JPH10142386A - Structure having cross joint and its assembling production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide a spent fuel rack with high accuracy, high quality and cheap cost by providing a long partition plate with a plurality of notch holes and a short partition plate with projection parts capable of inserting in these notches, inserting these projection parts in the notches and combining the long partition plate and the short partition plate in grid and welding them for making up a plate structure fuel rack. SOLUTION: A long partition plate 3D and the projection parts 4 of a short partition plate 2E inserted in the notch holes 15 of it are butt-welded. Then, the short partition plate 2E is set on it and symmetrical positions in the left and the right are fillet-welded and the dimensions of the butt welding and fillet welding are limited to share so that stress concentration is prevented and crack generation is prevented. Therefore, a spent fuel rack which increase the storage density and has a high accuracy and high reliability can be produced. Besides, stress concentration due to welding can be prevented and crack generation can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure having a cruciform joint and a method of assembling and manufacturing the same, and more particularly to a cruciform joint suitable for a plate structure in which low elongation plates such as a stainless steel plate containing boron are combined and welded. The present invention relates to a structure having the same and an assembling and manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, a method of welding and assembling a structure having a cross joint such as a spent fuel storage rack is disclosed in, for example,
There is an example described in -80189. When described with reference to FIG. 2 for convenience, the long partition plates 3A to 3E and the short partition plates 2A to 2E inserted from below are integrated by plug welding.

[0003]

However, such plug welding has a problem in that the amount of welding increases and the welding shrinkage stress increases. Further, the welding stress is concentrated at the end of the plug welding, and the welding stress is greatly changed at the end. As a result, a material that does not stretch, such as stainless steel containing high boron, has the disadvantage that cracks occur. An object of the present invention is to reduce the amount of welding and welding shrinkage in welding a cruciform joint having a lattice-like joint using a material with low elongation, such as stainless steel containing high boron, and to reduce the amount of welding at the end of the cut hole. It is an object of the present invention to provide a structure having a cruciform joint capable of reducing the stress concentration of the above and reducing the change in welding stress at the end of the weld bead, and a method of assembling and manufacturing the same.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, a feature of the present invention is to provide a structure such as a rack having a lattice-like joint using a material with low elongation, for example, stainless steel containing high boron. As a means to prevent weld cracking
In the butt welding of the projection portion inserted from below and the long partition plate, the groove depth should not exceed 2/3 of the plate thickness, and a short partition plate installed on the long partition plate. In the fillet welding, the welding stress is reduced so that the leg length does not exceed 2/3 of the plate thickness. Furthermore, by shifting the bead end of the butt welding and the bead end of the fillet welding without being aligned, it is possible to prevent the occurrence of welding bead cracks by preventing the occurrence of welding stress from changing abruptly, and to further reduce the length of the welding bead. The ends of the butt welding and the fillet welding were removed from the corners of the cut holes of the partition plate to gradually reduce the stress applied to the corners of the cut holes to prevent cracks from being generated in the corners. The invention described in each claim will be described below. According to the first aspect of the present invention, a cross formed by inserting a projection of a short partition into a cut hole provided in a long partition, further mounting a second short partition on the projection, and sequentially welding and assembling the cross. In the structure having a joint, the end portion of the long partition plate and the end portion of the butt welding of the projection portion, and the end portion of the long partition plate and the end portion of the fillet welding of the second short partition plate are the end portion. The slits are not overlapped with the corners of the cut holes. According to this structure, since the corner of the notch hole where stress concentration is apt to be concentrated and the beginning and end of welding do not coincide with each other, stress concentration at the corner of the notch hole is reduced, and welding cracks are reduced. It is possible to obtain a fuel rack or the like having no plate structure. Further, the invention according to claim 2 provides a plurality of cut holes in the long partition plate, a protrusion that can be inserted into the cut hole is provided in the short partition plate, and the protrusion is inserted into the cut hole from below. After assembling, butt welding is performed, then a second short partition is installed from the upper side, and fillet welding is performed between the long partition and the long partition, and the long partition and the short partition are formed in a lattice shape. In the method of assembling and manufacturing a structure having a cruciform joint manufactured in combination, the beginning and end of the butt welding of the long partition plate and the projection are separated from the corner of the cutout hole and welded, and then the The end portion of the fillet welding between the long partition plate and the second short partition plate is welded away from the corner. According to this method, the corners of the cut holes provided in the long partition plate do not overlap with the beginning and end of the butt welding or fillet welding, so that welding cracks can be eliminated. According to a third aspect of the present invention, the groove depth of the butt welding does not exceed 2/3 of the thickness of the long partition plate and is equal to or longer than the leg length of the fillet welding, that is, the leg length is butt welded. Not more than the groove depth, the leg length of the fillet welding,
Since the leg length is not more than 2/3 of the plate thickness of the long partition plate, the welding amount per unit of the butt weld portion is reduced, while the leg length of the fillet weld is also reduced to reduce the welding shrinkage. Reduces force and suppresses welding cracks. Further, the invention according to claim 4 is characterized in that the respective ends of the fillet welding and the butt welding are shifted so as not to coincide with each other, so that the welding shrinkage force of the welding end does not suddenly change. And the occurrence of welding cracks can be prevented. The invention according to claim 5 is characterized in that:
Since there is a gap at a predetermined interval between the projections inserted into the cut holes, the butt welding of the projections and the corners do not overlap, so that welding cracks in the corners can be prevented. it can. The invention according to claim 6 is characterized in that the projection of the long partition plate is formed with a roundness of a predetermined radius or more at the root, so that the root of the projection can be prevented from cracking, and a cross joint is provided. The structural strength of the object can be improved.

