JP2006231412A - Apparatus for producing bottomed vessel and metal billet for hot-expanding formation - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vessel and a cylinder object excellent in the edge face shape without requiring labor for producing them. <P>SOLUTION: A metallic billet 200 which is used in a hot-press forming method for thick metal cylinder object or a cylindrical vessel has a cross-sectional shape of a square at the front side 200b in the press-forming direction and the length of the diagonal of the square is smaller than the inside diameter of a container. Further, the metallic billet has the cross-sectional shape of a circular shape at the rear side 200a in the press-forming direction, and its diameter is nearly equal to the inside diameter of the container. After heating the metallic billet to the press-forming temperature and a hot-expanding formation is carried out while piercing the center part of the metallic billet with a piercing punch operated with the press-machine and thus, the thick metal-made cylinder object or the cylindrical vessel is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thick container in which a body part and a bottom part are integrally formed, or a thick tube that can be used as a cylinder of a large press machine. The present invention relates to a manufacturing apparatus for a bottomed container capable of manufacturing a meat container or a thick-walled cylinder, and a hot billet forming metal billet.

  Containers with cylinder heights and diameters of several meters are used for casks for storing, transporting, and temporarily storing spent nuclear fuel generated from nuclear reactors and for cylinders used in large press machines. ing. Some of these containers have a thickness of about several tens of centimeters from the viewpoint of shielding γ rays or withstanding high pressure. Here, a conventional container that has been used for these uses will be described by taking a cask for storing, transporting, and temporarily storing spent nuclear fuel as an example.

  FIG. 29 is a cross-sectional view showing an example of a conventional cask. The cask 500 has a barrel 501a and a bottom 501b made of stainless steel or carbon steel, and forms a container 501. The cask 500 is disposed in the container 501 and contains a spent nuclear fuel assembly, and an outer periphery of the container 501. The neutron shield 503 is provided. The neutron shield 503 is filled in a space between the outer cylinder 504 and the container 501, and a plurality of heat transfer fins (not shown) are provided between the container 501 and the outer cylinder 504. The basket 502 is made of a material added with boron having neutron absorption ability.

  A stainless steel or carbon steel bottom plate 501b is TIG-welded (tungsten-inert gas welding) or SAW (submerged-arc welding). A neutron shielding material 506 is sealed in the bottom plate 501b. A primary lid 507 and a secondary lid 508 are attached to the upper portion of the container 501 with bolts. A neutron shielding material 509 is enclosed in the secondary lid 508.

  Γ rays generated from the spent fuel assembly are shielded by the body 501a, the bottom plate 501b, the primary lid 507, and the secondary lid 508. Neutrons are shielded by a neutron shielding material 503, a bottom plate 501b, and a neutron shielding material 506 enclosed in a secondary lid 508 and a secondary lid 508 provided on the outer periphery of the container 501. The decay heat of the spent fuel assembly is transmitted from the container 501 to the outer cylinder 504 through the heat transfer fins, and is radiated to the outside from there.

  Next, the method that has been used to produce the cask bottomed container shown in FIG. 29 will be described. 30-1 to 30-5 are explanatory diagrams illustrating an example of a method for manufacturing the cask bottomed container illustrated in FIG. 29. First, as shown in FIG. 30A, a metal billet 61 forged to a predetermined size is installed on an anvil 62 with a perforated hole, and punching is performed with a punch 63. Next, as shown in FIGS. 30-2 to 30-3, the mandrel 65 is passed through the hole 64 of the metal billet 61, and the hole 64 is widened with a hammer 66 while rotating. Subsequently, as shown in FIG. 30-4, the mandrel 67 is replaced with a large-diameter mandrel, and hollow forging is performed using a hammer 68. Thereby, the metal billet 61 is thinned and a cylindrical body is formed (FIG. 30-5).

  FIGS. 31A and 31B are explanatory diagrams illustrating a method of manufacturing a bottomed container by the Erhardt perforation method. This method is a method of forming the metal billet 200 into a cylinder by pushing the punch 410 into the metal billet 200 charged in the container. The metal billet 200 has a rectangular cross-sectional shape, and the diagonal length is equal to the inner diameter of the barrel 300 of the container. Moreover, since the metal billet 200 has a rectangular cross section, a space 350 exists between the metal billet 200 and the container (the upper stage in FIG. 30-1). When the metal billet 200 is inserted into the barrel 300 of the container and the punch 410 is pushed into the central axis of the metal billet 200, a metal flow is generated by the metal bulging action of the punch 410. The metal flow fills the space 350, and a part of the metal flow rises within the container body 300, so that the metal billet 200 is formed into a cylindrical shape (lower stage in FIG. 30-1).

  Further, the container with the bottom of the cask can also be manufactured by a backward extrusion pressing method (not shown). The backward extrusion press method is a method in which a metal billet having a circular cross section substantially equal to the inner diameter of the container is inserted into the container, and then the punch and the container are pressed by the compressive force of the punch pressed along the central axis of the metal billet. A metal flow is caused between. And it is the press work method which shape | molds a metal billet into a elongate cylindrical shape, raising a metal back.

  When the cylindrical body 501a is formed by any of the methods described above, the bottom plate 501b is welded to the lower part. Furthermore, in order to remove the thermal stress due to the welding, the container 501 is heat treated.

"Nuclear Nuclear Eye" (issued April 1, 1998: Nikkan Kogyo Publishing Production)

  However, in the conventional cask 500, since the bottom plate 501b is joined to the cylindrical body 501a by welding in order to form a bottomed container, it is necessary to perform heat treatment after welding. For this reason, there was a problem of requiring labor for manufacturing. Further, in the Erhardt perforation method, as shown in FIGS. 31A and 31B, the temperature drop at the metal tip that rises in the space 350 is damaged, and scratches and corrugated defects are generated. Furthermore, as shown in the figure, a defective shape portion (FIG. 31-2) is inevitably generated at the end of the cylinder. Therefore, a certain amount of this portion must be discarded, which causes a significant decrease in yield. It was.

  In the backward extrusion press method, the metal billet is formed while generating a high friction between the container and the metal billet. For this reason, the metal billet has a problem that many defects such as a wrinkle-like wrinkle and a streak-like wrinkle are generated on the surface, and it takes a long time for the repair work.

  Further, in both the Erhardt perforation method and the backward extrusion press method, when the size and thickness of the container to be molded are increased, the pressure required for pressing becomes extremely large. Therefore, with these methods, it has been difficult to produce a container having a large size and thickness. Therefore, the present invention has been made in view of the above, and provides either a container that does not require labor for manufacturing, or a container that can suppress defects that occur on the cylindrical end or the container surface. The goal is to achieve.

  In order to achieve the above object, a manufacturing apparatus for a bottomed container according to the present invention includes at least a container body and a container bottom, and the container body and the container bottom are in an axial direction of the container body. A molding container that is relatively movable with respect to the molding machine, and an overhanging portion that is attached to the press machine and is inserted into the molding container and engages with an inlet end of a barrel portion of the molding container. And a perforating punch for pressurizing the hot billet forming metal billet.

  This bottomed container manufacturing apparatus includes a container in which a bottom part and a body part can move relatively. For this reason, when the metal billet tries to move the barrel of the container in the direction opposite to the press direction during the hot expansion molding, the barrel of the container moves in the direction opposite to the press direction together with the metal billet. That is, since the barrel part of the container and the metal billet to be molded hardly move relative to each other, it is possible to suppress an increase in press pressure during hot expansion molding.

  An apparatus for manufacturing a bottomed container according to the next invention includes at least a container body portion and a container bottom portion which are divided in the axial direction, and the container body portion and the container bottom portion are in an axial direction of the container body portion. A molding container that is relatively movable, and a heat that is attached to a press machine and is inserted into the molding container and engages with an inlet end of a barrel portion of the molding container. And a perforating punch for pressurizing the metal billet for inter-expansion forming.

  In this bottomed container manufacturing apparatus, since the container body extends over the entire axial direction, even when forming a metal billet that is long in the axial direction, the deformation of the metal billet in the axial direction during hot expansion forming Can be absorbed by the entire container. Therefore, even when a container that is long in the axial direction is formed, an increase in press pressure can be suppressed.

  A hot billet forming metal billet according to the next invention has at least one flat surface on its side surface, and has an overhanging portion that engages with the inlet end of the forming container at the rear end in the pressing direction. It is characterized by that.

  Since the metal billet for hot expansion forming is provided with an overhanging portion at the end on the rear side in the pressing direction, the overhanging portion locks the metal billet to the container end during hot expansion forming. By this action, the restraint between the container and the metal billet becomes stronger, and the upsetting of the metal billet on the front side in the pressing direction can be suppressed. In addition, since at least one plane is provided on the side surface, an effect of bending the plane and an effect of suppressing the flow of metal also occur. Therefore, the press pressure can be kept small by these interactions. Moreover, this metal billet is provided with an overhanging portion on the rear side in the pressing direction of the metal billet in advance during manufacture. For this reason, since the process of forming an overhang | projection part in the back side of a press direction on the trunk | drum of a container before moving to a hot expansion molding process becomes unnecessary, the manufacturing process of a container can be simplified. The metal billet has a constant cross-sectional shape over the axial direction.

  The hot billet forming metal billet according to the next invention has a polygonal cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction, and an inlet end portion of the forming container on the rear side in the pressing direction. An overhanging portion for engagement is provided.

  Since the metal billet for hot expansion forming has a protruding portion on the rear side in the pressing direction, the protruding portion locks the metal billet to the container end during hot expansion forming. By this action, the restraint between the container and the metal billet becomes stronger, and the upsetting of the metal billet on the front side in the pressing direction can be suppressed. Further, since the cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction is formed in a polygon, an action of bending this plane and an action of suppressing the flow of metal also occur. Therefore, the press pressure can be kept small by these interactions. Moreover, this metal billet is provided with an overhanging portion on the rear side in the pressing direction of the metal billet in advance during manufacture. For this reason, since the process of forming an overhang | projection part in the back side of a press direction on the trunk | drum of a container before moving to a hot expansion molding process becomes unnecessary, the manufacturing process of a container can be simplified.

  The metal billet for hot expansion forming according to the next invention has a polygonal cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction, and the front side in the pressing direction is gradually narrowed toward the pressing direction. At least one or more stepped portions are provided, and an overhanging portion that engages with the inlet end portion of the molding container is provided on the rear side in the pressing direction.

  Since the metal billet for hot expansion forming has a protruding portion on the rear side in the pressing direction, the protruding portion locks the metal billet to the container end during hot expansion forming. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. Further, since the cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction is formed in a polygon, an action of bending each side of the polygon cross-section and an action of suppressing metal flow also occur. Furthermore, since the front side of the press is gradually reduced toward the press direction, the timing at which the metal fills the bottom of the molding container can be delayed. Therefore, the press pressure can be kept small by these interactions. Moreover, this metal billet is provided with an overhanging portion on the rear side in the pressing direction of the metal billet in advance during manufacture. For this reason, since the process of forming an overhang | projection part in the back side of a press direction on the trunk | drum of a container before moving to a hot expansion molding process becomes unnecessary, the manufacturing process of a container can be simplified. In addition, since the front side of the press is thinned in steps, molding becomes relatively easy.

  The hot billet forming metal billet according to the next invention is provided with at least one plane on at least one of the side surface on the front side in the pressing direction or the side surface on the rear side in the pressing direction, and the front side in the pressing direction is in the pressing direction. It is characterized in that at least one or more stepped portions are provided so as to become narrower stepwise, and an overhanging portion that engages with the inlet end portion of the molding container is provided on the rear side in the pressing direction.

