JP6631413B2 - Girth weld inspection method - Google Patents

Description

  The present invention relates to a method for inspecting a girth weld formed to connect ends of a plurality of pipes. In particular, the present invention relates to a method for inspecting a girth weld that can accurately calculate the size of the defect regardless of the location of the girth weld where the defect exists.

  Conventionally, as disclosed in Patent Document 1, a tube wound on a reel called coiled tubing is known. This coiled tubing is unwound from a reel, for example, offshore and descends into a well such as an offshore oil field or an offshore gas field. Coiled tubing is used, for example, as an umbilical cable that functions as a control line connecting an offshore host facility and a submarine well. The umbilical cable includes an electric wire, a high-pressure hydraulic hose, an optical cable, and the like inside.

  Coiled tubing wound on one reel is a long tube generally exceeding 3000 feet. Therefore, coiled tubing is formed by applying circumferential welding to the ends of a plurality of tubes. Long tubes are widely used.

  One of the inspection items of the girth weld formed on the long pipe as described above is to detect a hollow defect called porosity that can occur at the time of casting the base material or at the time of girth welding. Can be Specifically, if porosity having a circle equivalent diameter of a certain ratio or more (for example, 10% or more) with respect to the thickness of the long tube exists in the girth weld, the girth weld is determined to be defective. Is determined. This is because the presence of porosity of a certain size or more lowers the mechanical properties and corrosion resistance of the girth weld.

Here, an X-ray inspection apparatus is generally used to detect a defect such as porosity existing inside the welded portion (for example, see Patent Document 2).
The method described in Patent Literature 2 includes an X-ray source that emits X-rays toward a welded pipe from a direction substantially perpendicular to a longitudinal direction of the welded pipe, and a position facing the X-ray source across the welded pipe. And an X-ray image detector that detects X-rays emitted from the X-ray source and transmitted through the welded pipe, and inspects the welded portion of the welded pipe using an X-ray inspection machine. It is considered that if the method described in Patent Document 2 is applied to the inspection of the girth weld, a defect existing in the girth weld can be visualized.

However, although this is not a problem when inspecting a welded portion such as a UO pipe or an electric resistance welded pipe in which a welding line extends in the longitudinal direction of the pipe, a long strip manufactured by circumferentially welding the ends of a plurality of pipes. When inspecting the girth weld of the pipe, when X-rays are emitted from the direction substantially perpendicular to the longitudinal direction of the long pipe toward the girth weld, the X-ray is located at the X-ray source side of the girth weld. The defect detected and the defect existing in the part on the X-ray image detector side are simultaneously detected by the X-ray image detector, and it is not possible to recognize in which part the detected defect exists. .
In addition, the magnification of the defect detected by the X-ray image detector differs depending on the location of the detected defect. This is because the magnification of a defect detected by the X-ray image detector is determined by a value obtained by dividing the distance between the X-ray source and the X-ray image detector by the distance between the X-ray source and the defect (the X-ray source and the defect). Is smaller, the magnification of the defect detected by the X-ray image detector is larger). For this reason, even if a defect has the same size, it is detected as a defect having a different size when it is detected by the X-ray image detector, depending on which part the defect exists. Therefore, as described above, it is not possible to accurately determine whether or not a defect having a circle equivalent diameter at a certain ratio or more with respect to the thickness of the long pipe exists in the girth welded portion. There is a possibility that the determination cannot be performed with high accuracy.

  The above-mentioned problem is caused by the fact that both the defect existing in the part on the X-ray source side and the defect existing in the part on the X-ray image detector side of the girth weld are simultaneously detected by the X-ray image detector. Therefore, X-rays are radiated toward the circumferential weld from a direction inclined with respect to a direction perpendicular to the longitudinal direction of the long tube so that only a defect existing on one side is detected (ie, It is also conceivable that X-rays are emitted only to the part of the girth weld on the X-ray source side, or X-rays are emitted only to the part of the girth weld on the X-ray image detector side). However, if X-rays are emitted from the inclined direction toward the circumferential weld, there is a possibility that the defect itself cannot be accurately evaluated. Also, since only one part of the girth weld can be inspected at a time, it takes time to inspect the entire girth weld. Therefore, a method of emitting X-rays from the inclined direction toward the circumferential weld is not preferable.

