JPH1133668A - Forging device of large diameter ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the forging device of the large diameter ring capable of forming a complete roundness cylinder at room temperature. SOLUTION: In a forging device, an inner circumferential surface of a large diameter ring 3 is supported by a core 1 which is supported at each end, an outer circumferential surface of the large diameter ring 3 is pressed by an anvil 2 to flatten the inner and outer circumferential surfaces. A part of the anvil 2 in contact with each end part of the large diameter ring 3 is swollen toward the large diameter ring side away from a part in contact with a center part, A part of the core 1 in contact with each end part of the large diameter ring 3 is retreated toward a counter large diameter ring side away from the part in contact with the center part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forging device for a large diameter ring.

[0002]

2. Description of the Related Art As a forging device for a large-diameter ring having an outer diameter exceeding 4 m, for example, those described in Japanese Patent Publication No. 58-48263 and Japanese Patent Application Laid-Open No. 61-232320 are known. The conventional one has an inner peripheral surface of a large-diameter ring supported on a core metal supported at both ends, and an outer peripheral surface of the large-diameter ring is pressed with an anvil to flatten the inner and outer peripheral surfaces of the large-diameter ring. Met.

[0003]

An important point in forging a large diameter ring is to machine the inner and outer surfaces into a true cylinder. However, it has been extremely difficult to make the longitudinal distribution of the inner and outer diameters of the large-diameter ring uniform with the conventional one. That is, when a ring-shaped forged product is manufactured by the free forging method, usually, the process involves compressing the heated ingot, drilling (drilling the center hole), expanding the diameter, adjusting the length, and then final ring forging. Work to determine the outer diameter. At this time, the inner diameter is determined if the outer diameter is determined. These operations are performed in a hot state of about 800 ° C or higher, but when cooled to room temperature, a ring-shaped (or drum-shaped) shape with both ends of the ring open to obtain a true cylindrical product Was difficult.

Accordingly, an object of the present invention is to solve the above-mentioned conventional problems and to provide a large-diameter ring forging apparatus which can be machined into a true cylinder.

[0005]

In order to achieve the above object, the present invention takes the following measures. That is, the feature of the present invention is that the inner peripheral surface of the large-diameter ring is supported by the core metal supported at both ends, and the outer peripheral surface of the large-diameter ring is pressed by anvil to make the inner and outer peripheral surfaces flat. In the large-diameter ring forging device, the portion of the anvil, which is in contact with both ends of the large-diameter ring, bulges toward the large-diameter ring from a portion that contacts the central portion,
The part of the core bar that comes into contact with both ends of the large-diameter ring is retracted to the side opposite to the large-diameter ring from the part that comes into contact with the central part.

The amount of expansion and retraction of the anvil and the metal core is determined by the difference in thermal expansion based on the processing temperature difference between the axial center and the end of the large diameter ring. Further, the amount of deflection of the core metal due to the pressurization of the anvil is added to the amount of retreat of the core metal. According to the present invention having the above configuration, since both ends of the anvil are swelled and both ends of the metal core are retracted,
In the hot working state, the inner and outer diameters at both ends in the longitudinal direction of the ring forged product are smaller than the diameter at the center.

[0007] Usually, the forged product is heated to about 1200 ° C, and the operation is completed at about 700 to 800 ° C. As a natural rule of cooling, the surface and the end face of the ring forged product have a rapid temperature drop, and at the end of the forging, have a lower temperature than other parts. If the same size is formed in a state where there is a difference in temperature distribution, there is a difference in the amount of shrinkage, so that a difference occurs in the room temperature size. In the present invention, since the inner and outer diameters at both ends in the longitudinal direction of the ring forged product are reduced by the difference in the amount of shrinkage, the product becomes a true cylindrical shape at room temperature.

