JPH09314241A - Manufacture of hollow member tapered in thickness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the working time and the cost by pressing a hollow disk stock by a projected spherical surface of a spherical punch to integrate a conical hollow member tapered in thickness in a manufacturing method of the hollow member tapered in thickness. SOLUTION: In a manufacturing method of a hollow member tapered in thickness, an ingot from which a riser part and an ingot bottom part are removed is heated, the heated ingot is made upsetting, a through hole is formed in a center part, a thick hollow disk stock having a through hole is formed, and then, the hollow disk stock is loaded on a lower die 5 having a recessed part 5a on an upper surface of the center part, and the upper surface of the hollow disk stock is pressed by a projected spherical surface 6a of a spherical punch 6 to make a conical hollow member 1 tapered in thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thick tapered hollow member for forming an end portion, that is, a head portion or a bottom portion of a pressure vessel used in the nuclear industry, chemical industry and the like.

[0002]

2. Description of the Related Art Since this type of thick walled tapered hollow member is a thick walled product, it is difficult to promote plastic flow through the entire wall thickness, and conventionally, in order to improve the yield, a plurality of thick walled hollow members are used. Weld and fix the tapered hollow member piece to the following (1),
It is manufactured by the method (2). (1) In the thick tapered hollow member 50 shown in FIG. 13, a fan-shaped thick tapered hollow member piece 51 obtained by dividing the thick tapered hollow member 50 in the circumferential direction is manufactured in advance by machining. A plurality (three in this example) of the thick tapered hollow member pieces 51 are butted and welded and fixed together by the welded portion 52. The thick tapered hollow member 50 is further machined to form a substantially hemispherical pressure vessel head or bottom.

(2) In the thick tapered hollow member 60 shown in FIG. 14, an annular thick tapered hollow member piece 61 obtained by dividing the thick tapered hollow member 60 in the central axis direction is previously machined. A plurality (two in this example) of the thick tapered hollow member pieces 61 are stacked and welded and fixed by the welded portion 62. This thick-walled tapered hollow member 60 is machined to form a substantially hemispherical pressure vessel head or bottom.

An annular thick tapered hollow member piece 61 is manufactured from an annular member 64 having a rectangular cross section. For example,
As shown in FIG. 15, while rotating the annular member 64 having the inner peripheral surface supported by the mandrel 63, the outer peripheral surface of the annular member 64 is uniformly struck by applying an upper anvil 65 of a predetermined width, and then the hatched portion The meat 64a is removed in an annular shape to form a conical thick walled tapered hollow member piece 61. Further, as shown in FIG. 16, the inner peripheral surface of the annular member 64 is supported by the mandrel 63,
The outer peripheral surface of the annular member 64 is partially struck by applying an upper anvil 67 having a narrow width to form a rough surface shape in which the outer peripheral surface forms a tapered surface. Then, as shown in FIG. 17, using a wide upper anvil 68, the outer peripheral surface is struck over the entire width to give a tapered shape parallel to the inner and outer peripheral surfaces.

However, in the conventional method of manufacturing a thick tapered hollow member shown in (1) above, the thick tapered hollow member piece 51 is formed by dividing the thick tapered hollow member 50 in the circumferential direction. Since a plurality (3 to 4) of the above are manufactured in advance by machining, it is difficult to form into a shape for improving the yield, and the welded portions 52 are formed at a plurality of places (3 to 4). Therefore, there is a technical problem that the reliability is likely to decrease due to welding defects.

Further, in the conventional method of manufacturing a thick tapered hollow member shown in the above (2), the thick tapered hollow member piece having a shape in which the thick tapered hollow member 60 is divided in the central axis direction. Since 61 is preliminarily manufactured by machining by the method as described above, it is difficult to process the shape into a shape for improving the yield, and since the welded portion 62 is formed, the reliability caused by the welding defect is increased. However, there is a technical problem in that In addition, when the wide upper anvil 68 is struck over the entire width as shown in FIG. 17, the center of gravity G of the annular member 64 is moved, so that the inclination angle θ of the inner peripheral surface of the annular member 64 is maximum. The maximum limit is 22 °,
There is a technical problem that it is difficult to give a desired shape.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional technical problems, and has the following configuration. The configuration of the invention of claim 1 is the feeder 10
Ingot 1 without a and ingot bottom 10b
0 is heated, the heated ingot 10 is upset, and the through hole 2a is formed in the central portion to form the thick hollow disk material 3 having the through hole 3a, and then the concave portion 5a is formed on the upper surface of the central portion. Place the hollow disc material 3 on the lower die 5 having
A method of manufacturing a thick tapered hollow member, characterized in that the convex spherical surface 6a of the spherical punch 6 pushes the upper surface of the hollow disk blank 3 to form a thick tapered hollow member 1 having a conical shape.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIGS. In FIG. 1, reference numeral 1 denotes a thick-walled tapered hollow member for forming an end, that is, a head or a bottom of a pressure vessel used in the nuclear industry, chemical industry, etc., and the thick-walled tapered hollow member 1 Is manufactured from the ingot 10 shown in FIG.

