JPH0724928B2 - Casting device using cast pin - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus for casting a product using a mold, such as a die casting method, for example, a low pressure casting method, and more specifically, a thermal conductivity. A well-balanced molten metal by forming casting pins from different materials and arranging each casting pin toward the spout according to the thermal conductivity of the material so that the thermal conductivity becomes low. The present invention relates to a casting apparatus using a casting pin, which promotes directional solidification, prevents casting defects occurring in a product structure, and improves durability of the casting pin.

[Background of the Invention] When casting a product by filling a molten metal into a product cavity defined in a mold, as in a die casting method, in order to form a hole portion such as a bolt hole of the product, a die cutting is performed. Pins are used. Moreover, this cast pin is conventionally used for the purpose of reducing the weight of the product.

Conventionally, such cast pin is manufactured by using hot tool steel (for example, JIS SKD61) among the steel materials,
Further, after being subjected to heat treatment such as quenching and tempering, it is used after being subjected to soft nitriding treatment (tufftride treatment) to impart heat resistance and wear resistance. This is because the cast pin is directly exposed to the high heat of the molten metal because it is immersed in the molten metal of high temperature in the mold.

When using such a casting pin, for example, when casting a product from a molten metal made of an aluminum alloy, because the affinity between the hot work tool steel, which is the material of the casting pin, and the molten metal is good, An alloy layer with aluminum is formed on the surface of the pin, and seizure with the cast product eventually occurs. In addition, since the temperature of the casting pin itself rises in the vicinity of the area where the casting pin and the molten metal come into contact with each other, the solidification of the molten metal is delayed, resulting in an imbalance with the progress of the solidification of the molten metal in the entire cavity. The inconvenience of casting defects such as cracks often occurs.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned inconveniences, and uses cast pins made of materials having different thermal conductivities, and the heat transfer is performed at a portion apart from the gate in the cavity. A casting pin made of a material with a high thermal conductivity is placed, and a casting pin made of a material with a low thermal conductivity is placed close to the sprue to promote well-balanced solidification of the molten metal directed to the sprue. It is an object of the present invention to provide a casting device using a casting pin which can prevent the occurrence of casting defects such as a hollow and can improve the service life of the casting pin itself.

[Means for Achieving the Object] In order to achieve the above-mentioned object, the present invention provides casting pins arranged in a plurality of casting holes communicating with cavities defined in a mold, respectively. In a casting apparatus for pressurizing and filling the injected molten metal into the cavity to obtain a cast product, the plurality of casting pins include a casting pin arranged in a first region distant from a gate and the first casting pin. ,,, and n-th cast-out pins arranged in the n-th region, which are sequentially located closer to the sprue, respectively, and the cast-out pins arranged in the first to n-th regions are
It is characterized in that it is made of a material whose thermal conductivity gradually decreases toward the gate.

[Embodiment] Next, a preferred embodiment of the casting apparatus using the die-cast pin according to the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a die casting mold. This die-casting die 10 comprises a fixed die 12, a movable die 14 which is displaceable so as to face the fixed die 12, the fixed die 12 and a set of slidably fitted to the movable die 14. It is basically composed of sliding types 16a and 16b. In this case, the fixed mold 12, the movable mold 14, and the sliding molds 16a, 16b are opposed to each other so that the product cavity corresponding to the shape of the cylinder block.
18 are defined.

First, the fixed die 12 includes a fixed die main body 20 and a cavity die 22 attached to the fixed die main body 20 and defining a part of the product cavity 18. A hole 24 is formed in one end of the fixed mold body 20, and one end of an injection sleeve 26 is fitted into the hole 24. The injection sleeve 26 is provided with an injection plunger 28 which is slidably fitted into the injection sleeve 26 under the driving action of an actuator (not shown). Further, a hot water supply hole 30 for replenishing the molten metal is defined at a predetermined position of the injection sleeve 26.