[0005]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are assembly drawings of a fuel rack having a plate structure having a cross joint. FIG. 1 is an overall perspective view of a plate-structured rack according to the present embodiment, and FIG. 2 is a sectional view of the plate-structured rack shown in FIG. As shown in these figures, in the plate-structured rack, a long partition bottom plate 11 is installed horizontally on the sheet 1, and then a short partition plate 2A is installed vertically on the long partition bottom plate 11. Next, the long partition 3A is set on the short partition 2A. The long partition plate 3A is provided with a slit 15 in advance, and the short partition plate 2A is provided with a projection 4. The combination of the long partition plate 3A and the short partition plate 2A corresponds to the projection 4 provided on the short partition plate 2A.
Are inserted into the cutout holes 15 provided in the long partition plate 3A and are combined in a lattice shape.

As shown in FIG. 2, short partition plates 2B to 2E are provided.
In the same manner as the short partition plate 2A, a projection 4 is provided,
Also, the long partition plates 3B to 3D are provided with the cut holes 15 similarly to the long partition plate 3A. When assembling, the projections 4 of the short partitions 2B to 2E are inserted into the cutouts 15 of the long partitions 3B to 3D and assembled in a grid.

Here, for reference, a conventional welded portion of a rack will be described. 12 to 17 are views for explaining a conventional welded portion shape. FIG. 12 is a detailed view showing a conventional assembling method for the part A in FIG. The projection 14 of the short partition plate 2C installed vertically is formed shallowly, and a groove (plug welding) 9 is formed in the cutout 15 of the horizontal long partition plate 3C.
Is set, and is filled with the deposited metal 10. 13 to 15
Is an EE cross section of FIG. FIG. 13 shows that the projections 14 of the short partition 2C are inserted into the cut holes 15 of the long partition 3C.
Is inserted. Thereby, the groove 9 is formed. FIG. 14 shows a state where the weld metal 10 is formed by plug welding the groove 9 and the short partition plate 2D is set above the weld metal 10 thus formed. FIG. 15 shows a cross section of a welded portion obtained by performing fillet welding 10 between the short partition plate 2D and the long partition plate 3C.

FIG. 16 shows a cross section taken along line FF of FIG. The plug welding 9 is implemented in the FF section of FIG. Since the plug welding 9 is rectangular and is welded to a thickness corresponding to the plate thickness, the welding amount increases and the welding shrinkage stress also increases. Further, since welding is performed up to the end of the cut hole 15, stress concentration tends to occur at the corner at the end. FIG. 17 shows G-
G section. In FIG. 17, the end of the plug weld 9 is located at the corner 16 where welding stress of the cut hole 15 is likely to occur.
Base material cracks 12 and weld bead cracks 13 have occurred.

As described above, in this conventional method, the notch hole 15 formed in the long partition plate 3C and the groove 9 formed by the short partition plate 2C are plug welded. The welding amount increases, and as a result, the welding shrinkage increases. In addition, welding is performed up to the corner portion 16 of the cut hole 15 where stress concentration is likely to occur. As a result, there is a defect that a base material crack 12 or a weld bead crack 13 is generated starting from the corner 16 of the cut hole 15.

