JP2003205385A - Method and device of repairing structural member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a stress generation and a structural variation due to a input heat to a structural member in a repairing work. <P>SOLUTION: A repairing welding method selected on the basis of running environment data of a part to be repaired is used, a welding power is adjusted on the basis of an output and working data, a welding for repairing work is performed within an allowable heat input range. The running environment data are the quality of water, temperature, irradiated amount of neutrons, material and helium content of the part to be repaired, the working data are the relations or the like between the welding condition and the aspect of the part to be repaired including the relation between the welding power and the heat input in the welding method or the relation between the welding output and the material, and the welding output is decided on the basis of factors including geometrical values decided by the dimension of an electrode which varies the output according to values including a voltage, a current and time, and the gap between the electrode and the structural member. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a structural member repairing method and a structural member repairing apparatus.

[0002]

2. Description of the Related Art Metallic materials undergo various aging changes in the environment in which they are used. Normally, the specifications of the structure are determined in consideration of strength, wall thickness, etc., but there is a possibility that cracks will occur in parts where large stress is applied, and in an oxidative environment, wall thinning due to corrosion will progress. there is a possibility.

By carrying out repair work for repairing cracks and wall thinning against these changes over time, it becomes possible to restore the structural member to a form that satisfies the original design specifications. In addition, it is possible to improve the safety of the structure by predicting the secular change and performing the same repair work on the portion before the progress of cracks and wall thinning. Furthermore, if there is a repair method that can satisfy the strength specifications of the structure, waste reduction, cost reduction, and
It is advantageous from the viewpoint of shortening the construction period.

As a general repair method, there is welding repair in which a metallic material is thermally melted to build up on a repair target portion. However, in this method, since the material to be built up and the structural member to be repaired are heated to the melting point or higher, thermal influence remains on the structural member to be repaired.

[0005]

When the electrode material is thermally melted and build-up welded to the structural member, the heat of the melted electrode material is conducted to the structural member, so that the heat-affected tissue exists near the repaired portion and the repaired portion. Occurs. Further, tensile stress is generated in the structural member due to thermal contraction when the built-up portion of the electrode material cools. Therefore, in order to reduce such changes in the structure and the generation of stress, it is very important to control the heat input during repair welding in order to secure the strength after repair. In particular, in the reactor internal structural member, helium is generated in the member by receiving neutron irradiation, so when heat is applied to it, helium aggregates and moves to the metal grain boundaries, resulting in a decrease in strength. Occurs.

The sensitivity to heat input (degree of thermal influence) depends on the stress and strain applied to the structural member during use, the water quality environment such as oxygen concentration and impurity concentration, the use temperature, the radiation dose, and the start of use. It is necessary to consider that it depends on the operating environment such as operating period and material.

Further, in order to improve the reliability of the repaired part, a secondary work such as heat treatment or stress relaxation may be carried out after the repair for the stress and the structure change due to the heat input of the repair welding. A method of repairing structural members that controls the amount of heat is required.

An object of the present invention is to propose a method for repairing a structural member capable of suppressing stress generation and structural change of a structural member to be repaired due to heat input by repair welding.

[0009]

According to the present invention, a welding method is selected based on the operating environment data of the repaired portion of the structural member such that the heat input during the repairing work is equal to or less than the allowable value of the structural member to be repaired. By adjusting the welding work output based on the work data of the welding method and carrying out repair welding, it is possible to suppress the stress generation and the microstructure change due to heat input to the structural member due to the repair.

Specifically, the first means is a structural member repairing method for repairing a structural member to be repaired by welding, wherein the heat input amount at the time of repairing is based on the operating environment data of the repaired portion of the structural member. It is characterized in that a welding method is selected so as to be equal to or less than the allowable value of the structural member to be repaired, and the welding work output is adjusted based on the work data of the welding method to carry out repair welding.