International Publication No. 1998/31499 JP-A-58-117445

  SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for inspecting a girth weld that can accurately calculate the size of the defect regardless of the location of the girth weld where the defect exists.

In order to solve the above-mentioned problems, the present inventors have conducted intensive studies and found that a normal X-ray inspection machine (emission of X-rays from a direction substantially perpendicular to the longitudinal direction of the tube to be inspected toward the tube to be inspected) is performed. An X-ray source and an X-ray image which is arranged at a position facing the X-ray source with the tube to be inspected interposed therebetween, and detects X-rays emitted from the X-ray source and transmitted through the tube to be inspected to generate an X-ray image Even if an X-ray inspection machine equipped with a detector) is used, it is possible to recognize a portion where a defect exists in the circumferential welded portion by revising the device. Specifically, it is as follows.
First, an X-ray image (first X-ray image) is generated using an X-ray inspection machine at an initial position, and a defect area (first defect area) in the generated X-ray image is extracted. Next, after rotating the X-ray inspection machine from the initial position by a predetermined angle around the circumferential direction of the tube to be inspected, an X-ray image (second X-ray image) is generated, and a defect area (second image) in the generated X-ray image is generated. 2 defect areas). If the defect corresponding to the first defect region and the defect corresponding to the second defect region are the same defect, the region where the defect exists in the girth weld (the region on the X-ray source side or the region on the X-ray image detector side) ), The moving direction of the second defective area with respect to the first defective area is different. Accordingly, by comparing the position of the first defect area in the first X-ray image with the position of the second defect area in the second X-ray image, and specifying the moving direction, it is possible to correspond to the first defect area. It has been conceived that it is possible to recognize whether the part where the defect exists is the part on the X-ray source side or the part on the X-ray image detector side.

The present invention has been completed based on the above findings of the present inventors.
That is, in order to solve the above-mentioned problems, the present invention provides an X-ray source that emits X-rays from a direction substantially perpendicular to the longitudinal direction of a tube to be inspected toward the tube to be inspected, An X-ray image detector that is arranged at a position facing the X-ray source and detects an X-ray emitted from the X-ray source and transmitted through the tube to be inspected to generate an X-ray image. A method for inspecting a girth weld of a pipe to be inspected using an inspection machine, characterized by including the following first to fourth steps.
(1) First step: generating a first X-ray image of the inspected pipe including the girth weld using the X-ray inspection machine at the initial position, and performing image processing on the generated first X-ray image Thus, the first defect area is extracted from the pixel area corresponding to the circumferential weld, and the size of the first defect area is calculated.
(2) Second step: After rotating the X-ray inspection machine from the initial position by a predetermined angle around the circumferential direction of the pipe to be inspected, use the rotated X-ray inspection machine to remove the circumferential weld. A second defect corresponding to the first defect region in a pixel region corresponding to the girth weld is generated by generating a second X-ray image of the tube to be inspected and performing image processing on the generated second X-ray image. Extract the region.
(3) Third step: the position of the first defect area in the first X-ray image generated in the first step, and the position of the second defect area in the second X-ray image generated in the second step Are compared, the moving direction of the second defect region with respect to the first defect region is determined. Based on the determined moving direction, the defect corresponding to the first defect region is determined by the X of the circumferential weld. It is determined which of the part on the source side and the part on the X-ray image detector side is the defect.
(4) Fourth step: Based on the determination result of the third step, a correction coefficient corresponding to a portion where a defect corresponding to the first defect area exists is determined, and the determined correction coefficient is determined in the first step. The calculated dimension of the first defect area is multiplied, and the result of the multiplication is determined as the dimension of the first defect area.