Next, a fuel rack having a plate structure according to the present invention will be described with reference to FIGS. FIG. 3 is a detailed view of a portion A in FIG. The projections 4 provided on the short partition plate 2C are inserted into the cut holes 15 provided on the long partition plate 3C installed horizontally, and are combined in a lattice shape. In the present embodiment, the height of the projection 4 is made higher than that of the conventional one,
A predetermined gap 17 is provided between the corner portions 16 at both ends. In addition, as shown by a dotted line in the figure, a predetermined roundness 18 of, for example, about 1R is formed at the root of the protruding portion 4, so that the assembling strength can be improved.

FIGS. 4, 5, and 6 are cross-sectional views taken along the line BB of FIG. FIG. 4 shows the assembly of the long partition plate 3C and the short partition plate 2C. The groove 5 is provided in the notch hole 15 provided in the long partition plate 3C, and the projection 4 is provided in the short partition plate 2C. The protrusion 4 is inserted into the notch hole 15 so that butt welding can be performed in combination. It is. The groove depth of the groove 5 and the leg length of the fillet weld 7 of the long partition plate 3C and the short partition plate 2D do not increase the amount of welding and prevent the welding stress from increasing. The dimensions are determined so as to be / 3 or less, and if the strength is insufficient, the welding length is increased. On the other hand, when the depth of the groove 5 is made smaller than the leg length of the fillet weld 7 between the long partition plate 3C and the short partition plate 2D placed vertically, the contraction stress of the fillet weld 7 causes the contraction stress shown in FIG. Thus, a crack 19 occurs in the welded portion. For this reason, the lower limit of the depth of the groove 5 is set to be longer than the leg length of the fillet weld 7.

FIG. 5 shows a state in which the groove 5 provided on the long partition plate 3C of FIG. 4 is butt-welded 6 to the projection 4 of the short partition plate 2C, and then the short partition plate 2D is set from above. Is shown. FIG. 6 shows the fillet weld 7 of the long partition plate 3C and the short partition plate 2D set from above. The leg length of the fillet weld 7 is the short partition plate 2D and the long partition plate 3C.
The welding cross-sectional area is made small so as not to exceed 2/3 of the thickness of the sheet. The other side of the butt weld 6 and the fillet weld 7 is insufficient in strength, and the fillet weld 8 may be performed if necessary.

FIG. 7 is a sectional view taken along the line CC of FIG. 6, and FIG. 8 is a sectional view taken along the line DD of FIG. A gap 17 which is not affected by welding is provided in the butt weld 6 between the cutout hole 15 and the projection 4 and the fillet weld 7 by about 3 mm, and the cutout hole 15 has an end corner 16 where stress concentration is likely to occur. , So that the welding stress does not act directly,
Of the corner 16 was not cracked. Regarding insufficient strength due to a decrease in the welding cross-sectional area of the butt weld 6, the length of the projection 4 in the horizontal longitudinal direction is increased to secure the overall strength of the welded portion. Further, if the strength is insufficient, the fillet welding 8 can be performed on the opposite side of the fillet welding 7 if necessary.

As described above, in the present invention, the depth of the groove 5 of the cut hole 15 provided in the long partition plate 3 and the fillet welding 7
Are not more than 2/3 of the plate thickness, and the length of the fillet weld 7 is set within the depth of the groove 5. Further, the butt weld 6 is separated from the end of the cut hole 15 by 3 mm or more, so that the stress concentration is easily generated in the cut hole 15.
The influence of the welding shrinkage force on the corner portion can be avoided, and the stress concentration can be avoided. As a result, it is possible to provide a welding method that does not cause cracking even in high boron materials.

FIG. 9 shows another embodiment of the present invention. The present embodiment is different from the embodiment of FIG. 7 in that the fillet weld 7C of the long partition plate 3C and the upper short partition plate 2D is made larger than the length of the cut hole 15 in the longitudinal direction, and the weld end is formed. That is, it is removed outside the corner 16 at the end of the cut hole 15. In this method, the end of the butt welding and the end of the fillet welding are not made to coincide with each other, and the end of the weld portion where the distribution of the welding stress tends to change is separated from the end of the cut hole. Thus, the cut hole 15
No cracking occurs because the weld bead is not stopped at the end.

