Pipeline processing method

Abstract

To provide a pipeline processing method that can easily perform butt welding for connecting pipelines together.SOLUTION: A pipeline processing method buts pipe ends in a plurality of pipelines and performs welding. According to the pipeline processing method, before welding, in order to form a groove in a first region from a pipe end in each pipeline to a first distance in an axial direction, a jig, which applies a pressure to an inner peripheral surface of a second region from the pipe end in the pipeline to a second distance longer than the first distance toward a radial direction outer side of the pipeline to increase a diameter in the second region of the pipeline, and after increasing the diameter in the second region and applies a pressure to an outer peripheral surface of a third region in the pipeline where the first region is excluded from the second region toward a radial direction center of the pipeline, is installed, in the state that the jig is installed, groove processing is performed for the first region of the pipeline, and after performance of groove processing, the pipelines, in which the groove is formed in the first region, are butted in the state that the jig is installed, and the pipelines butted to each other are temporarily fixed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a piping fabrication method for butt welding pipe ends together. [Background technology]

[0002] A plurality of pipes are connected by butting the ends of the pipes together and welding them. The dimensional tolerance determined for the pipe diameter may be approximately the same as the thickness of the pipe. In addition, pipes with a relatively large diameter are formed by rolling steel plates and welding the ends of the steel plates together, so there is a large variation in the roundness of each pipe. For these reasons, there is a risk that the misalignment in the thickness direction of the pipes, i.e., the radial direction of the pipes, will be large when the pipes are butted together.

[0003] Regarding the problem of variations in pipe diameter and roundness in such piping, for example, the following Patent Document 1 describes measuring the eccentricity and deformation of the piping and determining the groove processing specifications according to the eccentricity and deformation. Patent Document 1 also describes that if the eccentricity and deformation of the piping are too large for the groove processing machine to tolerate, an alarm is issued and the piping is corrected in advance before groove processing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 57-27609 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above method, the pipe diameter and roundness of the pipes remain in a state of variation, so the problem of misalignment when the pipes are butted together cannot be solved. Also, if the eccentricity and deformation of the pipes are too large for the groove processing machine during the groove processing, it is necessary to remove the pipes installed in the groove processing machine and correct the pipes separately, which makes the work process complicated.

[0006] In view of the above, an object of the present disclosure is to provide a piping processing method that can easily perform butt welding to connect pipes together. [Means for solving the problem]

[0007] A piping processing method according to one embodiment of the present disclosure is a piping processing method for butting and welding pipe ends of a plurality of pipes together, the method including, before performing the welding, applying pressure radially outward to an inner surface of a second region of the pipe from the pipe end to a second distance longer than the first axial distance to form a groove in the first region of the pipe, thereby expanding a diameter of the second region of the pipe, and after expanding the diameter in the second region, attaching a jig that applies pressure toward a radial center of the pipe to an outer surface of a third region of the pipe that is the second region excluding the first region, and performing groove processing on the first region of the pipe with the jig attached, and after performing the groove processing, butting the pipes having the groove formed in the first region together with the jig attached, and temporarily fixing the butted pipes together. Effect of the Invention

[0008] According to the present disclosure, butt welding for joining pipes together can be easily performed. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a flowchart showing the flow of a piping processing method according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a side view showing an example of a pipe before a groove is formed in this embodiment. [Diagram 3] FIG. 3 is a conceptual diagram showing an outline of the diameter expansion step in this embodiment. [Figure 4] FIG. 4 is a conceptual diagram showing an outline of the jig mounting step in this embodiment. [Diagram 5] FIG. 5 is a diagram showing a state in which the groove preparation step is carried out in this embodiment. [Figure 6] FIG. 6 is a diagram showing a state in which a step after groove preparation is carried out in this embodiment. [Figure 7] FIG. 7 is an image diagram for explaining a method for calculating a reference point of a pipe by measurement using an automatic processing machine used in this embodiment. [Figure 8] FIG. 8 is an image diagram for explaining a method for calculating the inner and outer diameters of a pipe by measuring them using an automatic processing machine used in this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [One embodiment] Hereinafter, a piping processing method according to one embodiment of the present disclosure will be described.

[0011] 1 is a flowchart showing a flow of a piping processing method according to an embodiment of the present disclosure. In the piping processing method according to the present embodiment, before welding the pipe ends of a plurality of pipes together, a groove is formed in a first region from the pipe end of each pipe to a first axial distance.

