JPH105908A - Flange-integrated end plate of pressure vessel, its manufacture, and its blank material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form with a small force by pressing the blank material whose whole periphery of a recessed disk is surrounded by a flank and the thickness of the disk is gradually increased in the outside direction from a disk center to form a tapered shape, and integrally forming a dome part and a flange part. SOLUTION: The whole periphery of the blank material 10 is surrounded by the flange 11. The thickness of the disk part of the blank material 10 is gradually increased by a tapered surface 13 from a center 0, and a thickened part 14 is formed. After heating the blank material 10 to a hot forming temperature, the blank material 10 is mounted on the die 16 of a press device. After putting the thickened part 14 in the opening part of the die 16, the flange 11 is placed on the die 16. By pushing the upper die 15 of the press device in the blind surface 12A of the recessed part 12 of the blank material 10, flange part 17C and dome part 17A are simultaneously formed. It is swelling work to decrease the thickness of each part of the recessed part 12, however, since the tapered surface 13 has been formed, the blank material 10 is formed without an underfill. Since the upper die 15 is smaller than the dome part 17A, working can be performed by a small press force without ironing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flange integrated head plate for a pressure vessel, a method of manufacturing the same, and a blank material thereof, and is used for a close head and a bottom head of a large pressure vessel.

[0002]

2. Description of the Related Art A steel pressure vessel has a closed head assembly (top dome, top torus, head) at both ends of a long cylindrical body in which several cylindrical members (shells) are connected and joined by means such as welding. And a bottom assembly (bottom dome, bottom torus). For example, Japanese Patent Publication No. 56-26526, Japanese Patent Publication No. And generally referred to as a mirror plate).

[0003] Each of these prior arts is a method of manufacturing a dome, and a torus and a flange are respectively joined to the dome by welding. When the torus and the flange are joined to the dome by welding in this manner, there is no structural reliability and the manufacturing cost is high, and a periodic inspection of the weld after installation is required.

For example, when particularly high safety is required as in the case of a steel reactor pressure vessel, it is necessary to periodically monitor the welded portion even during operation. If the dome, the torus and the flange can be formed integrally, the welded portion is eliminated, which is advantageous.
A dome (end plate) integrated with a flange was manufactured using the press molding apparatus shown in (1).

[0005] In Fig. 16, reference numeral 1 denotes a blank material obtained by forging a disk from a steel ingot and press-forming, etc., and has a maximum thickness of a flange portion (a flange corner portion which is the maximum in the normal direction from the inner peripheral curved surface). The dome (end plate) integrated with a flange using the press forming apparatus shown in FIG.
Was made. In FIG. 16, reference numeral 1 denotes a blank material obtained by forging a disc from a steel ingot and press-forming the same, and the maximum thickness of the flange portion (the distance from the inner peripheral curved surface to the flange corner portion which is the maximum in the normal direction). It is a material having a thickness. 2 is a male type (punch) of the press device, and 3 is a female type of the press device.

[0006]

The following problems arise when the blank 1 shown in FIG. 16 is bent (press-formed) while being heated to the hot forming temperature. A blank material having an excessively large thickness requires a large indentation force for bending and requires a pressing device having an extremely large capacity, which is practically impossible. The blank thickness is too large, the material yield for the final product shape is extremely poor, and the cutting time after pressing is too long, which is not economical. A springback phenomenon occurs during bending. Even if the thickened portion 1A is formed in the circumferential portion of the blank material and press-formed, the flange corner portion is cut off, and the intended flange-integrated end plate is not obtained. When a flange-integrated end plate is manufactured, heat treatment such as quenching and tempering is performed to ensure predetermined mechanical properties. However, the flange portion and the end plate portion have a thick flange portion and a thin end plate portion. However, since the difference in wall thickness is large, there is a difference in cooling rates during water cooling and quenching, which has been an obstacle to obtaining a uniform head plate.