FIG. 10 shows still another embodiment of the present invention. This embodiment is different from the embodiment of FIG.
The fillet weld 7 is shorter than the length of the butt weld 6. The end of the butt weld 6 does not coincide with the end of the fillet weld 7 so that the stress generated at the beginning and end of the bead does not suddenly change. Therefore, the stress is not concentrated on the end of the cutout hole 15 and the change in stress is not increased at the welded end, so that the stress is dispersed and no crack occurs.

As described above, a feature of these embodiments is to prevent weld cracking of a structure such as a rack having a lattice-like joint using a material with low elongation, such as stainless steel containing high boron. As means, the groove depth of the butt welding of the protrusion inserted from below and the long partition plate, and the leg length of the fillet welding of the long partition plate and the short partition plate installed thereon, The welding stress is reduced so as not to exceed 2/3 of the thickness and the leg length of the fillet welding is set within the groove depth of the butt welding. Furthermore, by shifting the bead end of the butt welding and the bead end of the fillet welding without being aligned, it is possible to prevent the occurrence of welding bead cracks by preventing the occurrence of welding stress from changing abruptly, and to further reduce the length of the welding bead. The ends of the butt welding and fillet welding were removed from the corners of the cut holes of the partition plate to gradually reduce the stress applied to the corners of the cut holes, thereby preventing cracking at the corners.

That is, as shown in FIG. 3 and subsequent figures, a structure such as a fuel rack having a cruciform joint according to the present invention is provided in a notch hole 15 formed in a long partition plate 3C.
In a structure having a cross joint assembled by inserting the projection 4 of C and further placing the upper short partition 2D thereon and welding it sequentially, the long partition 2C and the projection 4 are butted. A feature is that the start and end of the weld 6 and the start and end of the fillet weld 7 between the long partition 2C and the upper short partition 2D are not overlapped with the corner 16 of the cut hole 15. Thereby, the corner portion 16 of the cut hole 15 and
Since the start and end portions of the welding are displaced and do not coincide with each other, the stress concentration at the corner portion 16 is reduced, and a fuel rack or the like having a plate structure without welding cracks can be obtained.

In the welding assembly method according to the present invention, the end of the butt weld 6 between the long partition plate 3C and the projection 4 is separated from the corner 16 of the cutout 15 by welding.
Next, since the end portion of the fillet weld 7 between the long partition plate 3C and the upper short partition plate 2D is separated from the corner portion 16 and welded, the notch provided in the long partition plate 3C is provided. Since the corner 16 of the hole 15 does not overlap with the beginning and end of the butt weld 6 or the fillet weld 7, welding cracks can be eliminated. In this case, the depth of the groove 5 of the butt weld 6 and the leg length of the fillet weld 7 should not exceed 2/3 of the thickness of the long partition plate 3C, and the leg length of the fillet weld 7 should be opened. Since the welding depth is suppressed within the depth of the first 5, the welding amount per unit can be reduced, the welding shrinkage force can be reduced, and welding cracks can be suppressed. Further, since the ends of the fillet weld 7 and the butt weld 6 are shifted from each other, the welding shrinkage force at the weld end does not change abruptly, so that the occurrence of weld cracks can be prevented.
In addition, since a gap of 3 mm or more was provided between the corners 16 at both ends of the cut hole 15 and the projection 4, the butt welding 6
And the corner portion 16 do not overlap, so that welding cracking of the corner portion 16 can be prevented. In addition, when the projections 4 of the long partition plate 3C have a radius of at least 1R at the root, cracks at the root of the projections can be prevented, and the structural strength of the structure having the cross joint can be improved.

As described above, according to these embodiments,
Conventionally, the welding amount was large in the joints of racks, which caused welding stress and caused cracks.However, in the case of joints such as high-boron grid-shaped plate-structured racks, the welding amount was not increased, and in order to prevent the welding stress from increasing. In addition, the dimensions of butt welding and fillet welding are regulated, and for insufficient strength due to a decrease in the welding cross-sectional area, the length of the protrusion is increased to increase the strength without increasing the welding shrinkage force per unit. To secure it. Further, if the strength is insufficient, if necessary, by performing fillet welding on the opposite side of the fillet welding, it is possible to provide a joint that does not generate cracks.

[0021]

According to the present invention, in a structure having a cross joint having a lattice-like joint using a material with low elongation, such as stainless steel containing high boron, and a method for assembling and manufacturing the same, a butt joint is provided. By regulating the dimensions of welding and fillet welding, it is possible to reduce the welding deposition amount and welding shrinkage force, reduce the concentration of stress at the end of the cut hole, and reduce the change in welding stress at the end of the weld bead. .

