JP2016089871A - Coupling method with baking bolt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a baking work time as much as possible.SOLUTION: In one preferred embodiment of this invention, a heating coil 10 is heated to heat a baking bolt 4, after heating it, a temperature sensor 20 is installed at a heating coil mounting hole 4C and at the same time, a distance measurement device 30 capable of measuring a distance between a first nut 5A and a second nut 5B is mounted at a prescribed position. Then, a thermal expansion amount of the baking bolt 4 is calculated on the basis of an inner temperature of the baking bolt 4 detected by the temperature sensor 20 and a coefficient of expansion of the baking bolt 4. Then, when the baking bolt 4 is cooled down to a temperature before heating, a distance between the first nut 5A and the second nut 5B under a heated state of the baking bolt 4 for positioning the first nut 5A and the second nut 5B at a prescribed fastening position is determined as an adjustment distance on the basis of a thermal expansion amount of the baking bolt 4. Then, the distance between the first nut 5A and the second nut 5B is adjusted to the adjustment distance using the distance measurement device 30.SELECTED DRAWING: Figure 2

Description

  Embodiments of the present invention relate to a fastening method using a baked bolt.

  For example, a turbine casing in a steam turbine is divided into an upper half of the casing and a lower half of the casing. In such a turbine casing, usually, flanges are formed in each of the upper half and the lower half of the casing, and these flanges are fastened by bolts and nuts.

  In such a turbine casing, baking is generally employed for fastening the flange in the upper half of the casing and the flange in the lower half of the casing. In the baking, the bolts are heated and extended, the nuts screwed to the bolts are rotated to a predetermined rotational position, and then the bolts are cooled to press the nuts against the flanges. This is a method of fastening firmly.

  Usually, the bolt used by baking is a bolt (hereinafter referred to as a baking bolt) in which a heating coil installation hole penetrating along the axial direction is formed. In the baking, a heating coil is installed in the heating coil installation hole, and the heating coil is heated in this state, whereby the baking bolt is heated and extended from the inside.

  In such baking, generally, whether or not a desired fastening (fastening force) has been obtained is determined based on the amount of elongation of the fastening bolt after cooling. FIG. 3 is a diagram illustrating a general baking operation for determining whether or not a desired fastening has been obtained based on the amount of elongation of the bolt. FIG. 3 shows the main part of the turbine casing to be baked, reference numeral 1A indicates a first flange formed in the upper half of the casing that constitutes the turbine casing, and reference numeral 1B indicates The 2nd flange formed in the lower half part of the compartment which constitutes a Turbi compartment is shown. The first flange 1A is formed with a first hole 2A, and the second flange 1B is formed with a second hole 2B.

  In a general baking operation, first, as shown in FIG. 3A, the first hole 2A of the first flange 1A and the second hole 2B of the second flange 1B are arranged so as to overlap each other. Baking bolts 4 are inserted into the holes 2A and 2B. A first male screw portion 4A is formed on the outer peripheral surface extending from one end portion (upper end portion on the paper surface) to the central portion side of the fastening bolt 4, and from the other end portion (lower end portion on the paper surface) to the central portion side. A second male screw portion 4B is formed on the extending outer peripheral surface. After the baking bolt 4 is inserted into the holes 2A and 2B, the first nut 5A is screwed into the first male screw portion 4A of the baking bolt 4, and the second male screw portion 4B of the baking bolt 4 is inserted into the second male screw portion 4B. Two nuts 5B are screwed together. In this state, the reference length M at which the elongation amount of the tightening bolt 4 before heating is 0 is measured as the reference point (0 point).

  In the illustrated example, the measurement of the reference length M is performed by a measuring device 40 having a sleeve 41, a rod 42, and a micrometer 43. Specifically, the base end portion of the sleeve 41 is locked to the heating coil installation hole 4C on one end portion side of the baking bolt 4, and the rod 42 extending from the base end portion of the sleeve 41 is passed through the heating coil installation hole 4C. A disc-shaped locking portion 42 </ b> A provided at the lower end of 42 is locked to the other end portion of the baking bolt 4. In this state, the reference length M is measured by measuring the distance between the base end portion of the sleeve 41 and the other end portion of the tightening bolt 4 with the micrometer 43.