According to the method for inspecting a girth weld according to the present invention, by performing the first to third steps, the first defect region extracted by using the X-ray inspection device at the initial position is located around the periphery of the pipe to be inspected. It is possible to determine which of the welded portion on the X-ray source side and the X-ray image detector side portion is the defect. Therefore, it is possible to calculate the distance between the X-ray source and the defect, and thus the magnification of the defect detected by the X-ray image detector. Accordingly, in the fourth step, it is possible to determine a correction coefficient (corresponding to the distance between the X-ray source and the defect) corresponding to the part where the defect exists, and to use the determined correction coefficient to determine the first defect area. By correcting the size, the size of the defect can be calculated with high accuracy regardless of the location where the defect exists. Then, for example, the calculated size of the defect (the size of the determined first defect area) is compared with a predetermined criterion for determining the quality of the girth welded portion. It is possible to determine that the girth weld is normal if it is determined that the girth is bad and if it is less than the criterion for judging the quality of the girth weld.
In the present invention, “the X-ray inspection apparatus at the initial position” means that the X-ray source and the X-ray image detector included in the X-ray inspection apparatus are at the initial position.
In the present invention, "rotating the X-ray inspection apparatus" means that the X-ray source and the X-ray image detector included in the X-ray inspection apparatus are integrated (the X-ray source and the X-ray image Means to rotate (while maintaining a state of opposition across the tube).
In the present invention, if the “predetermined angle” for rotating the X-ray inspection machine is too small, the movement amount of the second defect area with respect to the first defect area becomes small, so that it is difficult to determine the moving direction. May become Conversely, if the “predetermined angle” is too large, the defect corresponding to the first defect region deviates from the range of the viewing angle of the rotated X-ray inspection apparatus, and the second defect region corresponding to the first defect region is removed. Extraction may not be possible. For this reason, it is preferable to set the lower limit of the “predetermined angle” to an angle such that the movement amount of the second X-ray image with respect to the first X-ray image (movement amount of the visual field) is equal to or larger than the size of the defect to be detected. It is preferable that the upper limit of the “predetermined angle” is set to an angle that is １ ／ of the viewing angle of the X-ray inspection apparatus.

If the defect present in the girth weld of the pipe to be inspected is porosity, as described above, the girth weld is determined to be defective if the porosity having a circle-equivalent diameter equal to or greater than a certain value exists in the girth weld. Is done.
Therefore, in the first step, it is preferable to calculate the equivalent circle diameter of the first defect area. That is, it is preferable that, in the first step, the area of the first defect region is calculated, and the equivalent circle diameter is calculated as the dimension of the first defect region based on the area of the first defect region.
According to the above preferred method, in the first step, a circle equivalent diameter is calculated as the dimension of the first defect area, and in the fourth step, the result of multiplying the circle equivalent diameter by the correction coefficient is the dimension of the first defect area. Will be determined as

Here, if the size of the first defect area calculated in the first step is clearly large or small, the quality of the girth weld is determined in accordance with the location of the defect corresponding to the first defect area. It is considered that correction is not always necessary. That is, for example, if a defect having a circle equivalent diameter of 10% or more of the thickness of the inspected pipe exists in the girth weld, the girth weld is determined to be defective, and the correction calculated in the first step is performed. If the size of the previous first defect area (equivalent circle diameter) is 50% of the thickness of the pipe to be inspected, it is apparent that the girth weld is determined to be defective regardless of whether or not the correction is made. It is. Further, for example, when the dimension (circle equivalent diameter) of the first defect area before correction calculated in the first step is 1% of the thickness of the pipe to be inspected, regardless of whether or not the correction is performed, the circumferential welded portion is formed. Is determined to be normal.
Even in the case described above, it is preferable to execute the second to fourth steps in order to perform the correction according to the location of the defect corresponding to the first defect area, because the inspection time is unnecessarily long. Absent.

Accordingly, when the pass / fail judgment of the girth weld based on the dimension of the first defect area calculated in the first step is likely to have a different result depending on whether correction is performed in the second to fourth steps. Only the second to fourth steps need to be performed. In order to perform the second step more accurately, the second defect area is calculated only when the dimension of the first defect area calculated in the first step is within a predetermined reference range (criterion separately determined from the quality judgment criteria of the girth welded portion). Performing the steps, the third step and the fourth step, and when the dimension of the first defect area calculated in the first step is outside the reference range, the second step, the third step and the third step are performed. It is preferable that the dimension of the first defect area calculated in the first step be determined as the dimension of the first defect area without performing the fourth step.
In addition, as the above-mentioned "reference range", whether the calculated size of the first defect region is equal to or larger than a criterion for determining the quality of the girth welded portion (for example, a circle equivalent diameter of 10% of the thickness of the pipe to be inspected). What is necessary is just to appropriately determine a range in which it is evident whether it is less than or not with or without correction. For example, if the reference range is a circle equivalent diameter of 3% or more and 30% or less of the thickness of the inspected tube, the dimension (circle equivalent diameter) of the first defect area calculated in the first step is within this reference range. Only in this case (that is, when the circle equivalent diameter of the first defect area is 3% or more and 30% or less of the wall thickness), the second to fourth steps are performed. If the equivalent circle diameter of the defect area is less than 3% or more than 30% of the wall thickness, the second step to the fourth step are not performed and the size of the first defect area calculated in the first step (equivalent to a circle) Diameter) is determined as the size (equivalent circle diameter) of the first defect region.