On the other hand, the cavity mold 22 is provided with a plurality of stepped hole portions 32a, 32b so as to face the positions corresponding to the bolt holes of the cylinder block in the product cavity 18, and in this case, the stepped hole portion 32a is an injection sleeve. Runner 3 communicating with 26 hollows
4, the stepped hole portion 32b is provided at a position closest to the runner 34. Cast pins are attached to the stepped hole portions 32a and 32b. The details of this cast pin will be described later. A cylinder sleeve 35 of the cylinder head is installed at the tip of the cavity type 22 that bulges toward the product cavity 18 side.

Next, the sliding dies 16a and 16b are connected to an actuator (not shown), and are configured to be movable back and forth under the driving action of this actuator. In this case, sliding type
16a and the cavity mold 22 of the fixed mold 12 define the runner 34 that communicates a part of the product cavity 18 with the inside of the injection sleeve 26.

On the other hand, the movable die 14 includes a movable die body 36 and a cavity die 38 mounted on the movable die body 36 and defining a part of the product cavity 18. The movable main body 36 is connected to an actuator (not shown) and is displaceable. The cavity type 38 also has stepped hole portions 40a, 40b facing the product cavity 18, and these stepped hole portions 40 are formed.
Of the a and 40b, the stepped hole portion 40a is provided at a position apart from the runner 34 in the cavity mold 38, and the stepped hole portion 40b is provided.
Is provided at a position close to the runner 34.

The die casting mold is basically constructed as described above. Next, the casting method will be described in detail below.

As shown in FIG. 2, casting pins 42 and 44 mounted in stepped hole portions 32a and 32b provided in the cavity die 22 of the fixed die 12
And the stepped hole 40 formed in the cavity mold 38 of the movable mold 14.
The cast pins 46 and 48 mounted on the a and 40b are made of the materials shown in Table 1 in a predetermined shape.

That is, as can be easily understood by comparing Table 1 and FIG. 2, the cast pin 42 entering the product cavity 18 at the position farthest from the runner 34 as a spout communicating with the product cavity 18 is provided. Is a tungsten alloy, and these cast pins 42, 44, 46, 48
Set the highest thermal conductivity among the above. In this case, as the tungsten alloy, for example, Ambloy 1150 (trade name, manufactured by Mitsubishi Metals Co., Ltd.) is preferably used. In contrast to such a casting pin 42, the casting pin 44 is used for the product cavity 18
In the position closest to the runner 34, and its material is a titanium alloy (Ti-
6Al-4V) is used. Hot-work tool steel is selected as the material for the casting pins 46 and 48 arranged between the casting pins 42 and 44. In this way, the cast pins that are located farther from the runner 34 as a whole are arranged so that the thermal conductivity is higher.
It should be noted that instead of titanium alloy, sialon (thermal conductivity), which is a ceramic material that has the same thermal conductivity as titanium alloy
0.014 / cal ・ cm ・ S ・ ° C) is replaced with tungsten alloy and molybdenum alloy (heat conductivity 0.327 / cal ・ cm ・
Even if S.degree. C.) is used, substantially the same effect can be obtained.

Therefore, the molten metal is supplied from the hot water supply hole 30 formed in the injection sleeve 26, and the injection plunger 28 is displaced under the driving action of an actuator (not shown) to fill the molten metal into the product cavity 18 via the runner 34. This time,
As casting conditions, the temperature of the molten aluminum alloy is 660
℃, the pressure applied by the injection plunger 28 is 900k
It is g / cm ² .

When the molten aluminum is filled in the product cavity 18, normally, the portion of the cavity mold 22 facing the runner 34 and the sliding mold 16b are heated by the heat of the molten metal supplied in the injection plunger 26. It is in a state of being. On the other hand, the portions of the cavity molds 22 and 28 that are separated from the runner 34 and the sliding mold 16a are less susceptible to the heat of the molten metal in the injection plunger 28. Therefore, the molten metal in product cavity 18 is
The coagulation tends to proceed toward the runner 34 from a portion distant from the 34.