[0012] FIG. 2 is a side view showing an example of a pipe before a groove is formed in this embodiment. As shown in FIG. 2, in this embodiment, in the state before the groove is formed, the first region A1 from the pipe end 1a to the first axial distance L1 is set as the region where the groove is formed. In addition, in the pipe 1 before the groove is formed, the pipe diameter R2 in the second region A2 from the pipe end 1a to the second distance L2 longer than the first axial distance L1 has a diameter larger than the pipe diameter R1 in the other region, that is, the axial central region. The second region A2 includes the first region A1. In addition, the pipe 1 before the groove is formed is fitted with a jig 2 that applies pressure to the radial center of the pipe 1 against the outer peripheral surface in the third region A3, which is the second region A2 excluding the first region A1. In FIG. 2, the difference between the second distance L2 and the first distance L1 is shown as a third distance L3.

[0013] 2, a first region A1 and the like are set at both ends of the pipe 1. However, when only one pipe end 1a of the pipe 1 is welded to another pipe 1, the setting of the first region A1 and the like is not required at the other pipe end 1a.

[0014] In order to form the pipe 1 before the groove is formed, first, pressure is applied to the inner peripheral surface of the second region A2 of the pipe 1 in the radial outward direction of the pipe 1, thereby expanding the diameter of the second region A2 of the pipe 1 (step S1). FIG. 3 is an image diagram showing an outline of the diameter expansion process in this embodiment. The material, size, etc. of the prepared pipe 1 are not particularly limited as long as the pipe can be welded at the pipe end 1a. For example, the pipe 1 is made of a stainless steel pipe or the like. The pipe 1 is formed by rolling a steel plate and welding the ends of the steel plate together. For this reason, it is assumed that the pipe 1 does not have sufficient roundness. The pipe 1 may be manufactured as a seamless pipe by drawing or the like. Even in this case, the pipe 1 may not have sufficient roundness.

[0015] In the diameter expansion process, the pipe 1 is arranged so that the diameter expansion jig 3a of the diameter expansion machine 3 is located inside the pipe 1. The diameter expansion jig 3a has a structure in which a cylinder is divided into multiple pieces in the circumferential direction. Furthermore, the diameter expansion jig 3a is configured so that the multiple pieces move radially outward when pressure is applied. The multiple pieces constituting the diameter expansion jig 3a move radially outward when pressurized, so that the outer peripheral surfaces of the multiple pieces press the inner peripheral surface of the pipe 1 through which it is inserted. This causes the second region A2 of the pipe 1 to be expanded in diameter. In the example of FIG. 3, both axial sides of the pipe 1 are expanded in diameter.

[0016] As a result, even if the pipe diameter R1 of the pipes 1 before expansion varies within the range of dimensional tolerance among the multiple pipes 1, the second region A2 of the pipes 1 is expanded to a predetermined diameter R2, so that the pipe diameters, i.e., circumferential lengths, in the second region A2 of the multiple pipes 1 can be unified. Therefore, it is possible to prevent misalignment due to different circumferential lengths when the multiple pipes 1 are butted together.

[0017] For example, the pipe diameter R2 of the second region A2 of the pipe 1 is set to the maximum value of the dimensional tolerance of the pipe diameter R1 of the pipe 1 before expansion. In this case, depending on the size of the pipe 1, the difference between the circumferential length of the pipe 1 before expansion and the circumferential length of the pipe 1 after expansion in the second region A2 may be less than 1%. Thus, in the expansion step, the degree of processing of the pipe 1 by the expander 3 may be low. For example, one of the reasons why the degree of processing of the pipe 1 cannot be increased is that the pipe 1 cannot be expanded to a large extent due to its product application or quality constraints.

[0018] For example, when the pipe 1 is an inner pipe of a multi-wall pipe, the degree of diameter expansion cannot be increased. The multi-wall pipe includes an inner pipe and an outer pipe that is concentrically arranged outside the inner pipe with a gap between the inner pipe and the outer pipe. The multi-wall pipe includes a double pipe, a triple pipe, and the like. The multi-wall pipe can be used when it is necessary to block heat from outside the pipe for a fluid flowing through the inner pipe. If the degree of diameter expansion of the inner pipe of such a multi-wall pipe is increased, the gap between the inner pipe and the outer pipe becomes small, and there is a risk of deterioration in heat insulation. In this disclosure, the inner pipe of the multi-wall pipe means the inner pipe of two pipes adjacent to each other in the radial direction, and the outer pipe of the multi-wall pipe means the outer pipe of two pipes adjacent to each other in the radial direction.

