JPH01306062A - Pin for hole as cast for casting - Google Patents

Abstract

PURPOSE:To improve the durability without exposing to extreme temp. change by coaxially engaging inner member composing of metal having high heat conductivity with outer member composing of heat resistant ferrous material and constituting them with integrated construction. CONSTITUTION:A pin 32 for hole as cast is constituted as coaxial double construction composing of the inner member 34 and the outer member 36, which are formed with different material, respectively. The inner member 32 is selected from alloy having good heat conductivity, such as copper alloy, and at the time of fitting the pin 32 for hole as cast in the upper die 14, the end part 37 thereof abuts on a cooling block 28 in wide area. Further, the outer member 36 fitted to outside of the inner member 34 is selected from the ferrous material having durability, such as cast iron, and a long hole 39 is demarcated along axial center and the pin part 38 of the inner member 34 is fitted to coaxially integrate both members. Therefore, the end part 37 of the inner member 34 is fitted to the cooling block 28 directly cooled with cooling water and as the inner member 34 is good heat conductive material, it is efficiently cooled. By this method, the outer member 36 also is indirectly cooled and the development of burning between molten metal and the outer member can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cast pin used in metal mold casting, and more particularly, to a pin that is coaxially formed into an inner and an outer pin using members made of different materials. The cast-out pin is constructed in a heavy structure, and in particular, the internal member is made of a material with high thermal conductivity such as a copper alloy, and the external member that directly contacts the molten metal is indirectly cooled through the internal member. This invention relates to a cast-out pin for casting, which allows a suitable cooling effect to be obtained without using a cooling medium and improves durability by alleviating the heat received from the molten metal. .

[Background of the Invention] In casting using a metal mold, such as the Kodie casting method and the low-pressure casting method, a cast pin is usually used to reduce the weight of the cast product or to form bolt holes.

Conventionally, cast pins were made of alloy steel, hot work tool steel (JIS
5KD61) was used as the material, and was manufactured by subjecting it to heat treatments such as quenching and tempering in order to further improve its heat resistance. This is because the casting pin is immersed in the high-temperature molten metal in the mold and is therefore directly exposed to the high heat of the molten metal.

In order to cope with the heat of the molten metal, a passage is formed in the core pin to allow a cooling medium such as cooling water to pass therethrough, and the water flowing through this passage directly cools the core pin. However, especially in the case of small-diameter cast pins, it is difficult to process them to form internal passages, so it is not possible to pass sufficient cooling water, resulting in seizing of the cast pins when they are cast. This shortcoming has been pointed out.

In addition, in order to flow cooling water into the passage inside the cast-out bottle,
Leakage prevention members such as 01J rings and packing must be installed at the joints with the cooling water passages provided in the mold. However, since the temperature of the mold rises to a considerable degree, these zero
Rings etc. deteriorate and are easily damaged. As a result, cooling water may leak into the mold or into the molten metal holding furnace provided below the mold. In particular, if the molten metal holding furnace is exposed to water and left unattended, the temperature of the molten metal holding furnace may drop, which can lead to a situation where it becomes impossible to proceed with subsequent casting cycles. be.

Furthermore, in this type of method where the cast pin is directly cooled by water, the temperature changes drastically between heating with the molten metal and cooling with the cooling water, and repeating this process exposes the cast pin to constant thermal shock. It turns out. Therefore, the cast pin cannot withstand long-term use, and problems have been pointed out from the viewpoint of durability.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and the present invention has been made by attaching a cast pin to an internal member made of a copper alloy material with high thermal conductivity, and to this internal member, for example, by sintering. It consists of an external member that is integrated by fitting, press-fitting, etc., and the cast pin can be attached to a cooling block, etc. through which a cooling medium flows, and the cooling effect of the cooling water is transferred to an internal member with good heat conduction. By transmitting the water to external parts that come into direct contact with the molten metal through the cooling water, the inconveniences that would occur when using direct cooling water are avoided, and in addition, in order to reduce thermal shock, the cooling water is not exposed to extreme temperature changes and durability is maintained. It is an object of the present invention to provide a cast-out pin for casting that enables improved performance.

[Means for achieving the object] In order to achieve the above object, the present invention includes a pin-shaped internal member made of a highly thermally conductive metal and a heat-resistant iron-based material surrounding the internal member. It is characterized in that it is configured to be coaxially combined with an external member to form an integral structure.