  Since the metal billet for hot expansion forming has a protruding portion on the rear side in the pressing direction, the protruding portion locks the metal billet to the container end during hot expansion forming. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. Further, since at least one plane is provided on at least one of the side surfaces of the metal billet, an action of bending the plane and an action of suppressing the flow of the metal also occur. Furthermore, since the front side of the press is gradually reduced toward the press direction, the timing at which the metal fills the bottom of the molding container can be delayed. Therefore, the press pressure can be kept small by these interactions. Moreover, this metal billet is provided with an overhanging portion on the rear side in the pressing direction of the metal billet in advance during manufacture. For this reason, since the process of forming an overhang | projection part in the back side of a press direction on the trunk | drum of a container before moving to a hot expansion molding process becomes unnecessary, the manufacturing process of a container can be simplified. In addition, since the front side of the press is thinned in steps, molding becomes relatively easy.

  In the container manufacturing apparatus according to the present invention, the container barrel and the container bottom are attached to a molding container in which the container barrel and the container bottom can move relative to the axial direction of the container barrel, and a press working machine. A perforated punch for pressurizing the inserted metal billet was provided. For this reason, since the barrel part of the container and the metal billet to be molded hardly move relative to each other during the hot expansion molding, an increase in press pressure during the hot expansion molding can be suppressed.

  In the container manufacturing apparatus according to the present invention, the body of the molding container is further divided in the axial direction. For this reason, even when forming a metal billet that is long in the axial direction, the deformation of the metal billet in the axial direction during hot expansion molding can be absorbed by the entire container. Therefore, an increase in press pressure can be suppressed.

  In addition, since the metal billet for hot expansion forming according to the present invention has an overhanging portion at the end on the rear side in the pressing direction, the overhanging portion relates the metal billet to the container end during the hot expansion forming. Stop. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. In addition, since at least one plane is provided on the side surface, an effect of bending the plane and an effect of suppressing the installation of the metal billet are also produced. Therefore, the press pressure can be kept small by these interactions. Moreover, since this metal billet was previously provided with the overhang | projection part at the back side of the press direction of the metal billet at the time of manufacture, the manufacturing process of a container can be simplified.

  Moreover, in the metal billet for hot expansion forming according to the present invention, since the overhanging portion is provided on the rear side in the pressing direction, the overhanging portion locks the metal billet to the container end during the hot expansion forming. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. Further, since the cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction is formed in a polygon, there is an effect of bending each side of the polygonal cross-section and suppressing the metal billet from being set up. Therefore, the press pressure can be kept small by these interactions. In addition, since this metal billet is provided with an overhang portion on the rear side in the pressing direction of the metal billet at the time of manufacture, the process of forming the overhang portion on the rear side in the press direction becomes unnecessary, and the manufacturing process of the container is simplified. Can be.

  Moreover, in the metal billet for hot expansion forming of this invention, since the overhang | projection part was provided in the back side of the press direction, this overhang part latches a metal billet to a container edge part at the time of hot expansion molding. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. In addition, since the cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction is formed into a polygon, the above-described bending action and the action of suppressing metal flow also occur. Furthermore, since the front side of the press is made to become thinner stepwise in the pressing direction, the upsetting phenomenon can be suppressed in the final stage of the hot expansion molding, and the increase in press pressure can be suppressed. Therefore, the press pressure can be kept small by these interactions. In addition, since the metal billet is provided with the overhanging portion on the rear side in the pressing direction of the metal billet at the time of manufacture, the step of forming the overhanging portion on the rear side in the pressing direction becomes unnecessary.

  Moreover, in the metal billet for hot expansion forming of this invention, since the overhang | projection part was provided in the back side of the press direction, this overhang part latches a metal billet to a container edge part at the time of hot expansion molding. By this action, the restraint between the container and the metal billet is further strengthened, and the upsetting on the front side in the pressing direction can be suppressed. In addition, since at least one plane is provided on at least one of the side surfaces of the metal billet, the bending action and the action of suppressing the metal flow also occur. Further, since the front side of the press is gradually reduced toward the press direction, the upsetting phenomenon can be suppressed in the final stage of the hot expansion molding, and the increase in press pressure can be suppressed. Therefore, the press pressure can be kept small by these interactions. In addition, since the metal billet is provided with the overhanging portion on the rear side in the pressing direction of the metal billet at the time of manufacture, the step of forming the overhanging portion on the rear side in the pressing direction becomes unnecessary.

    Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Moreover, the manufacturing method of the container or cylinder which concerns on this invention is not limited to the method disclosed below. Furthermore, the constituent elements of the following embodiments include those that can be easily assumed by those skilled in the art.

(Embodiment 1)
FIGS. 1-1 and 1-2 are explanatory diagrams illustrating an example of a bottomed container according to Embodiment 1. FIGS. FIGS. 2-1 to 2-5 are explanatory diagrams illustrating manufacturing steps of the bottomed container 1 illustrated in FIGS. 1-1 and 1-2. 3A to 3C are perspective views showing an example of the metal billet 200 used in the first embodiment. As shown in FIG. 1-1, the bottom 1b of the bottomed container 1 according to the first embodiment is formed integrally with the body 1a, and as can be seen from FIG. The cross-sectional shape of the bottomed container 1 according to 1 is circular.

  In this manufacturing method, the bottomed container 1 is manufactured by hot expansion molding using a punch. First, the metal billet used for this manufacturing process is demonstrated. The metal billet 200 is manufactured by a molten metal mold ingot or a metal ingot cutting or free forging before entering a hot expansion forming process described below. In this forging process, it is desirable to form at least the front side of the metal billet in the pressing direction into a square cross section. By doing in this way, the effect of hot expansion molding can be used more effectively. In the first embodiment, a seamless metal billet 200 is manufactured by freely forging a metal lump, but the metal billet that can be used in the present invention is not limited to this.

  As shown in FIGS. 3-1 to 3-3, the cross-sectional shape of the metal billet 200 used in the present embodiment is circular on the rear side in the press direction (hereinafter abbreviated as the press rear side) 200a, and in the press direction. The front side (hereinafter abbreviated as the front side of the press) 200b is a quadrangle. The outer diameter of the press rear side 200a is larger than the diagonal length of the press front side 200b. The outer diameter of the press rear side 200a is substantially equal to the inner diameter of the container 300, and the diagonal length of the press front side 200b. Is shorter than the inner diameter of the barrel 300 of the molding container (FIG. 3-2). In addition, the internal diameter of the trunk | drum 300 of a molding container is shown with the broken line.

  Further, in this example, the cross section 970 perpendicular to the axial direction on the press front side 200b of the metal billet 200 includes a projected image 920 of the cross section perpendicular to the axial direction of the punch punch 410 (FIG. 3-2). And FIG. 3-3). In addition, the cross-sectional shape, dimension, or external shape of the metal billet 200 is not limited to this example. Other examples of billets applicable to the present invention will be described later.

  Next, the hot expansion molding process will be described. Prior to hot expansion forming, the metal billet 200 is heated to a temperature at which it is easy to perform hot expansion forming in a heating furnace (not shown). Since the heating temperature is determined by the material of the metal billet 200 and the like, it is not uniquely determined. In addition, in the carbon steel material used for the body of a cask for storing, transporting, and temporarily storing spent nuclear fuel, it is desirable to set the heating temperature to 1100 ° C to 1300 ° C. If this range is exceeded, the crystal grains become coarse and surface oxidation and decarburization occur, and the material becomes brittle and easily cracked. In the case of carbon steel, the heating temperature decreases within the above range as the carbon ratio increases. The metal billet 200 heated to a temperature at which it is easy to perform hot expansion molding in an electric furnace or the like is inserted into the trunk portion 300 of the molding container as shown in FIG.

  The metal billet 200 inserted into the barrel 300 of the forming container is installed by a large punch 400 having an outer diameter substantially equal to or larger than the outer diameter of the metal billet 200, and the metal billet 200 is pushed rearward in the press direction. The side 200a forms an overhang 201 on the container 300 (see FIG. 2-2). By providing this overhanging portion 201 at the end of the metal billet 200, it is possible to increase the restraining force in the axial direction of the metal billet 200 in the hot expansion forming process using a punch. And by this effect | action, the upset phenomenon of the metal billet 200 can be suppressed and the flow of the metal which goes to a direction opposite to a press direction can be reduced, Therefore The raise of a press pressure can be suppressed. At the same time, the shape of the end face of the bottomed container after molding can be improved.

  Even if the protruding portion 201 is not provided on the metal billet 200, the upsetting phenomenon is suppressed by the frictional force generated between the inner wall of the barrel portion 300 of the molding container and the side surface 200a on the rear side of the metal billet 200. Can do. However, in order to further reduce the pressing pressure and obtain a more complete end surface shape, it is desirable to provide the overhang portion 201.

  After the overhang portion 201 is formed at the end of the metal billet 200, the process proceeds to a hot expansion forming process by the punching punch 410. In order to make a hole in the center of the metal billet 200, a punch 410 is first placed on the end face center of the metal billet 200 by a positioning guide 310 attached to the barrel 300 of the molding container (see FIG. 2-3). Next, the punching punch 410 is pushed in by a press machine (not shown), and the metal billet 200 is hot expanded.

  When the punching punch 410 is pushed into the metal billet 200 by the press machine, the overhanging portion 201 of the metal billet 200 is engaged with the upper end portion of the barrel portion 300 of the molding container, and the upsetting phenomenon of the metal billet 200 is suppressed. . Moreover, the metal of the thick part in the press back side 200a of the metal billet 200 deform | transforms so that the container 300 may be filled (refer FIG. 2-4). Then, since the metal on the press rear side 200a is pressed against the inner wall of the barrel portion 300 of the forming container, the upsetting phenomenon of the metal billet 200 can be suppressed also by this action. By these actions, an increase in press pressure can be suppressed, and the shape of the end face of the bottomed container after molding can be improved.

  When the punching punch 410 is pushed into the metal billet 200, the metal immediately below the punching punch 410 becomes a hemispherical metal lump and moves to the press front side 200 b together with the punching punch 410. Because of this phenomenon, the metal billet 200 needs to have a larger cross-sectional area perpendicular to the axial direction on the press rear side 200a than on the press front side 200b.

  Further, when the punching punch 410 is pushed into the metal billet 200, due to the good plastic deformation property of the steel heated to a high temperature and the phenomenon that the metal lump is supplied from the press rear side 200a, the front of the metal billet 200 is pressed. The metal on the side 200b is deformed so as to be spread toward the inner wall side of the container 300. That is, it is hot expansion molding. When the punching punch 410 is pushed to a predetermined depth, the hot expansion molding is completed (see FIG. 2-5).

  Here, the kind of metal billet 200 applicable to the manufacturing method of the present invention will be described. As shown in FIG. 3A, a metal billet having a polygonal cross-sectional shape perpendicular to the axial direction on the front side of the press can be applied to the manufacturing method of the present invention. If such a metal billet is used, the metal billet is deformed so as to be expanded toward the inner wall side of the molding container in the hot expansion molding, so that the pressing pressure can be suppressed as compared with backward extrusion or the like. In addition, although the cross section perpendicular | vertical to the axial direction of the metal billet 200 shown to FIGS. 3-1 is a square, it is not restricted to this.