[0019] In this way, even if the degree of processing of the pipe 1 by the expansion machine 3 is low, and the roundness of the pipe 1 is temporarily increased by the pipe 1 being corrected by the expansion jig 3a when it is expanded by the expansion jig 3a, when the expanded pipe 1 is removed from the expansion jig 3a, the elasticity of the pipe 1 may cause the roundness of the pipe 1 to decrease again.

[0020] Therefore, a jig 2 is attached to apply pressure to the outer circumferential surface of the expanded pipe 1 in the third region A3 toward the radial center of the pipe 1 (step S2). Fig. 4 is an image diagram showing an overview of the jig attachment step in this embodiment. The jig 2 includes a plurality of pieces having arc-shaped cutouts corresponding to the outer diameter of the pipe 1 in the second region A2. In this embodiment, the jig 2 includes two pieces 2a and 2b having semicircular arc-shaped cutouts.

[0021] The first piece 2a has a notch corresponding to the upper half of the outer circumferential surface of the pipe 1, and the second piece 2b has a notch corresponding to the lower half of the outer circumferential surface of the pipe 1. The lower part of the first piece 2a and the upper part of the second piece 2b have brackets 2c for fixing the first piece 2a and the second piece 2b to each other using fasteners 2d such as bolts. The bracket 2c of the first piece 2a and the bracket 2c of the second piece 2b are disposed opposite each other with the positions of the notches of the two pieces 2a, 2b aligned.

[0022] In this embodiment, the bracket 2c is fixed to both sides of each of the pieces 2a, 2b as shown in Fig. 2. However, in Fig. 4 and other figures, the bracket 2c is shown on only one side of each of the pieces 2a, 2b, and the bracket 2c on the other side is not shown. Note that the bracket 2c may be fixed to only one side of each of the pieces 2a, 2b.

[0023] The second piece 2b is placed on a base 5 on which a holder 4 for holding the two pieces 2a, 2b is installed so as to be held by the holder 4. The second region A2 of the pipe 1 is abutted against the cutout portion of the held second piece 2b, and the first piece 2a is attached from above so as to be held by the holder 4. This brings the cutout portions of the two pieces into contact with the outer circumferential surface of the pipe 1 in the second region A2.

[0024] In this state, a pressurizer 6 such as a hydraulic cylinder is attached to the top of the first piece 2a, and pressure is applied to the first piece 2a toward the piping 1 and the second piece 2b by the pressurizer 6. With a predetermined pressure being applied to the first piece 2a, the brackets 2c of the pieces 2a, 2b are fixed together using the fixing device 2d, thereby fixing the two pieces 2a, 2b together.

[0025] In this manner, the jig 2 is fixed with a predetermined pressure applied to the outer peripheral surface of the third region A3 that does not affect the groove processing in the expanded second region A2 of the pipe 1. As a result, the second region A2 including the third region A3 of the pipe 1 is corrected by the jig 2 to the shape of the notch of the jig 2, and the circularity is increased.

[0026] After the jig 2 is attached to the pipe 1, the first area A1 of the pipe 1 is subjected to groove processing with the jig 2 attached (step S3). The groove processing is performed by an automatic processing machine. The automatic processing machine may be, for example, a general-purpose automatic processing machine such as a machining center, or may be a dedicated automatic processing machine specialized for groove processing. The following describes an example in which a general-purpose automatic processing machine is used.

[0027] 5 is a diagram showing a state in which a groove processing step is performed in this embodiment. The automatic processing machine 7 is equipped with an installation table 8, a base 9, a support column 10, and a processing head 11. The installation table 8 is provided with a pipe 1 with a jig attached thereto. The installation table 8 can be moved horizontally relative to the base 9 by a first slider 12. The movement directions of the installation table 8 include a first direction and a second direction that are perpendicular to each other. The pipe 1 is installed so that its axis is along the first direction. The support column 10 is fixed to the base 9.

[0028] The processing head 11 holds a processing tool 13. The processing head 11 is supported by the support column 10 with the mounting axis of the processing tool 13 facing a first direction. The processing head 11 is movable in the height direction relative to the support column 10 by a second slider 14.