Accordingly, the present invention provides a method of manufacturing a flange-integrated end plate without using a large-capacity press device and without using a blank material having an excessively large thickness by working the shape of the blank material. Is the first purpose. Further, the present invention utilizes the C amount segregation, that is, the C amount (carbon amount) between the flange and the disk (dome portion) is set to a high C amount for the flange and a low C amount for the disk, so that the entire amount is reduced. It is a second object to provide a flange-integrated end plate and blank material having uniform mechanical properties throughout.

[0008]

The present invention employs the following technical means in order to achieve the first object. That is, the manufacturing method of the present invention according to claim 1 has a concave portion surrounded by a flange over the entire circumference of the disk, and has a tapered surface that gradually increases in thickness from the center of the disk to the entire radial direction. Forming an outer peripheral thickening portion, making a blank material in a shape connected to the flange through the outer peripheral thickening portion, when mounting the blank material to a lower die or a die of a press device, the lower die or the die The method is characterized in that the outer peripheral thickening portion is mounted in the opening, and then the upper die of the pressing device is pressed into the bottom surface of the concave portion to integrally mold the dome portion and the flange portion at a hot forming temperature. It is.

The blank material of the present invention according to claim 2 has a concave portion surrounded by a flange extending over the entire circumference of the disk, and the thickness of the concave portion gradually increases from the center of the disk to the entire radially outward direction. An outer peripheral thickened portion is formed by a tapered surface, and the outer peripheral thickened portion is connected to the flange through the outer peripheral thickened portion. In the blank material according to the second aspect, a tapered surface is formed on the opposite surface or both surfaces of the concave portion with the bottom surface or the flange, and the outer peripheral thickening portion can be provided (claim 3).

Further, in the manufacturing method of the present invention according to claim 4, at least one surface of the disk is a tapered surface which gradually increases in thickness from the center of the disk to the entire surface in the radial direction, and is connected to the tapered surface. Making a blank material having a wedge-shaped cross-section thickening portion, when mounting the blank material to the lower die or die of the press device, mounting the thickening portion in the opening of the lower die or die, Thereafter, the upper mold of the press device is pressed into the disk, and the dome portion and the flange portion are integrally formed at a hot forming temperature.

According to a fifth aspect of the present invention, at least one surface of the disk is formed as a tapered surface that gradually increases in thickness from the center of the disk to the entire surface in the radially outward direction, and is connected to the tapered surface. And having a wedge-shaped thickened portion on the outer periphery of the disk. In the blank material according to claim 5, one surface of the disk is formed into a flat surface, the other surface is formed into a tapered surface, or both surfaces of the disk are formed into a tapered surface, so that a thickened portion having a wedge-shaped cross section can be formed on the outer periphery of the disk. (Claims 6 and 7).

Further, in order to achieve the second object, the flange-integrated head plate of the present invention according to claim 8 is a flange-integrated head plate of a pressure vessel in which a dome portion and a flange portion are integrally formed. The C amount (carbon amount) between the dome portion and the flange portion is characterized in that the dome portion has a low C amount and the flange portion has a high C amount.
The blank material of the present invention according to claim 9 is a blank material having a concave portion surrounded by a flange or a thickened portion having a wedge-shaped cross section over the entire circumference of the disk, wherein the C amount of the concave portion and the flange or the thickened portion is The concave portion has a low C amount and the flange or the thickened portion has a high C amount.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are claims 1
2 (A) and 2 (B).
(C) shows a blank according to claim 2, that is, a blank used in the manufacturing method according to claim 1.

2 (A), 2 (B) and 2 (C), the blank material 10 has a concave portion 12 surrounded by a flange 11 over the entire circumference of the disk, and the bottomed portion 12A of the concave portion 12 has a flat surface. The inner peripheral portion 12B of the flange has a draft angle, and a tapered surface 13 that gradually increases in thickness from the center 0 of the disc to the entire surface in the radial direction of the concave portion 12 is formed on the surface opposite to the flange 11. The flange 11 has a shape connected to the flange 11 via an outer peripheral thickened portion 14 of the tapered surface 13.

The blank 10 is formed by cutting a columnar steel ingot and compressing (forging) it in the axial direction to form a thick disk. In some cases, a thick disk is created by performing sufficient forging by repeating compression and forging. Press molding (free forging) of this thick disk produces a
The previously described blank material 10 shown in (A), (B) and (C) is created.

