JP2000246438A - Structure and its welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of passes and the effect of welding heat by setting, at a specified value or higher, the ratio between the height of the initial layer bead of a structure welded by using a filler wire and the penetration depth into the welding base metal. SOLUTION: Made 1 or higher is the ratio H/D between the height H of the initial layer bead of a structure welded by using a filler wire and the penetration depth D into the welding base metal. Also made 1 or higher is the ratio Hn/Dn between the height Hn of the weld bead of the second layer onward and the penetration depth Dn of the preceding layer or the base metal. In addition, a relation between the filler wire supplied per unit length of the weld line and the input of a welding heat is desirably in the range surrounded by the heat input of (10 J/mm, 0.06 mm2), (10 J/mm, 0.2 mm2), (500 J/mm, 12 mm2), and (500 J/mm, 3 mm2), assuming the heat input (J/mm) is taken on the abscissa and the wire supply (mm2) is taken on the ordinate. The type of welding to the structure may be cladding by welding, joint welding or repair welding with a groove formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure in which the influence of welding heat on a base material is reduced and a method for welding the same.

[0002]

2. Description of the Related Art In a conventional arc welding method using a welding material such as a filler wire, a molten amount of a base material is large with respect to a deposited metal amount.
There were problems such as a large residual stress and cracking. In particular, in the welding of reactor internals containing helium inside the material subjected to neutron irradiation, if the temperature of the base metal rises due to heat input during welding and the area is large, helium diffuses into the grain boundaries and bubbles It is known that cracks occur due to the decrease in the grain boundary strength, and welding that suppresses heat input is required. As described in Japanese Patent Application No. 6-153300, a low heat input welding method for reactor internal structures is to perform spot welding continuously or intermittently and half-lap each point welded part to form a first layer welded part. Is formed, the second and subsequent layers are constructed by low heat input welding using a welding material. In this conventional welding, no consideration is given to the control of the weld bead shape, such as the penetration depth into the base metal or the bead height, and the relationship between the heat input and the supply of the welding material.

[0003]

In the prior art, when welding using a welding material in welding a structure, consideration is given to control of the shape of the weld bead, such as the relationship between the bead height and the penetration depth. Not. The welding of the reactor internals that has been subjected to neutron irradiation has a low penetration depth due to low heat input, but the amount of deposited metal decreases with the welding, thereby increasing the number of welding passes. As the influence of the multi-pass, there is a concern that the change in the base material structure due to the increase in the total heat input and the occurrence of cracks may occur.

SUMMARY OF THE INVENTION An object of the present invention is to provide a low heat input welding of a structure, in which the penetration depth into a base material or a pre-layer weld bead is kept to a minimum necessary for obtaining a sound fusion connection, and one welding pass. It is an object of the present invention to provide a welding method capable of reducing the number of passes by increasing the amount of weld metal as much as possible and suppressing the influence of welding heat, and a structure to which the welding is applied.

[0005]

In order to achieve the above object, according to the present invention, in a structure welded by using a filler wire, a bead height H of a first layer weld bead and penetration into a weld base metal. The ratio H / D of the depth D is set to 1 or more.

[0006] Further, in a structure which is multi-layer welded using a filler wire, the ratio H / D of the bead height H of the first layer weld bead to the penetration depth D into the welding base metal is set to 1 or more,
The ratio Hn / Dn of the bead height Hn of the second and subsequent weld beads to the penetration depth Dn into the front layer or the base material is set to 1 or more.

In a structure welded using a filler wire, the amount of filler wire supplied per unit length of welding line and the amount of heat input to welding are shown in FIG.
J / mm, 0.06 mm ² ), b (10 J / mm, 0.2 mm ² ),
c (500 J / mm, 12 mm ² ), d (500 J / mm, 3 mm
² ) Within the range enclosed by.

Further, in a reactor internal structure welded using a filler wire, a ratio H / D of a bead height H of a first layer weld bead to a penetration depth D into a welding base metal is set to 1 or more. .