[0029] Such automatic machining device 7 performs groove machining on the outer peripheral surface and the inner peripheral surface of the first region A1 of the pipe 1.

[0030] It should be noted that the configuration of the automatic processing machine 7 is not limited to the above. For example, the automatic processing machine 7 may be configured such that the pipe 1 is fixed to a base 9 and the processing head 11 moves three-dimensionally relative to the base 9.

[0031] After the groove processing, the pipes 1 with the grooves formed in the first region A1 are butted together with the jig 2 attached, and the butted pipes 1 are temporarily fixed to each other (step S4). FIG. 6 is a diagram showing the implementation state of the process after the groove processing in this embodiment. By butting the pipes 1 together with the jig 2 attached, the pipes 1 are butted together with the roundness of the first region A1 where the grooves are formed in the pipes 1 corrected. The diameter expansion process suppresses the deviation of the circumferential length of the first region A1 in the multiple pipes 1, and by butting the pipes 1 together with the first region A1 being highly round by attaching the jig 2, the amount of misalignment in the radial direction between the butted pipes 1 is suppressed.

[0032] In this state, the pipes 1 are temporarily fixed to each other, thereby realizing a joint with a small misalignment. For example, the temporary fixing can be performed by temporary welding, which is also called tack welding.

[0033] After the temporary fixing, the jig 2 is removed before performing the main welding (step S5). By removing the jig 2, the circularity of the first region A1 of the pipe 1 may decrease, but the temporary fixing maintains the small misalignment between the pipes 1.

[0034] After removing the jig 2, the actual welding is performed (step S6). In this embodiment, the actual welding is performed by an automatic welding machine 15. The automatic welding machine 15 is, for example, configured by an articulated robot having joints on multiple axes. The automatic welding machine 15 executes various kinds of tracking control when welding the groove portion of the pipe 1. As a result, even if the roundness of the pipe 1 has decreased to some extent compared to when the jig 2 was attached, the misalignment between the pipes 1 is small due to the temporary fixation, so that appropriate welding can be easily performed.

[0035] As described above, according to the piping processing method of the present embodiment, the pipe end of the pipe 1 is expanded to a predetermined circumferential length, and the jig 2 is attached to the pipe 1 in a pressurized state. Therefore, the pipe ends of the pipes 1 are held with the same circumferential length and high roundness in a plurality of pipes 1. With the jig 2 attached in this manner, a groove is formed in the first region A1 including the pipe end, and the plurality of pipes 1 with the groove formed are butted together. This reduces the amount of misalignment between the pipes 1 when butting together, and makes it easy to perform butt welding to connect the pipes 1 together. The jig 2 is attached to the third region A3, which avoids the first region A1 where the groove is formed on the outer circumferential surface of the pipe 1, and therefore the jig 2 can be prevented from interfering with the formation of the groove.

[0036] Furthermore, by forming grooves and butting multiple pipes 1 together while the jig 2 is attached, it is possible to increase the accuracy of butting the pipes 1 together even if the degree of processing in the diameter expansion process is low. Therefore, the pipe processing method of this embodiment can be easily applied to pipes 1 that cannot be processed to a high degree due to product applications or quality constraints.

[0037] In addition, because the jig 2 is maintained in an attached state when the pipes 1 are butted together, the radial misalignment between the butted pipes 1 matches with high accuracy. The pipes 1 are temporarily fixed together in this state, thereby realizing a joint with a small misalignment. As a result, butt welding for joining the pipes 1 together can be easily performed. Therefore, butt welding can be automated, and welding with high accuracy and productivity can be realized.

[0038] Moreover, according to this embodiment, after the temporary fixing, the jig 2 is removed before the main welding is performed, so that the jig 2 is prevented from getting in the way during the main welding. Therefore, the automatic welding machine 15 can be easily introduced during the main welding.

[0039] Furthermore, according to this embodiment, the jig 2 includes multiple pieces 2a, 2b each having an arc-shaped notch, and the multiple pieces 2a, 2b are fixed together in a state where the cutout portions of the multiple pieces 2a, 2b are brought into contact with the outer circumferential surface of the third region A3 of the pipe 1 and pressure is applied to one of the multiple pieces 2a, 2b. This makes it possible to easily configure the jig 2 for applying pressure to the outer circumferential surface of the third region A3 of the pipe 1 toward the radial center of the pipe 1 to increase the roundness of the pipe 1.