  Furthermore, the metal billet applicable to the manufacturing method of the present invention may have the following relationship. That is, the cross section perpendicular to the axial direction on the rear side of the press has a relationship including the projected image of the cross section perpendicular to the axial direction on the front side of the press. Further, the projection image of the cross section perpendicular to the axial direction on the rear side of the press has a relationship included in the inner side of the cross section of the molding container perpendicular to the axial direction. Here, the inner shape of the cross section of the molding container perpendicular to the axial direction may be the same as the projected image of the cross section perpendicular to the axial direction on the rear side of the press. It is desirable to use a metal billet that satisfies such a relationship when forming a large and thick bottomed container.

  The projection image will be described with reference to FIG. Here, the projected image is represented by a broken line and the cross section is represented by a solid line. The left side of FIG. 3-3 shows a state in which a cross section 950 perpendicular to the axial direction on the rear side in the pressing direction of the metal billet includes a projection image 900 of a cross section perpendicular to the axial direction on the front side in the pressing direction. The center of FIG. 3-3 shows a state in which a projection image 910 having a cross section perpendicular to the axial direction on the rear side in the pressing direction is included in the cross section inside 960 of the molding container perpendicular to the axial direction. Further, the right side of FIG. 3C shows a state of the punching punch in which the projection image 920 of the cross section perpendicular to the axial direction is included in the cross section 970 perpendicular to the axial direction on the front side in the pressing direction of the metal billet. . A projected image 920 of a cross section perpendicular to the axial direction on the right side of FIG. 3-3 is a projected image of the punching punch.

  “Inclusion” as used in the present invention means that all of the part surrounded by the broken line representing the projected image exists inside the part surrounded by the solid line representing the cross section. In the case where there is even a part surrounded by a broken line outside a part surrounded by a solid line, it is not included in the concept of “inclusion” in the present invention. Further, when the cross-sectional shape and the projected image are the same, they are not included in the concept of “inclusion” in the present invention.

  The projected image of the punch is preferably included in a cross section perpendicular to the axial direction of the metal billet on the front side of the press (see the right side of FIG. 3-3). However, the projection image perpendicular to the axial direction of the punching punch and the cross section perpendicular to the axial direction on the front side of the press of the metal billet may be the same. Further, the cross section perpendicular to the axial direction of the punching punch may include a projection image of the cross section perpendicular to the axial direction on the front side of the metal billet in the press.

  However, when the cross section perpendicular to the axial direction of the punch punch includes a projected image of the cross section perpendicular to the axial direction on the front side of the metal billet, the punch punch is formed when the cross sectional area of the punch punch increases. Since the wall thickness of the container body is reduced, the container body is easily broken during hot expansion molding. Therefore, when the cross section perpendicular to the axial direction of the punching punch includes a projection image of the cross section perpendicular to the axial direction on the front side of the metal billet, the punching punch is within the range where the container body does not break. It is necessary to suppress the cross-sectional area of.

  FIGS. 4-1 to 4-5 are explanatory diagrams illustrating examples of other metal billets according to the first embodiment. In these examples, as is clear from FIGS. 4-1 to 4-4, the cross section 950 perpendicular to the axial direction on the press rear side 200a of the metal billet 200 is perpendicular to the axial direction on the press front side 200b. The condition that the projected image 900 of the cross section is included (right side of FIG. 3-3) is satisfied.

  When the cross section of the press front side 200b as shown in FIG. 4A and FIG. 4B is a quadrangle, a force that is mainly directed outward in the radial direction of the barrel part 300 of the container at the time of hot expansion molding, The side surface of the provided metal billet is deformed by a force to bend toward the inner wall side of the barrel 300 of the molding container.

  FIG. 5 is a conceptual diagram showing the state of this deformation. The broken line in the figure shows the process in which the metal billet 200 expands toward the inner wall side of the barrel 300 of the molding container. When the cross section perpendicular to the axial direction is a quadrangle, the punch F is pushed in, so that a force F is applied from the center of the metal billet 200 toward the outside in the radial direction of the barrel 300 of the molding container. Since this force F bends the side surface of the metal billet 200 toward the inner wall side of the molding container, the metal billet 200 is expanded to the inner wall side of the molding container by the action of this bending. In particular, this bending action works effectively when a metal billet having a flat surface on the side surface is inserted into a forming container having a circular inner section.

  Therefore, if the metal billet is expanded by the action of the bending, the press pressure required for hot expansion molding can be reduced, and defects such as cracks generated during molding can be suppressed. Even if hot expansion molding is performed using a metal billet having a square cross section perpendicular to the axial direction and a perforated punch having a square cross section perpendicular to the axial direction, it is expanded by the above bending action. Accordingly, in this case as well, the press pressure required for hot expansion molding can be reduced, and defects such as cracks occurring during molding can be suppressed.

  When the cross section perpendicular to the axial direction of the press front side 200b as shown in FIG. 4-3 is circular, the above effect is slightly reduced, but the metal billet 200 is formed between the press front side 200b and the container body 300. There is a space between the inner wall. Therefore, the metal on the front side of the press expands into this space during the hot expansion molding, so that the expansion deformation of the metal billet is not constrained by the barrel portion 300 of the molding container, and the press pressure can be reduced. . Further, in this case, when the hot expansion is performed by using a punch having a square cross-sectional shape perpendicular to the axial direction, the above bending action works. For this reason, compared with the case where hot expansion molding is performed using a punch having a circular cross-sectional shape perpendicular to the axial direction, the press pressure can be reduced.

  As shown in FIGS. 4-1, 4-3, and 4-4, the cross section perpendicular to the axial direction of the press rear side 200a is circular, and the diameter thereof is substantially equal to the diameter of the barrel 300 of the molding container. In this case, the overhang portion 201 (see FIG. 3-2) formed on the trunk portion 300 of the molding container can be formed evenly. Therefore, at the time of hot expansion molding, the overhanging portion 201 can more effectively suppress the upsetting phenomenon of the metal billet 200, so that the press pressure can be kept low, and the shape of the end face of the container after molding can be reduced. Can be good.

  As shown in FIG. 4B, when the cross section of the press rear side 200a is a quadrangle and the diagonal length is substantially equal to the diameter of the barrel 300 of the molding container, the overhang 201 is the container barrel. It will be partially formed at the upper end of the part 300. For this reason, compared with the case where the overhang portion 201 is not provided, the effect of suppressing the upsetting phenomenon of the metal billet 200 is great, but compared with the case where the overhang portion 201 is formed over the entire circumference of the upper end of the barrel portion of the molding container. Then the effect is slightly reduced.

  Furthermore, the metal billet in which the cross-sectional shape perpendicular to the axial direction of the press front side 200b or the press rear side 200a of the metal billet 200 is formed in a pentagon or more or a triangular shape is also applied to the manufacturing method according to the first embodiment. Can do. Further, as shown in FIG. 4-4, when the side surface of the press front side 200b is provided with at least one or more planes, this portion is hot-extended by bending as described above, so the press pressure is kept low. An effect is obtained.

  Further, when the number of planes provided on the side surface of the metal billet 200 is three or more, that is, when the cross section perpendicular to the axial direction of the metal billet 200 is a triangle or more, the effect of suppressing the pressing pressure is increased. However, when the number of the planes increases, that is, when the corners of the polygonal cross-sectional shape perpendicular to the axial direction increase, the polygonal cross-sectional shape approaches a circle, so that the effect of suppressing the pressing pressure is reduced. Therefore, it is desirable to select the number of side surfaces on the press front side 200b within a range where the effect of suppressing the press pressure is low. Further, as long as the side surface of the metal billet 200 is provided with a flat surface, the metal billet of the present invention includes a case where the cross-sectional shape perpendicular to the axial direction of the metal billet is substantially drum-shaped as shown in FIG. .

  6A to 6C are perspective views showing other metal billets that can be applied to the first embodiment. The metal billet 200 is provided with a stepped portion on the press front side 200b so as to become thinner stepwise in the pressing direction. By doing in this way, the time which the metal of the press front side 200b is filled near the bottom part of the trunk | drum 300 of a shaping | molding container at the time of hot expansion shaping | molding can be delayed. Therefore, it is possible to suppress an increase in press pressure particularly in the final stage of the hot expansion molding. Moreover, since a minute flow in the pressing direction is formed by the stepped portion, the degree of forging of the molded product can be increased, and further, the shortage of forging can be prevented. Furthermore, since the change of the cross section is gradual, the manufacturing becomes easier as compared with the case where a taper described below is provided. Note that the number of the stepped portions is not limited to the above example, and can be appropriately increased or decreased depending on press conditions.

  Further, as shown in FIG. 6B, even if a taper is formed such that the press front side 200b is narrowed toward the press direction, the same operation and effect as when the step portion is provided on the press front side 200b can be obtained.

  Further, as shown in FIG. 6-3, when the metal billet 200 is manufactured, an overhang portion 201 that engages with the upper end portion of the molding container 300 may be provided in advance on the metal press rear side 200a. By doing in this way, the process which forms the overhang | projection part 201 in the press direction back side 200a of the metal billet 200 on the trunk | drum 300 of a container before hot expansion molding becomes unnecessary, and simplifies the manufacturing process of a container. be able to.

  FIGS. 7-1 to 7-3 are explanatory views showing other metal billets applicable to the first embodiment. As shown in FIGS. 7A to 7C, the metal billet 200 has a cross section perpendicular to the axial direction that is constant in the press direction, and one end of the metal billet 200 engages with the upper end of the molding container 300. A feature is that the portion 201 is provided. Even when such a metal billet 200 is used, a phenomenon in which the metal billet is placed at the time of hot expansion forming can be suppressed by the overhanging portion 201, so that an increase in press pressure can be suppressed. The cross-sectional shape of the metal billet 200 is not limited to a quadrangle, and the cross-sectional shape may be a polygon, and the side surface of the metal billet 200 may include at least one plane. The overhang portion 201 may be provided on the metal billet 200 in advance, or the overhang portion 201 may be provided after the metal billet 200 is loaded into the molding container 300.

  When the metal billet 200 is expanded and deformed so as to be spread toward the inner wall side of the container 300 (see FIGS. 2-4 and 2-5), a frictional force is generated between the metal of the metal billet 200 and the inner wall of the container 300. To do. This frictional force is due to the fact that the metal on the front side 200b of the press moves along the inner wall of the container body 300 to the side opposite to the press direction. In the intermediate process of the hot expansion molding in the manufacturing method according to the first embodiment, this frictional force is hardly generated. However, in the final stage of the hot expansion molding, the friction force is generated because the lower part of the molding container is filled with metal. The body 300 of the molding container tends to move in the direction opposite to the pushing direction of the punch 410 by this frictional force.

  Here, when the barrel 300 of the molding container and the bottom 301 of the molding container are fixed, the metal on the front side of the press moves against the frictional force, and the final stage of hot expansion molding. Then, an extra load is required. In order to solve this problem, the first embodiment has a structure in which the barrel 300 of the molding container and the bottom 301 of the molding container can move relatively.

  With such a structure, when the barrel 300 of the molding container is about to move in the direction opposite to the pushing direction of the punch 410 due to the frictional force, the punch 410 together with the metal billet 200 to be molded is also formed. It moves in the direction opposite to the pushing direction of (Fig. 2-5). That is, since the relative movement of the barrel 300 of the molding container and the metal billet 200 to be molded hardly occurs, an increase in load in the final stage of the hot expansion molding can be suppressed.

  In the present embodiment, not only the barrel 300 of the molding container and the bottom 301 of the molding container can move relative to each other, but also the barrel 300 of the molding container is divided to form the entire metal billet 200. The barrel 300 of the container is movable. By doing in this way, even if it is a case where a bottomed container long in the direction of an axis is formed, an increase in load in the final stage of hot expansion molding can be controlled.

