JPH06142866A - Centrifugal casting method - Google Patents

Abstract

PURPOSE:To prevent the generation of chill part and penetration of molten metal at the tip part of a tube in the front part side of the molten metal without directly abutting the molten metal on a metal-made band by arranging a heat resistant sheet in the inner surface of the band at the front part side of the molten metal. CONSTITUTION:The band 2 at the casting side A of the metallic mold 1 for centrifugal casting for manufacturing the straight tube and the inner surface of the metallic mold 1 are formed by a mold coating 14. On the other hand, in the inner surface of the band 3 at the front part side B of the molten metal, the heat resistant sheet 15 composed of flexible mix fiber laminated body is arranged with organic or inorganic adhesive material. Then, even if the molten metal flowing to the front part side B from the casting side A is abutted on the heat resistant sheet 15 arranged to the inner surface of the band 3 in the front part side B, as the sheet 15 is not detached, the molten metal is directly abutted on the metal-made band 3 and the chill part and the penetration of the molten metal are not generated at the tip part of the tube in the front part side B. Further, as the tip part of the tube can be cooled at the speed similar in the cooling speed at the time of forming the mold coating 14, even in the case of casting the tube with a flange, as the flange part is not slowly cooled, on crack on the base part is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal casting method for cylindrical bodies such as straight pipes and flanged pipes.

[0002]

2. Description of the Related Art As is well known, a centrifugal casting method is known as a method for casting a tubular body such as a straight pipe or a flanged pipe. In the centrifugal casting method, as shown in FIG. 3, metal casting bands 2 and 3 are attached to the openings of both ends of a centrifugal casting mold 1 and rotatably supported on a rotating roller 4. Then, the molten metal 5 is cast from the opening of the band 2 on the casting side A, and the molten metal 5 is poured into the mold 1.
It is a method in which a cylindrical body is obtained by adhering to the inner peripheral surface of the above by the action of centrifugal force and solidifying it. A coating mold is formed on the inner surfaces of the centrifugal force casting mold 1 and the bands 2 and 3 to prevent the seizure of the molten metal.

[0003]

However, at the time of pouring the molten metal, the molten metal cast in the mold 1 flows vigorously from the pouring side A to the pouring side B, and the pouring side B. Hit the inner surface of band 3 of. For this reason, the coating mold formed on the inner surface of the band 3 on the tip side B is peeled off, the chill enters the end portion on the tip side of the casting pipe, and the scale is formed on the outer peripheral edge of the pipe end. FIG. 4 shows a cross section of the tip end side of the straight pipe 7, and FIG. 5 shows a cross section of the same end of the flanged pipe 8, where 9 is a chilled portion and 10 is a scale.

In casting the flanged pipe, it was attempted to attach a sand-shaped core to the inner surface of the band in order to prevent chills or graduations from being formed on the flange 11. Although the casting defect was prevented, since the flange portion 11 was gradually cooled with respect to the straight pipe portion 12, the flange portion
A crack occurred at the root of 11. The present invention has been made in view of the above problems, and an object of the present invention is to provide a centrifugal casting method that does not cause chilling or grading at the end of the front pipe.

[0005]

According to the centrifugal casting method of the present invention, a mold for centrifugal force casting having a band for preventing molten metal attached to both end openings is rotated, and molten metal is cast from the opening of the band. In the centrifugal casting method, a heat resistant sheet is attached to the inner surface of the band on the tip side.

[0006]

[Function] The heat resistant sheet attached to the inner surface of the band on the tip side is less likely to peel off than the coating type, and does not have high heat insulation like the sand type, so it flows from the casting side to the tip side. Even when the molten metal hits the heat-resistant sheet attached to the inner surface of the band on the tip side, the molten metal is not peeled off, and it can be cooled at a speed close to the cooling speed at the time of forming the coating mold.

[0007]

EXAMPLE FIG. 1 shows a centrifugal force casting mold 1 for manufacturing a straight pipe for carrying out the present invention. The band 2 on the casting side A and the inner surface of the mold 1 are the same as those in the conventional case. , A coating mold 14 is formed. The coating mold 14 is usually formed to have a thickness of about 0.5 to 0.9 mm by spray coating a slurry composed of a heat resistant base material, bentonite and water.

On the other hand, a heat resistant sheet 15 is attached to the inner surface of the band 3 on the tip side B by an organic or inorganic adhesive material. As the heat-resistant sheet 15, a ceramic fiber laminate having a thickness of about 2 to 4 mm is preferable because it is excellent in flexibility and heat resistance. Various ceramic fiber laminates are commercially available as substitutes for asbestos sheets (for example, trade name: Fineflex, manufactured by Nichias) and are easily available.

FIG. 2 shows a centrifugal casting mold 1A for manufacturing a flanged pipe, which is the same as FIG. 1 except that a flange casting cavity 17 is formed at the end on the tip side. is there. Using the centrifugal force casting mold of FIG. 2, an inner diameter of 100 mm,
15mm thick pipe with flange for transporting chemicals (material: 0.5
Chromium cast iron of 1.0% Cr) was centrifugally cast. A 3 mm ceramic fiber laminate was used as the heat resistant sheet. Casting temperature is 1400 ° C, mold rotation speed is G No. 10
It is 0. Although chrome cast iron is a material that easily contains chill, there was no chill or grading in the cast pipe.

[0010]

As described above, according to the centrifugal casting method of the present invention, since the heat resistant sheet is attached to the inner surface of the band on the tip side, the molten metal flowing from the casting side to the tip side is the tip. Even if you hit the heat resistant sheet attached to the inner surface of the side band,
Since the sheet is not peeled off, the molten metal does not directly hit the metal band, and chilling or grading does not occur at the tip of the front end side pipe. In addition, since the pipe end can be cooled at a rate similar to the cooling rate at the time of forming the mold, even when casting a pipe with a flange, the flange is not gradually cooled, so cracks may occur at the root of the flange. There is no.

[Brief description of drawings]

FIG. 1 is a sectional view of a centrifugal force casting mold for producing a straight pipe according to an embodiment.

FIG. 2 is a sectional view of an essential part of a centrifugal force casting mold for manufacturing a flanged pipe according to another embodiment.

FIG. 3 is an overall explanatory view of a centrifugal casting device.

FIG. 4 is a cross-sectional view of a tip end side pipe end portion of a conventional straight pipe.

FIG. 5 is a cross-sectional view of a tip end side flange pipe end of a conventional flanged pipe.

[Explanation of symbols]

 1,1A Mold for centrifugal force casting 2 Band 14 Coating type 15 Heat resistant sheet

Claims (1)

[Claims] 1. A centrifugal casting method in which a casting mold for centrifugal force, in which a band for preventing melt is attached to both end openings, is rotated to cast molten metal from the openings of the band, the inner surface of the band on the tip side is A centrifugal casting method characterized in that a heat resistant sheet is attached.