Further, in a nuclear reactor internal structure which is multi-layer welded using a filler wire, a ratio H / D of a bead height H of a first layer weld bead to a penetration depth D into a welding base metal is set to 1 or more. The ratio Hn / Dn between the bead height Hn of the second and subsequent weld beads and the penetration depth Dn into the front layer or the base metal is set to 1 or more.

[0010] Further, in a reactor internal structure welded using a filler wire, the amount of filler wire supplied per unit length of a welding line and the amount of heat input to welding are shown in FIG. 1 of the present application as a (10 J / mm, 0.06 mm ² ), b (10 J / mm,
2 mm ² ), c (500 J / mm, 12 mm ² ), d (500 J / mm)
/ Mm, 3 mm ² ).

Further, the welding performed on the structure may be build-up welding on a surface of the structure having a flat surface or a curvature.

The welding performed on the structure may be welding of a joint having a groove formed on the structure.

[0013] The welding performed on the structure may be repair welding in which a groove is formed in the structure.

Further, the welding performed on the above-mentioned structure has depths and widths A (width 1 mm, depth 5 mm), B (width 1 mm, depth 20 mm), and C (width 5 mm, Depth 50mm), D
It is effective to weld a joint in which a groove within a range surrounded by (width 5 mm, depth 35 mm) is formed in a structure.

Further, the welding performed on the above-described structure has depths and widths A (width 1 mm, depth 5 mm), B (width 1 mm, depth 20 mm), C (width 5 mm, Depth 50mm), D
It is effective to use repair welding in which a groove within a range surrounded by (width 5 mm, depth 35 mm) is formed in a structure.

[0016] It is preferable that the welding performed on the structure is performed by laser welding.

[0017] In addition, even if the first layer welded portion is welded by laser welding and the second and subsequent layers are welded by TIG welding, it is effective.

In the above structure, the portion to be welded may be a metal containing helium.

In the above structure, the portion to be welded may be austenitic stainless steel containing helium.

In the above structure, the portion to be welded may be a metal irradiated with neutrons or an austenitic stainless steel.

Further, in the welding method using a filler wire for obtaining the above structure, the ratio H / D of the bead height H of the initial layer weld bead to the penetration depth D into the welding base metal is set to 1
Above.

Further, in the above welding method, the ratio H / D of the bead height H of the first layer weld bead to the penetration depth D into the welding base metal is at least one, and the bead height of the weld bead of the second and subsequent layers is set. The ratio Hn / Dn between the depth Hn and the penetration depth Dn into the front layer or the base material is set to 1 or more. In addition, in the above welding method, the amount of filler wire supplied per unit length of the welding line and the amount of welding heat input are shown by a (10 J / mm, 0.
06 mm ² ), b (10 J / mm, 0.2 mm ² ), c (500
J / mm, 12 mm ² ) and d (500 J / mm, 3 mm ² ).

In the above welding method, it is preferable to use a laser as a heat source for welding. Further, in the above-mentioned welding method, there is also an effect that a laser is used for the first layer welding and the second and subsequent layers are welded as TIG welding.

In the above welding method, the depth and the width are A (width 1 mm, depth 5 mm) and B (width 1 m) shown in FIG.
m, depth 20 mm), C (width 5 mm, depth 50 mm), and D (width 5 mm, depth 35 mm) are effective when multi-layer welding is performed on a groove.

In the above welding method, the depth and the width are A (width 1 mm, depth 5 mm) and B (width 1 m) shown in FIG.
m, depth 20 mm), C (5 mm wide, 50 mm deep), D (5 mm wide, 35 mm deep) It is effective to energize the wire and preheat the filler wire with the generated Joule heat.

[0026]

(Embodiment 1) A first embodiment is shown in FIG. In this embodiment, the surface of the SUS304 structure 4 has a diameter of 0.
The build-up welded portion 3 is formed by a YAG laser using a 6 mm Y316ULC filler wire. Laser output 1k
W, welding speed 25 mm / s, beam spot diameter at the processing point 1.5 mm, filler wire feeding speed 33 mm / s when applied at a build-up height H and penetration depth D, H / D
Is not less than 2.5, and no weld defect is generated in the weld overlay 3 and the weld heat affected zone 5.