Therefore, in the product cavity 18, the cast pin 42 that is fitted in the part farthest from the gate is made of a tungsten alloy having good thermal conductivity, so the heat of the molten metal is taken away through the cast pin 42. The coagulation in the vicinity of this site is advanced first. Then runner at Product Cavity 18
Since the casting pins 46 and 48 fitted on the way to the 34 are made of hot work tool steel having a lower thermal conductivity than the tungsten alloy, the solidification promoting effect on the molten metal is not as great as that of the casting pin 42. Therefore, the directional coagulation is further promoted, and the second
As shown in the figure, the solidification of the molten metal in the product cavity 18 proceeds toward the runner 34 sequentially from the position farthest from the runner 34, as indicated by the arrow. For this reason, coagulation delay does not occur in a specific site, and cavities caused by this coagulation delay,
It is possible to obtain a good quality product without casting defects such as cracking. Since the cast pin 44 made of titanium alloy made of the material having the lowest thermal conductivity does not rapidly take the retained heat from the molten metal, it does not deteriorate the hot running property in the vicinity of the portion closest to the runner 34. , The molten metal in this part eventually solidifies.

By the way, as a result of continuously operating the die casting mold 10 under the above casting conditions to cast a cylinder block, the casting pins 42, 44, 46 and 48 can withstand 20,000 shots of continuous casting. It has been found. On the other hand, under the same casting conditions, all of the die-cast pins were SKD61 made of hot work tool steel.
Manufactured with these casting pins and continuously using 10,000
The results of the durable life of the die-cast pin at this time are shown in Table 2.

Thus, for example, when the cast pin made of hot work tool steel was arranged near the runner 34, it could withstand only 2000 shots.

From the above, conversely, by changing the material of the casting pin in the product cavity 18, respectively, to proceed the directional solidification toward the runner 34 in a well-balanced manner as in the present embodiment,
It is empirically clear that even the same hot work tool steel casting pin can withstand 20,000 casting cycles depending on its location.

[Effects of the Invention] As described above, according to the present invention, each of the casting pins is made of a material having a different thermal conductivity, and the casting pin having a high thermal conductivity so as to direct the solidification direction of the molten metal in a certain direction. Is placed at a position away from the sprue, and a casting pin having low thermal conductivity is placed close to the sprue. The effect of removing the retained heat of the molten metal is different due to the difference in the thermal conductivity of the die-cast pin, which promotes the directional solidification of the molten metal, thus preventing casting defects caused by delays in solidification and other high quality castings. It is also possible to obtain the effect of improving the durability of the cast pin.

Although the present invention has been described with reference to the preferred embodiment, the present invention is not limited to this embodiment,
It goes without saying that various improvements and design changes can be made without departing from the scope of the present invention.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a die casting mold, and FIG. 2 is a partially omitted vertical cross-sectional view when a die casting mold shown in FIG. 10 …… Casting mold, 12 …… Fixed type 14 …… Movable type, 16a, 16b …… Sliding type 18 …… Product cavity, 20 …… Fixed type body 22 …… Cavity type, 26 …… Injection sleeve 28 …… Injection plunger, 30 …… Hot water supply hole 32a, 32b …… Stepped hole, 34 …… Runner 35 …… Cylinder sleeve, 36 …… Movable body 38 …… Cavity type, 40a, 40b …… Stepped holes 42, 44, 46, 48 ... Cast pin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-30068 (JP, A) Actual development: S62-127353 (JP, U) JP-B-45-36674 (JP, B1) JP-B51- 41087 (JP, B2) JP-B-55-41298 (JP, B2)

Claims (2)

[Claims] 1. A casting product is obtained by arranging casting pins in a plurality of casting holes communicating with a cavity defined in a mold, and filling a molten metal injected from a spout into the cavity under pressure. In the obtained casting device, the plurality of casting pins are the casting pins arranged in a first region distant from the gate, and the second, ..., Nth regions sequentially approaching the gate from the first region. And the casting pin arranged in each of the first to n-th regions,
A casting apparatus using a casting pin, which is made of a material whose thermal conductivity gradually decreases toward the gate. 2. The apparatus according to claim 1, wherein the plurality of casting pins are casting pins arranged in the first to third regions, and the material of the casting pins arranged in the first region. Is a tungsten alloy, the material of the die-casting pin arranged in the second region is hot work tool steel, and the material of the die-casting pin arranged in the third region is titanium alloy. A casting device using a cast pin.