[0040] Furthermore, in this embodiment, during groove processing, a predetermined dimension of the pipe 1 after diameter expansion and attachment of the jig 2 can be measured, and it can be determined whether the predetermined dimension is within a predetermined reference range. As described above, in this embodiment, groove processing is performed by the automatic processing machine 7. The automatic processing machine 7 can automatically select and attach a processing tool 13 to be attached to the processing head 11 from among the multiple processing tools 13. The multiple processing tools 13 include a touch probe 13a. During groove processing, the automatic processing machine 7 measures the predetermined dimension of the pipe 1 by contacting the touch probe 13a with a predetermined position in the first area A1 of the pipe 1 with the pipe 1 to which the jig 2 is attached being placed at a predetermined position.

[0041] In this embodiment, the predetermined dimensions include a maximum inner diameter value Rix and a minimum outer diameter value Ron. In order to measure these values, the automatic processing machine 7 uses a touch probe 13a to identify a reference point C, which is the radial center position of the pipe 1, for the pipe 1 placed on the placement table 8.

[0042] FIG. 7 is an image diagram for explaining a method of calculating the reference point of a pipe by measurement using an automatic processing machine used in this embodiment. In FIG. 7, with the pipe 1 installed on the installation table 8, the left-right direction is the X direction, the up-down direction is the Y direction, and the central axis direction is the Z direction. First, the automatic processing machine 7 moves the touch probe 13a in the Z direction from the pipe end 1a of the pipe 1 at a predetermined XY direction position, and measures the Z coordinate of the position where the touch probe 13a abuts on the surface of the jig 2. The automatic processing machine 7 performs this measurement at multiple XY direction positions, and sets the average value of the measured Z coordinates as the reference position Zo in the Z direction. For example, the Z coordinate is measured at one point above and one point below the pipe 1. In the subsequent measurements, the position of the touch probe 13a is fixed at the reference position Zo in the Z direction.

[0043] Next, the automatic machining device 7 moves the touch probe 13a in the Y direction from the outside of the pipe 1 in the Y direction at the X-direction operating center Xa of the machining head 11 of the automatic machining device 7 to bring it into contact with the outer surface of the pipe 1. The automatic machining device 7 measures a Y coordinate YaH of the position where the touch probe 13a abuts against the pipe 1 when the touch probe 13a is moved from above the pipe 1 to below it, and a Y coordinate YaL of the position where the touch probe 13a abuts against the pipe 1 when the touch probe 13a is moved from below the pipe 1 to above it. The automatic machining device 7 calculates the midpoint Ya of the two obtained Y coordinates YaH, YaL.

[0044] Next, the automatic machining device 7 moves the touch probe 13a in the X direction from the outside in the X direction of the pipe 1 at the calculated point Ya in the Y direction to bring it into contact with the outer surface of the pipe 1. The automatic machining device 7 measures the X coordinate XoL of the position where the touch probe 13a abuts on the pipe 1 when the touch probe 13a is moved from left to right of the pipe 1, and the X coordinate XoR of the position where the touch probe 13a abuts on the pipe 1 when the touch probe 13a is moved from right to left of the pipe 1. The automatic machining device 7 calculates the midpoint Xo of the two obtained X coordinates XoL, XoR.

[0045] Next, at the calculated point Xo in the X direction, the automatic machining device 7 again moves the touch probe 13a in the Y direction from the outside of the pipe 1 in the Y direction to abut against the outer surface of the pipe 1. The automatic machining device 7 measures a Y coordinate YoH of the position where the touch probe 13a abuts against the pipe 1 when the touch probe 13a is moved from above the pipe 1 to below it, and a Y coordinate YoL of the position where the touch probe 13a abuts against the pipe 1 when the touch probe 13a is moved from below the pipe 1 to above it. The automatic machining device 7 calculates a midpoint Yo of the two obtained Y coordinates YoH, YoL.

[0046] The coordinates (Xo, Yo, Zo) obtained in this manner become the coordinates of the reference point C. Note that the Y coordinate Ya obtained in the above method may be the Y coordinate of the reference point C.

[0047] Furthermore, the automatic processing machine 7 measures the inner diameter value and the outer diameter value at a plurality of circumferential positions of the pipe 1 using the obtained reference point C. Fig. 8 is an image diagram for explaining a method for calculating the inner diameter and the outer diameter of the pipe by measurement using the automatic processing machine used in this embodiment.