Furthermore, the present invention is configured such that a flange portion is formed at the tail end of the internal member to engage the cooling member that is directly cooled by cooling water, so that the cooling effect of the cooling member is transmitted to the internal member. It is characterized by

Furthermore, the present invention is characterized in that the external member is integrated with the internal member by shrink fitting or press fitting, or the external member is cast into the internal member.

[Embodiments] Next, preferred embodiments of the casting pin according to the present invention will be listed, and will be described in detail below with reference to the attached drawings in relation to the casting mold in which this casting pin is used. explain.

In FIG. 1, reference numeral 10 indicates a casting mold into which a cast pin according to the present invention is installed. This casting mold 10
is a lower mold 12, an upper mold 14 located above the lower mold 12,
It is composed of a sliding mold 16 that is displaceably fitted to the lower mold 12 and the upper mold 14.

In this case, the sliding molds 16 are configured as a pair of left and right parts, one of which is shown in FIG. A cavity I8 is defined by the opposing surfaces of the lower mold 12, upper mold 14, and sliding mold 16.

Therefore, a sprue (not shown) is provided in the lower mold 12 on the right end side of the page, and the molten metal in the holding furnace installed below the casting mold 10 is poured from this sprue into a predetermined area through a stalk or the like using the low-pressure casting method. The cavity 18 is filled with a pressure of . In addition, a plurality of passages 20 are formed in the lower mold 12, through which cooling water circulates to cool the lower mold 12.

Next, the sliding mold 16 is connected to an actuator (not shown) via a connecting member 22, and is configured to be able to move forward and backward under the driving action of an actuator such as a cylinder. Similar to the lower mold 12, this sliding mold 16 also has a plurality of passages 24 through which cooling water is circulated.

On the other hand, the upper die 14 is integrally attached to a movable die base 26, which is configured to be movable up and down by a drive means such as a cylinder (not shown), with a cooling block 28 in between. Therefore, the upper die 1 is integrated with the movable die base 26.
4 is freely displaceable in the vertical direction. A plurality of passages 30 are formed in the cooling block 28, and these passages 30
Similar to the lower mold 12 and the sliding mold 16, cooling water flows through the mold.

A stepped hole 31 is bored in a predetermined portion of the upper mold 14, and the casting pin 32 according to the present invention is inserted through the stepped hole 31 of the upper mold 14 so that its tip faces the cavity 18. Moreover, its tail end is engaged with and held by the cooling block 28.

FIG. 2 shows details of the cast pin 32. The cast-out pins 32 have internal members 34 each formed from a different material.
and an external member 36 as a coaxial double structure. In this case, the material for the internal member 34 is selected from an alloy with good thermal conductivity, such as a copper alloy.

The internal member 34 is composed of a flange-shaped tail end 37 and a bottle part 38, and when the casting pin 32 is attached to the upper mold 14, the tail end 37 is attached to the cooling block 28 over a large area. It comes into contact with the

On the other hand, for the external member 36 that fits externally into the internal member 34, a heat-resistant iron-based material such as cast iron, cast steel, or steel is selected as the material, and in this embodiment, die steel is used as the material. It is used for

A long hole 39 corresponding to the shape of the pin portion 38 of the internal member 34 is defined along the axis of the external member 36, and by fitting the pin portion 38 of the internal member 34 into the long hole 39, both are coaxially integrated. In particular, the diameter of the elongated hole 39 is set smaller than the outer diameter of the pin portion 38 of the internal member 34, in other words, a press-fitting allowance is provided and the parts are integrated by burning out or press-fitting.

On the other hand, the tail end 40 of the outer member 34 is formed in the form of a flange to prevent it from being pulled out. In addition, in order to provide some clearance between the external member 36 and the stepped hole 31 formed in the upper mold 14, a stepped part 41 is formed on the outer periphery of the external member 36, and the cast pin 32 is A gap is defined to receive the thermal expansion.

In addition, when the material of the external member 36 is cast iron or cast steel, it may be formed by casting.

On the other hand, when the casting pin 32 is actually attached to the upper mold 14, the tip end 42 of the external member 36 is located in the cavity 1.
8 for a predetermined length, and this tip 42 forms a bolt hole in the cast product solidified in the cavity 18. In addition, in FIG. 1, reference numeral 44
indicates the core that forms the hollow part of the casting.

The cast pin for casting according to the present invention is basically constructed as described above, and its functions and effects will be explained next.