  FIGS. 8-1 and FIGS. 8-2 are sectional views showing a divided portion of the trunk portion 300 of the molding container used in the first embodiment. As shown in FIG. 8A, the dividing part of the molding container body 300 has a structure in which the dividing parts overlap each other, and the molding container bodies 300a and 300b move relatively during hot expansion molding. May be. Further, as shown in FIG. 8-2, a concave portion is formed in the barrel portion 300a of one molding container, a convex portion is provided in the barrel portion 300b of the other molding container, and both are combined. At the time of expansion molding, the body portions 300a and 300b of the molding container may be relatively moved.

  In the present embodiment, the body portion 300 of the pre-molding container is divided into two parts, but the number of divisions can be appropriately changed according to the height of the metal billet 200. Further, only the barrel 300 of the molding container is divided, or the barrel 300 of the molding container and the bottom 301 of the molding container can be relatively moved without dividing the barrel 300 of the molding container. However, there is an effect of suppressing an increase in load during hot expansion molding.

  When the punch 410 is pushed to a predetermined depth set in advance, the hot expansion molding ends there (FIG. 2-5). In addition, as shown in the lower stage of FIG. 2-5, if a cylindrical spacer 302 is placed instead of the bottom 301 of the molding container and the bottom of the metal billet 200 is punched, a cylindrical object can be molded by this manufacturing method. When manufacturing a thick container with a length of several meters in the axial direction by the above manufacturing method, the press pressure can be reduced to a fraction of the conventional pressure due to the effect of the hot expandable diameter, so it can be manufactured with conventional equipment. . Moreover, since the bottomed container which united the bottom part and the trunk | drum can be manufactured by one process, it does not require a labor for manufacture and is suitable for mass production.

  The metal billet 200 that has been subjected to hot expansion forming is cooled to room temperature while performing natural cooling, forced cooling, or controlled cooling. Then, in order to adjust the shape of the end face, or to finish the outer shape or inner shape of the molded container to a desired dimension, cutting or the like may be performed.

  Next, the result of the specific example which manufactured the bottomed integral cylindrical container by the said method is shown. As a comparative example, a result of manufacturing a bottomed integrated cylindrical container by applying the Erhardt perforation method which has been conventionally used is also shown.

  Both the specific example and the comparative example were molded using a cylindrical container having an inner diameter of 943 mm. As the material of the cylindrical container, carbon steel having a carbon (C) ratio of 0.1% is used, but stainless steel may be used. First, the carbon steel metal billet was heated to 1250 ° C., and then forged into a metal billet having a different cross-sectional shape with a substantially T-shaped axial cross section by a free forging method. The front side of the metal billet has a square cross section with a diagonal length of 875 mm which is smaller than the inner diameter of the molding container, and the axial length is 1896 mm. The rear side of the press has a circular cross section having an outer diameter of 928 mm, which is substantially equal to the inner diameter of the molding container, and the length in the axial direction is 574 mm. The metal billet was heated again to 1250 ° C. and then charged into a molding container, and the center of the workpiece was hot-expanded with a punch to form an elongated cup-shaped cylindrical container having a length of 2420 mm and a thickness of 165 mm.

  On the other hand, in the comparative example, the same carbon steel as that of the specific example is used as the material of the cylindrical container, and after heating the metal billet to 1250 ° C., a square shape having the same cross-sectional shape over the entire length in the axial direction by a free forging method. Forged into a metal billet. The cross-sectional shape of this metal billet is a square, and its diagonal length is 928 mm, which is substantially equal to the inner diameter of the molding container. The axial length is 2470 mm. This metal billet was again heated to 1250 ° C. and then subjected to hot expansion molding to produce a cylindrical container having the same size as the above specific example.

Table 1 shows the evaluation results of the forming load and the end face shape by the both press methods. As is clear by comparing the two, it can be seen that according to the manufacturing method of the present invention, the press molding load is small and the product yield is high as compared with the conventional manufacturing method. In addition, since there were almost no defects in the end face shape found in the conventional manufacturing method, it was possible to finish the product with simple processing even after hot expansion molding.

  Here, an example in which the outer side and the inner side of the molded bottomed container are cut for use in a radioactive substance storage container such as a cask or a canister will be described. FIG. 9 is a schematic view showing an apparatus for cutting the outside of a hot-expanded bottomed container. The bottomed container 1 is placed on a rotation support base 154 provided with a roller and can freely rotate in the circumferential direction. A fixed table 141 is provided outside the bottomed container 1, and a movable table 142 that slides on the fixed table 141 in the axial direction of the bottomed container 1 is provided. A cutting tool 160 is attached to the movable table 142, and the outer periphery of the bottomed container 1 is cut by the cutting tool 160.

  A roller 161 attached to the rotation support base 154 is connected to a motor 162. The rotation of the motor 161 is transmitted to the bottomed container 1 via the roller 161 and rotates the bottomed container 1. When the motor 161 rotates and the bottomed container 1 starts to rotate in the direction of the arrow in the figure, the movable table 142 is moved in the axial direction of the bottomed container 1 by the servo motor 157 and the ball screw 158 provided at the end of the fixed table 141. The outer periphery of the bottomed container 1 is cut by the cutting tool 160 attached to the movable table 142. Further, if the outer periphery is cut by a face mill or the like to provide a flat surface, a container with a bottom having a polygonal shape as well as a circular shape can be formed in addition to a circular cross section perpendicular to the axial direction.

  Next, an example of cutting the inside of the molded bottomed container will be described. FIG. 10 is a schematic view showing an apparatus for processing the inside of the bottomed container. The processing apparatus 140 includes a fixed table 141 that penetrates the body body 101 and is placed and fixed inside the bottomed container 1, a movable table 142 that slides on the fixed table 141 in the axial direction, and a movable table 142. It comprises a saddle 143 positioned and fixed above, a spindle unit 146 comprising a spindle 144 and a drive motor 145 provided on the saddle 143, and a face mill 147 provided on the spindle shaft. Further, on the spindle unit 146, a reaction force receiver 148 in which a contact portion is formed in accordance with the inner shape of the bottomed container 1 is provided. The reaction force receiver 148 is detachable and slides in the direction of the arrow in the figure along a dovetail groove (not shown). The reaction force receiver 148 has a clamp device 149 for the spindle unit 146 and can be fixed at a predetermined position.

  Further, a plurality of clamping devices 150 are attached in the lower groove of the fixed table 141. The clamp device 150 includes a hydraulic cylinder 151, a wedge-shaped moving block 152 provided on the shaft of the hydraulic cylinder 151, and a fixed block 153 that abuts the moving block 152 on an inclined surface. The part side is attached to the groove inner surface of the fixed table 141.

  When the shaft of the hydraulic cylinder 151 is driven, the moving block 152 comes into contact with the fixed block 153, and the moving block 152 moves slightly downward (indicated by a dotted line in the figure) due to the wedge effect. Thereby, since the lower surface of the moving block 152 is pressed against the inner surface of the cavity 102, the fixing table 141 can be fixed inside the bottomed container 1.

  Further, the bottomed container 1 is placed on a rotation support base 154 made of a roller, and is rotatable in the radial direction. Further, by attaching a spacer 155 between the spindle unit 146 and the saddle 143, the height of the tool 147 on the fixed table 141 can be adjusted. The thickness of the spacer 155 is the same as the dimension of one side of the square pipe constituting the basket. The saddle 143 moves in the radial direction of the trunk body 101 by rotating a servo motor 156 provided on the movable table 142. Movement of the movable table 142 is controlled by a servo motor 157 and a ball screw 158 provided at the end of the fixed table 141. In addition, since the shape inside the bottomed container 1 changes as processing proceeds, it is necessary to change the reaction force receiver 148 and the moving block 152 of the clamp device 150 to those having an appropriate shape.

  FIGS. 11A and 11B are explanatory diagrams illustrating an example of a processing method inside the bottomed container 1. First, the fixing table 141 is fixed at a predetermined position inside the bottomed container 1 by the clamping device 150 and the reaction force receiver 148. Next, as shown in FIG. 11A, the spindle unit 146 is moved at a predetermined cutting speed along a fixed table (not shown), and the inside of the bottomed container 1 is cut by the tool 147. When the cutting at the position is completed, the clamp device 150 is removed and the fixed table 141 is released. Next, as shown in FIG. 11B, the trunk body 101 is rotated 90 degrees on the rotation support base 154, and the fixing table 141 is fixed by the clamp device 150. And it cuts with the tool 147 like the above. Thereafter, the same process as described above is further repeated twice.

  Next, the spindle unit 146 is rotated 180 degrees, and the cavity 102 is sequentially cut as shown in FIG. Also in this case, the processing is repeated while rotating the trunk body 101 by 90 degrees as described above. Thereafter, as shown in FIG. 11-4, a spacer 155 is attached to the spindle unit 146 to raise the position of the spindle unit. And the tool 147 is sent to an axial direction in the said position, and the inside of the bottomed container 1 is cut. By repeating this while rotating 90 degrees, the shape necessary for inserting a square pipe (not shown) for storing spent nuclear fuel is almost completed. In addition, it can process also with a general horizontal centering machine and a vertical type intermediate boring machine without depending on an exclusive machine.

  In the above description, the example in which the bottomed container 1 is laterally cut outside and inside is described. However, the bottomed container 1 is vertically cut and the outside and inside of the container are cut by the processing apparatus described below. May be.

  Specifically, the processing apparatus includes a rotary table for placing and rotating a bottomed container to be processed, a crane for placing the bottomed container on the rotary table, and moving the rotary base from the rotary table after processing, a base A movable table placed on the movable table, a saddle that can be moved on the movable table in a direction perpendicular to the movable direction of the movable table, a column that supports the arm that is placed on the saddle and moves up and down, and a column. It is attached to the vertical direction so that it can be moved up and down, is equipped with an attachment with a tool attached to the tip, and is provided with an arm that moves up and down with respect to the workpiece to process the workpiece. This processing apparatus can cope with various processes such as milling and drilling by changing the attachment attached to the tip of the arm.

  When processing the bottomed container is started, the bottomed container to be processed is placed on the rotary table by the crane, and after centering, the bottomed container is fixed on the rotary table. When the outside of the bottomed container is cut into a cylindrical shape, a cutting tool is attached to the attachment attached to the arm, and the bottomed container is cut with the cutting tool while rotating the rotary table at a predetermined rotation speed. Here, since the column to which the arm is attached is placed on the saddle, the arm can be moved by moving the saddle and the movable table. Therefore, an arbitrary cutting amount can be set by moving the arm to an arbitrary position. Further, since the arm can move up and down, the entire side surface of the bottomed container can be cut by moving this arm over the entire axial direction of the bottomed container. Since these movements require accuracy, it is desirable to move the movable table or the like by converting the rotational movement of a servo motor or stepping motor into a linear movement using a ball screw or the like.

  When cutting the outer periphery of a bottomed container having a circular outer shape in the radial direction and processing it into a polygonal column shape such as an octagonal column, for example, an attachment for a face mill is attached to the arm and the bottom container is removed by face milling. Cut the sides. When the arm is moved up and down to cut one surface over the entire axial direction of the bottomed container, the rotary table is rotated 45 degrees to process the next side surface. If this operation is repeated eight times, a bottomed container having an octagonal outer diameter in the radial direction can be manufactured. In this way, a bottomed container having an arbitrary polygonal cross section can be manufactured.