[0048] The automatic machining device 7 sets a virtual line direction extending from the reference point C in the radial direction of the pipe 1, moves the touch probe 13a from the position of the reference point C toward the virtual line direction, and measures the X and Y coordinates of the position where the touch probe 13a contacts the inner surface of the pipe 1. The automatic machining device 7 performs similar measurements in multiple virtual line directions. In the example of FIG. 8, the multiple virtual line directions are set in eight directions centered on the reference point C. Note that the number of multiple virtual line directions may be more or less than eight directions. In this manner, the coordinates of the inner surface positions U1, ..., U8 corresponding to the multiple virtual line directions are measured.

[0049] Furthermore, the automatic processing machine 7 moves the touch probe 13a from the outside of the pipe 1 toward the reference point C in the directions of the multiple imaginary lines, and measures the X and Y coordinates of the position where the touch probe 13a contacts the outer circumferential surface of the pipe 1. In this manner, the coordinates of the outer circumferential surface positions T1, ..., T8 corresponding to the directions of the multiple imaginary lines are measured.

[0050] The automatic machining device 7 calculates inner diameter values ​​for a plurality of imaginary line directions by calculating the distance between the reference point C and each of the inner peripheral surface positions U1, ..., U8. Similarly, the automatic machining device 7 calculates outer diameter values ​​for a plurality of imaginary line directions by calculating the distance between the reference point C and each of the outer peripheral surface positions T1, ..., T8. The automatic machining device 7 sets the largest value among the calculated inner diameter values ​​as the maximum inner diameter value Rix, and sets the smallest value among the calculated outer diameter values ​​as the minimum outer diameter value Ron. The automatic machining device 7 also stores the position having the minimum inner diameter value Rin, which is the smallest value among the calculated inner diameter values, and the position having the maximum outer diameter value Rox, which is the largest value among the calculated outer diameter values.

[0051] The automatic machining device 7 determines whether the set maximum inner diameter value Rix and minimum outer diameter value Ron are within a predetermined reference value range, thereby determining whether the pipe 1 can be grooved. The automatic machining device 7 stores a target inner diameter value Rt and a dimensional tolerance range for the target inner diameter value Rt as a target value of the inner diameter value in the first region A1 after groove processing. The dimensional tolerance range for the target inner diameter value Rt includes a positive dimensional tolerance range Tp, which is a dimensional tolerance range on the outer diameter side, and a negative dimensional tolerance range Tm, which is a dimensional tolerance range on the inner diameter side.

[0052] Furthermore, the automatic processing machine 7 stores a minimum wall thickness dimensional tolerance Dn, which is the minimum dimensional tolerance for the thickness in the first region A1 before groove processing. These set values ​​may be input and set in the automatic processing machine 7 each time, or may be stored in the memory of the automatic processing machine 7 in advance.

[0053] The automatic machining device 7 uses these set values, the maximum inner diameter value Rix, and the minimum outer diameter value Ron to make the following judgment. First, the automatic machining device 7 judges whether the value obtained by subtracting the minimum wall thickness dimensional tolerance value Dn from the minimum outer diameter value Ron is greater than the maximum inner diameter value Rix. In other words, the automatic machining device 7 judges whether the first condition Ron-Dn>Rix is ​​satisfied. If the first condition is not satisfied, the automatic machining device 7 judges that groove processing is not possible because there is a risk that the minimum thickness cannot be secured in the state before groove processing.

[0054] Furthermore, the automatic processing machine 7 determines whether the value obtained by subtracting the negative dimension tolerance width Tm from the target inner diameter value Rt is less than or equal to the value obtained by subtracting the minimum wall thickness tolerance value Dn from the minimum outer diameter value Ron. That is, the automatic processing machine 7 determines whether it satisfies Rt - Tm ≤ Ron - Dn as the second condition. If the second condition is not satisfied, the automatic processing machine 7 may not be able to set the processing inner diameter value Rp described later within the dimension tolerance range W (Rt - Tm ≤ W ≤ Rt + Tp) with respect to the target inner diameter value Rt, or may not be able to ensure the root surface within the range of the target stagger amount after ensuring the minimum thickness. Therefore, it is determined that the chamfering process cannot be performed.