  On the other hand, in the state where the first nut 5A and the second nut 5B are screwed to the baking bolt 4, when the baking bolt 4 is cooled after being heated, the nuts 5A and 5B are positioned at the target fastening positions. A relation point representing the rotation angle of the first nut 5A and the second nut 5B for obtaining a desired fastening (fastening force) between the first flange 1A and the second flange 1B is the first nut 5A and the second nut. 5B and the first flange 2A and the second flange 2B are marked with chalk or the like. Such relation points can be calculated in advance theoretically and empirically.

  Thereafter, as shown in FIG. 3B, a rod-shaped heating coil 10 is installed in the heating coil installation hole 4C of the baking bolt 4, and the baking bolt 4 is heated and extended. And in the state after this heating, the 1st nut 5A and the 2nd nut 5B are rotated to the relational point mentioned above. Then, it cools until the baking bolt 4 becomes the same temperature as the temperature before a heating. This cooling generally takes a long time such as 10 hours. Here, when the baking bolt 4 contracts due to cooling, the first nut 5A and the second nut 5B are pressed against the first flange 2A and the second flange 2B. Thereby, flange 2A, 2B can be fastened firmly.

  And after cooling, as shown in FIG.3 (C), the displacement length M1 which the baking bolt 4 displaced from the reference | standard length M is measured by the measuring device 40 mentioned above. By subtracting M from M1, the amount of elongation of the baking bolt 4 after baking can be obtained. Here, if the amount of elongation (M1-M) is within a predetermined range, it is determined that the desired fastening has been obtained. On the other hand, if the elongation amount (M1-M) is outside the predetermined range, the baking bolt 4 is heated again, the nuts 5A and 5B are tightened, and the baking bolt 4 is cooled again, and the elongation amount (M1-M). The operation is repeated until is within a predetermined range.

JP-A-5-79302

  By the way, in the general baking described above, when the baking bolt 4 is cooled after being heated, the nuts 5A and 5B are positioned at the target fastening positions and desired between the first flange 1A and the second flange 1B. The relationship point representing the rotation angle of the first nut 5A and the second nut 5B for obtaining the fastening (fastening force) is calculated in advance, and after the baking bolt 4 is heated, the first nut 5A and the second nut If the two nuts 5B are set, theoretically, a desired bolt elongation amount can be obtained and a desired fastening can be obtained.

  However, in an actual site, due to improper marking of related points or the like, it is often the case that the intended amount of expansion of the baked bolt 4 cannot be obtained and reworking occurs. When such a re-working of baking is generated, a long time is required for the cooling of the baking bolt, which takes a lot of time. Therefore, due to the rework, the construction period may be greatly delayed.

  The present invention has been made in view of the above circumstances, and it is possible to prevent the reworking of baking from occurring, and to fasten the working time required for baking as much as possible by using a fastening bolt. It aims to provide a method.

  The fastening method using the tightening bolt according to the embodiment includes the fastening with the tightening bolt that fastens the first flange formed on the first structure and the second flange formed on the second structure using the tightening bolt. Is the method. In the method, a caulking bolt is inserted into a hole formed in the first flange and a hole formed in the second flange, and a first nut is screwed onto the caulking bolt from one end of the caulking bolt. And a step of screwing a second nut from the other end of the baking bolt to the baking bolt, and a heating member installed in a heating member installation hole formed in the baking bolt, Heating the baking bolt by heating the member, removing the heating member from the heating member installation hole after heating the baking bolt, and installing a temperature sensor in the heating member installation hole; A step of installing a distance measuring device capable of measuring a distance between the first nut and the second nut at a predetermined position; and a temperature inside the baking bolt detected by the temperature sensor; A step of calculating a thermal expansion amount of the baking bolt based on a linear expansion coefficient of the baking bolt; and the first nut and the second nut when the baking bolt is cooled to a temperature before heating. The distance between the first nut and the second nut in a state where the tightening bolt is heated is set as the adjustment distance to the thermal expansion amount of the tightening bolt. And a step of adjusting the distance between the first nut and the second nut to the adjustment distance using the distance measuring device.

It is the figure which showed the principal part of the turbine casing where the fastening method of the fastening bolt by embodiment is applied. It is a figure explaining the process of the fastening method of the fastening bolt by embodiment. It is a figure explaining the general baking operation | work which judges whether desired fastening was obtained based on the elongation amount of a volt | bolt.

  Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a diagram illustrating a main part of a turbine casing to which a fastening method of a fastening bolt according to an embodiment is applied. First, the main part of the turbine casing will be described. In addition, the same code | symbol is shown about the component which is common in the turbine casing demonstrated in FIG. 3 among the components of the turbine casing shown in FIG.

  In FIG. 1, reference numeral 1A denotes a first flange formed in the upper half (corresponding to the first structure) constituting the turbine compartment, and reference numeral 1B denotes a vehicle constituting the turbine compartment. The second flange formed in the lower half of the room (corresponding to the second structure) is shown. The first flange 1A is formed with a first hole 2A, and the second flange 1B is formed with a second hole 2B.

  Reference numeral 4 denotes a baking bolt, and the baking bolt 4 is inserted into the first hole 2A and the second hole 2B that are arranged to overlap each other. A first male screw portion 4A is formed on the outer peripheral surface extending from one end portion (the upper end portion on the paper surface) to the central portion side, and the other end portion (the lower end portion on the paper surface) is located on the center side. A second male screw portion 4B is formed on the outer peripheral surface extending in the direction. A first nut 5A is screwed into the first male screw portion 4A of the baking bolt 4 from one end portion of the baking bolt 4, and the other end of the baking bolt 4 is connected to the second male screw portion 4B of the baking bolt 4. The second nut 5B is screwed from the portion.

  In the state shown in FIG. 1, the first nut 5A and the second nut 5B are not screwed so as to fasten (press) the first flange 1A and the second flange 1B. In the fastening method using the baking bolt 4 according to the present embodiment, first, the baking bolt 4, the first nut 5A, and the second nut 5B are installed in the state shown in FIG. Thereafter, the first flange 1A and the second flange 1B are fastened by baking, for example, by heating the baking bolt 4, and the first nut 5A and the second nut 5B are positioned at predetermined fastening positions. It is determined that a desired fastening (fastening force) has been obtained.

  Hereinafter, the fastening method according to the present embodiment will be described in detail with reference to FIG. 2A to 2D sequentially show the steps of the fastening method according to the present embodiment.

  After the state shown in FIG. 1, in this embodiment, first, the temperature inside the baking bolt 4 before heating (T2 to be described later) is measured, and thereafter, as shown in FIG. The heating coil 10 corresponding to the heating member is installed in the heating coil installation hole 4C corresponding to the heating member installation hole formed in the fastening bolt 4, and the heating coil 10 is heated to heat the baking bolt 4. Thereby, the baking bolt 4 is thermally expanded and extended. The temperature inside the baking bolt 4 before heating may be the temperature of the inner peripheral surface of the heating coil installation hole 4C formed in the baking bolt 4 or the environmental temperature.

  After that, as shown in FIG. 2B, the heating coil 10 is removed from the heating coil installation hole 4C, the temperature sensor 20 is installed in the heating coil installation hole 4C, and between the first nut 5A and the second nut 5B. A distance measuring device 30 capable of measuring the distance is installed at a predetermined position. Here, in the present embodiment, a rod-shaped temperature sensor fitted into the heating coil installation hole 4 </ b> C is used as the temperature sensor 20. The rod-shaped temperature sensor 20 is fitted into the heating coil installation hole 4C so as to contact the inner peripheral surface of the heating coil installation hole 4C over a wide range. Thereby, the temperature inside the baking bolt 4 can be detected accurately.

  In the present embodiment, as the distance measuring device 30, a device that includes the first device 31 and the second device 32 and that can measure the distance between the first device 31 and the second device 32 is used. Here, in the present embodiment, the first device 31 is installed on the top surface 51 of the first nut 5A facing the one end portion side (upper side of the paper) of the baking bolt 4, and the second device 32 is the second nut. It is installed on the top surface 52 facing the other end side (the lower side of the drawing) of the baking bolt 4 in 5B. In the present embodiment, the distance measuring device 30 measures the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B.

  As the distance measuring device 30, a laser displacement meter or an ultrasonic displacement meter can be used. The distance measuring device 30 can be configured by the first device 31 and the second device 32 as long as laser and ultrasonic waves can be transmitted and received between the first device 31 and the second device 32. However, when it is difficult for a member positioned between the first device 31 and the second device 32 to transmit and receive laser and ultrasonic waves between them, at a position away from the first flange 1A and the second flange 1B, A device that transmits a laser or an ultrasonic wave toward the first device 31 and the second device 32 may be used.