  ADVANTAGE OF THE INVENTION According to the inspection method of a girth welded part which concerns on this invention, the dimension of a defect can be calculated with high precision regardless of the site | part where a defect exists in a girth weld.

FIG. 1 is a plan view schematically showing a schematic configuration of a long pipe manufacturing facility to which a method for inspecting a girth weld according to an embodiment of the present invention is applied. FIG. 2 is a diagram schematically illustrating a schematic configuration of an X-ray inspection machine included in the X-ray inspection apparatus main body illustrated in FIG. FIG. 3 is a diagram schematically showing a schematic configuration of the X-ray leakage suppression mechanism shown in FIG. FIG. 4 is a diagram schematically showing a state before and after rotation of the X-ray inspection machine in the method for inspecting a girth weld according to one embodiment of the present invention. FIG. 5 is an explanatory diagram illustrating the content of image processing performed by the image processing apparatus illustrated in FIG. FIG. 6 is an explanatory diagram illustrating the contents of the third step of the method for inspecting a girth welded portion according to one embodiment of the present invention. FIG. 7 is an explanatory diagram illustrating the contents of the third step of the method for inspecting a girth weld according to one embodiment of the present invention. FIG. 8 is a plan view illustrating movements of the welding device and the X-ray inspection device according to the procedure executed by the control device shown in FIG. FIG. 9 is a plan view illustrating movements of the welding device and the X-ray inspection device according to a procedure executed by the control device illustrated in FIG. 1. FIG. 10 is a plan view illustrating movements of the welding device and the X-ray inspection device according to the procedure executed by the control device shown in FIG. FIG. 11 is a plan view illustrating the operation of the welding device and the X-ray inspection device according to the procedure executed by the control device shown in FIG. FIG. 12 is a plan view illustrating movements of the welding device and the X-ray inspection device according to the procedure executed by the control device shown in FIG. FIG. 13 is a plan view illustrating the operation of the welding device and the X-ray inspection device according to the procedure executed by the control device illustrated in FIG. 1.

Hereinafter, a method for inspecting a girth welded portion according to an embodiment of the present invention will be described with reference to the accompanying drawings as an example in a case where the method is applied to a facility for manufacturing a long pipe such as a coiled tubing. First, the overall configuration of the manufacturing facility will be described.
FIG. 1 is a plan view schematically illustrating a schematic configuration of a long pipe manufacturing facility to which the method for inspecting a girth weld according to the present embodiment is applied.
As shown in FIG. 1, a long pipe manufacturing facility (hereinafter, simply referred to as “manufacturing facility”) 100 according to the present embodiment includes a transport device 1, a welding device 2, a winding device 3, And a line inspection device 4. Further, the manufacturing equipment 100 according to the present embodiment includes a control device 5 that controls the operations of the transport device 1, the welding device 2, the winding device 3, and the X-ray inspection device 4. Further, the manufacturing facility 100 according to the present embodiment includes the loading table 6 on which the plurality of pipes P are placed.
As a preferable configuration of the manufacturing equipment 100 according to the present embodiment, the welding device 2 and the X-ray inspection device 4 can be moved separately from each other along the transport device 1. That is, the welding device 2 and the X-ray inspection device 4 can be moved separately from each other along the transport direction of the pipe P (the longitudinal direction of the pipe P). Specifically, for example, the welding device 2 and the X-ray inspection device 4 are respectively attached to driving devices (not shown) such as air cylinders, and wheels (not shown) are respectively attached to lower portions. I have. Further, a rail (not shown) is provided on the floor surface along the transport direction of the pipe P. By driving the driving device by the control device 5, the welding device 2 and the X-ray inspection device 4 can move independently of each other along the transport device 1 with the respective wheels rolling on the rails. ing. Therefore, as described later, when the X-ray inspection device 4 determines that the girth weld is defective, it is not necessary to drive the transport device 1 and the winding device 3 in the reverse direction. Further, for example, if the distance between the welding device 2 and the X-ray inspection device 4 is adjusted according to the length of the pipe P on which the circumferential welding is to be performed and the distance is set to be substantially equal to the length of the pipe P, 2 and the inspection of the girth weld by the X-ray inspection device 4 can be performed in parallel to increase the production efficiency.