First, a feeder 10a containing impurities as shown in FIG.
And the ingot 10 from which the ingot bottom 10b has been removed by gas cutting is heated to 1000 to 1250 ° C., the ingot 10 is hot upset forged, and the thick disk-shaped or columnar material 2 shown in FIG. In addition, the punch 11 shown in FIG. 7 punches a through hole 2a in the center of the material 2. The material 2 having this through hole 2a is 1000 to 1
The material 2 is heated to 250 ° C., and the material 2 is subjected to hot upsetting as shown in FIG. That is, the heated material 2 is placed on the lower anvil 12, and the entire upper surface is tapped by the upper anvil 13 to compress it into a disc-shaped body having a predetermined thickness.

Then, as shown in FIGS. 9 and 10, the material 2
Is placed on the rotary table 14, and the upper surface of the raw material 2 is partially tapped with a fan-shaped anvil 15 until it is compressed to a predetermined thickness. Furthermore, the material 2 is 1000-1
After heating to 250 ° C., the lower surface of one end of the material 2 is supported by the supporting member 16 and the lower surface of the other end is supported by the fan-shaped lower anvil 17 as shown in FIG. By tapping the upper surface of the part with a fan-shaped upper anvil 18 and sequentially compressing it over the entire circumference between the upper and lower anvils 17, 17 has a through hole 3a in the central part as shown in FIG. It is formed into a thick disk-shaped (thickness: 300 to 1000 mm) hollow disk material 3 having a disk shape.

Next, by using the lower die 5 and the spherical punch 6 having a convex spherical surface 6a having a missing spherical shape shown in FIG.
The hollow disk material 3 heated to ˜1200 ° C. is formed into a thick tapered hollow member 1 having a conical shape as shown in FIG. The lower die 5 has a recess 5a on the upper surface side of the central portion. The recess 5a is actually a through hole 5b formed in the center of the lower mold 5.
And a tapered hole 5c that is connected to the upper portion of the through hole 5b and gradually increases in diameter upward. The hollow disc material 3 is placed on the annular upper surface 5d of the lower die 5, the convex spherical surface 6a of the spherical punch 6 is directed downward, and a pressing force from a press device (not shown) acts on the spherical punch 6 to form a hollow circle. Push in the upper surface of the central portion of the plate material 3. As a result, the hollow disc material 3 becomes
As shown in Fig. 4, the convex spherical surface 6a of the spherical punch 6 and the tapered hole 5c
It is sandwiched between and and transforms into a conical shape. Reference numeral 7 is a pressing ring for causing the pressing force of the pressing device to act on the spherical punch 6. Thereby, the thick tapered hollow member 1 having the through hole 1a in the center is formed.

By using the spherical punch 6, the convex spherical surface 6a of the spherical punch 6 which was initially in contact with the upper surface of the central portion of the hollow disk material 3, that is, the peripheral edge portion of the upper end of the through hole 3a is lowered by the spherical punch 6. As a result, the hollow disk material 3 is smoothly contacted toward the outer diameter side. in this way,
The convex spherical surface 6a of the spherical punch 6 gradually contacts the outer diameter portion of the upper surface of the hollow disk material 3, and the lower surface of the hollow disk material 3 is deformed while being pressed and supported by the tapered hole 5c. As a result, the hollow disk material 3 is molded into the hollow conical thick walled tapered hollow member 1.

The radius R of the convex spherical surface 6a of the spherical punch 6 is set according to the thickness t and the radius r of the hollow disc material 3 shown in FIG. The radius R of the convex spherical surface 6a is set to be larger as r is larger, and the radius R of the convex spherical surface 6a is set to be smaller as the thickness t of the hollow disk material 3 is thicker, and the cone shape is moderately conical while suppressing an increase in pressing force. It is desired to mold the thick-walled tapered hollow member 1 that has been deformed into. Further, the radius R of the convex spherical surface 6a is the radius R ₂ is set to be smaller than the lower radius R ₁ of the upper end portion 6b as shown in FIG. 4, the conical thickened tapered hollow member 1 shown in FIG. 1 It is possible to prevent the occurrence of indentations due to the pressure contact between the inner surface and the upper end portion 6b of the convex spherical surface 6a during the processing of.