[0055] Furthermore, the automatic processing machine 7 determines whether the value obtained by adding the positive dimension tolerance width Tp to the target inner diameter value Rt is greater than or equal to the maximum inner diameter value Rix. That is, the automatic processing machine 7 determines whether it satisfies Rt + Tp ≥ Rix as the third condition. If the third condition is not satisfied, the automatic processing machine 7 may not be able to set the processing inner diameter value Rp described later within the dimension tolerance range W (Rt - Tm ≤ W ≤ Rt + Tp) with respect to the target inner diameter value Rt, or may not be able to ensure the root surface within the range of the target stagger amount after ensuring the minimum thickness. Therefore, it is determined that the chamfering process cannot be performed.

[0056] When the automatic processing machine 7 satisfies any of the first condition, the second condition, and the third condition, it is determined that the chamfering process is possible. In this way, it is possible for the automatic processing machine 7 to determine before the chamfering process whether the pipe 1 has an appropriate circumferential length and roundness by the diameter expansion process and the jig mounting process.

[0057] When it is determined that the chamfering process is possible, the automatic processing machine 7 calculates the processing inner diameter value Rp when actually performing the chamfering process according to the following case division.

[0058] (Case 1) When Rt + Tp ≤ Ron - Dn and Rt - Tm ≥ Rix → Rp = Rt (Case 2) When Rt + Tp > Ron - Dn and Rt - Tm < Rix →Rp = (Ron - Dn + Rix) / 2 (Case 3) When Rt + Tp ≤ Ron - Dn and Rt - Tm < Rix →Rp = (Rt + Tp + Rix) / 2 (Case 4) When Rt - Tm ≥ Rix and Rt + Tp > Ron - Dn →Rp = (Rt - Tm + Rix - Dn) / 2

[0059] The automatic processing machine 7 performs beveling on the pipe 1 based on the processed inner diameter value Rp calculated as described above and the coordinates (Xo, Yo, Zo) of the reference point C. Note that during machining on the outer peripheral surface side, the automatic processing machine 7 starts the cut in the beveling from the position of the maximum outer diameter value Rox. During machining on the inner peripheral surface side, the automatic processing machine 7 starts the cut in the beveling from the position of the minimum inner diameter value Rin. In this way, by setting the processed inner diameter value Rp based on the actually measured values in the pipe 1 determined to be bevelable, more appropriate beveling conforming to the actual object can be performed. Also, by setting the machining start position based on the actually measured values, the occurrence of machining defects can be prevented and the machining accuracy can be improved.

[0060] As described above, the embodiments of the present disclosure have been explained. However, the present disclosure is not limited to the above embodiments, and various improvements, changes, and modifications are possible without departing from the spirit thereof.

[0061] [Other Embodiments] For example, in the above embodiment, an example where the automatic welding machine 15 performs the present welding is shown. However, instead of this, the present welding may be performed manually. Similarly, in the above embodiment, an example where the automatic processing machine 7 performs the beveling is shown. However, the beveling may be performed manually.

[0062] Also, in the above embodiment, an example where the jig 2 is removed after temporary fixing and before the present welding is shown. However, the present welding may be performed with the jig 2 attached.

[0063] Furthermore, in the above embodiment, an example has been shown in which the jig 2 has two pieces 2a and 2b, but the jig 2 may have three or more pieces.

[0064] Also, temporary welding may be performed by an automatic welding machine 15. The temporary fixing does not have to be performed by welding as long as the pipes 1 can be temporarily fixed to each other. For example, the pipes 1 may be temporarily fixed to each other via a dedicated jig that is fixed to the pipes 1 by using a bolt or the like. Also, for example, the pipes 1 may be temporarily fixed to each other by an adhesive or an adhesive tape or the like.

[0065] [Summary of this disclosure] [Item 1] A piping processing method according to one embodiment of the present disclosure is a piping processing method for butting and welding pipe ends of a plurality of pipes together, the method including, before performing the welding, applying pressure radially outward to an inner surface of a second region of the pipe from the pipe end to a second distance longer than the first axial distance to form a groove in the first region of the pipe, thereby expanding a diameter of the second region of the pipe, and after expanding the diameter in the second region, attaching a jig that applies pressure toward a radial center of the pipe to an outer surface of a third region of the pipe that is the second region excluding the first region, and performing groove processing on the first region of the pipe with the jig attached, and after performing the groove processing, butting the pipes having the groove formed in the first region together with the jig attached, and temporarily fixing the butted pipes together.

[0066] According to the above method, the pipe end of the pipe is expanded to a predetermined circumferential length, and the jig is attached to the pipe under pressure. Therefore, the pipe ends of the multiple pipes are maintained with the same circumferential length and high roundness. With the jig attached in this manner, a groove is formed in the first region including the pipe end, and the multiple pipes with the groove formed are butted together. This reduces the amount of misalignment between the pipes when butting together, making it easy to perform butt welding to join the pipes together.

[0067] [Item 2] In the pipe processing method of item 1, after the temporary fixing, the jig may be removed before the main welding is performed. This prevents the jig from getting in the way during the main welding. Therefore, an automatic welding machine can be easily introduced during the main welding.

[0068] [Item 3] In the pipe processing method of item 1 or 2, the jig includes a plurality of pieces having an arc-shaped cutout corresponding to the outer diameter of the third region of the pipe, and is capable of fixing the plurality of pieces together with each of the cutout portions of the plurality of pieces abutting against the outer peripheral surface of the third region, and may fix the pieces together while applying pressure to any one of the plurality of pieces when attaching the jig. This makes it possible to easily configure a jig for applying pressure to the outer peripheral surface of the third region of the pipe toward the radial center of the pipe to increase the roundness of the pipe.

[0069] [Item 4] In any one of the pipe processing methods of items 1 to 3, the groove processing is performed by an automatic processing machine, and the automatic processing machine is equipped with a touch probe, and during the groove processing, the pipe to which the jig is attached is installed in a predetermined place, and the touch probe is brought into contact with a predetermined position in the first region of the pipe to measure a predetermined dimension of the pipe, and it is determined whether a predetermined condition is satisfied using the predetermined dimension, and if the condition is not satisfied, the groove processing may not be performed. In this case, the automatic processing machine determines that the groove processing is possible when the condition using the predetermined dimension of the pipe is satisfied. In this way, it is possible to determine whether the pipe has an appropriate circumference and roundness by the diameter expansion process and the jig mounting process before the groove processing by the automatic processing machine.

[0070] [Item 5] In the piping processing method according to any one of items 1 to 4, the piping may be an inner pipe of a multi-pipe structure in which an outer pipe and an inner pipe are concentrically arranged with a gap therebetween. [Explanation of symbols]

[0071] 1 Piping 2 Jig 2,2b piece 7 Automatic processing machine 13a Touch probe 15 Automatic welding machine A1 1st area A2 2nd area A3 3rd area

Claims

1. A piping processing method for butt-welding pipe ends of a plurality of pipes, comprising the steps of: Before performing the welding, a groove is formed in a first region from a pipe end to a first axial distance in each pipe, applying pressure radially outward to an inner circumferential surface of a second region of the pipe from the pipe end to a second distance that is longer than the first axial distance, thereby expanding a diameter of the second region of the pipe; After the diameter in the second region is enlarged, a jig is attached to the outer circumferential surface of the pipe in a third region, which is a region of the pipe that is the second region excluding the first region, and the jig is adapted to apply pressure toward a radial center of the pipe; With the jig attached, groove processing is performed on the first region of the pipe, After performing the groove processing, the pipes having the groove formed in the first region are butted together with the jig attached, and the butted pipes are temporarily fixed to each other. This is a piping processing method.

2. The piping processing method according to claim 1 , wherein the jig is removed after the temporary fixing and before a main welding is performed.

3. the jig includes a plurality of pieces having arc-shaped cutouts corresponding to an outer diameter of the third region of the pipe, and is capable of fixing the plurality of pieces together in a state in which each of the cutout portions of the plurality of pieces is in contact with an outer circumferential surface of the third region; 3. The pipe processing method according to claim 1, wherein when the jig is attached, the pieces are fixed to each other while applying pressure to any one of the pieces.

4. The groove processing is performed by an automatic processing machine, the automated processing machine is equipped with a touch probe; During the groove processing, the pipe to which the jig is attached is installed in a predetermined location, and the touch probe is brought into contact with a predetermined position in the first region of the pipe to measure a predetermined dimension of the pipe; The piping processing method according to claim 1 or 2, further comprising: determining whether a predetermined condition is satisfied using the predetermined dimension; and performing the groove processing if the condition is satisfied.

5. 3. The piping processing method according to claim 1, wherein the piping is an inner pipe of a multi-walled pipe, in which an outer pipe and an inner pipe are concentrically arranged with a gap therebetween.

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