  When a bottomed container is used as a cask for storing spent nuclear fuel, it is desirable that the inner shape of the bottomed container be a shape that matches at least a part of the outer periphery of the basket that stores the spent nuclear fuel assembly. This is because the basket can be easily inserted and fixed in the container. An example of such a cross-sectional shape is shown in FIG. In order to form the inside of the bottomed container into such a shape, the attachment attached to the arm is changed to that for an end mill, for example, and the corners in the cross section are processed into a stepped shape.

  First, the saddle and the movable table are moved to move the arm over the bottomed container placed on the rotary table. Next, the arm is lowered and an attachment with an end mill is inserted into the bottomed container to position the end mill. Thereafter, the inside of the bottomed container is cut by giving a predetermined cutting amount. Cutting is performed several times, and once a predetermined shape is obtained, the first cutting is completed. When the necessary stepped shape is obtained at one corner, the turntable is rotated 90 degrees to process the next corner. When this operation is repeated four times, a cask bottomed container having a shape in the radial cross section as shown in FIG.

  In addition, when the inside of the bottomed container is cut, there is no escape space for cutting waste and cutting oil, so that cutting cannot be performed during the machining. For this reason, for example, it is desirable to remove cutting waste and the like from the inside of the bottomed container being processed by discharge means such as a vacuum pump.

  When the bottomed container is cut vertically, the processing of cutting scraps and the like is required as compared with the case where the container is placed horizontally, but the influence of deformation due to gravity can be reduced. Note that if the processing apparatus is configured upside down, the bottomed container is processed with the opening facing down, so that chips and the like can be easily discharged when the inside of the bottomed container is cut.

  Next, an example in which the bottomed container manufactured by the method of the present invention is applied to a cask that is a used nuclear fuel storage container will be described. 12-1 and 12-2 show the cask according to the embodiment of the present invention, FIG. 12-1 is an axial sectional view, and FIG. 12-2 is a radial sectional view. The cask 100 includes a bottomed container 1 having a basket 3 therein, a neutron shielding material 2 such as a resin or silicone rubber provided outside the bottomed container 1, and an outer cylinder 4 serving as an outer surface of the cask 100. It is composed of The bottomed container 1 is formed by molding the inner side and the outer side by the above-described cutting process.

  A primary lid 5 and a secondary lid 6 are provided at the top of the bottomed container 1, and a resin 7 for shielding neutrons is sealed in the secondary lid 6. The bottomed container 1 has a bottomed cylindrical shape formed by punching drawing and is made of carbon steel or stainless steel having a γ-ray shielding function.

  The neutron shielding material 2 is a polymer material containing a large amount of hydrogen and has a neutron shielding function. Further, a shielding body 9 enclosing a neutron shielding material 8 such as resin or silicone rubber is attached to the bottom of the bottomed container 1. The basket 3 is configured by arranging cells for containing spent nuclear fuel assemblies (not shown) in a lattice shape, and is made of a composite material of boron and aluminum.

  In addition, a metal gasket is provided between the primary lid 5 and the secondary lid 6 and the bottomed container 1 in order to ensure sealing performance as a pressure vessel. A plurality of copper internal fins 10 that conduct heat are welded between the bottomed container 1 and the outer cylinder 4, and the neutron shielding material 2 is in a fluidized state in a space formed by the internal fins 10. Injected and exothermic solidified. The primary lid 5 and the secondary lid 6 are made of carbon steel or stainless steel having a γ-ray shielding function.

  Since the cask 100 uses the bottomed container 1 with a bottom, it is possible to save the labor of manufacturing as compared with the case where a conventional bottom plate is welded. In addition, since the bottom plate is conventionally welded to the bottomed container, the hermeticity of the part is affected by the quality of the welding. There are very few problems of sealing in the part. In realizing the cask 100 of the present invention, the shape and material of the basket 3 in the bottomed container 1, the filling state of the neutron shielding material 2, the number and positions of the internal fins 10 are as shown in FIG. It is not limited to the example shown in FIG.

  The manufacturing method of the bottomed container according to the first embodiment is suitable for manufacturing a so-called thick container having a large thickness with respect to the diameter of the cylinder. Furthermore, the manufacturing method of the present invention is suitable for manufacturing a container having an axial length and an inner diameter of 1: 1 or more among so-called thick containers. If this ratio is exceeded, in general hot working, the press pressure increases as the forming progresses, but the manufacturing method according to the present embodiment does not increase the press pressure significantly at the beginning and end of processing. is there. Specifically, the manufacturing method according to the present embodiment is, for example, when manufacturing a cask or the like that is a large bottomed container having a thickness that is thick with respect to the diameter and that has an axial length of several meters. Especially suitable for.

  Conventionally, in order to manufacture such a large and thick-walled bottomed container, a tens of thousands of ton scale press machine has been required. However, when such a so-called thick large bottomed container is manufactured by the manufacturing method according to the present invention, the press pressure is only about 10,000 tons, so that an existing large press can be used without using a tens of thousands ton press. Can be molded by machine. Moreover, since the container after molding is excellent in the end face shape, and the surface and internal defects are hardly generated, the modification after molding becomes almost unnecessary. In addition, the manufacturing method of this invention is not restricted to such a thick large bottomed container, The canister which is a radioactive substance storage container with comparatively thin thickness can also be manufactured.

  In addition, according to the manufacturing method of the present invention, a cylinder for a large press machine, a container for a chemical plant, a reactor container for an oil refining plant, an ammonia synthesis tank, a container for a heat exchanger, a pressure vessel such as a boiler, or a water turbine for hydroelectric power generation. A casing for a large rotating device to be housed, a trunk of a submarine or a submarine can be manufactured. In addition to carbon steel, materials that can be used in the method of the present invention include non-ferrous metals such as nickel alloys, aluminum alloys, copper alloys, and magnesium alloys, as well as ferrous materials such as stainless steel and low alloy steel.

(Embodiment 2)
FIG. 13 is a perspective view showing a bottomed container according to Embodiment 2 of the present invention. The bottomed container 1 shown in FIG. 13 is characterized in that both its outer shape and inner shape are octagonal. Further, at least one of the outer shape and the inner shape of the container may be a polygon. Since the bottom container of the cask, which is the radioactive substance storage container, contains a basket that supports the assembly of fuel rods, especially in the cask, the inner shape of the bottom container is formed into a shape that matches the basket. Is preferred. Accordingly, the inner shape of the cask is preferably a polygonal shape rather than a circular shape. When the inner shape of the cask is a polygon, it is advantageous in terms of size and weight to make the thickness of the cask barrel as uniform as possible. desirable. This bottomed container can meet such a demand.

  FIGS. 14A and 14B are cross-sectional views illustrating a container body and a punch for manufacturing the bottomed container according to the second embodiment. The barrel 300 of the molding container has a substantially octagonal cross-sectional shape inside, and the outer shape of the punching punch 410 is also a substantially octagonal shape. If the barrel 300 of the molding container and the perforated punch 410 are used in the hot expansion molding method described in the first embodiment, an increase in load during the hot expansion molding is suppressed, and processing after the molding is completed. It is possible to manufacture a bottomed container having a polygonal cross section that suppresses surface defects of an object and has an excellent end face shape.

  15-1 to 15-4 are cross-sectional views perpendicular to the axial direction illustrating an example of a bottomed container that can be formed by the manufacturing method according to the second embodiment. A bottomed container having such a cross-sectional shape can be formed by appropriately changing the cross-section of the forming container barrel and the outer shape of the perforated punch. In particular, it is desirable that the punching punch 410 forming the inner shape of the cask is appropriately changed in accordance with the shape of the basket for storing the spent nuclear fuel. For example, if a punching punch having an inner cross-sectional shape as shown in FIG. 15-4 as its outer shape is used, an inner shape matching the shape of the basket can be formed.

  16-1 to 16-4 are axial cross-sectional views illustrating examples of bottomed containers that can be formed by the manufacturing method according to the second embodiment. These containers can be molded by matching the inner shape of the bottom of the molding container 300 and the tip shape of the perforated punch 410 with the shape of the bottom of the bottomed container. The container shown in FIG. 16-4 may be perforated at the bottom after molding, or may be molded by a perforating punch provided with a protrusion at the tip. The container formed in this way can be used for a container in which the bottom part formed integrally with the body part requires a curved surface instead of a flat surface. For example, the present invention can be applied to a casing for a large-sized rotating device that houses a water turbine for hydroelectric power generation.

(Embodiment 3)
FIG. 17 is an axial cross-sectional view showing a bottomed container according to Embodiment 3. The bottomed container 1 is characterized in that the body and the bottom are formed integrally, and at the same time, a spotted portion is formed on the bottom of the container. Conventionally, the bottom provided with a counterbore on a thick cylinder was attached by welding, but this manufacturing method requires a welding process and a heat treatment process after welding in addition to the process of providing a counterbore on the bottom. There was a problem that it took time and effort. According to the method for manufacturing a bottomed container according to the present invention, the bottom provided with the counterbore portion in one step can be formed integrally with the body, and thus there is an advantage that the manufacturing becomes very easy.

  18-1 to 18-5 are explanatory views showing a method of providing the spotted portion 800 in the bottomed container. As shown in FIG. 18A, before the punch 410 is pushed in and subjected to hot expansion molding, a cylinder 302 as a cylindrical member is provided in advance on the bottom 301 of the molding container. Here, the counterbore portion 800 can be formed only by the cylinder 302, but an annular metal plate 303 may be previously placed on the upper portion of the cylinder 302 so that the cylinder 302 can be easily taken out after the metal billet 200 is formed ( FIG. 18-1). The annular metal plate 303 has a slightly larger radial width than the radial width of the cylinder 302. By doing in this way, after shape | molding the metal billet 200 to a bottomed container, the cylinder 302 can be easily removed. In this case, the annular metal plate 303 is fitted into the bottom after the bottomed container is formed.

  When the counterbore 800 is formed only by the cylinder 302, it is desirable that the diameter of the cylinder on the side where the cylinder contacts the metal billet 200 be smaller than the diameter on the side where the cylinder contacts the bottom 301 of the molding container 300. That is, it is desirable to provide the cylinder 302 with a taper so that the diameter of the cylinder 302 increases in the pressing direction. By doing in this way, it becomes easy to remove the cylinder 302 from the metal billet 200 after hot expansion molding.

  The metal billet 200 is loaded into the container body 300 and placed on the cylinder 302 and the annular metal plate 303 (FIG. 18-2), and the punch 410 is pushed into the billet 200 to be hot-expanded into the shape of a bottomed container. Molding is performed (FIG. 18-3). An annular groove is formed by a cylindrical 302 and an annular metal plate 303 at the bottom of the metal billet 200 thus formed, as shown in FIG. Since the annular groove is merely provided as it is, the columnar portion which is a columnar portion existing inside the annular groove is cut by a cutting means (not shown) such as a gas burner in order to form the counterbore 800. To do. In this manner, a bottomed container having a counterbore 800 at the bottom can be manufactured (FIG. 18-5). The counterbore 800 may be finished by cutting or the like as necessary.

  Further, as shown in the lower part of FIG. 18-2, the counterbore 800 can be formed on the bottom of the bottomed container even if the column 304 is used instead of the cylinder 302. In this case as well, the metal plate 305 can be placed on the cylinder 304 and formed (lower stage in FIG. 18-3). Unlike the case where the cylinder 302 is used, when the column 304 is used, a counterbore 800 can be formed on the bottom of the bottomed container at the same time as the bottom (FIG. 18-5, lower stage). For this reason, although the process of cut | disconnecting the cylindrical part shown to FIGS. 18-4 is unnecessary, on the other hand, a bigger press pressure is required rather than the case where the cylinder 302 is used. Therefore, it is desirable to determine which one of the cylinder 302 and the column 304 is used in consideration of the performance of the press machine, the size of the bottomed container to be manufactured, and the like.

