Device for centrifugal casting of special-shaped cast pipe and casting method

Abstract

The invention belongs to the technical field of metal casting, and particularly relates to a device for centrifugal casting of a special-shaped cast pipe and a casting method.The device comprises an outer pipe, end covers located at the two ends of the outer pipe and a mold arranged in the outer pipe, the mold comprises a mold cylinder, and spring wedge blocks are distributed in the circumferential direction of the inner wall of the mold cylinder at the positions, with creases, of the inner wall of the mold cylinder. In the centrifugal process after casting, due to the influence of thermal expansion and cold contraction, the cast pipe can contract towards the axial center of the cast pipe and can be stressed to deform and even break at the edge fold part, the spring wedge block is arranged on the inner wall of the die barrel to move in a certain small range distance, the force enabling the edge fold part to deform and even break due to stress is absorbed, and the casting effect is improved. The stress condition of the edge fold part is improved, the complete special-shaped cast pipe is prepared, cracks are reduced, and the cast pipe is prevented from being broken.

Description

Technical Field

[0001] The invention relates to the technical field of metal casting, in particular to a device and a casting method for centrifugal casting of special-shaped cast pipes. Background Art

[0002] Centrifugal casting is a casting method that uses centrifugal force. Its main principle is to pour molten metal into a rotating mold, and use centrifugal force to move the molten metal along the mold wall to form the desired casting. Centrifugal casting technology usually includes the following aspects: Mold design: Use appropriate materials to make rotating molds. The shape and material of the mold directly affect the quality and production efficiency of the cast pipe; the inner wall of the mold can be designed to be smooth or have a specific texture to affect the structure and performance of the cast pipe. Metal smelting: Select a suitable metal alloy and melt it in a high-temperature furnace; commonly used materials include cast iron, cast aluminum, copper, etc. The temperature and chemical composition need to be controlled during the smelting process to ensure the quality of the casting. Centrifugal casting equipment: The equipment is mainly used to generate rotary motion. It can be divided into horizontal centrifugal casting and vertical centrifugal casting. The specific choice depends on the specifications and application requirements of the cast pipe. Casting process: Including the pouring speed of molten metal, the rotation speed, the cooling method, etc., reasonable process parameters can effectively improve the organizational structure and mechanical properties of the cast pipe. Post-processing technology: After casting, the cast pipe may need to undergo post-processing processes such as heat treatment, machining, and surface treatment to improve its performance and durability. Quality Control: Strict quality inspection is required throughout the entire process, including appearance inspection, dimensional measurement, physical property testing, etc., to ensure that the cast pipe meets the design requirements and usage standards.

[0003] The advantages of centrifugal casting pipe technology include: ① There is almost no metal consumption in the pouring system and riser system, which improves the process yield; ② No core is required when producing hollow castings, so the metal filling capacity can be greatly improved when producing long tubular castings, reducing the ratio of casting wall thickness to length or diameter, and simplifying the production process of sleeve and pipe castings; ③ The casting has high density, few defects such as pores and slag inclusions, and high mechanical properties; ④ It is easy to manufacture composite metal castings such as tubes and sleeves, such as steel-backed copper sleeves, bimetallic rollers, etc.; when forming castings, the centrifugal motion can be used to improve the metal filling capacity, so thin-walled castings can be produced.

[0004] The disadvantages of centrifugal casting technology include: ① There are certain limitations when used to produce special-shaped castings; ② The inner hole diameter of the casting is inaccurate, the inner hole surface is relatively rough, the quality is poor, and the processing allowance is large; ③ The casting is prone to specific gravity segregation, so it is not suitable for castings where alloys are prone to specific gravity segregation (such as lead bronze), especially not suitable for casting alloys where the specific gravity of impurities is greater than that of the molten metal.

[0005] At present, centrifugal casting technology has reached a mature stage, but for some special-shaped casting pipes (such as Figure 1There are still major problems in centrifugal casting (as shown in the figure): for example, during the centrifugal process, the rapid cooling of the molten metal causes thermal expansion and contraction, which may lead to cracks and even breakage of the casting. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the main purpose of the present invention is to provide a device and a casting method for centrifugal casting of special-shaped cast pipes.

[0007] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0008] A device for centrifugal casting of special-shaped cast pipes comprises an outer pipe, end covers at both ends of the outer pipe, and a mold arranged in the outer pipe. The mold comprises a mold barrel, and spring wedges are arranged along the circumference of the inner wall of the mold barrel at the part with ridges.

[0009] As a preferred solution of the device for centrifugal casting of special-shaped cast pipes described in the present invention, the outer tube and the mold barrel of the mold are connected and fixed by a connecting piece.