Further, it is desirable that the inclination angle of the tapered hole 5c be substantially matched with the outer shape of the thick walled hollow member 1 as a product. Of course, the outer shape of the spherical punch 6 is set to be larger than the through hole 3a of the hollow disc material 3 and the through hole 1a of the thick tapered hollow member 1.

Since such a thick tapered hollow member 1 is hot forged by the time the ingot 10 is formed into the annular hollow disc material 3, the defects during solidification are forged and pressed to mechanical properties. Has been improved. Further, according to this molding method, it is possible to form the inclination angle θ of the inner peripheral surface of the thick-walled tapered hollow member 1 shown in FIG. The thick-walled tapered hollow member 1 is subjected to heat treatment such as normalization and tempering for the purpose of fine graining and strain removal. In addition, it is substantially impossible to apply the spinning process to such a thick (thickness: 300 to 1000 mm) hollow disc material 3 to form the thick tapered hollow member 1. .

The thick tapered hollow member 1 is cut into a predetermined shape to form the head or bottom of the pressure vessel.
That is, as shown in FIG. 12, the thick tapered hollow member 1
The diagonally shaded portion 1a is subjected to cutting work to obtain a product 8 having a substantially hemispherical shape. If the thick tapered hollow member 1 is used as the product 8, for example, what was conventionally made from a 600t ingot can be made from a 350t ingot 10 and a significant improvement in yield can be achieved.

[0017]

As will be understood from the above description,
According to the method of manufacturing the thick tapered hollow member according to the present invention, the following effects can be obtained. (1) Since the hollow circular plate material is pushed by the convex spherical surface of the spherical punch to integrally mold the conical thick walled tapered hollow member, the time required to manufacture the thick walled tapered hollow member is shortened. At the same time, the end portion of the substantially hemispherical container can be formed with relatively high yield, and the cost can be reduced. (2) Since the forging is performed by hot upsetting from the ingot to the formation of the hollow disc material, defects during solidification are forged and pressed. As a result, a high-quality thick-walled tapered hollow member can be obtained.

(3) Since the thick-walled tapered hollow member is integrally molded and no welded portion is formed, a highly reliable thick-walled tapered hollow member that secures the required mechanical properties as a whole can be obtained. (4) Since the defects at the time of solidification of the ingot are forged and pressure-bonded and no welds are formed, the necessity of defect detection is also reduced.

[Brief description of drawings]

FIG. 1 is a side view showing in section a method of manufacturing a thick tapered hollow member according to an embodiment of the present invention.

FIG. 2 is a side view showing a cross-section of the same method for manufacturing a hollow member with a thick taper.

FIG. 3 is a cross-sectional view showing the same hollow disk material.

FIG. 4 is a side view showing a spherical punch.

FIG. 5 is a view showing an ingot.

FIG. 6 is a diagram showing the same material.

FIG. 7 is a side view showing the manufacturing process of the hollow member with the thick taper in a partial cross section.

FIG. 8 is a side view showing the manufacturing process of the hollow member with the thick taper in a partial cross section.

FIG. 9 is a plan view showing the manufacturing process of the hollow member with the same thick wall taper.

FIG. 10 is a side view showing the manufacturing process of the hollow member with the thick taper in a partial cross section.

FIG. 11 is a side view showing, in a partial cross section, a manufacturing process of the hollow member with a thick taper, similarly.

FIG. 12 is an explanatory view showing a processing step of the hollow member having the same thick wall taper.

FIG. 13 is a perspective view showing a conventional thick-walled tapered hollow member.

FIG. 14 is a perspective view showing a conventional thick-walled tapered hollow member.

FIG. 15 is an explanatory view showing a method of manufacturing a thick tapered hollow member piece in the same manner.

FIG. 16 is an explanatory view showing a method for manufacturing a thick tapered hollow member piece in the same manner.

FIG. 17 is an explanatory view showing a method of manufacturing a thick tapered hollow member piece in the same manner.

[Explanation of symbols]

1: Thick walled hollow member, 2: Material, 2a: Through hole,
3: Hollow disk material, 3a: Through hole, 5: Lower mold, 5a: Recessed part, 6: Spherical punch, 6a: Convex spherical surface, 10: Ingot, 10a: Feeder, 10b: Ingot bottom part.

Claims (1)

[Claims] 1. An ingot (10) from which a feeder (10a) and an ingot bottom portion (10b) have been removed is heated, and the heated ingot (10) is upset-molded and a through hole (2a) is formed in the central portion. After forming and forming a thick hollow disc material (3) having a through hole (3a), a hollow disc material (3) is formed on a lower die (5) having a recess (5a) in the central upper surface. Is placed, and the upper surface of the hollow disk material (3) is pressed by the convex spherical surface (6a) of the spherical punch (6) to form a thick tapered hollow member (1) having a conical shape. A method for manufacturing a thick tapered hollow member.