  When the counterbore 800 is formed only by the column 304, it is desirable to provide a taper that increases toward the front side in the pressing direction. That is, it is desirable that the cylinder 304 has a trapezoidal cylinder in the axial direction. By doing in this way, it becomes easy to remove the cylinder 302 from the metal billet 200 after hot expansion molding.

  The counterbore 800 having a desired cross-sectional shape can be formed by changing the cross-sectional shape perpendicular to the axial direction of the cylinder 302 and the column 304. For example, a counterbore portion 800 having a polygonal inner surface shape can be formed by making the cross-sectional shape perpendicular to the axial direction a polygonal shape. By doing in this way, since the spot part according to the external shape of the bottomed container can be formed, the radial thickness in the spot part can be kept constant.

  19-1 to 19-3 are axial cross-sectional views showing examples of a bottomed container that can be formed by the manufacturing method according to the present invention. The bottomed container 1 shown in FIGS. 19A and 19B can be formed by appropriately selecting the diameter of a cylinder or a column in the above description. FIG. 19-3 is an example in which a two-step counterbore 800 is provided at the bottom. In order to provide the two-step counterbore part 800, for example, it can be formed by placing a forming jig having a convex shape in the axial direction on the bottom of the metal billet 200, which is formed by stacking two cylinders having different diameters. . Moreover, it can also shape | mold by installing two cylinders from which a diameter and height differ in the bottom of the metal billet 200. FIG. Further, a step portion may be provided on the outer side surface of the cylinder with respect to the axial direction.

(Embodiment 4)
20-1 and 20-2 are axial sectional views showing a bottomed container according to Embodiment 4 of the present invention. This bottomed container 1 is characterized in that, in the manufacturing method shown in Embodiment 1, the overhang portion 201 (see FIG. 2-2) formed before hot expansion molding is used as it is as a flange of the container. . The cask, which is a used nuclear fuel storage container, encloses a helium gas of several atmospheres between the primary lid and the secondary lid, so that a large force is applied to the attaching portion of the secondary lid. In addition, since the secondary lid may be subject to a drop impact, the flange portion, which is the attachment portion of the secondary lid, is required to have a strong structure. In the container according to the present invention, the flange is formed integrally with the body, and since the diameter is larger than the diameter of the body, it is easy to take means such as arranging bolts in two rows. Therefore, the secondary lid can be more firmly fixed.

  In the conventional cask, since the flange portion is separately manufactured and welded to the cask body, it takes time and effort. According to the manufacturing method of the present invention, a thick-walled container with a bottom having an excellent end surface shape can be manufactured, so that the overhang 201 (see FIG. 2-2) formed on the end surface of the container is used as a flange with almost no processing. it can. Therefore, the welding and post-weld heat treatment steps can be omitted, and the manufacturing process can be simplified. In FIGS. 20-1 to 20-3, the overhang portion 201 (see FIG. 2-2) formed before the hot expansion molding is used as it is as the flange of the container, but this overhang portion 201 is used. It can be removed by cutting or the like, and the inside of the container opening can be processed to form a flange without an overhang that has been used so far. Also in this case, since the flange portion and the body are integrally formed, it is possible to sufficiently ensure the strength and the sealing performance.

(Embodiment 5)
Next, another method for manufacturing the bottomed container 1 will be described. FIG. 21-1 to FIG. 26-4 are explanatory views showing a manufacturing process of the bottomed container 1 of the cask 100 shown in FIGS. 12-1 and 12-2. The bottomed container 1 is formed by combining an upsetting process and a punching and drawing process.

  First, a ring-shaped first die 21, second die 22, and third die 23 are stacked on a slide table 20 of a press machine (not shown), and the first die 21 to the third die 23 have a first one. The pressurizing table 24, the second pressurizing table 25, and the third pressurizing table 26 are arranged to constitute a mold (FIG. 21-1). A punching punch 27 is located on the upper surface of the metal billet W. This punching punch 27 is pressurized by a stem 28 attached to a punch of a press machine (FIG. 21-2). The metal billet W is installed in the first die 21. The metal billet W is made of low carbon steel or stainless steel formed by vacuum casting, and has a truncated cone shape whose upper surface is circular and whose lower surface is smaller than the upper surface (the inclination angle is not shown). At the time of pressure processing, the metal billet W is heated within a range of 1000 ° C to 1200 ° C. The heating is performed in an electric furnace and is placed on the slide table 20 in a red state. Here, between the first die 21 and the metal billet W, the above-described cylinder 302 and the annular metal plate 303 (see FIG. 18A) may be provided, and a spotted portion may be formed at the bottom.

  Next, when the metal billet W is installed, the punching punch 27 is pressurized to perform upsetting (FIG. 21-3). Since the inner end portion of the first die 21 has an opening shape, the material flows between the punching punch 27 and the opening portion 21a of the first die, and the metal billet W is deformed into a dish shape. Subsequently, the stem 28 is lifted together with the first die 21 using the lifting jig 29 (FIG. 21-4), the slide table 20 is moved and carried out, and the first pressure table 24 is removed ((FIG. 21-5)). .

  When the metal billet W is lifted together with the first die 21, the spacer 30 is placed on the second die 22 in this state (FIG. 22-1). Subsequently, the slide table 20 is moved to carry in the mold (FIG. 22-2), the punching punch 27 is pushed down as it is, and the first die 21 is punched and drawn (FIG. 22-3). As a result, when the metal billet W passes through the first die 21, the top plate-like portion is squeezed, becomes a cup shape, and is positioned in the second die 22. Next, the stem 28 and the hanging jig 29 are retracted upward, the slide table 20 is moved, the metal billet W and the mold are carried out, and the spacer 30 is removed (FIG. 22-4).

  In this state, the punching punch 27 remains at the bottom of the metal billet W having a cup shape (FIG. 23-1). Next, with the spacer 30 removed, the stem 28 is lowered and pressurized by the punching punch 27 (FIG. 23-2). As a result, the metal billet W is further installed, the material flows from between the opening 22a of the second die 22 and the punching punch 27, and the metal billet W is deformed. Subsequently, the second die 22 is lifted together with the metal billet W using the lifting jig 29 (FIG. 23-3). In this state, the slide table 20 is moved to carry out the mold, and the second pressure table 25 is removed (FIG. 23-4).

  Next, the spacer 31 is installed on the third die 23 (FIG. 24-1). Subsequently, the slide table 20 is moved to carry in the mold (FIG. 24-2), the punching punch 27 is pushed down as it is, and the punching process is performed by the second die 22 (FIG. 24-3). Thereby, when the metal billet W passes through the second die 22, the abdomen is squeezed into a cup shape. Next, the stem 28 and the hanging jig 29 are retracted upward, the slide table 20 is moved, the metal billet W and the mold are carried out, and the spacer 31 is removed (FIG. 24-4). In this state, the punching punch 27 remains at the bottom of the metal billet W having a cup shape.

  Next, the slide table 20 is moved so that the metal billet W is positioned below the stem 28 (FIG. 25-1), the stem 28 is lowered and the metal billet W is pressurized by the punching punch 27 (FIG. 25-2). . As a result, the metal billet W is further installed, and the material flows from between the opening 23a of the third die 23 and the punching punch 27, and the metal billet W is deformed. Subsequently, the third die 23 is lifted together with the metal billet W using the lifting jig 29 (FIG. 25-3). In this state, the slide table 20 is moved to remove the third pressure table 26 (FIG. 25-4).

  Next, the spacer 32 is installed on the slide table 20 (FIG. 26-1). Subsequently, the slide table 20 is moved to carry the spacer 32 (FIG. 26-2), the punching punch 27 is pushed down as it is, and the punching and drawing process is performed by the third die 23 (FIG. 26-3). Thereby, when the metal billet W passes through the third die 23, the abdomen is squeezed. Next, the stem 28 and the hanging jig 29 are retracted upward, the slide table 20 is moved, the metal billet W is carried out, and the spacer 32 is removed (FIG. 26-4). In this state, the perforated punch 27 remains on the bottom of the metal billet W having a cup shape, but is used as the bottom of the bottomed container 1 as it is. It is also possible to use the punching punch 27 after removing it. When the slide table 20 is moved and the spacer 32 is carried in (FIG. 26-2), a cylindrical spacer 302 (see the lower stage in FIG. 2-5) is provided inside the spacer 32, and the metal billet W is formed by the punching punch 27. A cylindrical container can be formed also by this method by punching through the bottom of the container.

  When the above molding is completed, a predetermined heat treatment is performed to machine the inner surface of the bottomed container. The bottomed container 1 thus molded has a cross-sectional reduction rate from the metal billet W of about 40%. Moreover, compared with the case where a bottomed container is formed by normal backward extrusion molding, the bottom portion of the bottomed container becomes thicker and the cask weight is increased in comparison with the case of backward extrusion molding. Further, a press machine having a large pressure is required, and it may not be possible to manufacture depending on the scale of the bottomed container. On the other hand, according to the manufacturing method according to this embodiment, since the molding is performed by combining the upsetting and the punching-out drawing as described above, the pressure at the time of upsetting or drawing may be small. For this reason, it becomes possible to shape | mold using the large sized press processing machine conventionally used.

  FIGS. 27-1 to 27-4 are explanatory diagrams illustrating another method for manufacturing the bottomed container. In the above manufacturing method, as described above, the cylindrical punch punch 27 and the pressurizing bases 24 to 26 and the inner circular ring-shaped dies 21 to 23 are used. The shape is not limited. For example, as shown in 27-2, when the outer shape of the bottomed container 1 is an octagon, the internal shapes of the first die 21b to the third die may be an octagon. In this case, the pressure table 24b installed in the die is also octagonal.

  Further, when the inner shape of the bottomed container 1 is an octagonal shape, the punching punch 27c may be an octagonal prism as shown in FIG. The metal billet W in this case has an octagonal frustum shape (details of the taper angle are not shown). Further, when the inner shape of the bottomed container 1 is stepped, as shown in FIG. 27-4, the punching punch 27d may be a stepped prism. Although not shown, when the inner shape of the bottomed container is octagonal, the die 21b shown in FIG. 27-2 and the punching punch 27c shown in FIG. 27-3 may be used. Moreover, even if it is not an octagon, according to the manufacturing method of the said invention, it can shape | mold similarly to the above by changing shapes, such as a punching punch and a die. The punching punch 27c shown in FIG. 27-3 and 27d shown in FIG. 27-3 can also be applied to the manufacturing method according to the first embodiment.

  FIG. 28-1 to FIG. 28-6 are explanatory views showing embodiments of different manufacturing methods. This manufacturing method is realized by installing the stem 51 on the slide table 52 of the press machine, attaching the punch punch 53 to the top of the stem 51, and attaching the pressurizing table 54 to the punch 55 of the press machine. That is, as shown in FIG. 28A, the metal billet W is placed on the punching punch 53 and the punch 55 of the press machine is lowered to perform the upsetting process of the metal billet W by the first die 56.

  Next, when the lower end of the metal billet W is deformed into a dish shape, the punch 55 is retracted and carried out together with the metal billet W (not shown). Then, a plurality of spacers 57 are placed on top of the first die 56 and are carried below the punch 55. Further, the pressure table 54 is removed from the punch 55 in advance. When the punch 55 is lowered and pressed in this state, the metal billet W is squeezed by the first die 56 as shown in FIG. The first die 56 is retracted as it is.