[0010] As a preferred solution of the device for centrifugal casting of special-shaped cast pipes described in the present invention, the spring wedge is fixed to the inside of the mold barrel and is integrated with the mold.

[0011] As a preferred embodiment of the device for centrifugal casting of special-shaped cast pipes described in the present invention, the spring wedge is composed of a spring and a wedge, and the two ends of the wedge are respectively marked as a large end and a small end, and the small end is connected to the inner wall of the mold barrel through a spring.

[0012] As a preferred solution of the device for centrifugal casting of special-shaped cast pipes described in the present invention, the large end of each wedge block is farther away from the axial center of the cast pipe than the small end.

[0013] As a preferred embodiment of the device for centrifugal casting of special-shaped cast pipes described in the present invention, a pouring port is provided on at least one end cover.

[0014] To solve the above technical problem, according to another aspect of the present invention, the present invention provides the following technical solution:

[0015] A method for centrifugal casting of a special-shaped cast pipe, using the above-mentioned device for centrifugal casting of a special-shaped cast pipe, comprises the following steps:

[0016] S1. After pouring the molten metal into the mold cavity, the cavity is sealed;

[0017] S2. The mold is rotated by external force, and centrifugal casting is achieved with the help of centrifugal force.

[0018] As a preferred embodiment of the centrifugal casting method for a special-shaped cast pipe described in the present invention, in the step S1, different molds are replaced according to the structure of the special-shaped cast pipe.

[0019] As a preferred embodiment of the method for centrifugal casting of a special-shaped cast pipe described in the present invention, in which: in the step S2, during the centrifugal process after casting, the cast pipe will shrink toward the axial center of the cast pipe due to thermal expansion and contraction, and will be deformed or even broken at the ridges and folds. The spring of the spring wedge block arranged on the inner wall of the mold barrel is used to realize the movement of the spring wedge block within a certain small range, thereby absorbing the force that causes the ridges and folds to be deformed or even broken.

[0020] The beneficial effects of the present invention are as follows:

[0021] The present invention provides a device and a casting method for centrifugal casting of a special-shaped cast pipe, the device comprising an outer pipe, end caps at both ends of the outer pipe, and a mold arranged in the outer pipe, the mold comprising a mold barrel, and spring wedges are arranged along the circumference of the inner wall at a portion of the inner wall of the mold barrel having ridges. During the centrifugal casting process, the cast pipe will shrink toward the axial center of the cast pipe due to thermal expansion and contraction, and will be deformed or even broken at the ridges. The spring of the spring wedge arranged on the inner wall of the mold barrel is used to realize the movement of the spring wedge within a certain small range, absorb the force that causes the ridges to be deformed or even broken, improve the stress condition of the ridges, prepare a complete special-shaped cast pipe, reduce the generation of cracks and avoid the breakage of the cast pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the structure of special-shaped cast pipe.

[0024] Figure 2 A schematic diagram of a mold for centrifugal casting of special-shaped cast pipes.

[0025] Figure 3 for Figure 2 Cross-section along AA.

[0026] Figure 4 for Figure 3 Enlarged view of point A in the middle.

[0027] Figure 5 It is a cross-sectional view of the connection structure between the outer tube and the mold barrel.

[0028] In the figure, 1-outer tube, 2-mold cylinder, 3-end cover, 4-casting port, 5-wedge block, 6-spring.

[0029] The realization of the effects, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The present invention provides the following technical solutions:

[0032] like Figure 1-4 As shown, a device for centrifugal casting of special-shaped cast pipes includes an outer tube 1, end covers 3 located at both ends of the outer tube 1, and a mold arranged in the outer tube 1. The mold includes a mold barrel 2, and spring wedges are arranged along the circumference of the inner wall of the mold barrel 2 at the part with ridges on the inner wall.

[0033] Special-shaped cast pipes are as follows Figure 1 The tubular casting shown is cylindrical in shape, coaxial but with variable diameter (with multiple different cross-sectional diameters), and the inner wall shape of the mold barrel 2 is consistent with the outer wall shape of the special-shaped cast pipe. During the centrifugal process after casting, the cast pipe will shrink toward the axial center of the cast pipe due to thermal expansion and contraction, and will be deformed or even broken at the ridges and folds. The spring 6 of the spring wedge block set on the inner wall of the mold barrel 2 is used to realize the movement of the spring wedge block within a certain small range, absorb the force that causes the ridges and folds to be deformed or even broken, improve the stress condition of the ridges and folds, prepare a complete special-shaped cast pipe, reduce the generation of cracks and avoid the breakage of the cast pipe.