Although the anvil has relatively high rigidity, the core bar is supported at both ends, so that the central portion bends when the anvil is pressed down. Therefore, by using a medium-sized cored bar, this amount of bending is offset, and processing with higher precision can be performed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a diagram showing a forging process of a large-diameter ring, in which a steel ingot is roughly pressed, compressed, a center hole is drilled,
Then, after performing the diameter expansion and forging, the lengths in the axial direction are adjusted, and finally, the diameter expansion is performed to complete the forging.

The apparatus used in the diameter expanding operation in the final step is the apparatus for forging a large diameter ring according to the present invention.
FIG. 1 shows a forging device for the large-diameter ring. This large-diameter ring forging apparatus has a core 1 supported at both ends and an anvil 2 attached to a movable plate of a press machine. The inner peripheral surface of the large-diameter ring 3 is supported by the metal core 1. Then, the outer peripheral surface of the large-diameter ring 3 is pressed by the anvil 2.

The metal core 1 is formed into a curved surface having a convex central portion in the longitudinal direction, and the anvil 2 is formed into a curved surface having a concave central portion in the longitudinal direction. That is, the portion of the anvil 2 that contacts both ends of the large-diameter ring 3 bulges toward the large-diameter ring from the portion that contacts the central portion, and the core bar 1 contacts both ends of the large-diameter ring 3. The curved surface of the anvil is retracted on the side opposite to the large-diameter ring from the portion in contact with the central portion,
It is determined as follows.

The forged material (large-diameter ring 3) usually has an outer diameter of about 5 m and a wall thickness of about 300 to 400 mm.
The temperature distribution at the end of the forging is such that the surface at both end surfaces is about 700 ° C. and becomes higher toward the center in the longitudinal direction.
It is about 0 ° C. The difference in the amount of heat shrinkage due to this temperature difference, that is, the dimension ΔRA of the curved surface is determined by the following equation. ΔRA = (1/2) × 5000 × (850-700) × 14 × 10 ⁻⁶ ≒ 5 mm The curvature of the curved surface is obtained from the temperature distribution.

[0013] However, since the conditions are not always constant, as shown in FIG.
In this case, a gentle curved surface was formed between the both end surfaces at a distance of about 500 mm, and the central portion 2 m was linear. The dimensional difference ΔRc of the cored bar 1 was further increased by 5 mm from ΔRA to 10 mm. It is a value determined by the pressing force, the core metal diameter, and the span in consideration of the bending curve of the core bar 1 during rolling, but in this example, it was determined by actual measurement in actual work.

A large-diameter ring 3 manufactured by using the above-mentioned apparatus.
As shown in FIG. 3, the inner and outer diameters became uniform along the axial direction, and a perfect cylindrical shape was obtained. Note that the present invention is not limited to the above embodiment.

[0015]

According to the present invention, a large-diameter ring of a true cylinder can be obtained at room temperature.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view of an anvil.

FIG. 3 is a sectional view of a large-diameter ring.

FIG. 4 is a forging process diagram of a large-diameter ring.

[Explanation of symbols]

 1 core metal 2 anvil 3 large diameter ring

Claims (3)

[Claims] 1. A large-diameter ring forging device in which an inner peripheral surface of a large-diameter ring is supported on a core metal supported at both ends, and an outer peripheral surface of the large-diameter ring is pressurized with an anvil to flatten the inner and outer peripheral surfaces. In the anvil, the portion in contact with both ends of the large-diameter ring swells toward the large-diameter ring from the portion in contact with the center portion, and the core metal, the portion in contact with both ends of the large-diameter ring, A forging device for a large-diameter ring, wherein the forging device is retracted to a side opposite to the large-diameter ring from a portion in contact with a central portion. 2. The swelling amount and retreat amount of the anvil and the core metal are as follows:
2. The large diameter ring forging device according to claim 1, wherein the forging device is determined by a thermal expansion difference based on a processing temperature difference between an axial center portion and an end portion of the large diameter ring. 3. The forging device for a large diameter ring according to claim 2, wherein the amount of retraction of the metal core is added to the amount of bending of the metal core due to pressurization of the anvil.