve, the molten metal filling rate is the ratio of the light alloy for molten die casting to the inner volume of the sleeve, and the initial temperature is the sleeve before pouring the light alloy for molten die casting. Is the temperature of.

[0032]

[Table 2] By the way, in FIG. 6 showing the experimental results, the solid line shows the one by the sleeve of the present invention, and the broken line shows the one by the conventional sleeve. As is clear from the figure, the time required for the temperature of the molten metal of the aluminum alloy for die casting (ADC12) to drop to 580 ° C. which is the solidification temperature after pouring into the sleeve is
In the conventional sleeve, the decrease was 0.7 sec, but in the present invention, it was 1.9 sec.

On the other hand, the temperature of the sleeve is 150 to 400 ° C. in 10 seconds after pouring the molten metal in the conventional sleeve.
Although the temperature has risen up to 400 ° C. in the sleeve of the present invention even after 10 seconds have passed after pouring the molten metal, the sleeve of the present invention has a heat retention effect (insulation effect) of 2.7 times that of the conventional sleeve. It is understood that there is. In the die casting machine, considering that the time from pouring the molten metal into the sleeve to the injection into the mold is usually 1 to 1.5 sec, the sleeve 1 of the present invention pours the molten metal. The molten metal can be injected into the mold before a solidified layer is formed at the portion in contact with the inner surface of the sleeve 1, and a die-cast product having excellent quality can be molded.

FIG. 7 shows another embodiment of the present invention.
This applies the vibration of the vibrator 12 to the lining member 3 in the foundry sand 7 via the transmission member 13, and the lining member 3
It is configured so that vibration is applied to the molten iron alloy that replaces the vanishing model 8. Even with this structure, the same effect as that of the above-described embodiment can be obtained.

The present invention is not limited to the embodiments described above and shown in the drawings, and the following expansions and modifications are possible. The material of the lining member 3 is not limited to alloy tool steel. The casting method of the sleeve body 2 is not limited to the vanishing model casting method. The outer peripheral surface of the lining member 3 may be formed in an uneven shape by knurling, threading, or the like to enhance the coupling with the sleeve body 2.

[0036]

As is apparent from the above description, according to the present invention, the following effects can be obtained. Claim 1
According to the invention, since the sleeve is excellent in heat retention, the molten die-casting metal can be supplied into the mold without solidifying, and the lining member is made of metal, so the manufacturing cost is higher than that of ceramics. Is low, the toughness is high, cracks and chips are unlikely to occur, and the life is long.

According to the second aspect of the present invention, the lining member can be cast-in at the same time when the sleeve body is cast, and the post-process such as shrink fitting is unnecessary, and the manufacturability is excellent.

According to the invention of claim 3, since the sleeve is cast by the disappearance model casting method, the mold can be easily manufactured.

According to the fourth aspect of the present invention, the connection between the sleeve body and the lining member becomes stronger due to the unevenness of the lining member. According to the invention of claim 5, since the outer peripheral surface of the inner lining member is subjected to the antioxidant treatment, the wettability between the inner lining member and the molten metal is improved, and the inner lining member and the sleeve body are more firmly coupled. According to the invention of claim 6, since the alloy layer is formed on the boundary between the lining member and the molten metal by the metal film on the outer peripheral surface of the lining member, the lining member and the sleeve body are more firmly coupled.

According to the invention of claim 7, from room temperature to 400
It is possible to specifically provide an iron alloy having a thermal conductivity of 20 W / m · K in the range of ° C. According to the invention of claim 8, the adhesion between the lining member and the molten metal is further improved by the vibration applied during the casting of the sleeve body.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a mold showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a sleeve.

FIG. 3 is a partially enlarged sectional view of a lining member.

FIG. 4 is a thermal conductivity characteristic diagram of a Ni—Fe alloy.

FIG. 5 is a diagram showing the composition of an iron alloy.

FIG. 6 is a heat retention characteristic diagram shown in comparison with a conventional sleeve.

FIG. 7 is a view corresponding to FIG. 1 showing another embodiment of the present invention.

[Explanation of symbols]

In the figure, 1 is a sleeve, 2 is a sleeve body, 3 is a lining member, 6 is a vibrator, 9 is a metal film, and 12 is a vibrator.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B22D 19/08 B22D 19/08 Z 27/08 27/08 C22C 38/00 302 C22C 38/00 302Z 38/08 38/08 // B29C 45/62 9350-4F B29C 45/62 (72) Inventor Zenichi Mochizuki 2068-3 Ooka, Numazu City, Shizuoka Prefecture Toshiba Machine Co., Ltd. Numazu Plant (72) Inventor Naotaka Kawaguchi Shizuoka 2068-3 Ooka, Numazu City, Japan Numazu Plant, Toshiba Machine Co., Ltd.

Claims (8)

[Claims] 1. A sleeve for supplying molten metal poured into a die of a die casting machine by pressurizing it with a plunger, and from a ferrous alloy having a thermal conductivity of 20 W / m · K or less in the range of room temperature to 400 ° C. A sleeve for a die-casting machine, comprising: a tubular sleeve body, and a tubular metal lining member provided inside the sleeve body. 2. The method for manufacturing a sleeve according to claim 1, wherein the sleeve is provided outside the tubular metal lining member provided in the mold.
A tubular sleeve body formed of the iron alloy by pouring a molten metal made of an iron alloy having a thermal conductivity of 20 W / m · K or less in the range of room temperature to 400 ° C. and casting the inner lining member. A method of manufacturing a sleeve of a die casting machine, comprising manufacturing a sleeve having the inner lining member provided inside thereof. 3. A cylindrical vanishing model is arranged outside the liner member provided in the mold, and the molten metal made of an iron alloy is replaced with the vanishing model to cast the liner member. 2. A method for manufacturing a sleeve of a die casting machine according to 2. 4. The method for manufacturing a sleeve of a die casting machine according to claim 2, wherein the outer peripheral surface of the inner lining member is formed in an uneven shape. 5. The method for manufacturing a sleeve of a die casting machine according to claim 2, wherein the outer peripheral surface of the lining member is surface-treated to prevent oxidation. 6. The die casting machine according to claim 2, wherein a metal coating for promoting a melting / diffusion reaction between the lining member and the molten metal composed of an iron alloy is attached to the lining member. For manufacturing sleeves. 7. The iron alloy contains 5 to 50% by weight of N.
3. The method for manufacturing a sleeve for a die casting machine according to claim 2, wherein the content of Si is 7% or less. 8. The method for manufacturing a sleeve of a die casting machine according to claim 2, wherein the molten metal poured outside the lining member is cast and wrapped while vibrating.