  The pipe P of the present embodiment is, for example, a stainless steel pipe. When a long pipe P1 formed by performing circumferential welding on the pipe P by the welding device 2 is used as an umbilical cable, it is preferable that the pipe P be used. It is a stainless steel pipe. The pipe P may be an electric resistance welded pipe or a seamless pipe.

  The transport device 1 is a device that is driven by the control device 5 and transports the pipe P linearly in the longitudinal direction (the X direction shown in FIG. 1). Specifically, in the present embodiment, a plurality of pipes P placed on the loading table 6 are sequentially loaded toward the transport device 1 in a direction orthogonal to the longitudinal direction (Y direction shown in FIG. 1), and transported. The apparatus 1 conveys the plurality of pipes P carried in the longitudinal direction. Note that the loading table 6 includes a predetermined loading mechanism (not shown), and a plurality of pipes P are sequentially loaded by driving the loading mechanism by the control device 5.

The transport device 1 of the present embodiment includes a side clamp roller 11 and a V roller 12.
The side clamp roller 11 is disposed on the upstream side in the conveying direction (X direction) of the pipe P with respect to the welding device 2 so as to sandwich the pipe P in the horizontal direction. The side clamp roller 11 applies a driving force in the longitudinal direction of the pipe P by rotating using a motor or the like as a driving source.
The V roller is disposed below the pipe P (including the long pipe P1) between the position where the pipe P is loaded from the loading table 6 and the winding device 3. The V roller supports the pipe P from below, and rotates as the pipe P is transported in the longitudinal direction.
With the above configuration, the tube P before being subjected to the circumferential welding by the welding device 2 and the long tube P1 before being wound on the reel 31 by the winding device 3 are driven by the side clamp roller 11 in the longitudinal direction. The long tube P <b> 1 that has been provided and wound on the reel 31 by the winding device 3 is provided with a driving force in the longitudinal direction by the winding device 3, and is conveyed in the longitudinal direction.
In the present embodiment, the configuration in which the transport device 1 includes the side clamp roller 11 that applies a driving force and the V roller 12 that is driven only without applying the driving force has been described. Not something. As the transfer device, various configurations are adopted as long as a plurality of tubes P can be transferred in the longitudinal direction, for example, a pusher that pushes the tubes P from the upstream to the downstream in the transfer direction is used instead of the side clamp roller 11. It is possible.

The welding device 2 is arranged along the transfer device 1. The welding device 2 is a device that is driven by the control device 5 and performs circumferential welding on the ends of the plurality of pipes P transported by the transport device 1 to form a long pipe P1.
The welding device 2 of the present embodiment includes a girth welding machine (circumferential welding machine) 21 and a pair of gripping devices arranged along the conveying direction of the pipe P (the longitudinal direction of the pipe P) with the girth welding machine 21 interposed therebetween. 22. Further, the welding device 2 of the present embodiment also includes a cooling device (not shown). As a cooling method of the cooling device, for example, forced air cooling can be exemplified.

  The control device 5 stops the operations of the transport device 1 and the winding device 3 and drives each gripping device 22 at the timing when the end of each pipe P arrives at the position where the girth welding machine 21 is arranged. Thereby, each gripping device 22 grips the end of each pipe P. That is, the tip of the pipe P located on the upstream side in the transport direction is gripped by the gripping device 22 arranged on the upstream side in the transport direction of the pipe P, and the gripping device 22 located on the downstream side in the transport direction is gripped downstream by the gripping device 22. The rear end of the located tube P (long tube P1) is gripped. Then, each gripping device 22 adjusts the position of each pipe P so that the axis of each pipe P matches. Next, the control device 5 drives the girth welding machine 21, and the girth welding machine 22 performs girth welding on the ends of the pipes P whose positions have been adjusted. Finally, the control device 5 drives the cooling device, and the cooling device cools the formed girth weld PW. After the cooling of the girth welding portion PW is completed, the control device 5 releases the gripping by each gripping device 22, drives the transport device 1 and the winding device 3, and transports the long pipe P1.

The winding device 3 is arranged downstream of the pipe P (long pipe P1) in the transport direction with respect to the welding device 2 along the transport device 1. The winding device 3 is a device that is driven by the control device 5 and winds the long tube P1 conveyed by the conveying device 1 around the reel 31.
Specifically, the winding device 3 of the present embodiment includes a rotation mechanism (not shown) for rotating the reel 31 around its central axis and a moving mechanism (for moving the reel 31 in the central axis direction (Y direction)). (Not shown)). The winding device 3 winds the long tube P1 on the outer surface of the reel 31 by rotating the reel 31 by the rotating mechanism and moving the reel 31 by the moving mechanism.

The X-ray inspection apparatus 4 is an apparatus for executing a method for inspecting a girth weld PW according to an embodiment of the present invention. The X-ray inspection device 4 is disposed between the welding device 2 and the winding device 3 along the transport device 1. The X-ray inspection device 4 is driven by the control device 5 and inspects the circumferential weld PW of the long pipe P1.
The control device 5 determines the position of the circumferential weld PW of the long pipe P1 formed by the welding device 2 at the position of the X-ray inspection device 4 (specifically, the position at which X-rays are emitted by the X-ray source 412 described below). ), The operation of the transport device 1 and the winding device 3 is stopped to stop the long tube P1, and the X-ray inspection device 4 is driven.

The X-ray inspection apparatus 4 includes an X-ray inspection apparatus main body 41 and an X-ray leakage suppression mechanism 42 attached near the entrances on the entrance and exit sides of the X-ray inspection apparatus main body 41. In the X-ray inspection apparatus main body 41, the long tube P1 has openings on the entrance side (upstream in the transport direction of the long tube P1) and the exit side (downstream side in the transport direction of the long tube P1) of the X-ray inspection apparatus main body 41. The circumferential welded portion PW of the long pipe P1 is inspected in a state of protruding from the outside. The X-ray leakage suppressing mechanism 42 is connected to the outside of the X-ray inspection apparatus main body 41 through the entrance and exit openings while the X-ray inspection apparatus main body 41 is inspecting the circumferential weld PW of the long pipe P1. The leakage of X-rays to
Hereinafter, a more specific configuration of the X-ray inspection apparatus 4 will be described with reference to FIGS. 2 and 3 as appropriate.

  As shown in FIG. 1, the X-ray inspection apparatus main body 41 includes a housing 41a, a pair of sleeves 41b provided on the entrance side and the exit side of the housing 41a, and communicating with the housing 41a. And an X-ray inspection machine 41c arranged at the same position. This X-ray inspection machine 41c is an X-ray inspection machine used for executing the inspection method of the girth weld PW according to one embodiment of the present invention. The main body 41 of the X-ray inspection apparatus performs circumferential welding of the long tube P1 by the X-ray inspection device 41c in a state where the long tube P1 is inserted into the X-ray inspection device 41c and each sleeve 41b arranged in the housing 41a. Inspect section PW.

FIG. 2 is a diagram schematically illustrating a schematic configuration of an X-ray inspection machine 41c included in the X-ray inspection apparatus main body 41. FIG. 2A is a perspective view, and FIG. 2B is a front view of the long tube P1 as viewed from the longitudinal direction.
As shown in FIG. 2, the X-ray inspection machine 41c includes a rotation mechanism 411, an X-ray source 412, an X-ray image detector 413, and an image processing device 414.