In FIG. 1, a molten metal made of aluminum alloy is poured into a cavity 18 in a casting mold 10 by a low-pressure casting method.
Pressurize and fill. In this case, the cast pin 32 is attached to the upper die 14 in advance.

When the cavity 18 is filled with molten metal, the cast-out pin 32
The tip is immersed in the molten metal. Therefore, after a predetermined period of time has elapsed, the cooling block 2 attached to the back of the upper mold 14 is
Cooling water is made to flow through the passage 30 of No.8. Note that cooling water is also allowed to flow through the passage 20 of the lower mold 12 and the passage 24 of the sliding mold 16 according to the casting conditions.

Therefore, as shown in FIG. 2, the cooling block 28 is directly cooled by the cooling water flowing in the passage 30, and the cooling effect is applied to the molten metal in the cavity 18 via the upper mold 14, and the molten metal is transferred to the upper mold 14. It is indirectly cooled through the The cooling effect of the cooling block 28 is then transmitted to the internal member 34 that constitutes the cast pin 32.

That is, since the tail end 37 of the internal member 34 is attached to the cooling block 28 which is directly cooled by the cooling water flowing through the passage 30, the internal member 34 is made of a copper alloy having extremely good thermal conductivity. Due to the selected material of the system, the cooling effect is transmitted to the internal member 34 very efficiently. As a result, the outer member 36 that fits into the inner member 34 is indirectly cooled. Therefore, the tip R42 of the external member 36 that comes into direct contact with the molten metal is
As mentioned above, since it is indirectly cooled, the occurrence of seizure between the metal and the molten metal is suitably prevented.

In addition, the temperature of the cast pin 32 is raised to a considerable level by the heat of the molten metal, but the cooling effect is not directly cooled by introducing cooling water, but is performed via a cooling block through an internal member 34 made of a copper alloy. Since the cooling effect of the pin 28 is transmitted indirectly, the temperature of the cast pin 32 does not drop suddenly. Therefore, as a result of the temperature change of the cast pin 32 in one casting cycle being not so rapid,
It becomes possible to alleviate the thermal shock acting on the cast pin 32 to a considerable extent.

In this way, the mold is opened after the molten metal solidifies and the casting cycle is completed, but when the same casting cycle is repeated, deterioration of the mechanical properties such as the strength of the cast pin 32 due to thermal shock is prevented. It is understood that it is possible to improve the durability.

[Effects of the Invention] As described above, according to the present invention, the cast pin is made of an internal member made of a copper alloy material with good thermal conductivity and an external member made of a heat-resistant steel material etc. that comes into direct contact with the molten metal. It consists of. In order to cool the cast-out pin, the cooling effect of the cooling block to which the cast-out pin is attached is indirectly transmitted through the internal member without using cooling water, so it is not possible to cool the cast-out pin as in the prior art. No inconveniences such as water leakage occur,
It becomes possible to carry out good casting work without burning the cast pin.

In addition, the fact that direct forced cooling with cooling water is not performed means that the temperature change in the cast pin is not sudden, making it possible to alleviate thermal shock and significantly improving its durability. This has the effect that the degree of improvement can be improved.

Although the present invention has been described above with reference to preferred embodiments, the present invention is not limited to these embodiments.
Of course, various improvements and changes in design are possible without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted sectional view of a casting mold to which a cast pin according to the present invention is applied, and FIG. 2 is an enlarged sectional view illustrating the configuration of the cast pin in FIG. 1. 10... Casting mold 12... Lower mold 14.
...Upper mold 16...Sliding mold 18...
Cavity 28...Cooling block 30...
・Passage 31...Stepped hole portion 32...
Casting pin 34... Internal member 36... External member 37... Tail end portion 38... Bin portion 39... Long hole FIG, 1 FIG, 2

Claims (3)

[Claims] (1) A pin-shaped internal member made of a highly thermally conductive metal and an external member made of a heat-resistant iron-based material surrounding the internal member are coaxially combined to form an integral structure. Features a cast-out pin for casting. (2) In the cast pin according to claim 1, the tail end of the internal member is formed with a flange portion for engaging a cooling member that is directly cooled by cooling water, so that the cooling effect of the cooling member is A cast-out pin for casting, characterized in that it is configured to be transmitted to a member. (3) The cast pin according to claim 1, characterized in that the external member is integrated with the internal member by shrink fitting or press fitting, or the external member is cast around the internal member. pin.