JPH0631420A - Metallic mold for centrifugal casting - Google Patents

Abstract

PURPOSE:To reduce the entrapment of impurities and the development of shrinkage cavity in a casting produced by solidifying molten metal. CONSTITUTION:In a metallic mold for centrifugal casting in which molten metal Y is fed into an inner space part R in the metallic mold body 5 from the end opening part 6a in the axial P direction of the metallic mold body 5 while rotating the cylindrical metallic mold body 5 around the axis P, fins 7 for pushing the outer air into the inner space part R from the opening 6a of the metallic mold body 5 accompanying the rotation around the axis P of the metallic mold body 5 is arranged at the opening end part of the metallic mold body 5.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Regarding molds used in centrifugal casting,
Specifically, a cylindrical mold body is provided, and in a state where the mold body is rotated about its axis, an inner space of the mold body is opened from an end opening of the mold body in the axial direction. The present invention relates to a centrifugal casting mold for casting molten metal into a casting.

[0002]

2. Description of the Related Art Conventionally, this type of centrifugal casting mold has a cylindrical mold body with lids provided with openings for pouring molten metal at both ends thereof for rotating about a horizontal axis. There is a structure in which a rotary driving force is received from a roller that is in contact with the outer peripheral surface of the mold body to rotate around the mold axis.

[0003]

In the centrifugal casting method, the molten metal is cast into the rotating mold as described above, and the centrifugal force acting on the molten metal causes the light impurities floating in the molten metal to move to the inner peripheral side. It is floated and collected, and the molten metal is pressed against the die on the outer peripheral surface side to solidify it, so the casting itself is dense and has few defects, so it was cast into the die. It is preferable that the solidification of the molten metal starts from the outer peripheral portion and finally the inner peripheral portion where the impurities are accumulated solidifies.

However, in the conventional centrifugal casting mold, the heat of the cast molten metal is radiated to the mold and also to the air on the inner peripheral side. Since the air on the side of the peripheral portion can freely flow out of the mold, the molten metal is cooled by the air, and there is a risk that the molten metal solidifies from both the inner and outer circumferences.

If both peripheral surfaces of the molten metal solidify first, there will be no portion left inside to absorb the solidification shrinkage of the molten metal, and as a result, there will be cavities (hereinafter referred to as "shrinkage cavities") inside the casting. There is a problem that impurities formed in the molten metal are hindered from floating toward the inner peripheral surface of the molten metal and solidified in the molten metal as it is, leading to deterioration of cast material.

In order to solve this problem, the opening of the mold is closed after casting the molten metal so as to be in a state of being shielded from the outside air so as to reduce the heat radiation from the molten metal in the inner space, or the cast molten metal. A method is considered in which a flux is added to the inner peripheral surface to form a heat insulating layer on the inner peripheral surface.

However, it is difficult for the former method to be realized without stopping the rotation of the mold under the high temperature condition after casting the molten metal, and for the latter method, the flux itself is mixed in the molten metal. As a result, there is a risk that the quality of the casting will be deteriorated.

Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a die for centrifugal casting in which impurities are less likely to be mixed in the casting and shrinkage cavities are less likely to occur.

[0009]

To achieve the above object, the centrifugal casting mold of the present invention has a characteristic structure in which the cylindrical mold main body is rotated about its axis, and In a centrifugal casting mold for casting molten metal from the end opening in the axial direction of the mold body to the inner space of the mold body, with rotation of the mold body around the axis. A fin for external air pressure for pushing the outside air from the opening of the mold body to the inner space is provided at the opening end of the mold body.

[0010]

According to the mold for centrifugal casting of the present invention, the outside air is pushed into the inner space from the opening of the mold body as the mold body rotates about the axis, and the air in the inner space is blown. Since an external air pressure input fin that makes it difficult to escape (hereinafter referred to as "inside air") is provided at the opening end of the mold main body, the external pressure input fin can be rotated by rotating the mold main body around the axis. The fins also rotate around the axis, which makes it possible to seal the inside air in the inner space and prevent it from escaping to the outside.

As described above, by forming a state in which the inside air does not easily escape to the outside, the molten metal poured into the inner space is kept warm by the inside air and heat release to the inner peripheral surface side is suppressed. Since it is possible to solidify in the state,
The outer peripheral portion of the molten metal having a large heat release amount solidifies first, and the solidified region gradually expands to the inner peripheral surface side.

Therefore, since light impurities floating in the molten metal can be tolerated without significantly hindering the floating to the inner peripheral surface side of the molten metal, the casting is made in a state where the impurities are collected on the inner peripheral surface side of the molten metal. Can be formed and can be solidified without leaving the strain due to solidification shrinkage of the molten metal inside the casting, so it is possible to prevent impurities from entering into the casting and the occurrence of shrinkage cavities. Becomes

That is, the molten metal can be solidified without shrinkage cavities or inclusion of impurities in the cast molten metal without using flux or the like as in the conventional case. It is possible to improve the quality of the cast article produced by solidification of the molten metal, and since it is possible to omit the flux itself and the time and effort required to put it in, it is possible to improve both economic efficiency and work efficiency.