Subsequently, the thermal expansion amount Y of the baking bolt 4 is calculated based on the temperature inside the baking bolt 4 detected by the temperature sensor 20 and the linear expansion coefficient of the baking bolt 4. The thermal expansion amount Y is L (the length of the baking bolt 4 before being heated by the heating coil 10) (see FIG. 1), and the baking bolt after being heated by the heating coil 10 detected by the temperature sensor 20. 4 is calculated by the following equation (1), where T1 is the internal temperature of T4, T2 is the internal temperature of the baking bolt 4 before being heated by the heating coil 10, and α is the linear expansion coefficient of the baking bolt. it can. In addition, the length L of the baking bolt 4 is a design dimension.
Y = α × L × (T1-T2) (1)

  Then, when the baking bolt 4 is cooled to the temperature before heating, the first nut 5A and the second nut 5B are positioned in a predetermined fastening position and the first bolt in a state where the baking bolt 4 is heated. The distance between the top surface 51 of the nut 5A and the top surface 52 of the second nut 5B is determined as the adjustment distance X based on the thermal expansion amount Y of the baking bolt.

Here, in FIG. 2C, the thickness F1 of the first flange 1A, the thickness F2 of the second flange 1B, the height H1 of the first nut 5A, and the height H2 of the second nut 5B are shown. Yes. In the present embodiment, in addition to these parameters, the length L of the baking bolt 4 before being heated by the heating coil 10 described above, and the baking after being heated by the heating coil 10 detected by the temperature sensor 20 Using the temperature T1 inside the bolt 4, the temperature T2 inside the baking bolt 4 before being heated by the heating coil 10, and the linear expansion coefficient α of the baking bolt as an example, the adjustment distance X is Calculated according to equation (2).
X = α × L × (T1−T2) + F1 + F2 + H1 + H2 (2)

  When the adjustment distance X is calculated by the equation (2) and the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is adjusted to the adjustment distance X, When the baking bolt 4 is cooled to the temperature before heating, the first nut 5A comes into contact with the first flange 1A without any gap and the second nut 5B comes into contact with the second flange 1B without any gap. In such a state, due to the shrinkage of the baking bolt 4 after heating, the baking bolt 4 presses the first nut 5A against the first flange 1A and the second nut 5B against the second flange 1B. It can be evaluated that the first flange 1A and the second flange 1B are firmly fastened.

  In addition, when the baking bolt 4 is cooled to the temperature before heating, the first nut 5A is in contact with the first flange 1A with no gap and the second nut 5B is in contact with the second flange 1B with no gap. The distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is F1 + F2 + H1 + H2. Further, in a state where the baking bolt 4 is heated, the baking bolt 4 is extended by a thermal expansion amount Y of α × L × (T1-T2), and the baking bolt 4 is cooled to a temperature before heating. In this case, the total movement amount of the first nut 5A and the second nut 5B becomes equal to the contraction amount of the baking bolt 4, that is, the thermal expansion amount Y. Therefore, in the formula (2), the adjustment distance X is derived as a value obtained by adding the thermal expansion amount Y and F1 + F2 + H1 + H2.

  Then, after the adjustment distance X is determined, as shown in FIG. 2C, the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is used using the distance measuring device 30. Is adjusted to be the adjustment distance X. Here, the adjustment to the adjustment distance X is performed by manually rotating the first nut 5A and the second nut 5B, for example.

  After that, cooling is waited until the baking bolt 4 reaches a temperature before heating. At the time of this cooling, as shown by an arrow β in FIG. 2D, finally, the tightening bolt 4 presses the first nut 5A to a position where the first nut 5A comes into contact with the first flange 1A without any gap, The first nut 5B is pressed to a position where the second nut 5B contacts the second flange 1B without a gap. Thereby, the 1st nut 5A and the 2nd nut 5B are positioned in a predetermined fastening position, and flange 2A, 2B can be fastened firmly. The distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is F1 + F2 + H1 + H2 (F1: thickness of the first flange 1A, F2: thickness of the second flange 1B, H1 : Height of the first nut 5A, and H2: height of the second nut 5B).