[Brief description of the drawings]

FIG. 1 is an assembly view of a plate-structured fuel rack showing one embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrows AA in FIG. 1;

FIG. 3 is an enlarged view of a portion A in FIG. 2;

FIG. 4 is a view taken in the direction of arrows BB in FIG. 3;

FIG. 5 is a sectional view showing the butt welding of FIG. 4;

FIG. 6 is a sectional view showing the fillet welding of FIG. 5;

FIG. 7 is a side view showing butt welding and fillet welding, as viewed in the direction of arrows CC in FIG. 6;

FIG. 8 is a top view showing butt welding and fillet welding, as viewed in the direction of arrows DD in FIG. 7;

FIG. 9 is a top view showing butt welding and fillet welding according to another embodiment of the present invention.

FIG. 10 is a top view showing butt welding and fillet welding according to still another embodiment of the present invention.

FIG. 11 is a diagram showing cracks due to shrinkage stress in butt welding and fillet welding.

FIG. 12 is an enlarged view of a welded portion of the conventional fuel rack corresponding to FIG. 3 of the present invention.

FIG. 13 is a view taken along the line EE in FIG. 12;

FIG. 14 is a sectional view showing the plug welding of FIG. 13;

FIG. 15 is a sectional view showing the fillet welding of FIG. 14;

FIG. 16 is a view as viewed in the direction of arrows FF in FIG. 15;

FIG. 17 is a view as viewed in the direction of arrows GG in FIG. 16;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plate structure fuel rack base plate 2, 2A, 2B, 2C, 2D, 2E Short partition plate 3, 3A, 3B, 3C, 3D Long partition plate 4 Projection part 5 Long partition plate groove 6 Butt welding 7 Fillet Welding 8 Back welding 9 Plug welding 10 Plug welding welded metal 11 Long partition bottom plate 12 Base material crack generated from corner of cut hole 13 Crack generated in weld bead 14 Conventional projection 15 Cut hole 16 Corner of cut hole 17 Gap 18 Roundness 19 Shrinkage stress cracking of welded part

Claims (6)

[Claims] A cruciform joint formed by inserting a projection of a short partition into a cut hole provided in a long partition, further mounting a second short partition on the projection, and sequentially welding the cross. In the structure having, the end part of the butt welding of the long partition plate and the protrusion, and the end part of the fillet welding of the long partition plate and the second short partition plate, A structure having a cruciform joint, wherein the structure does not overlap with a corner portion of the cut hole. 2. A plurality of cut holes are provided in a long partition plate,
Protrusions that can be inserted into the cut holes are provided on the short partition plate, the protrusions are inserted into the cut holes from below, assembled, and then butt-welded.
A method for assembling and manufacturing a structure having a cruciform joint in which a short partition plate is installed and fillet welding is performed between the long partition plate and the long partition plate and the short partition plate are combined in a lattice pattern. In, the beginning and end of the butt welding of the long partition plate and the protruding portion is welded away from the corner portion of the cut hole, and then the long partition plate and the second short partition plate A method for assembling and manufacturing a structure having a cruciform joint, wherein the end of the fillet weld between the ends is welded away from the corner. 3. The method for assembling and manufacturing a structure having a cruciform joint according to claim 2, wherein a groove depth of the butt welding does not exceed 2/3 of a plate thickness of the long partition plate. And more than the leg length of the fillet welding, the leg length of the fillet welding,
A method for assembling and manufacturing a structure having a cross joint, wherein the length of the leg does not exceed 2/3 of the thickness of the long partition plate. 4. The method for assembling and manufacturing a structure having a cruciform joint according to claim 2, wherein ends of the fillet welding and the butt welding are shifted so as not to coincide with each other. An assembly manufacturing method for a structure having a joint. 5. The method for assembling and manufacturing a structure having a cruciform joint according to claim 2, wherein: between the corners at both ends of the cutout hole and the projection inserted into the cutout hole.
A method for assembling and manufacturing a structure having a cruciform joint, wherein a gap having a predetermined interval is provided. 6. A method of assembling and manufacturing a structure having a cruciform joint according to claim 2, wherein the protrusion of the long partition plate has a base rounded to a predetermined radius or more. An assembly manufacturing method for a structure having: