JPH07284925A - Method for butt-welding tube materials - Google Patents

Abstract

PURPOSE:To prevent the stress corrosion cracking caused by the remained stress of welding. CONSTITUTION:The parts 7, 8 to be cut are before and formed at the inside part at least near the joining end part of two tube materials 1, 2 to be mutually joined with a butt-welding and chamfer parts 9, 10 extended in the peripheral directions are formed at the joining ends of both tube materials 1, 2. The welding work is performed along the peripheral directions of both tube materials 1, 2 from the outside of both tube materials 1, 2 to the welding beveling 11 constituted by facing the chamfer parts 9, 10 of the joining ends to form a welded seam 12 for joining both tube materials 1, 2. After that, the chips 7, 8 and the welded seam part 12a between chips 7, 8 are cut. By this method, the residual stress is reduced and the stress corrosion cracking can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butt welding method for pipe materials.

[0002]

2. Description of the Related Art Butt welding is carried out as one means for connecting two pipe members to each other.

FIG. 9 shows an example of butt-welding dimensions for pipe materials, in which chamfered portions 3 and 4 extending in the circumferential direction are formed at the respective connection ends of the two pipe materials 1 and 2 to be connected. The two pipe materials 1 and 2 are arranged so that they face each other at a predetermined distance, and the welding groove 5 formed by the double-sided chamfers 3 and 4 is connected to the welding pipe 5 from outside the pipe materials 1 and 2. Welding work is performed along the circumferential direction of both pipe materials 1, 2.

At this time, when the welded joint 6 is formed between the pipe members 1 and 2, so that the wall thicknesses of the pipe members 1 and 2 are relatively large with respect to the pipe diameter, it is indicated by S in FIG. When residual stress with such a distribution state occurs, and when it is thin,
The residual stress in the distributed state as shown by S in FIG.

10 and 11, reference numeral 1a indicates the inner surface of the pipe members 1 and 2, and 1b indicates the outer surface of the pipe members 1 and 2.

[0006]

However, in the above-mentioned butt welding method for pipe materials, if the above-mentioned residual stress is excessive, cracks (stress corrosion) due to the residual stress will occur in the vicinity of the welded joints 6 of both pipe materials 1, 2. There is a problem that cracks may occur.

[0007]

[Knowledge based on research results] As a result of intensive studies by the inventors in order to solve the above-mentioned problems, as a result, at least one of the inner part and the outer part of two pipes connected to each other by butt welding is surrounded by the pipe perimeter. We have come to the knowledge that residual stress is reduced when cutting is performed substantially evenly in the direction.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a pipe jointing method capable of reducing the residual stress generated in a welded joint based on the above findings.

[0009]

According to a first aspect of the present invention, cutting allowances 7 and 8 are formed in advance on at least the inner portions of the two pipe members 1 and 2 to be connected to each other by butt welding at least near the connecting ends. Chamfered portions 9, 10 extending in the circumferential direction are formed at the respective connection ends of the two pipe materials 1, 2, and the chamfered portions 9, 10 of the connection ends are formed.
Welding for connecting the pipe materials 1 and 2 by performing welding work from the outside of the pipe materials 1 and 2 to the welding groove 11 formed by facing the pipe materials 1 and 2 along the circumferential direction of the pipe materials 1 and 2. After the joint 12 is formed, the shaving allowances 7, 8 and the welded joint portion 12a between the shaving allowances 7, 8 are cut to provide a butt welding method for pipe materials.

In the second aspect of the invention, the cutting allowances 13 and 14 are formed in advance on at least the outer portions near the connecting ends of the two pipe materials 1 and 2 to be connected to each other by butt welding. A chamfer 1 extending in the circumferential direction at each connection end
5, 16 are formed, and the chamfered portions 15, 16 of the connecting ends are opposed to each other with respect to the welding groove 17 from the outside of the pipe materials 1, 2 along the circumferential direction of the pipe materials 1, 2. Welded joint 18 for connecting both pipe materials 1 and 2 by performing welding work by
Is formed, and then the cutting margins 13 and 14 and the weld joint portion 18a between the cutting margins 13 and 14 are cut to provide a butt welding method for pipe materials.

In a third aspect of the invention, two pipes 19, 20 to be connected to each other by butt welding are made thicker than a predetermined value, and the pipes 19, 20 are circumferentially connected to their respective connection ends. From the outside of both pipes 19, 20 to the welding groove 23 formed by forming the extended chamfers 21, 22 and confronting the chamfers 21, 22 of the connection ends, the circumference of the pipes 19, 20 is surrounded. A butt welding method for pipe materials is characterized in that welding work is performed along the direction to form a welded joint 24 that connects the pipe materials 19 and 20, and then the pipe materials 19 and 20 are cut to a predetermined size.

In a fourth aspect of the present invention, the cutting allowances 25, 26 are formed in advance by welding overlay on at least the inner portions of the two pipe materials 1, 2 to be connected to each other by butt welding in the vicinity of the connecting ends, and the cutting allowances 25, 26 are formed. After performing annealing treatment on 26,
Chamfered portions 9 and 10 extending in the circumferential direction are formed at the respective connection ends of the two pipe materials 1 and 2, and the two pipe materials are welded to the welding groove 11 formed by facing the chamfered parts 9 and 10 of the connection ends. Welding joint 1 for connecting both pipe materials 1 and 2 by performing welding work from the outside of the pipe materials 1 and 2 along the circumferential direction of the pipe materials 1 and 2.
2 is formed, and then the cutting margins 25, 26 and the welded joint portion 12a between the cutting margins 25, 26 are cut to provide a butt welding method for pipe materials.

In a fifth aspect of the present invention, the cutting margins 27, 28 are formed in advance by welding overlay on at least the outer portions of the two pipe materials 1, 2 to be connected to each other by butt welding in the vicinity of the connecting ends, and the cutting margins 27, 28 are formed. After annealing 28,
Chamfered portions 15, 16 extending in the circumferential direction are formed at the respective connection ends of the two pipe materials 1, 2, and the chamfered portions 15, 1 of the connection ends are formed.
Welding for connecting the pipe materials 1 and 2 by performing welding work from the outside of the pipe materials 1 and 2 along the circumferential direction of the pipe materials 1 and 2 to the welding groove 17 formed by facing each other. After forming the joint 18, the shaving allowances 27, 28 and the weld joint portion 18a between the shaving allowances 27, 28 are cut to provide a butt welding method for pipe materials.

[0014]

Therefore, according to the first aspect of the present invention, after the welding work is performed, the cutting margins 7 and 8 formed in advance inside the pipe members 1 and 2 and the weld joint portion 12a between the cutting margins 7 and 8 are welded. The residual stress due to is reduced.

In the second aspect of the present invention, after the welding work is carried out and the cutting margins 13 and 14 formed in advance on the outside of the pipe members 1 and 2 and the weld joint portion 18a between the cutting margins 13 and 14 are cut, the residue remains due to welding. Stress is reduced.

In the third aspect of the present invention, the residual stress due to welding is reduced by cutting the pipes 19, 20 to a predetermined diameter after carrying out the welding work.

In the fourth aspect of the present invention, after the welding work is performed, the welding allowances 25 and 26 preliminarily formed by welding and overlaying the inside of the pipe materials 1 and 2 and thereafter, and the weld joint portion 12a between the cutting allowances 25 and 26. Cutting and reduces the residual stress due to welding.

In the fifth aspect of the present invention, after welding work is carried out, the weld margins 27, 28 formed beforehand by welding overlaying and annealing on the outside of the pipe materials 1, 2 and the weld joint portion 18a between the trim allowances 27, 28. Cutting and reduces the residual stress due to welding.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual view of an embodiment of the butt welding method for pipe materials of the first invention, in which the same parts as those in FIG. 9 are designated by the same reference numerals.

Reference numerals 1 and 2 denote two pipe members to be connected to each other by butt welding, and cutting margins 7 and 8 are preliminarily formed in the inner portions of the both pipe members 1 and 2 in the vicinity of respective connecting ends.
Chamfered portions 9 and 10 extending in the circumferential direction are formed at the respective connection ends of the two pipe materials 1 and 2.

Then, the chamfered portions 9 and 10 of the above-mentioned connection ends.
So that they face each other at a predetermined interval.
2 is arranged and welding work is performed from the outside of both pipe materials 1 and 2 along the circumferential direction of both pipe materials 1 and 2 to a welding groove 11 constituted by facing chamfered portions 9 and 10. To form a welded joint 12 that connects the two pipe materials 1 and 2.

After that, the cutting margins 7 and 8 and the welded joint portion 12a between the cutting margins 7 and 8 are cut to finish the inner surfaces of the pipe materials 1 and 2 to be smooth.

According to the above, after performing the welding work, the cutting margins 7 and 8 formed in advance inside the pipe members 1 and 2 and the weld joint portion 12a between the cutting margins 7 and 8 are cut. Therefore, the residual stress due to welding is reduced, and the occurrence of stress corrosion cracking can be prevented.

Further, since the cutting allowances 7 and 8 are formed inside the pipe materials 1 and 2, the cutting allowances 7 and 8 can be cut by means such as boring, and the pipe materials cannot be moved after the welding operation. Easy to apply.

FIG. 2 is a conceptual diagram of an embodiment of the butt welding method for pipe materials of the second invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals.

Reference numerals 1 and 2 denote two pipe members to be connected to each other by butt welding. Cutting margins 13 and 14 are formed in advance on the outer portions of the two pipe members 1 and 2 near the respective connection ends. Chamfered portions 15 and 16 extending in the circumferential direction are formed at the respective connection ends of the pipe materials 1 and 2.

Then, the chamfered portions 15 and 1 at the above-mentioned connection ends.
The two pipe materials 1 and 2 are arranged so that they face each other at a predetermined interval, and the pipe materials 1 and 2 are external to the welding groove 17 formed by the facing double-sided chamfers 15 and 16. Then, a welding operation is performed along the circumferential direction of the pipe materials 1 and 2 to form a welded joint 18 connecting the pipe materials 1 and 2.

After that, the cutting margins 13 and 14 and the welded joint portion 18a between the cutting margins 13 and 14 are cut to finish the outer surfaces of the pipe materials 1 and 2 smooth.

According to the above, after performing the welding operation, the cutting allowances 13 and 14 formed in advance on the outer sides of the pipe materials 1 and 14, respectively.
Since the welding joint portion 18a between the cutting margins 13 and 14 is cut, the residual stress due to welding is reduced and the occurrence of stress corrosion cracking can be prevented.

Further, the cutting allowances 13, 1 are provided on the outer sides of the pipe materials 1, 2.
Since No. 4 is formed, the cutting allowances 13 and 14 can be cut by means such as lathe processing and can be applied to a pipe material that can be moved after welding work.

FIG. 3 is a conceptual diagram of an embodiment of the butt welding method for pipe materials of the third invention.

In this embodiment, as the two pipe members 19 and 20 to be connected to each other by butt welding, those having a wall thickness larger than the wall thickness of the pipe required at the time of completion are used.

Chamfered portions 21 and 22 extending in the circumferential direction are formed at the connection ends of the two pipe members 19 and 20, respectively.

Then, the chamfered portions 21 and 2 of the above-mentioned connecting ends.
Both pipe materials 1 so that 2 face each other at a predetermined interval.
Both pipe materials 19, 20 are attached to the welding groove 23 constituted by the double-sided chamfered portions 21, 22 in which 9, 20 are arranged.
A welded joint 24 for connecting both pipes 19 and 20 by performing welding work from the outside of the pipes along the circumferential direction of the pipes 19 and 20.
To form.

After that, the inner surfaces of both the pipe members 19 and 20 are finished to be smooth according to the required desired pipe diameter.

Depending on the target pipe diameter, both pipe materials 19,
The outer surface of 20 may be finished smooth.

According to the above, after the welding work is performed, the inner surfaces of the pipe members 19 and 20 are cut.
Residual stress due to welding is reduced, and the occurrence of stress corrosion cracking can be prevented.

Further, since the shaving allowance is the same as that of the pipe members 19 and 20 itself, the residual stress generated in the vicinity of the welded joint portion of the two pipe members 19 and 20 is further reduced as compared with the case where the two members are different.

FIG. 4 is a conceptual view of an embodiment of the butt welding method for pipe materials of the fourth invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals.

Reference numerals 1 and 2 denote two pipe members which are to be connected to each other by butt welding, and the cutting margins 25 and 26 are preliminarily formed on the inner portions of the two pipe members 1 and 2 in the vicinity of respective connecting ends by welding overlay. After the shaving margins 25 and 26 are annealed, chamfered portions 9 and 10 extending in the circumferential direction are formed at the connecting ends of the two pipe materials 1 and 2.

Then, the chamfered portions 9 and 10 at the above-mentioned connection ends.
So that they face each other at a predetermined interval.
2 is arranged and welding work is performed from the outside of both pipe materials 1 and 2 along the circumferential direction of both pipe materials 1 and 2 to a welding groove 11 constituted by facing chamfered portions 9 and 10. To form a welded joint 12 that connects the two pipe materials 1 and 2.

After that, the cutting margins 25 and 26 and the welded joint portion 12a between the cutting margins 25 and 26 are cut to finish the outer surfaces of the pipe materials 1 and 2 smooth.

According to the above, after performing the welding work, the cutting allowances 25, 26 previously formed inside the pipe materials 1, 2
Since the welding joint portion 12a between the cutting margins 25 and 26 is cut, the residual stress due to welding is reduced and the occurrence of stress corrosion cracking can be prevented.

Further, since the cutting allowances 25 and 26 are formed by the weld overlay, the material cost can be reduced.

FIG. 5 is a conceptual diagram of an embodiment of the butt welding method for pipe materials of the fifth invention, in which the same parts as those in FIG. 1 are designated by the same reference numerals.

Reference numerals 1 and 2 denote two pipe members which are to be connected to each other by butt welding, and cutting margins 27 and 28 are preliminarily formed by welding build-up on the outer portions of the both pipe members 1 and 2 in the vicinity of respective connecting ends. After the shaving margins 27 and 28 are annealed, chamfered portions 15 and 16 extending in the circumferential direction are formed at the connection ends of the two pipe materials 1 and 2.

Then, the chamfered portions 15 and 1 at the above-mentioned connection ends.
The two pipe materials 1 and 2 are arranged so that they face each other at a predetermined interval, and the pipe materials 1 and 2 are external to the welding groove 17 formed by the facing double-sided chamfers 15 and 16. Then, a welding operation is performed along the circumferential direction of the pipe materials 1 and 2 to form a welded joint 18 connecting the pipe materials 1 and 2.

After that, the cutting margins 27 and 28 and the welded joint portion 18a between the cutting margins 27 and 28 are cut to finish the outer surfaces of the pipe materials 1 and 2 smooth.

According to the above, after the welding work is carried out, the cutting allowances 27, 28 previously formed inside the pipe members 1, 2 are formed.
Since the welding joint portion 18a between the cutting margins 27 and 28 is cut, the residual stress due to welding is reduced and the occurrence of stress corrosion cracking can be prevented.

Further, since the cutting allowances 27 and 28 are formed by weld overlay, the material cost can be reduced.

FIG. 6 is a stress diagram showing the decreasing tendency of the residual stress which is reduced by the butt welding method of the pipe materials shown in FIGS.
Inner surfaces of 2, 19, 20 and 1b are pipe materials 1, 2, 19, 20
, S1 is the residual stress before cutting the cutting allowance, S2
Indicates the residual stress after cutting the cutting allowance.

FIG. 7 shows an embodiment in which the pipe butt welding method of the present invention is applied to a mounting structure of a stub tube 29 of a control rod drive mechanism to a lower end plate portion 31 of a reactor pressure vessel.

The stub tube 29 at the time of completion has a thickness larger than that required for the stub tube 29, and the inner surface has a thickness that can be used as a cutting allowance 30, and is drilled at a predetermined position of the lower end plate portion 31 for mounting the stub tube 29. The connecting end of the material of the stub tube 29 having the same inner diameter as the through hole 32 is formed into a predetermined shape corresponding to the inner surface of the lower end plate 31 of the through hole 32, and the connecting end is circumferentially formed. Chamfer 3 extending to
3 is formed.

The stub tube 29 is formed so that the connection end chamfered portion 33 of the material of the stub tube 29 faces the inner surface of the lower mirror plate portion 31 in which the through hole 32 is formed at a predetermined interval. Then, a hollow metal pad 34 is fitted inside the confronting portion of the through hole 32 and the material of the stub tube 29.

Then, the inner surface of the lower end plate portion 31 and the material of the stub tube 29 which are opposed to each other are connected to each other at both ends of the chamfered portion 3.
The welding groove 35 constituted by 3 and 3 is welded from the outside of the material of the stub tube 29 along the circumferential direction of the material of the stub tube 29 to perform the welding work.
A welded joint 36 for connecting the material of No. 9 and the lower end plate portion 31 is formed.

After that, the material of the stub tube 29 and the inner surface of the through hole 32 are cut together with the contact metal plate 34 to complete the stub tube 29 and the through hole 32 having desired dimensions. The reference numeral 31a is a weld overlay portion formed on the inner surface of the lower end plate.

According to the above, after performing the welding operation, the inner surface of the material of the stub tube 29 is cut, so that the residual stress due to welding is reduced and the occurrence of stress corrosion cracking can be prevented.

In the embodiment shown in FIG. 7, the inner diameters of the stub tube 29 and the through hole 32 are set to desired inner diameters without finishing allowances, and instead of the pad 34, as shown in FIG. Shaving allowances 7 and 8 shown in FIG. 4 or Shaving allowances 2 shown in FIG.
A cutting margin similar to that of Nos. 5 and 26 may be formed on the inner side of the stub tube 29 and the through hole 32 in the vicinity of the connection end, and after the stub tube 29 and the lower end plate portion 31 are welded, the cutting margin may be removed by cutting. .

FIG. 8 is a residual stress distribution diagram after cutting the inner surface of the stub tube 29 in which the Inconel pipe material is welded to the lower end plate portion 31 having the Inconel welding overlay on the inner surface of the low alloy steel material by the Inconel welding rod. This is an example, usually 30
Kg / mm ² approximately of the residual stress indicates that they are reduced to 16Kg / mm ² max. In the figure, S3 represents the residual stress on the outer surface side of the stub tube 29, and S4 represents the residual stress on the inner surface side of the stub tube 29.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0062]

According to the butt welding method for pipe materials of the present invention, various excellent effects as described below can be obtained.

I) It is possible to reduce the residual stress after welding and prevent the occurrence of stress corrosion cracking.

II) It can be applied to welding a stub tube of a reactor pressure vessel, and the reliability of the welded portion can be improved.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an outline of an embodiment of a butt welding method for pipe materials of the first invention.

FIG. 2 is a conceptual diagram showing an outline of an embodiment of a butt welding method for pipe materials of the second invention.

FIG. 3 is a conceptual diagram showing an outline of an embodiment of a butt welding method for pipe materials of the third invention.

FIG. 4 is a conceptual diagram showing an outline of an embodiment of a butt welding method for pipe materials of the fourth invention.

FIG. 5 is a conceptual diagram showing an outline of an embodiment of a butt welding method for pipe materials of the fifth invention.

FIG. 6 is a stress distribution diagram showing a tendency of reducing residual stress of the pipe material related to FIGS. 1 to 5;

FIG. 7 is a conceptual diagram showing an outline of one embodiment in which the butt welding method for pipe materials of the present invention is applied to a mounting structure of a stub tube of a control rod drive mechanism to a lower end plate of a reactor pressure vessel.

FIG. 8 is a residual stress distribution diagram of the stub tube related to FIG.

FIG. 9 is a conceptual diagram schematically showing an example of a conventional butt welding method for pipe materials.

FIG. 10 is a residual stress distribution diagram relating to FIG. 9 when the tube material plate thickness is relatively large.

FIG. 11 is a residual stress distribution diagram relating to FIG. 9 when the tube material plate thickness is relatively thin.

[Explanation of symbols]

1,2,19,20 Pipe material 7,8,13,14,25,26,27,28 Cutting allowance 9,10,15,16,21,22 Chamfered portion 11,17,23 Weld groove 12,18, 24 Welded joint 12a, 18a, 24a Welded joint part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G21C 13/00

Claims (5)

[Claims] 1. Two to be interconnected by butt welding
Shaving allowances (7) and (8) are formed in advance on at least the inner portions of the two pipe members (1) and (2) in the vicinity of the connection ends, and the pipe members (1) and (2) extend in the circumferential direction at the respective connection ends. The chamfered portions (9) and (10) are formed, and the chamfered portions (9) and (10) of the connection ends are opposed to each other. After welding work is performed from the outside along the circumferential direction of the pipe materials (1) and (2) to form a welded joint (12) for connecting the pipe materials (1) and (2), the cutting allowance (7) is formed. ) (8) and the welding joint portion (12a) between the cutting margins (7) and (8) are cut, and a butt welding method for pipe materials is provided. 2. To be interconnected by butt welding 2
Shaving allowances (13) and (14) are formed in advance on at least the outer portions of the two pipe members (1) and (2) in the vicinity of the connection ends, and the pipe members (1) and (2) extend in the circumferential direction at their respective connection ends. The chamfered portions (15) and (16) are formed, and the chamfered portions (15) and (16) of the connecting ends are opposed to each other. After welding work is performed from the outside along the circumferential direction of the pipe materials (1) and (2) to form a welded joint (18) connecting the pipe materials (1) and (2), the cutting allowance (13) is applied. ) (14) and the welding joint portion (18a) between the cutting allowances (13) and (14) are cut, but a butt welding method for pipe materials. 3. Two to be interconnected by butt welding
One pipe material (19) (20) having a wall thickness larger than a predetermined value is used, and chamfered portions (21) (22) extending in the circumferential direction are formed at respective connection ends of both pipe materials (19) (20). ,
Both pipe materials (1) to the welding groove (23) formed by facing the chamfered portions (21) (22) of the connection end.
9) Both pipes (19) and (20) are welded from the outside of the pipes (19) along the circumferential direction of the pipes (19) and (20).
A butt welding method for pipe materials, which comprises forming a welded joint (24) for connecting the pipes, and then cutting both pipe materials (19) (20) to a predetermined size. 4. Two to be interconnected by butt welding
The cutting margins (25) and (26) are formed in advance by welding overlay on at least the inner portions of the two pipe materials (1) and (2) near the connection ends, and the cutting margins (25) and (26) are annealed. After that, a chamfered portion (9) (10) extending in the circumferential direction is formed at each connection end of both pipe materials (1) and (2), and the chamfered portions (9) (10) at the connection ends are made to face each other. The welding groove (11) is welded from the outside of both pipe materials (1) and (2) along the circumferential direction of both pipe materials (1) and (2) to both pipe materials (1) and (2). Weld joint (1
After forming 2), the cutting allowance (25) (26)
And the welding joint portion (12) between the cutting allowance (25) and (26)
a) A butt welding method for pipe materials, characterized in that 5. Two to be interconnected by butt welding
The cutting allowances (27) and (28) are preliminarily formed by welding overlay on at least the outer portions of the two pipe materials (1) and (2) near the connection ends, and the cutting allowances (27) and (28) are annealed. After that, a chamfered portion (15) (16) extending in the circumferential direction is formed at each connection end of both pipe materials (1) and (2), and the chamfered portions (15) (16) at the connection ends are made to face each other. Both pipe materials (1) (2) for weld groove (17)
After the welding work is performed from the outside of the pipe material along the circumferential direction of the pipe materials (1) and (2) to form a welded joint (18) for connecting the pipe materials (1) and (2), the cutting allowance ( 27) (2
8) and the welding allowance (27) (28) between the welding joint portion (1
8a) is cut. Butt welding method for pipe materials.