  Next, the metal billet W is carried out in the same manner as described above, the spacer 57 is removed, the pressurizing table 54 is attached, and the metal billet W is carried again below the punch 55 (not shown). A second die 58 is attached to the punch 55 side. In this state, the punch 55 is lowered, and the metal billet W is placed and pressurized (FIG. 28-3). Subsequently, after the metal billet W is once carried out, a plurality of spacers 59 are installed on the second die 58 and the pressurizing table 54 is removed and carried in again. When the punch 55 is lowered and pressurized in this state, the abdomen of the bottomed container 1 is squeezed as shown in FIG. 28-4. The second die 58 retreats as it is.

  Subsequently, similarly to the above, the metal billet W is carried out, the spacer 59 is removed, and it is carried again below the punch 55 (not shown). A third die 60 and a pressure table 54 are attached to the punch 55 side. When the punch 55 is lowered in this state to pressurize the metal billet W, the metal billet W is further deformed as shown in FIG. 28-5. Then, once the metal billet W is carried out, a plurality of spacers 61 are installed on the third die 60 and the pressurizing table 54 is removed and carried in again. When the punch 55 is lowered and pressurized in this state, the abdomen of the bottomed container 1 is squeezed as shown in FIG. 28-6. The third die 60 is retracted downward as it is. The materials that can be used in the method of the present invention include non-ferrous metals such as nickel alloys, aluminum alloys, copper alloys, and magnesium alloys in addition to ferrous materials such as carbon steel, stainless steel, and low alloy steel.

Specific molding conditions will be described. When a low billet steel billet is heated to 1000 ° C. and the strain rate is 0.1 to 1 s, the deformation resistance is 1.5 to 3 kgf / mm ² . For example, assuming that the length of 1 m is punched out in 1 minute and the outer diameter is reduced from 2500 mm to 2200 mm with a 30-degree die, if the inner diameter is 1420 mm, the strain is
ln ((2500 ² -1420 ² ) / (2200 ² -1420 ² )) = 0.4
This is processed at time (2500-2200 / 2 / tan30 °) / (1000/60) = 15.6 sec. Therefore, the strain rate at this time is 0.025 ⁻¹ s.

Next, when the punching force is 0.3 kgf when the deformation resistance is 3 kgf / mm ² ,
3 × π / 4 × (2200 ² -1420 ² ) × ln ((2500 ² -1420 ² ) / (2200 ² -1420 ² )) × (1 + 0.1 × 0.3 / tan 30 °) + 4π / (6 · 3.√3) = 5460640kgf
It becomes. However, since the temperature is high at the initial stage, the punching force is half of 2730 tonf. In addition, the final thickness to prevent the bottom from coming out when
540640 / (3 / √3) / π / 1420 = 707 mm
Therefore, more is needed.

When the product length is 4885mm, the material length is
4885 × (2200 ² -1420 ² ) / 2200 ² = 2850 mm
Therefore, if the amount of upsetting at one time is 1/3 of 950 mm and the height to the mold restraining part is 700 mm of the final bottom thickness, the required upsetting force is
3 × π / 4 × 1420 ² × (1 + 0.3 × 1420/700/2) = 6196700 kgf
It becomes. With such a pressure, it can be molded by an 8000 ton press that has been used.

On the other hand, the extrusion force in the case of backward extrusion molding is
3 × π / 4 × 2200 ² × (ln (2200 ² / (2200 ² -1420 ² )) × (1 + 2 × 0.5 / tan 45 °)) + 4π / (4 · 3 · √3) = 19186103 kgf
Therefore, a 20000 ton press is required.

(Appendix)
In the hot press molding method for a thick metal cylinder or cylindrical container according to the next invention, the front side in the pressing direction is a member having a cross-sectional shape having an outer diameter smaller than the inner diameter of the container or an outer diameter of a diagonal length. A seam with a different cross-sectional shape consisting of a member with a cross-sectional shape with an outer diameter equivalent to the inner diameter of the container and a cross-sectional member with an outer diameter or diagonal length equivalent to the inner diameter of the container on the rear side The metalless billet is heated to a press processing temperature and then charged into a press molding container, and then pressed while punching the center of the workpiece of the seamless metal billet with a punch.

  In this press molding method, since the metal in the thick portion on the rear side of the press is processed while filling the container, the restraining force is increased, the upsetting phenomenon of the seamless metal billet is suppressed, and the end face shape is improved. In addition, the front side of the press is processed while being expanded to the side with the effect of good plastic working of steel that is supplied with metal from the rear side of the press and heated to a high temperature, thus filling the space of the container Therefore, it is manufactured from a seamless metal billet into a pressed product having a predetermined shape. As a result, the seamless metal billet reduces the press molding load and improves the product yield, and further, a press molded product having an excellent end face shape can be obtained.

  In the hot press molding method for a thick metal cylinder or cylindrical container according to the next invention, the front side in the pressing direction is a member having a cross-sectional shape having an outer diameter smaller than the inner diameter of the container or an outer diameter of a diagonal length. A cross-section member with an outer diameter of the diagonal length equivalent to the inner diameter of the container, and a cross section member having a cross-section shape with an outer diameter or diagonal length equivalent to the inner diameter of the container on the rear side After the metal-free billet is heated to the press processing temperature, it is inserted into the press-molding container, and the metal billet is pushed in so that the rear side in the pressing direction of the metal billet extends to the inlet side end of the molding container. After that, it is characterized in that it is pressed while punching the center of the workpiece of the seamless metal billet with a punch.

  This hot metal cylindrical or cylindrical container hot press forming method includes a step of extending the rear side of the metal billet in the press direction on the body of the container before hot expansion forming. Since this extending portion has an action of locking the metal billet to the container end during hot expansion molding, the restraint between the container and the metal billet becomes stronger, and upsetting on the front side in the press direction can be suppressed. . In addition, the front side of the press is processed while being spread laterally with the effect of good plastic working of the steel that is supplied with metal from the rear side of the press and heated to a high temperature, thus filling the container space Therefore, it is manufactured from a seamless metal billet into a pressed product having a predetermined shape. Due to these interactions, in this manufacturing method, a thick-walled container can be formed with a smaller pressing pressure than in the backward extrusion method or the like.

  The metal billet according to the next invention is characterized in that a cross-sectional shape perpendicular to the axial direction on at least the front side in the pressing direction is formed into a polygon.

  Since this metal billet for hot expansion forming has a polygonal cross-sectional shape perpendicular to the axial direction at least on the front side in the pressing direction, the metal billet is bent by the action of bending each side of the polygon during hot expansion forming. Expansion molding toward the inner wall. At the time of hot expansion molding, the metal billet expands into a space existing between the front side in the pressing direction and the container body, so that the phenomenon of metal flowing in the opposite direction to the pressing direction is suppressed. With these actions, this hot-extrusion metal billet can form a thick container having a ratio of axial length to diameter of 1 or more with a press pressure that is a fraction of that of the prior art. Moreover, the defect which arises in the edge part and surface of a container after shaping | molding can also be suppressed.

  A hot billet forming metal billet according to the next invention is characterized in that at least one of a side surface on the front side in the pressing direction or a side surface on the rear side in the pressing direction is provided with at least one flat surface.

  This hot-extrusion metal billet has at least one plane on the side surface, and is expanded by the action of bending the plane toward the inner wall of the molding container. Can be smaller than when the is a curved surface. Therefore, it is possible to form a thick container that is long in the axial direction with a smaller pressing pressure than in the past. Also, internal defects such as cracks can be reduced as compared with the case where the side surface is a curved surface.

  The metal billet for hot expansion forming according to the next invention is such that, in the metal billet for hot expansion molding, a taper that is tapered toward the pressing direction is further provided on the front side in the pressing direction of the metal billet. Features.

  The metal billet for hot expansion forming according to the next invention is the above-mentioned metal billet for hot expansion molding, and further, at least one or more so that the front side of the metal billet in the pressing direction is gradually reduced toward the pressing direction. The step portion is provided.

  Since the metal billet for hot expansion forming described above can delay the timing at which the metal on the front side in the press direction fills the periphery of the bottom in the final stage of the hot expansion forming, it is possible to suppress the installation of the metal billet. As a result, the press pressure during hot expansion molding can be reduced.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape of the outer diameter with a diagonal length equal to or less than the inner diameter of the container, and the rear side is press-molded after heating a metal billet having a cross-sectional shape with an outer diameter substantially equal to the inner diameter of the container to the pressing temperature And a step of pressing while punching the center of the workpiece of the metal billet with the punching punch.

  In this method, a metal billet having a square cross section whose diagonal length is smaller than the inner diameter of the container is used on the front side in the pressing direction, so that the pressing pressure is increased by the action of bending the side surface formed by the plane on the front side in the pressing direction. It can be made smaller than before. In addition, since the rear side of the metal billet in the pressing direction suppresses the upsetting of the front side in the pressing direction, defects on the end and the container surface can be suppressed, and the pressing pressure can be reduced.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape having an outer diameter with a diagonal length smaller than the inner diameter of the container, and a metal billet having a cross-sectional shape with a diagonal length substantially equal to the inner diameter of the container on the rear side is heated to a pressing temperature. It is characterized by comprising a step of charging into a post-press molding container and a step of pressing while punching the center of the workpiece of the metal billet with a punch.

  In this method, a metal billet having a square cross section whose diagonal length is smaller than the inner diameter of the container is used on the front side in the pressing direction, so that the pressing pressure is increased by the action of bending the side surface formed by the plane on the front side in the pressing direction. It can be made smaller than before. Further, since the metal billet used in this method has an angular cross-sectional shape on both the front side and the rear side in the pressing direction, the metal billet can be processed relatively easily as compared with the round cross-sectional shape.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape with an outer diameter smaller than the inner diameter of the container, and the rear side is a container for press molding after heating a metal billet having a cross-sectional shape substantially equal to the inner diameter of the container to the press working temperature And a step of pressing while punching the center of the workpiece of the metal billet with a punch.

  In the container manufacturing method described above, the metal billet is expanded to the space formed between the metal billet and the inner wall of the molding container because the diagonal length of the front side in the pressing direction is smaller than the inner diameter of the container. To do. For this reason, a press pressure can be made smaller than before. In addition, since the rear side of the metal billet in the pressing direction suppresses the upsetting of the front side in the pressing direction, defects on the end and the container surface can be suppressed, and the pressing pressure can be reduced.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape of the outer diameter with a diagonal length equal to or less than the inner diameter of the container, and the rear side is for press forming after heating a metal billet having a cross-sectional shape with an outer diameter substantially equal to the inner diameter of the container to the press working temperature A step of charging the container, a step of extending the rear side in the pressing direction of the metal billet to the inlet side end of the molding container by pushing the metal billet, and processing the metal billet with the punching punch And a step of pressing while drilling the center of the object.

  This manufacturing method of a cylinder or a container includes a step of extending the rear side of the metal billet in the pressing direction on the body portion of the container before hot expansion forming. Since this extending portion has an action of locking the metal billet to the container end during hot expansion molding, the restraint between the container and the metal billet becomes stronger, and upsetting on the front side in the press direction can be suppressed. . Further, since a metal billet having a square cross section whose diagonal length is smaller than the inner diameter of the container is used on the front side in the pressing direction, it is expanded by the action of bending each side of the square cross section. Further, the rear side of the metal billet in the pressing direction suppresses the upsetting of the front side in the pressing direction. Due to these interactions, in this manufacturing method, a thick-walled container can be formed with a smaller pressing pressure than in the backward extrusion method or the like.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape with a diagonal length smaller than the inner diameter of the container, and the rear side is heated to a pressing temperature with a metal billet with a diagonal length approximately equal to the inner diameter of the container. A step of inserting the metal billet into the press-side container, a step of extending the rear side of the metal billet in the pressing direction to the inlet side end of the molding container, and a punch And a step of performing press working while drilling the work center of the billet.