If the pressing force is sufficient, the depression 12 and the like can be formed by one pressing, but if it is difficult to perform the pressing once, the pressing is performed several times. It is desirable that the material forged in this way be subjected to a sufficient heat treatment so that at the time of the material, the finished product, that is, the mechanical properties required for the head plate of the pressure vessel are provided, 2 (A), 2 (B), and 2 (C) by machining the entire surface or partially according to
Create

The blank 10 is heated to a hot forming temperature, for example, a temperature of 700 to 1200 ° C.
As shown in (B), the upper die 15 is mounted on a die 16 of a press device and pressed by a hemispherical punch to form the die. When the blank material 10 is mounted on a die 16 of a press device, the outer peripheral thickening portion 14 enters the opening of the die 16 and the flange 11 is
And the disc center is mounted with the center 0 as the die center.
A, and the dome portion and the flange portion are integrally formed at the hot forming temperature.

Here, the bottomed surface 12A of the concave portion 12 is a portion corresponding to the dome portion 17A of the end plate 17 when it is pressed and molded in the axial direction (vertical direction) with the upper die 15, and the thickened portion 14 is Similarly, the flange 11 is a portion corresponding to the torus portion 17B, and the flange 11 is also a portion corresponding to the flange portion 17C. The bottom surface (part) 12A of the concave portion 12 becomes a bulging process (bending process) for reducing the thickness of each portion. , Its center 0
Is formed as a tapered surface 13 which gradually increases in thickness in the radially outward direction to form a dead metal in contact with the upper die 15 to expand (extend) the periphery when bulging out. The rupture is prevented by the thickened portion 14 without losing the thickness.

Since the upper mold 15 has a substantially partially spherical shape and a diameter smaller than the inner diameter of the dome portion 17A, the contact area between the upper mold 15 and the bottomed surface 12A is small and ironing is substantially performed. Arrow F1 in FIG. 1 (B)
Thus, it is sufficient to extend uniformly in the normal direction as shown in FIG.

The blank 10 shown in FIG. 2 is obtained by completely preforming the flange 11, and the dimensions of the flange 11 are such that the flange 17 C of the end plate 17 has some extra thickness. It is desirable. The bent end plate 17 is taken out of the press device and subjected to necessary processing (for example, formation of a bolt insertion hole in the flange 17C) to be a complete product.

FIGS. 3A and 3B show an embodiment employing a female die (lower die) 16A having a die 16 as the molding means of the press device. The shape of the blank 10 is the same as that of FIG. The common parts are indicated by common reference numerals, and the female mold 16A is a ring type and is divided as shown in the figure, and the mold surface 16B is a curved surface along the outer peripheral surface shape of the dome portion 17A.

FIGS. 4A and 4B show an embodiment corresponding to claims 4 and 5, in which the shape of the blank material 10 is different. That is, the blank material 10 has a flat surface 12A on one surface of the disk and a tapered surface 13 whose other surface gradually increases in thickness from the center of the disk to the entire surface in the radial direction.
A concave portion 12 surrounded by the thickened portion 14 is formed on the die 16 side so that the thickened portion 14 having a wedge-shaped cross section is connected to the tapered surface 13 and is formed on the outer periphery of the disk. Have been.

That is, the blank 10 shown in FIGS. 4 (A) and 4 (B) is a portion where the thickened portion 14 having a wedge-shaped cross section corresponds to the torus 17B and the flange 17C of the end plate 17, and the shape is a mold. The product opening side end face after
The flange 17C has a gradient by an angle θ such that the outer peripheral surface of the flange 17C is perpendicular to the center of the outer peripheral radius at an angle θ of 5 to 20 °. Is a dimension called so-called cutback).

The angle θ may change depending on the required final shape of the product. FIGS. 4A and 4B
2 is the blank material 1 shown in FIG.
Although the excess material is slightly larger than that of 0, the material upset is shallow and the material yield is improved. Thus, FIG.
As shown in (A), when the blank material 10 is mounted on the lower die 16A or the die 16 of the press device, the lower die 16A
Alternatively, the thickened portion 14 is inserted into the opening of the die 16 and mounted, and then the upper die 15 of the pressing device is pressed into the flat surface 12A of the disc, and the dome portion and the flange portion are formed at the hot forming temperature. Are integrally molded.