  In the period until the baked bolt 4 reaches the temperature before heating, the value of “T1−T2” changes in the above-described equation (2), and thus the adjustment distance X also changes, while the distance measuring device. 30, the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B can be measured. Here, first, the adjustment distance X and the distance D that change with the passage of time from the time when the distance D is adjusted to the adjustment distance X to the time when the tightening bolt 4 reaches the temperature before heating. If there is a difference between them, the distance between the first nut 5A and the second nut 5B may be readjusted so that the adjustment distance X and the distance D coincide with each other. When such readjustment is performed, the first nut 5A and the second nut 5B are more reliably positioned at a predetermined fastening position, and a desired fastening is performed between the first flange 1A and the second flange 1B. Can be obtained.

  In the fastening method according to the present embodiment described above, the thermal expansion amount Y is calculated based on the temperature inside the tightening bolt 4 detected by the temperature sensor 20. When the thermal expansion amount Y of the baking bolt 4 can be recognized based on the temperature inside the baking bolt 4 detected by the temperature sensor 20 as described above, the baking bolt 4 is cooled to the temperature before heating. The positions of the first nut 5A and the second nut 5B can be accurately predicted. Therefore, it is possible to accurately determine the adjustment distance X described above for positioning the first nut 5A and the second nut 5B at a predetermined fastening position when the baking bolt 4 is cooled to the temperature before heating. it can. In the present embodiment, by using the distance measuring device 30, the distance between the first nut 5A and the second nut 5B can be adjusted to the adjustment distance X with high accuracy. Thereby, when the baking bolt 4 is cooled to the temperature before heating, the first nut 5A and the second nut 5B can be positioned at predetermined fastening positions with high probability, and desired fastening can be obtained. it can.

  Therefore, according to the fastening method of the present embodiment, it is possible to prevent the reworking of baking from occurring, and to shorten the work time required for baking as much as possible.

  In the present embodiment, the distance measuring device 30 includes the first device 31 and the second device 32, and can measure the distance at which the first device 31 and the second device 32 are separated from each other. 31 is installed on the top surface 51 of the first nut 5A, and the second device 32 is installed on the top surface 52 of the second nut 5B. In this case, since the installation of the distance measuring device 30 is easy, it does not take time to install the distance measuring device 30.

(Modification)
In the embodiment described above, when the baking bolt 4 is cooled to the temperature before heating, the first nut 5A contacts the first flange 1A without any gap and the second nut 5B contacts the second flange 1B. The distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is F1 + F2 + H1 + H2 (F1: thickness of the first flange 1A, F2: thickness of the second flange 1B) , H1: height of the first nut 5A, H2: height of the second nut 5B), the desired positions of the first nut 5A and the second nut 5B after cooling, that is, "predetermined fastening position" Are treated as When the first bolt 5A and the second nut 5B reach this “predetermined fastening position” when the baking bolt 4 is cooled to the temperature before heating, the first flange 1A and the second flange It is evaluated that 1B is firmly fastened.

On the other hand, as a modification, the first nut 5A contacts the first flange 1A with no gap, the second nut 5B contacts the second flange 1B with no gap, and the tightening bolt 4 extends by the target elongation amount S. This state can also be treated as a desired position of the first nut 5A and the second nut 5B after cooling, that is, a “predetermined fastening position”. In this case, the thickness F1 of the first flange 1A, the thickness F2 of the second flange 1B, the height H1 of the first nut 5A, the height H2 of the second nut 5B, and baking before being heated by the heating coil 10 The length L of the bolt 4, the temperature T1 inside the baking bolt 4 detected by the temperature sensor 20, the temperature T2 inside the baking bolt 4 before being heated by the heating coil 10, and the linear expansion of the baking bolt Using the coefficient α, the adjustment distance X can be calculated by the following equation (3).
X = α × L × (T1-T2) + F1 + F2 + H1 + H2-S (3)

  When the adjustment distance X is calculated by the expression (3) and the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B is adjusted to the adjustment distance X, When the baking bolt 4 is cooled to the temperature before heating, the first nut 5A is applied to the first flange 1A in a state where the distance of the target elongation amount S is left as a shrinkage allowance due to cooling. The second nut 5B comes into contact with the second flange 1B while coming into contact. From this state, the baked bolt 4 tries to shrink by the distance of the target elongation amount S, but is pressed against the first nut 5A and the second nut 5B to inhibit the shrinkage, and the first nut 5A and the second nut. A reaction is received from 5B, and the target elongation amount S is increased. Therefore, the target elongation amount S is obtained for the tightening bolt 4 by adjusting the adjustment distance X in consideration of the target elongation amount S.