(Embodiment 2) FIGS. 4 and 5 show a second embodiment. In the embodiment shown in FIG. 4, a Y308ULC filler wire having a diameter of 0.6 mm is fed to a groove 6 formed in a SUS304 structure 4 which has been irradiated with neutrons of 1.0 × 10 ²³ n / m ² or more. Multi-layer welding by laser is performed. Laser output 1
kW, welding speed 25 mm / s, beam spot diameter at processing point 1.5 mm, bead height H of first layer 7 and penetration depth into base metal 4 when applied at filler wire feed speed 29 mm / s H / D, which is the ratio of D, and the ratio H between the bead height Hn of the weld bead 8 in the second and subsequent layers and the penetration depth Dn into the front layer
n / Dn is 2 to 2.5. At this time, the weld metal 7,
No defects such as cracks occur in the heat-affected zone 8 and the welding heat-affected zone 5,
The reliability of the structure is maintained. As shown in FIG. 5, the first layer welded portion 7 in contact with the surface of the structure 4 is constructed by laser welding,
It is also possible to increase the amount of deposited metal per pass and reduce the number of welding passes by applying the TIG welding to the welded portions 9 of the second and subsequent layers.

(Embodiment 3) FIG. 6 shows a third embodiment. In this embodiment, the joint of the SUS316L structure 4 has a width of 2 mm and a depth of 1 mm.
A narrow groove 6 having a diameter of 0 mm is formed, and a Y308L filler wire having a diameter of 0.8 mm is fed into the groove 6, and a multilayer welded portion is formed by a YAG laser. Laser power 1kW, welding speed 15mm / s, beam spot diameter at processing point 2.0mm,
When installed at a filler wire feed rate of 25 mm / s, 1
A multilayer one-pass weld is obtained. Also, H / D, which is the ratio between the bead height H of the first layer 7 and the penetration depth D into the base material 4, and the bead height Hn of the second and subsequent weld beads 8 and the penetration depth into the front layer Hn / Dn, which is the ratio of Dn, is 4 to 5
Range. At this time, no defects such as cracks occurred in the weld metals 7 and 8 and the weld heat affected zone 5. By energizing the filler wire fed to the groove 6 and preheating the wire with the generated Joule heat, the amount of deposited metal per pass can be increased and the amount of melting of the base material can be reduced. The shape of the groove 6 is A (width 1 mm, depth 5
mm), B (width 1 mm, depth 20 mm), C (width 5 mm, depth 5
0 mm) and D (5 mm in width, 35 mm in depth), sound welding can be performed within the range 2. By narrowing the groove, the amount of penetration into the base material 4 and the front layer is reduced, and the number of welding passes is significantly reduced.
The effect of welding heat such as cracking, deformation and residual stress is suppressed.
In any of the first to third embodiments, the welding is performed using a laser which is a high-density heat source, so that the diameter of the heat source is 1.5 to 2 mm.
And the TIG welding is small, and the amount of melting of the base material 4 changes significantly depending on the supply amount of the filler wire. The amount of filler wire supplied per unit length of the welding line is shown in FIG.
/ Mm, 0.06 mm ² ), b (10 J / mm, 0.2 mm ² ), c
(500 J / mm, 12 mm ² ), d (500 J / mm, 3 mm ² )
In the range 1 surrounded by the circles, H / D, which is the ratio of the bead height H of the first layer 7 to the penetration depth D into the base material 4, and the bead height of the weld bead 8 in the second and subsequent layers Hn / Dn, which is the ratio of the depth Hn to the penetration depth Dn into the front layer, can be set to 1 or more.

In any of the first to third embodiments, the laser used for welding may be a CO ₂ laser in addition to the YAG laser. Similar effects can be obtained even if the structural component material and the welding material are other austenitic stainless steels or other metals.

According to this embodiment, it is possible to provide a structure having improved welded portion reliability by reducing penetration into the base material and suppressing thermal effects in welding the structure.

According to this embodiment, in multi-layer welding of a structure, by increasing the amount of deposited metal in one pass as much as possible, the total number of passes is reduced and the construction efficiency can be improved.
In addition, the reduction in the total heat input reduces the change in the base metal structure and the welding residual stress, and reduces the deformation, thereby further improving the reliability of the structure. Furthermore, heat treatment after welding is not always necessary, and the welding process can be simplified.

According to the present embodiment, it is possible to reduce the amount of heat input during the welding of the structure, to minimize the thermal effects such as structural change and deformation of the base material, and to obtain reliability without defects such as cracks. Structure can be provided. In particular, the effect is large when a material having high crack susceptibility to heat input is used for a welded portion of a structure.

According to the present embodiment, in the welding of the reactor internal structure, the penetration into the base metal is reduced to suppress the heat effect, thereby providing a reactor internal structure with improved welded portion reliability. it can.

According to the present embodiment, in addition to the effect of the third aspect of the present invention, in multi-layer welding of reactor internals, 1
By increasing the amount of deposited metal in the passes as much as possible, the total number of passes is reduced and the construction efficiency can be improved. In addition, the reduction in the total heat input reduces the change in the base metal structure and the welding residual stress, and reduces the deformation, so that the reliability of the furnace internal structure is further improved.

According to the present embodiment, it is possible to reduce the amount of heat input during welding of the internal structure of the nuclear reactor, extremely suppress the thermal effects such as the structural change and deformation of the base material, and reduce the defects such as cracks. It is possible to provide a highly reliable furnace internal structure. In particular, the effect is large when a material having high crack susceptibility to heat input is used for the welded portion of the furnace internals. According to the present embodiment, the effects of the inventions of claims 1 to 6 can be obtained even if the welding performed on the structure is overlay welding on the surface of the structure. In particular, when the overlay welding is intended for alloying, it is possible to provide a structure whose function is significantly improved by alloying.

According to this embodiment, even if the welding performed on the structure is welding of a joint having a groove formed on the structure,
The above effects can be obtained.

According to this embodiment, the above-mentioned effects can be obtained even if the welding performed on the structure is repair welding in which a groove is formed in the structure.

According to this embodiment, in addition to the effect of the invention of claim 8, the microstructure of the base metal can be obtained by greatly reducing the groove cross-sectional area in welding the structure and significantly reducing the total volume of the deposited metal. Thermal effects such as change and deformation are further suppressed, and a highly reliable furnace internal structure can be provided.

According to the present embodiment, in addition to the above-described effects, the groove cross-sectional area in the welding of the structure is greatly reduced, and the total volume of the deposited metal is significantly reduced, so that the structural change and deformation of the base metal are reduced. Is further suppressed, and a highly reliable furnace internal structure can be provided. According to the present embodiment, the above-described effects can be easily achieved by using a laser as the welding heat source, making the heat source diameter extremely small, and reducing the heat affected range.

According to the present embodiment, by using laser for the first layer welding, the thermal influence on the base material is minimized, and TIG welding is applied to the second and subsequent layers to increase the amount of deposited metal in one pass. The effects of the inventions of claims 1 to 6 are efficiently achieved.

According to this embodiment, in addition to the effects described above,
Even if the welded portion of the structure is a metal containing helium, it is possible to provide a reactor internal structure free from cracks due to helium bubble formation, thereby improving the reliability of a nuclear power plant.

According to this embodiment, in addition to the effects described above,
Even if the welded part of the structure is austenitic stainless steel containing helium, there is no crack due to helium bubble formation, and the internal structure of the reactor where the precipitation of chromium carbide at the crystal grain boundaries due to thermal effects is suppressed And the reliability of the nuclear power plant is improved.

According to this embodiment, even if the welded portion of the structure is a metal or austenitic stainless steel which has been irradiated with neutrons in the nuclear reactor during operation of the nuclear power plant, the effects of the inventions of claims 4 to 6 can be obtained. Can be obtained, and the life of the nuclear power plant can be extended.

According to the present embodiment, it is possible to improve the reliability of the welded portion by reducing the penetration into the base metal and suppressing the heat effect in welding using the filler wire.

According to this embodiment, in addition to the effect of the seventeenth aspect, in multi-layer welding using a filler wire, the amount of deposited metal in one pass is increased as much as possible, so that the total number of passes is reduced. Efficiency can be improved.
Further, due to the decrease in the total heat input, changes in the base metal structure and welding residual stress are reduced, and deformation is reduced. Furthermore, heat treatment after welding is not always necessary, and the welding process can be simplified.

According to this embodiment, the amount of heat input during welding can be reduced, and thermal effects such as structural change and deformation of the base metal can be extremely suppressed. The effect is particularly great when welding a material having high crack sensitivity.

According to this embodiment, the effect of the inventions of claims 17 to 19 can be easily achieved by using a laser as the welding heat source, making the diameter of the heat source extremely small, and reducing the heat affected range.

According to the present embodiment, by using a laser for the first layer welding, the thermal influence on the base material is minimized, and the TIG welding is applied to the second and subsequent layers to increase the amount of deposited metal in one pass. Thus, the above-described effects can be efficiently achieved.

According to the present embodiment, by greatly reducing the cross-sectional area of the groove and significantly reducing the total volume of the deposited metal, thermal effects such as structural change and deformation of the base material are further suppressed, and reliability is improved. Is improved.

According to the present embodiment, in addition to the above-described effects, the amount of energy to be supplied is reduced by supplying heat to the filler wire to carry out residual heat, and the filler wire is preferentially melted so that the base material or the front layer is melted. Can be reduced into the weld metal, and the effect of further reducing the effect of welding heat such as structural change, deformation, and residual stress of the base metal can be obtained.

[0051]

According to the present invention, a welded structure having a small heat affected zone can be obtained.

[Brief description of the drawings]

FIG. 1 is a graph showing a condition range of a welding heat input amount and a filler wire supply amount per unit length of a welding line in one welding pass.

FIG. 2 is a graph showing a relationship between a width and a depth of a welding groove.

FIG. 3 is an example of the present invention, and is a cross-sectional view of a structure welding portion.

FIG. 4 is an example of the present invention, and is a cross-sectional view of a structure welding portion.

FIG. 5 is an embodiment of the present invention and is a cross-sectional view of a structure welding portion.

FIG. 6 is an example of the present invention, and is a cross-sectional view of a structure welding portion.

[Explanation of symbols]

1. Condition range of welding heat input and filler wire supply per unit length of welding line 2. Condition range of groove width and depth 3.
... Overlay welded part, 4 ... structure which is a welding base material, 5 ... heat affected zone of base metal, 6 ... groove, 7 ... first layer welded part, 8 ...
Second and subsequent welds, 9... Second and subsequent welds by TIG welding.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) B23K 28/02 B23K 28/02 (72) Inventor Mitsuo Nakamura 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratories (72) Inventor Takahiko Kato 3-1-1, Sachimachi, Hitachi-shi, Ibaraki Pref. Hitachi, Ltd.Hitachi Plant (72) Inventor Masato Koshiishi, Sachi-cho, Hitachi-shi, Ibaraki Hitachi 1-1, Hitachi Ltd. (72) Inventor Takao Funamoto 3-10-2 Bentencho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Kyowa Engineering Co., Ltd. 4E081 AA01 BA03 BB07 CA11 CA19 DA04 DA35 DA57

Claims (20)