In this case, the operating environment data includes at least one of water quality, temperature, neutron irradiation amount, material, and helium content of the repaired portion, and the work data is welding work output and heat input amount of the welding method. The relationship between the welding condition and the property of the repaired part including the relation between the relationship or the relationship between the welding output and the material. The welding work output is set on the basis of factors including the size of the electrode and the geometrical numerical value depending on the distance between the electrode and the structural member, the output of which can be changed depending on the value including the voltage value, the current value, and the time.

A second means is a structural member repairing method for repairing a structural member to be repaired by welding, in which a voltage is applied to an electrode to generate a short-time discharge between the structural member and the electrode to generate a discharge heat. Using the welding method of welding the evaporated electrode components to the structural members, the repair welding is performed based on the operating environment data of the repair section and setting the welding work output so that the heat input during repair is below the allowable value. And

A third means is a structural member repairing method for repairing a structural member to be repaired by welding, in which a voltage is applied to the electrodes to generate a short-time discharge between the structural member and the electrodes to evaporate by discharge heat. Using the welding method of welding the electrode component to the structural member, the oxide film on the surface of the repair site is measured in advance and the work output is adjusted based on the electrode polarity and the damage data to destroy and remove the film. After that, based on the operating environment data of the repaired part, repair welding is performed with the welding work output obtained by referring to the work data so that the heat input to the repaired part during welding work will be below the allowable value. And

In these cases, the operating environment data includes at least one of water quality, temperature, neutron irradiation amount, material, and helium content of the repair section, and the construction data is a correlation between discharge output and heat input, Includes the relationship between welding conditions, including the relationship between discharge output and material, and the properties of repaired parts. The discharge output is set based on factors such as voltage, current, discharge pulse shape, pulse period, pulse width, and the size of the electrode that can change the discharge output and a geometrical value depending on the distance between the electrode and the structural member. It

A fourth means is, in a structural member repairing apparatus for repairing a structural member to be repaired by welding, an electrode,
It is equipped with a construction output control unit, a scanning arm for moving and scanning the electrode facing the repair site, a drive mechanism, and a storage unit for storing the operation history data of the repair unit, construction data, and film destruction data. And

[0016]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a first structural member repairing method according to the present invention.
2 is a driving environment database, which is a flowchart showing the embodiment of FIG.

In FIG. 1, first, in step 1, the state of the repair section is grasped by referring to the operating environment data. As shown in FIG. 2, the operating environment data includes the material (M1, M2 ...) Of the repair portion and the neutron irradiation amount (N1, N).
2 ...) is stored in the driving environment database. This operating environment database is a mill sheet on which materials for repair parts are written, work records of welding and processing at the time of production, and integrated values of operating periods based on operation records, thermometers, dissolved oxygen meters, conductivity, and dissolved oxygen meter instructions. Create from value. In the operating environment database shown in FIG. 2, when repairing the part A (for example, the reactor shroud), it is found that the material is Ml and the neutron irradiation dose is Nl. Also, part B
In the case of (for example, a reactor pressure vessel), the material is M2 and the neutron irradiation dose is N2. Note that A to D, material M, neutron irradiation amount N, temperature T, atmosphere C, and operating period TM in FIG. 2 are specifically as shown in FIG. The stress is measured for each object and the measurement result is used.

Next, in step 2, the allowable heat input amount is determined. The allowable heat input can be found in the literature (for example, Weldability of
neutron irradiated austenitic stainless steels, Jo
As shown in urnal of Nuclear Materials 264, P8 (1999)), there is a correlation with the helium concentration. On the other hand, in the structural member, helium is generated by the nuclear reaction equations (1) and (2) when the alloy elements and impurities are transmuted by neutron irradiation, and in the case of stainless steel, the amount of helium generated is 1
It is shown in the Stainless Steel Handbook P143 issued by Nikkan Kogyo Shimbun that the concentration is 5.5 ppm per × 10 ²² n / cm ² .

⁵⁸ Ni (n, γ) ⁵⁹ Ni (n, α ) ⁵⁶ Fe ... (Reaction Formula 1) ¹⁰ B (n, α ) ⁷ Li ... (Reaction Formula 2) From the above, the allowable heat input amount and helium are shown. From the correlation of the concentration and the correlation of the helium concentration and the neutron irradiation dose, it is understood that the allowable heat input changes depending on the neutron irradiation dose, and the neutron irradiation dose and the allowable heat input have a correlation. The correlation between the neutron irradiation dose and the allowable heat input amount is schematically shown in FIG.

From the correlation between the neutron irradiation dose and the allowable heat input amount shown in FIG. 3, in the case where the repair portion is the site A, the heat input amount with respect to the neutron irradiation amount Nl of the material Ml is Hl or less, and in the case of the site B, It can be seen that the amount of heat input to the material M2 with respect to the neutron irradiation amount N2 is H2 or less.

In step 3, a repairing method that can satisfy the allowable heat input amounts Hl and H2 according to the repaired portion is selected. The repair method is characterized in that the heat input amount increases according to the repair work output, as in the work data shown in FIG. R
l, R2, and R3 schematically show the repair work output and heat input amount of the repair method. For example, Rl corresponds to a discharge welding method, R2 corresponds to a laser welding method, and R3 corresponds to a gas welding or arc welding method. In the case of the allowable heat input amounts Hl and H2 determined in step 2, the discharge welding method Rl is selected for repairing the allowable heat input amount Hl, and the laser welding method R2 is selected for repairing the allowable heat input amount H2. It is possible to carry out repairs that satisfy the conditions below the amount of heat.

In step 4, when the repair work output is set as the initial condition, the repair work output that can satisfy the allowable heat input amounts Hl or less and H2 or less is Wl or W2 from the work data shown in FIG. Become. This repair work output can be changed by controlling the voltage value and the current value.

In the above steps 1 to 4, a repair method and a repair work output capable of satisfying the heat input amount according to the repair site are determined and set.

In step 5, the repair construction range is X,
Input and set in Y-axis coordinates.

In step 6, the repair work output is applied to the work head to start the repair.

In step 7, the drive mechanism is controlled to perform the repair while moving and scanning the construction head in the repair range set by the X and Y axis coordinates.

At step 8, it is confirmed that the repair is completed within the set repair range.

In step 9, the repair is stopped.

FIG. 5 shows a second structural member repairing method according to the present invention.
6 is a discharge execution data, and FIG. 7 is a discharge execution output control characteristic diagram. The second embodiment is a discharge pulse welding in which a voltage is applied to electrodes in a pulsed manner to generate a short-time discharge between a structural member and the electrode, and an electrode component evaporated by discharge heat is welded to the structural member. It is an example of the repair method which set the method.

In FIG. 5, the discharge welding method is determined as the repair method in the repair method selection step in steps 1 to 3 similar to the first embodiment.

In step 4, initial discharge conditions are set. This initial discharge condition is set by setting the initial discharge output to the heat input amounts Hl and H as shown in the discharge construction data shown in FIG.
According to 2, W1 and W2 are set. Also, the discharge output is
It can be changed by changing the voltage value or the current value, but here, the method of changing the discharge output by adjusting the time width of the discharge pulse is adopted.

In discharge pulse welding, as shown in FIG.
When a pulse voltage having a constant voltage is applied for a time width τl, a current i flows during this period, and when the pulse voltage is stopped, the current value becomes zero. When the pulse voltage is repeatedly applied at intervals of τ2, the construction output gradually increases according to the integrated value of the current i, and reaches the set value Wl when the construction time T has elapsed.

In step 5, the repair range is input and set by the X and Y coordinates.

In step 6, a discharge pulse is applied to the construction head (electrode) to start repair.

Since steps 7 to 9 are the same as those in the first embodiment, their description will be omitted.

FIG. 8 shows a third structural member repairing method according to the present invention.
9 is a characteristic diagram showing the relationship between the operating time of the structural member and the thickness of the film formed on the structural member, and FIG. 10 is a film removal execution output and film removal amount (thickness). 3] FIG.

The third embodiment is a repairing method in which the coating formed on the structural member to be repaired is destroyed and removed, and then the overlay welding for repairing is performed on the structural member.

This embodiment is characterized in that a procedure for removing the film in steps A to D is added. Since steps 1 to 8 are the same as those in the second embodiment described above, the description thereof will be omitted.

In step A, the film thickness of the repaired portion is determined based on the material, water quality, and operating period of the operating environment data shown in FIG. The film thickness is, as shown in FIG.
The thickness D1 can be determined mainly by the water quality and the operating period. In addition, if the part is used in the air, it can be determined by the atmospheric gas concentration and the operating period.

In step B, the destruction output required to destroy and remove the film thickness D1 is set to B1 based on the destruction data shown in FIG.

In step C, the film removal range is X,
Input by Y coordinate and set.

In step D, the coating of the repaired portion is removed by the destruction output B1.

At step E, the end is determined.

The steps after step 5 after the removal of the film are the same as those in the first embodiment.

FIG. 11 is a perspective view of a structural member repairing apparatus showing a fourth embodiment for carrying out the structural member repairing method of the present invention. This structural member repairing device is a device suitable for carrying out the structural member repairing method described in the first to third embodiments.

This structural member repairing apparatus has a repairing electrode 2 for repairing the structural member 1 and a storage section 3 for storing a database of operating environment data, construction data, film destruction data and the like.
An arithmetic unit 4 for performing the determination process, a drive mechanism 6 for driving the scanning arm 5 holding the repair electrode 2, a drive mechanism operation panel 7 for controlling the scan of the repair electrode 2 facing the repair site, An output control unit 8 that adjusts the repair work output to a set value and applies the repair work output to the repair electrode 2, a display device 9 that displays data and results of determination processing, and an input device that inputs and sets the repair range and the like. 10 is provided.

The output control unit 8 is configured to change the repair work output by changing the voltage or current value, the discharge pulse cycle or the pulse width, and is adjusted using the database stored in the storage unit 3. Output the repair work output.
The repair construction range is input from the input device 10 to the drive mechanism operation panel 5 with the coordinates of the X axis and the Y axis so as to cover the repair target portion 11, and the drive mechanism 6 is controlled to drive the scanning arm 5. The repair electrode 2 is moved and scanned to perform repair work. The removal of the oxide film is carried out by moving the electrode 2 to a predetermined position in the same procedure.

FIG. 12 shows an example of the movement scanning locus of the electrode 2. This moving scanning locus is a scanning locus that moves in a rectangular zigzag pattern on the structural member 1 along the X axis and the Y axis.

Although the present invention can be applied to all structural members, it is particularly suitable for preventive maintenance such as repair of structural members such as nuclear facilities and power generation facilities.

[0051]

EFFECTS OF THE INVENTION The present invention selects a welding method in consideration of the allowable heat input amount of a repair target member, and can perform repair welding with a construction output satisfying the constraint of the allowable heat input amount. It is possible to prevent subsequent stress generation and structural change. Furthermore, secondary work such as heat treatment after repair can be omitted, and the work period until restoration can be shortened.

In addition to the overlay repair with a low heat input, the overlay repair with a high heat input is also possible in consideration of efficiency.

Furthermore, the above-mentioned build-up repair can be carried out on the structural member having the coating formed on the repair target portion after the coating is removed.

[Brief description of drawings]

FIG. 1 is a flowchart showing a first embodiment of a structural member repairing method of the present invention.

FIG. 2 is a diagram showing an example of an operating environment database referred to in the structural member repairing method of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a neutron irradiation amount of a structural member and an allowable heat input amount.

FIG. 4 is a characteristic diagram showing the relationship between repair work output and heat input.

FIG. 5 is a flowchart showing a second embodiment of the structural member repairing method of the present invention.