In the above two embodiments, the material of the blank 10 is SA-508, class 2 or class 3, that is, manganese-molybdenum steel is used, which is particularly effective in a pressure vessel of a nuclear reactor. It is. Also, in each of the above embodiments, the press device is exemplified by a vertical press, but this may be a horizontal press device, in which case the upper die is a male type and the lower die is a female type. Not even.

Further, in the shape of the blank material, the disc means not only a perfect disc but also an ellipse, etc.
Further, although the end plate is not shown with a nozzle, it is needless to say that a nozzle plate can be used.

[0027]

[Example] The material is ASME section IISA508, class 3 (equivalent to JIS, SFV) which is a typical reactor material.
A thick disk having an outer diameter of 5,000 mm and a thickness of 1600 mm was prepared by forging a steel ingot having a weight of 300 tons containing Q2A) as a component. From this thick disk to 1200 ° C to 800
Free forging in the temperature range of 3 ° C., a concave portion having an inner diameter of 3500 mm in the center, a punch for free forging, and heat treatment such as launch annealing, quenching, and tempering.
A blank material 10 having a height of 1,500 mm, a depth of the recess 12 of 870 mm, and an inner diameter of the recess 12 of 4050 mm was prepared.

The blank material 10 is heated at 1200 ° C. to 110 ° C.
After being heated to a hot forming temperature range of 0 ° C., it was mounted on a lower die of a press device and then subjected to a pressing process by an upper die (a pressing force of 11,000 tons, a pressing depth of 1400 mm,
Pushing time required 20 minutes. The indented (bent) end plate was formed by integrally forming the dome portion and the flange portion without underfilling the torus portion.

FIGS. 5 to 7 show another embodiment of the blank material 10 according to the first or second aspect. FIG. 5 shows that the bottom surface 12A of the concave portion 12 gradually increases from the center O of the disk to the radially outward direction. This is formed on a thick tapered surface 13 and an outer peripheral thickened portion 14 is formed by the tapered surface (having a bottom surface) 13. An anti-having bottom surface 12C is a blank material 10 which is a flat surface. According to the blank 10 of FIG.
The material yield can be made better than the blank material shown in FIG.

The blank 10 shown in FIG. 6 has both a bottomed surface 12A and an opposite bottomed surface 12C formed on a tapered surface 13 with different taper directions. 10 is formed on the tapered surface 13 with both the bottomed surface 12A and the opposite bottomed surface 12C, and the taper direction is the same and the direction is different, but the taper angle is different in both of FIGS. An outer peripheral thickened portion 14 is formed.

FIG. 8 shows a blank 1 according to claim 4 or 5.
0 is another embodiment in which a tapered surface 13 is also formed on the side pushed by a male shape (tool), and the other configuration is the same as that of FIG. According to the blank material 10 shown in FIGS. 5 to 8, a portion (surface) where the tool 15 contacts.
Is tapered in the radially outward direction from the center O of the disk, the center deviation of the tool 15 is small, and the tool 15 can be pushed, that is, formed with high precision.

FIGS. 9 to 15 show an embodiment according to claims 8 and 9. FIGS. 9 (1) to 9 (8) show a large steel ingot 100.
2 shows a process of forming the blank material 10 by forging using the method shown in FIG. Ingot 100 undergoes segregation with different component concentrations depending on the position, carbon C is an element that is easily segregated, the top of the ingot 100 is high, the bottom is low, and the degree of segregation increases as the ingot 100 increases in size. On the other hand, carbon C is a quench hardening element, and the higher the C content, the higher the strength.

In the hot forging of the blank material 10, the material of the contact surface of the tool is fixed by friction, and the fixed portion is pressed into the whole material as a wedge.
In consideration of the above, the procedure for preparing the blank 10 will be described below with reference to FIGS. 9 (1) to 9 (8). Steel ingot 10
After rough forging 0, cut off the bottom unnecessary part 100A,
As shown in FIG. 9 (2), compression is applied in the axial direction.
Forging again and adding sufficient forging to the entire ingot (Fig. 9 (3))
reference).

Then, after cutting off the unnecessary portion of the top of the steel ingot 100 and the feeder portion 100B (see FIG. 9 (4)), preliminary compression and finish compression are performed again, and the outer peripheral curved surface of the disk is formed. Department was trained. That is, in the pre-compression, the entire compression is performed by a wide tool that hits the entire compression surface, and the material on the contact surface of the tool is pushed into the entire material as a fixed wedge and fixed to the bottom surface of the concave portion serving as a head plate, while the finish compression is performed in 5 mm ~
Using a narrow tool having a contact surface of 25%, the top was compressed, the material was moved in the plane direction and positioned on the thick flange, and then a recess was formed using a punch 100C shown in FIG. 9 (7). .

When the punch 100C is pushed, the punch 100C is pushed to a position shifted from the center of the disk, and is sequentially pushed in a circumferential direction and on a concentric circle to produce a blank material 10 as shown in FIG. 9 (8). . As shown in FIG. 10, the carbon material (C content) of the bottom (recess) 10A of the disk and the inner peripheral portion 11A of the flange 11 has a low carbon content in the bottom 10A. The peripheral portion 11A has a high C content, and is prepared using the die or lower die and punch described above with reference to FIG. 1 or FIG. 2 using the blank material 10 considering the C content segregation. The end plate is shown in FIG.
As shown by, uniformity of material strength could be achieved.

After the end plate was formed using the blank material 10 shown in FIG. 10, quenching and tempering were performed. FIG.
The cooling curves of the respective parts A, B, C and D of the head plate shown in FIG.
, Each part A, B, from 880 ° C to 550 ° C
Table 1 shows the average cooling rates C and R of C and D.

[0037]

[Table 1]

Further, FIGS. 14 and 15 and Table 2 show the heating curves at the time of tempering and the tempering parameter values representing the tempering effect of the parts A, B, C and D shown in FIG. (Flange) has a low rate of temperature rise, so that tempering in the same time reduces the tempering effect. For this reason, the flange is made to have a high C content to achieve uniform material strength. I have.

[0039]

[Table 2]

As is clear from Table 2, the yield points (Y · S) of the B and D parts have the same value, and it can be understood that the material strength can be made uniform by taking into account the segregation of C amount. In addition,
In Table 2, T · S is the tensile strength, _V E ₂₀ indicates the impact value. In addition, it is needless to say that each of the blanks shown in FIGS. 1 to 8 can be made a more useful flange-integrated end plate by taking into account the C amount segregation shown with reference to FIG.

[0041]

As described above in detail, according to the present invention, a dome portion and a flange portion can be integrally formed and a head plate having no welded portion can be formed with a small amount of force without requiring a powerful press device. The manufactured head plate is useful as a head plate of a large-sized pressure vessel in which there are few structural defects and safety is particularly required because there is no welded portion.

Further, by taking into account the segregation of C amount, the mechanical properties can be made uniform and the safety can be further improved.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a first embodiment according to claim 1 of the present invention, wherein (A) is before pressing and (B) is after pressing.

FIG. 2 shows a blank according to claim 2 of the present invention,
(A) is a cross-sectional view, (B) is a partial cross-section of a planar perspective, (C)
Is a partial sectional view of a bottom perspective view.

FIG. 3 shows a second embodiment according to claim 1 of the present invention,
(A) is before pressing and (B) is after pressing.

4A and 4B show a third embodiment of the present invention and a blank thereof, wherein FIG. 4A is a cross-sectional view, and FIG.

FIG. 5 is a sectional view showing a second embodiment of a blank material.

FIG. 6 is a sectional view showing a third embodiment of a blank material.

FIG. 7 is a sectional view showing a fourth embodiment of a blank material.

FIG. 8 is a sectional view showing a fifth embodiment of a blank material.

FIG. 9 is a process chart showing a procedure for producing a blank material.

FIG. 10 is a cross-sectional view of a blank material in which C segregation is taken into account.