  In addition, after cooling, it may be confirmed whether or not the target elongation amount S is obtained in the baking bolt 4. In this case, for example, by confirming whether or not the distance between both ends of the baking bolt 4 is within the length L + target elongation amount S ± allowable error range of the baking bolt 4 before being heated, It may be confirmed whether or not the target elongation amount S is obtained in the baking bolt 4.

  Although the embodiment of the present invention has been described above, the above embodiment is presented as an example, and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. This embodiment and its modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, in the above-described embodiment, the turbine casing is fastened. However, the fastening method similar to the present embodiment is generally the flange portion in the turbine high-pressure or intermediate-pressure chamber configured to be separable. The flange portion of the main steam pipe may be applied.

  A plurality of baked bolts 4 are installed on the first flange 1A and the second flange 1B as described above. In the above-described embodiment, the fastening method by baking a single baking bolt 4 has been described. However, the fastening method may be performed simultaneously by a plurality of baking bolts 4. In this case, the fastening of the first flange 1A and the second flange 1B can be more efficiently advanced.

  In the above-described embodiment, the distance measuring device 30 measures the distance D between the top surface 51 of the first nut 5A and the top surface 52 of the second nut 5B. The distance measuring device 30 measures the distance between the bottom surface of the first nut 5A (the surface facing the first flange 1A) and the bottom surface of the second nut 5B (the surface facing the second flange 1B). It may be. In this case, the adjustment distance X may be determined using, for example, an expression obtained by subtracting the height H1 of the first nut 5A and the height H2 of the second nut 5B from the right side of the above-described expression (2).

  In the above-described embodiment, the distance measuring device 30 is installed after the baking bolt 4 is heated. However, the distance measuring device 30 may be installed before the baking bolt 4 is heated. Further, although the heating coil 10 is used for heating the baking bolt 4, other heating members may be used.

  1A 1st flange, 1B 2nd flange, 2A 1st hole, 2B 2nd hole, 4 Baking bolt, 4A 1st male screw part, 4B 2nd male screw part, 4C Heating coil installation hole, 5A 1st nut, 5B 1st 2 nuts, 10 heating coil, 20 temperature sensor, 30 distance measuring device, 31 first device, 32 second device.

Claims (3)

A fastening method using a tightening bolt for fastening a first flange formed on a first structure and a second flange formed on a second structure using a tightening bolt,
Inserting a baking bolt into the hole formed in the first flange and the hole formed in the second flange, and screwing the first nut from one end of the baking bolt to the baking bolt; A step of screwing a second nut from the other end of the baking bolt to the baking bolt;
Installing a heating member in a heating member installation hole formed in the baking bolt, and heating the baking bolt by heating the heating member;
After heating the baking bolt, removing the heating member from the heating member installation hole, and installing a temperature sensor in the heating member installation hole;
Installing a distance measuring device capable of measuring a distance between the first nut and the second nut at a predetermined position;
Calculating a thermal expansion amount of the baking bolt based on an internal temperature of the baking bolt detected by the temperature sensor and a linear expansion coefficient of the baking bolt;
The first nut in a heated state for positioning the first nut and the second nut at a predetermined fastening position when the baking bolt is cooled to a temperature before heating. Determining the distance between the second nut and the second nut as an adjustment distance based on the amount of thermal expansion of the baked bolt;
Adjusting the distance between the first nut and the second nut to the adjustment distance using the distance measuring device;
A fastening method using a baked bolt. The fastening method using a tightening bolt according to claim 1, wherein the distance measuring device is installed after the baking bolt is heated. The distance measuring device includes a first device and a second device, and is capable of measuring a distance between the first device and the second device,
The first device is installed on a top surface of the first nut facing the one end side of the baking bolt, and the second device is configured to connect the other end side of the baking bolt in the second nut. The fastening method using a bolt according to claim 1, wherein the fastening method is performed on a facing top surface.

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