FIG. 6 is a characteristic diagram showing a relationship between a discharge execution output and a heat input amount.

FIG. 7 is a characteristic diagram of discharge execution output control.

FIG. 8 is a flowchart showing a third embodiment of the structural member repairing method of the present invention.

FIG. 9 is a characteristic diagram showing a relationship between an operating time of a structural member and a film thickness.

FIG. 10 is a characteristic diagram showing the relationship between the coating removal work output and the breakdown coating thickness.

FIG. 11 is a perspective view of a structural member repair device according to a fourth embodiment of the present invention.

FIG. 12 is an example of an electrode scanning locus in the structural member repair device according to the fourth embodiment of the present invention.

[Explanation of symbols]

1 Structural member 2 repair electrodes 3 storage 4 arithmetic unit 5 scanning arm 6 Drive mechanism 7 Drive mechanism operation panel 8 Output control section 9 Display device 10 Input device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideya Anzai             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division (72) Inventor Hiroto Yokoi             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Eiji Nishioka             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd.

Claims (10)

[Claims] 1. A structural member repair method for repairing a structural member to be repaired by welding, wherein the heat input during repairing is less than or equal to an allowable value of the structural member to be repaired based on the operating environment data of the repaired portion of the structural member. A welding method is selected so that the welding operation output is adjusted based on the operation data of the welding method, and the repair welding is performed. 2. The method for repairing a structural member according to claim 1, wherein the operating environment data includes at least one of water quality, temperature, neutron irradiation dose, material, and helium content of a repair site. 3. The welding data includes a welding operation condition including a relationship between a welding operation output of a welding method and a heat input amount, or a relationship between a welding operation output and a material, and a relationship between repair part properties. The method for repairing a structural member described. 4. The welding process output includes a voltage value, a current value,
The method for repairing a structural member according to claim 1, wherein the setting is performed based on an element including a geometrical numerical value depending on a size of the electrode and an interval between the electrode and the structural member, the output of which can be changed by a value including time. 5. A structural member repair method for repairing a structural member to be repaired by welding, wherein an electrode component evaporated by discharge heat by applying a voltage to an electrode to generate a short-time discharge between the structural member and the electrode. Is used to weld structural members to a structural member, and based on the operating environment data of the repair section, the welding work output is set so that the heat input during repair is below the allowable value, and the structural welding is performed. Repair method. 6. A structural member repair method for repairing a structural member to be repaired by welding, wherein a voltage is applied to an electrode to generate a short-time discharge between the structural member and the electrode, thereby removing an electrode component vaporized by discharge heat. Using the welding method of welding to structural members, the oxide film on the surface of the repaired part is measured in advance to adjust the work output based on the work output and the destruction data or the electrode polarity and the damage data to destroy and remove the film, and then the repair. A structural member characterized by performing repair welding with a welding work output obtained by referring to the work data so that the heat input to the repaired part during welding work will be below an allowable value based on the operating environment data of the part Repair method. 7. The operating environment data is the water quality of the repair section,
7. The method for repairing a structural member according to claim 5, further comprising at least one of temperature, neutron irradiation dose, material quality, and helium content. 8. The structure according to claim 5, wherein the construction data includes a relationship between a discharge output and a heat input amount, a welding condition including a relationship between the discharge output and a material, and a property of a repair portion. Material repair method. 9. The discharge output is based on factors such as a voltage, a current, a discharge pulse shape, a pulse period, a pulse width, a size of an electrode capable of changing the discharge output, and a geometrical value depending on an interval between the electrode and a structural member. 7. The method for repairing a structural member according to claim 5, wherein the repair is performed by setting. 10. A structural member repairing device for repairing a structural member to be repaired by welding, comprising: an electrode, a construction output adjusting part, a scanning arm for moving and scanning the electrode so as to face the repaired part, and a driving mechanism. A structural member repair device comprising a storage unit for storing operation history data, construction data, and film destruction data of the repair unit.