FIG. 11 is a sectional view of a head plate in which C segregation is taken into account.

FIG. 12 is a diagram in which a position is specified to indicate cooling of each part of the end plate shown in FIG. 11;

13 is a diagram showing a cooling curve of each part shown in FIG.

14 is a diagram showing a heat treatment heating curve of each part shown in FIG.

FIG. 15 is a diagram showing tempering parameter values at respective positions shown in FIG. 12;

FIG. 16 is a configuration diagram of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Blank material 11 Flange 12 Concavity 13 Tapered surface 14 Thickening part 15 Upper die 16 Dies 16A Lower die

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Takeuchi 2-3-1 Shinhama, Arai-machi, Takasago City, Hyogo Prefecture Inside Kobe Steel, Ltd. Takasago Works (72) Inventor Michio Kiguchi 2-Hama, Araimachi, Takasago-shi, Hyogo Prefecture No.3-1 Kobe Steel, Ltd. Takasago Works (72) Inventor Eiichi Oku 2-3-1, Araimachi Shinhama, Takasago-shi, Hyogo Kobe Steel Co., Ltd. Takasago Works

Claims (9)

[Claims] A concave portion surrounded by a flange extending over the entire circumference of the disk, and an outer peripheral thickened portion is formed by a tapered surface which gradually increases in thickness from the center of the disk to the outer surface in the radial direction; Making a blank material of a shape connected to the flange through the outer peripheral thickening portion, when mounting the blank material to the lower die or die of the press device, the outer peripheral thickening portion in the opening of the lower die or die. A method for manufacturing a flange-integrated head plate for a pressure vessel, wherein the dome portion and the flange portion are integrally formed at a hot forming temperature by pressing an upper mold of a press device into the bottom surface of the recess. . 2. A concave portion surrounded by a flange extending over the entire circumference of the disk, and an outer peripheral thickened portion is formed by a tapered surface which gradually increases in thickness from the center of the disk to the entire surface in a radially outward direction. A blank material for a flange-integrated head plate of a pressure vessel, wherein the blank material has a shape connected to the flange via an outer peripheral thickening portion. 3. The blank of claim 2, wherein the concave portion has a tapered surface formed on the bottom surface or the surface opposite to the flange or on both surfaces thereof to provide an outer peripheral thickening portion. Wood. 4. At least one surface of the disk is a tapered surface that gradually increases in thickness from the center of the disk to the entire surface in the radial direction, and has a wedge-shaped thickened portion connected to the tapered surface. When a blank material is made and the blank material is mounted on a lower die or a die of a press device, the thickened portion is mounted in an opening of the lower die or the die, and then the upper die of the press device is mounted on the disk. A method of manufacturing a flange-integrated end plate for a pressure vessel, wherein the dome portion and the flange portion are integrally formed at a hot forming temperature by being pressed. 5. At least one surface of the disk is a tapered surface which gradually increases in thickness from the center of the disk to the entire surface in the radially outward direction. A blank material for a flange-integrated head plate of a pressure vessel, characterized in that the blank material has a shape as described above. 6. The pressure according to claim 5, wherein one surface of the disk is formed as a flat surface and the other surface is formed as a tapered surface, and a thickened portion having a wedge-shaped cross section is provided on the outer periphery of the disk. Blank material for end plate integrated with container flange. 7. Both surfaces of a disk are formed as tapered surfaces,
6. A flange integrated head plate for a pressure vessel, a method for producing the same, and a blank material therefor, according to claim 5, wherein a thickened portion having a wedge-shaped cross section is provided on the outer periphery of the disk. 8. A flange-integrated end plate of a pressure vessel in which a dome portion and a flange portion are integrally formed, wherein the dome portion has a low carbon content (carbon content).
A flange-integrated end plate for a pressure vessel, characterized in that the flange portion has a high C amount by volume. 9. A blank material having a flange surrounded by a flange or a wedge-shaped thickened portion extending over the entire circumference of a disk, wherein the C content of the recess and the flange or the thickened portion is such that the recess has a low C content. A blank material for a flange-integrated head plate of a pressure vessel, wherein the flange or the thickened portion has a high carbon content.