[0034] In one embodiment of the present invention, Figure 5 As shown, the outer tube 1 is fastened to the mold barrel 2 of the mold by means of threaded connection or the like. Specifically, the mold barrel 2 of the mold can be an integral piece, or it can be assembled from multiple halves of the mold barrel 2 (for example, a three-halves mold barrel). For the case where multiple halves of the mold barrel 2 are assembled, each half of the mold barrel 2 is fastened to the outer tube 1 by means of threaded connection or the like.

[0035] In one embodiment of the present invention, the spring wedge block is fixed to the inside of the mold barrel 1 and is combined with the mold as a whole. The spring wedge block is set so as not to affect the outer shape of the cast pipe outer wall corresponding to the ridged part of the inner wall of the mold barrel 2. Even if the shape of some parts is affected during the casting process, it can be processed through subsequent processing.

[0036] In one embodiment of the present invention, the spring wedge block is composed of a spring 6 and a wedge block 5. The two ends of the wedge block 5 are respectively marked as a large end and a small end. The small end is connected to the inner wall of the mold cylinder 2 through the spring 6.

[0037] In one embodiment of the present invention, the large end of each wedge 5 is farther away from the axial center of the casting pipe than the small end.

[0038] In one embodiment of the present invention, a pouring port 4 is provided on at least one end cover 3 .

[0039] The present invention also provides the following technical solution:

[0040] A method for centrifugal casting of a special-shaped cast pipe, using the above-mentioned device for centrifugal casting of a special-shaped cast pipe, comprises the following steps:

[0041] S1. After pouring the molten metal into the mold cavity, the cavity is sealed;

[0042] S2. The mold is rotated by external force, and centrifugal casting is achieved with the help of centrifugal force.

[0043] In one embodiment of the present invention, in step S1, different molds are replaced according to the structure of the special-shaped cast pipe.

[0044] In one embodiment of the present invention, in step S2, during the centrifugal process after casting, the cast pipe will shrink toward the axial center of the cast pipe due to thermal expansion and contraction, and the ridges and folds will be deformed or even broken by stress. The spring 6 of the spring wedge block arranged on the inner wall of the mold barrel 2 is used to realize the movement of the spring wedge block within a certain small range, absorb the force that causes the ridges and folds to be deformed or even broken, improve the stress condition of the ridges and folds, prepare a complete special-shaped cast pipe, reduce the generation of cracks and avoid cast pipe breakage.

[0045] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A device for centrifugal casting of special-shaped cast pipes, characterized in that: The device comprises an outer tube, end covers at both ends of the outer tube, and a mold arranged in the outer tube. The mold comprises a mold barrel, and spring wedges are arranged along the circumference of the inner wall of the mold barrel at the position where the inner wall of the mold barrel has ridges.

2. The device for centrifugal casting of special-shaped cast pipes according to claim 1, characterized in that: The outer tube and the mold barrel of the mold are connected and fixed via a connecting piece.

3. The device for centrifugal casting of special-shaped cast pipes according to claim 1, characterized in that: The spring wedge is fixed to the inside of the mold barrel and is integrated with the mold.

4. The device for centrifugal casting of special-shaped cast pipes according to claim 1, characterized in that: The spring wedge is composed of a spring and a wedge. The two ends of the wedge are respectively marked as a large end and a small end. The small end is connected to the inner wall of the mold barrel through a spring.

5. The device for centrifugal casting of special-shaped cast pipes according to claim 4, characterized in that: The large end of each wedge is farther away from the axial center of the casting pipe than the small end.

6. The device for centrifugal casting of special-shaped cast pipes according to claim 1, characterized in that: A pouring port is arranged on at least one end cover.

7. A method for centrifugal casting of a special-shaped cast pipe, characterized in that: The device for centrifugal casting of special-shaped cast pipes according to any one of claims 1 to 6 comprises the following steps: S1. After pouring the molten metal into the mold cavity, the cavity is sealed; S2. The mold is rotated by external force, and centrifugal casting is achieved with the help of centrifugal force.

8. The method for centrifugal casting of special-shaped cast pipe according to claim 7, characterized in that: In the step S1, different molds are replaced according to the structure of the special-shaped cast pipe.

9. The method for centrifugal casting of special-shaped cast pipe according to claim 7, characterized in that: In step S2, during the centrifugal process after casting, the cast pipe will shrink toward the axial center of the cast pipe due to thermal expansion and contraction, and the ridges and folds will be deformed or even broken due to stress. The spring of the spring wedge block arranged on the inner wall of the mold barrel is used to realize the movement of the spring wedge block within a certain small range, thereby absorbing the force that causes the ridges and folds to be deformed or even broken.

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