  This manufacturing method of a cylinder or a container includes a step of extending the rear side of the metal billet in the pressing direction on the body portion of the container before hot expansion forming. Since this extending portion has an action of locking the metal billet to the container end during hot expansion molding, the restraint between the container and the metal billet becomes stronger, and upsetting on the front side in the press direction can be suppressed. . Further, since a metal billet having a square cross section whose diagonal length is smaller than the inner diameter of the container is used on the front side in the pressing direction, it is expanded by the action of bending each side of the square cross section. Further, the rear side of the metal billet in the pressing direction suppresses the upsetting of the front side in the pressing direction. Due to these interactions, in this manufacturing method, a thick-walled container can be formed with a smaller pressing pressure than in the backward extrusion method or the like. Furthermore, since the metal billet used in this method has a square cross-sectional shape on both the front side and the rear side in the pressing direction, it is relatively easy to process the metal billet as compared with a metal billet having a round cross-sectional shape.

  In the method for manufacturing a cylinder or a container according to the next invention, when a metal billet is inserted into a molding container and the metal billet is hot expanded by a punching punch operated by a press press machine, the front side in the press direction Is a cross-sectional shape with an outer diameter smaller than the inner diameter of the container, and the rear side is for press molding after heating a metal billet having an outer diameter substantially equal to the inner diameter of the container to the press working temperature A step of inserting the metal billet, a step of extending the rear side of the metal billet in the pressing direction to an end of the inlet side of the molding container by pushing the metal billet, and a center of the workpiece of the metal billet with a punch. And a step of pressing while drilling.

  This manufacturing method of a cylinder or a container includes a step of extending the rear side of the metal billet in the pressing direction on the body portion of the container before hot expansion forming. Since this extending portion has an action of locking the metal billet to the container end during hot expansion molding, the restraint between the container and the metal billet becomes stronger, and upsetting on the front side in the press direction can be suppressed. . Moreover, since the rear side of the metal billet in the pressing direction is substantially the same diameter as the inner diameter of the molding container, it is possible to suppress the upsetting of the front side in the pressing direction. Due to these interactions, in this manufacturing method, a thick-walled container can be formed with a smaller pressing pressure than in the backward extrusion method or the like. Furthermore, since the metal billet used in this method has a circular cross-sectional shape on both the front side and the rear side in the pressing direction, it is relatively easy to process as compared with metal billets having different cross-sectional shapes.

  As described above, the manufacturing apparatus of a bottomed container and the hot billet forming metal billet according to the present invention are a thick-walled container in which a body part and a bottom part are integrally formed, or a thick-walled container that can be used as a cylinder of a large press machine. This is useful for manufacturing the thick container and particularly for manufacturing the thick container and the thick tube without requiring labor.

FIG. 3 is an explanatory diagram illustrating an example of a bottomed container according to Embodiment 1. FIG. 3 is an explanatory diagram illustrating an example of a bottomed container according to Embodiment 1. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 1-1 and FIGS. 1-2. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 1-1 and FIGS. 1-2. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 1-1 and FIGS. 1-2. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 1-1 and FIGS. 1-2. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 1-1 and FIGS. 1-2. 1 is a perspective view showing an example of a metal billet used in Embodiment 1. FIG. 1 is a perspective view showing an example of a metal billet used in Embodiment 1. FIG. 1 is a perspective view showing an example of a metal billet used in Embodiment 1. FIG. It is explanatory drawing which shows the other billet concerning Embodiment 1. FIG. It is explanatory drawing which shows the other billet concerning Embodiment 1. FIG. It is explanatory drawing which shows the other billet concerning Embodiment 1. FIG. It is explanatory drawing which shows the other billet concerning Embodiment 1. FIG. It is explanatory drawing which shows the other billet concerning Embodiment 1. FIG. It is the conceptual diagram which showed the mode of the deformation | transformation of a metal billet. It is a perspective view which shows the other metal billet applicable to Embodiment 1. FIG. It is a perspective view which shows the other metal billet applicable to Embodiment 1. FIG. It is a perspective view which shows the other metal billet applicable to Embodiment 1. FIG. It is explanatory drawing which shows the other metal billet applicable to Embodiment 1. FIG. It is explanatory drawing which shows the other metal billet applicable to Embodiment 1. FIG. It is explanatory drawing which shows the other metal billet applicable to Embodiment 1. FIG. FIG. 3 is a cross-sectional view showing a division part of the trunk part of the container used in the first embodiment. FIG. 3 is a cross-sectional view showing a division part of the trunk part of the container used in the first embodiment. It is the schematic which shows the apparatus which cuts the outer side of the bottomed container which carried out hot expansion molding. It is the schematic which shows the apparatus which processes the inner side of a bottomed container. It is explanatory drawing which shows an example of the processing method inside a bottomed container. It is explanatory drawing which shows an example of the processing method inside a bottomed container. It is explanatory drawing which shows an example of the processing method inside a bottomed container. It is explanatory drawing which shows an example of the processing method inside a bottomed container. It is an axial sectional view showing a cask according to an embodiment of the present invention. It is radial direction sectional drawing which shows the cask which concerns on embodiment of this invention 6 is a perspective view showing a bottomed container according to Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. 6 is a cross-sectional view perpendicular to the axial direction showing an example of a bottomed container that can be formed by the manufacturing method according to Embodiment 2. FIG. 6 is a cross-sectional view perpendicular to the axial direction showing an example of a bottomed container that can be formed by the manufacturing method according to Embodiment 2. FIG. 6 is a cross-sectional view perpendicular to the axial direction showing an example of a bottomed container that can be formed by the manufacturing method according to Embodiment 2. FIG. 6 is a cross-sectional view perpendicular to the axial direction showing an example of a bottomed container that can be formed by the manufacturing method according to Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. It is sectional drawing which shows the container cylinder and punch for manufacturing the bottomed container which concerns on Embodiment 2. FIG. 6 is an axial cross-sectional view showing a bottomed container according to Embodiment 3. FIG. It is explanatory drawing which showed the method of providing a counterbore part in a bottomed container. It is explanatory drawing which showed the method of providing a counterbore part in a bottomed container. It is explanatory drawing which showed the method of providing a counterbore part in a bottomed container. It is explanatory drawing which showed the method of providing a counterbore part in a bottomed container. It is explanatory drawing which showed the method of providing a counterbore part in a bottomed container. It is the axial direction sectional view showing the example of the bottomed container which can be fabricated with the manufacturing method concerning the present invention. It is the axial direction sectional view showing the example of the bottomed container which can be fabricated with the manufacturing method concerning the present invention. It is the axial direction sectional view showing the example of the bottomed container which can be fabricated with the manufacturing method concerning the present invention. 6 is an axial cross-sectional view showing a bottomed container according to Embodiment 4. FIG. 6 is an axial cross-sectional view showing a bottomed container according to Embodiment 4. FIG. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 12-1, FIG. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 12-1, FIG. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 12-1, FIG. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 12-1, FIG. It is explanatory drawing which shows the manufacturing process of the bottomed container shown to FIGS. 12-1, FIG. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the manufacturing process of the container with a bottom of the cask shown to FIGS. 12-1, 12-2. It is explanatory drawing which shows the other manufacturing method of the said bottomed container. It is explanatory drawing which shows the other manufacturing method of the said bottomed container. It is explanatory drawing which shows the other manufacturing method of the said bottomed container. It is explanatory drawing which shows the other manufacturing method of the said bottomed container. It is explanatory drawing which shows embodiment of a different manufacturing method. It is explanatory drawing which shows embodiment of a different manufacturing method. It is explanatory drawing which shows embodiment of a different manufacturing method. It is explanatory drawing which shows embodiment of a different manufacturing method. It is explanatory drawing which shows embodiment of a different manufacturing method. It is explanatory drawing which shows embodiment of a different manufacturing method. It is sectional drawing which shows an example of the conventional cask. It is explanatory drawing which shows an example of the method of manufacturing the bottomed container of the cask shown in FIG. It is explanatory drawing which shows an example of the method of manufacturing the bottomed container of the cask shown in FIG. It is explanatory drawing which shows an example of the method of manufacturing the bottomed container of the cask shown in FIG. It is explanatory drawing which shows an example of the method of manufacturing the bottomed container of the cask shown in FIG. It is explanatory drawing which shows an example of the method of manufacturing the bottomed container of the cask shown in FIG. It is explanatory drawing which shows the method of manufacturing a bottomed container by the Erhardt perforation method. It is explanatory drawing which shows the method of manufacturing a bottomed container by the Erhardt perforation method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Cask 1 Bottomed container 1a Body 1b Bottom 2 Resin 3 Basket 4 Outer cylinder 5 Primary lid 6 Secondary lid 7, 8 Resin 9 Shield 10 Internal fin 20 Slide table 21-23 Dice 21a Opening part 24-26 Pressurization Table 28 Stem 29 Suspension jig 30-32 Spacer W, 200 Metal billet 201 Overhang portion 202 Rim 203 Protrusion 300, 300a, 300b Container body 301 Container bottom 302 Cylindrical spacer 303 Annular metal plate 304 Column 305 Metal plate 310 Positioning guide 350 Space 400 Large punch 27, 410, 411 Drilling punch 800 Spot face 900, 910, 920 Projection image of cross section perpendicular to the axial direction 950, 960, 970 Cross section perpendicular to the axial direction

Claims (6)

A container having at least a container body and a container bottom, wherein the container body and the container bottom are movable relative to the axial direction of the container body; and
A punching punch that pressurizes a hot billet forming metal billet that is attached to a press machine and is inserted into the molding container and has an overhanging portion that engages with an inlet end of a barrel portion of the molding container. When,
An apparatus for producing a bottomed container, comprising: A container body and a container bottom part that are divided at least in the axial direction, the container body part and the container bottom part being movable relative to the axial direction of the container body part; and
A punching punch that pressurizes a hot billet forming metal billet that is attached to a press machine and is inserted into the molding container and has an overhanging portion that engages with an inlet end of a barrel portion of the molding container. When,
An apparatus for producing a bottomed container, comprising:   A hot billet forming metal billet comprising at least one flat surface on a side surface and an overhanging portion engaging with an inlet end portion of a forming container at an end portion on a rear side in a pressing direction.   A cross section perpendicular to the axial direction on at least the front side in the pressing direction is formed in a polygonal shape, and an overhanging portion that engages with the inlet end of the molding container is provided on the rear side in the pressing direction. Metal billet for hot expansion forming.   At least one step is provided so that the cross section perpendicular to the axial direction at least on the front side in the pressing direction is polygonal, and at least one step is provided so that the front side in the pressing direction becomes gradually narrower in the pressing direction. A hot billet forming metal billet comprising an overhanging portion that engages with an inlet end of a forming container on a rear side in the direction.   At least one flat surface is provided on at least one of the side surface on the front side in the pressing direction or the side surface on the rear side in the pressing direction, and the front side in the pressing direction is gradually reduced toward the pressing direction. A hot billet forming metal billet characterized by further comprising an overhanging portion that engages with an inlet end of the molding container on the rear side in the pressing direction.

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