[0014]

As described above, according to the centrifugal casting mold of the present invention, it is possible to prevent impurities from being mixed in the casting and to reduce the occurrence of shrinkage cavities without extra labor, and the centrifugal casting method is used. It is possible to improve the casting quality and the economical efficiency, and also improve the working efficiency.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a state in which the centrifugal casting mold 1 of the present invention is installed on the support roller 2. The support rollers 2 are individually abutted against the abutting portions 3 formed of a large diameter portion provided on the outer peripheral portion of the die 1, so that the die 1 can be rotatably supported around its axis P. A plurality of molds are provided below the mold 1 so as to face each other.

A part of the support roller 2 is operably connected to the rotation driving device 4, and the rotation driving force of the rotation driving device 4 is transmitted from the contact portion 3 to the mold 1. , The mold 1 can be rotated around the axis P.

Further, the support roller 2 is formed in a cylindrical shape and is rotatable about a rotation axis, and its shape is such that one end of the rotation shaft is a collar shape, and the collar portion is the support roller 2.
The displacement of the mold 1 in the axial center P direction is prevented by contacting the side surface of the contact portion 3 of the mold 1 placed on the top.

Next, the mold 1 of the embodiment will be described. As shown in FIG. 1, a cylindrical mold body 5 is provided, and a pair of the ring-shaped abutting portions are provided on the outer periphery of the mold body 5. 3 are provided at intervals in the direction of the axis P, and at both ends of the mold body 5,
The lid member 6 formed in an annular shape is fixed to the inner fitting state.

The lid member 6 is formed in a ring shape as described above, and through the opening 6a at the center of the ring,
When the molten metal Y is cast into the inner space R of the rotating mold body 5, the molten metal Y that spreads along the inner peripheral surface of the mold body 5 due to centrifugal force moves outward from the end of the mold body 5. It has a function to prevent leakage.

The lid member 6 has the mold body 5
The external air pressure introducing fins 7 for pushing the outside air into the inner space R of the mold body 5 in accordance with the rotation around the axis P are provided in a state of protruding to the opening 6a. The external air pressure introducing fin 7 is formed of a plurality of blades 7a. Since the blades 7a are provided in an inclined posture around the axis P, the fins 7a around the axis P of the mold body 5 are provided. With the rotation, the external air pressure can be introduced into the inner space R.

The mold 1 is made of heat resistant cast iron or heat resistant steel.

According to the mold 1 of this embodiment, after the mold 8 is applied to the inner peripheral surfaces of the mold body 5 and the lid member 6, the mold 1 is rotated around the axis P, By pouring the molten metal Y from the end opening 6a into the inner space R, the molten metal Y spreads along the inner peripheral surface of the coating mold 8 and the external pressure introducing fins 7 rotating around the axis P are used to Since the outside air is press-fitted into the inner space R through the opening 6a and casting can be performed in a state where the heat retaining / pressurizing state of the inner space R is maintained, the molten metal Y contacts the coating mold 8. It is possible to start solidification from the above and gradually expand the solidification region to the inner space R side to solidify, so that a casting of good quality can be produced.

[Other Embodiments] <1> The external air pressure introducing fins 7 are not limited to those fixed to the lid member 6 described in the previous embodiment. For example, the mold body 5 may be used. May be provided in the mold 1 or may be provided separately, and in short, the outside air may be provided so as to be press-fitted into the inner hollow portion R of the mold 1. Therefore, the blade body 7a that constitutes the external pressure introducing fin 7
Also, the shape and quantity of the above are not limited to those in the previous embodiment.

<2> The mold 1 has openings 6a provided at both ends as described in the previous embodiment, one end side is closed, and the opening 6a is provided only at the other end side. There may be, and in that case, the external air pressure introducing fin 7 may be provided on the other end side.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a centrifugal casting mold of an example.

FIG. 2 is a perspective view showing an installation state of a centrifugal casting mold according to an embodiment.

[Explanation of symbols]

 5 Mold main body 6a Opening 7 External pressure inlet fin P Shaft center R Inner cavity Y Molten metal

Claims (1)

[Claims] 1. A cylindrical mold body (5) is provided, and the mold body (5) is rotated about its axis (P),
For casting the molten metal (Y) from the end opening (6a) in the axial center (P) direction of the mold body (5) to the inner space (R) of the mold body (5). A mold for centrifugal casting, wherein the mold body (5) is rotated around the axis (P) from the opening (6a) of the mold body (5) to the inner space (R). A die for centrifugal casting, wherein an external air pressure introducing fin (7) for pushing the outside air into the die is provided at the open end of the die body (5).