[Claims] In a structure welded using a filler wire, a ratio H / D of a bead height H of a first layer weld bead to a penetration depth D into a welding base metal is 1 or more. Structure. 2. A structure obtained by multi-layer welding using a filler wire, wherein a ratio H / D of a bead height H of an initial layer weld bead to a penetration depth D into a welding base material is 1 or more, and A structure characterized in that a ratio Hn / Dn of a bead height Hn of a weld bead after a layer and a penetration depth Dn into a front layer or a base material is 1 or more. 3. In a structure welded using a filler wire, the amount of filler wire supplied per unit length of a welding line and the amount of heat input to welding are shown by a (10 J / m 2) shown in FIG.
m, 0.06 mm ² ), b (10 J / mm, 0.2 mm ² ), c (5
(J / mm, 12 mm ² ), d (500 J / mm, 3 mm ² ). 4. The structure according to claim 1, wherein the welding is build-up welding on a flat or curved surface of the structure. 5. The structure according to claim 1, wherein the welding is welding of a joint having a groove formed in the structure. 6. The structure according to claim 1, wherein the welding is repair welding in which a groove is formed in the structure. 7. The structure according to claim 1, wherein the depth and width of the weld are A as shown in FIG.
(Width 1mm, depth 5mm), B (width 1mm, depth 20mm), C
(5 mm in width, 50 mm in depth) and a joint formed by forming a groove in the structure within a range surrounded by D (5 mm in width, 35 mm in depth). 8. The structure according to any one of claims 1 to 3, wherein the depth and width of the weld are A as shown in FIG.
(Width 1mm, depth 5mm), B (width 1mm, depth 20mm), C
(5 mm in width, 50 mm in depth) and repair welding in which a groove formed in a range surrounded by D (5 mm in width, 35 mm in depth) is formed on the structure. 9. The structure according to claim 1, wherein the structure is welded by a laser. 10. The structure according to any one of claims 1 to 3, wherein the first-layer weld is formed by laser welding, and the second and subsequent welds are formed by TIG welding. A structure characterized by the following. 11. The structure according to claim 1, wherein the portion to be welded is a metal containing helium. 12. The structure according to claim 1, wherein a portion to be welded is austenitic stainless steel containing helium. 13. The structure according to claim 1, wherein a portion to be welded is a metal or an austenitic stainless steel irradiated with neutrons. 14. A welding method using a filler wire, wherein the ratio H / D of the bead height H of the initial layer welding bead to the penetration depth D into the welding base metal is 1 or more. . 15. A welding method using a filler wire, wherein a ratio H / D of a bead height H of a first layer weld bead to a penetration depth D into a welding base material is 1 or more, and welding of a second layer and subsequent layers is performed. A welding method, wherein a ratio Hn / Dn of a bead height Hn of a bead to a penetration depth Dn into a front layer or a base material is 1 or more. 16. In a welding method using a filler wire, the amount of filler wire supplied per unit length of a welding line and the amount of welding heat input are as shown by a (10 J / mm, 0.0) shown in FIG.
6 mm ² ), b (10 J / mm, 0.2 mm ² ), c (500 J / m
m, 12 mm ² ) and d (500 J / mm, 3 mm ² ). 17. The welding method according to claim 14, wherein a laser is used as a heat source for welding. 18. The welding method according to claim 14, wherein a laser is used for the first layer welding and TIG welding is performed for the second and subsequent layers. 19. The welding method according to claim 14, wherein the depth and the width are A as shown in FIG.
(Width 1mm, depth 5mm), B (width 1mm, depth 20mm), C
(5 mm in width, 50 mm in depth) and a welding method characterized by performing multi-layer welding on a groove within a range surrounded by D (5 mm in width, 35 mm in depth). 20. The welding method according to claim 14, wherein the depth and width are A (width 1 mm, width 1 mm,
5mm deep), B (1mm wide, 20mm deep), C (5mm wide,
When performing multi-layer welding on a groove that is within the range surrounded by 50 mm (depth 50 mm) and D (width 5 mm, depth 35 mm), the filler wire fed into the groove is energized and the filler wire is generated by Joule heat generated. Welding method characterized by performing preheating.