The rotation mechanism 411 includes, for example, an outer ring member 411A surrounding the circumference of the long pipe P1 and an inner ring member 411B rotatably mounted on the inner side of the outer ring member 411A with respect to the outer ring member 411A. Is provided.
The X-ray source 412 is a device that emits X-rays from a direction substantially perpendicular to the longitudinal direction of the long tube P1 to be inspected toward the long tube P1. The X-ray source 412 is attached to the inner ring member 411B of the rotation mechanism 411, and rotates around the circumferential direction of the long tube P1 by rotating the inner ring member 411B with respect to the outer ring member 411A. As shown in FIG. 2B, the X-ray source 412 repeatedly rotates and stops, and X-rays at a plurality of predetermined positions (three positions at 60 ° pitch in the example shown in FIG. 2B). Radiate.
The X-ray image detector 413 is disposed at a position facing the X-ray source 412 with the long tube P1 interposed therebetween, detects X-rays emitted from the X-ray source 412 and transmitted through the long tube P1, and performs X-ray detection. This is an apparatus for generating an image, and for example, a flat panel detector (FPD) is suitably used. The X-ray image detector 413 is also attached to the inner ring member 411B of the rotation mechanism 411, and the inner ring member 411B is rotated with respect to the outer ring member 411A, so that the X-ray image detector 413 is integrated with the X-ray source 412 (elongated tube P1). (While maintaining a state of facing the X-ray source 412 with the interposition therebetween), the elongate tube P1 rotates around the circumferential direction.
The image processing device 414 is a device that performs image processing on the X-ray image generated by the X-ray image detector 413 and inspects the circumferential weld PW of the long pipe P1. The image processing device 414 detects a defect such as porosity present in the girth weld PW by executing the method for inspecting the girth weld PW according to the embodiment of the present invention, calculates the size of the defect, and calculates the size of the girth weld. The quality of the unit is determined. The specific contents will be described later.

FIG. 3 is a diagram schematically illustrating a schematic configuration of the X-ray leakage suppression mechanism 42. FIG. 3A is a front view showing a state of the X-ray leakage suppressing mechanism 42 when the circumferential weld PW of the long pipe P1 is inspected by the X-ray inspection apparatus main body 41, and FIG. (A) is a cross-sectional view taken along the arrow bb. FIG. 3C shows the state of the X-ray leakage suppression mechanism 42 when the inspection of the circumferential weld PW of the long pipe P1 is completed by the X-ray inspection apparatus main body 41 and the transport apparatus 1 transports the long pipe P1. FIG. 3D is a sectional view taken along line dd in FIG. 3C.
As described above, the X-ray leakage suppression mechanism 42 is attached near the entrances on the entrance and exit sides of the X-ray inspection apparatus main body 41. Specifically, the X-ray leakage suppression mechanism 42 is attached near a substantially circular opening 410 of a pair of sleeves 41b provided in the X-ray inspection apparatus main body 41. More specifically, the X-ray leakage suppression mechanism 42 is provided in the vicinity of the opening 410 on the upstream side of the pair of sleeves 41b with respect to the sleeve 41b provided on the upstream side in the transport direction of the long tube P1. Attached to the sleeve 41b provided on the downstream side in the transport direction of the long pipe P1, it is attached near the opening 410 on the downstream side. Since the X-ray leakage suppression mechanisms 42 attached to the entrance and exit sides of the X-ray inspection apparatus main body 41 have the same configuration, only one X-ray leakage suppression mechanism 42 will be described here.

The X-ray leakage suppression mechanism 42 includes a closing member 421. The closing member 421 is composed of a plurality of members (in the example shown in FIG. 3, two half-divided members 42 a and 42 b) that can be opened and closed in the radial direction (the radial direction of the long tube P <b> 1). , 42b are in the radially closed position (the state shown in FIGS. 3A and 3B), a substantially circular opening 421a through which the long tube P1 is inserted is formed inside. Specifically, each member 42a, 42b is attached to a driving device (not shown) such as an air cylinder, and by driving this driving device, each member 42a, 42b is moved in a radial direction (FIG. 3). In the example shown in (1), it can be opened and closed (movable forward and backward). The members 42a and 42b constituting the closing member 421 are formed of, for example, stainless steel.
In addition, in the example shown in FIG. 3, although each member 42a, 42b can be opened and closed in the up-down direction, it is not limited to this, but the radial direction of the long tube P1 (in the longitudinal direction of the long tube P1). A member that can be opened and closed in other directions, such as a horizontal direction, is also possible as long as it is in the direction perpendicular to the direction. Further, in the example shown in FIG. 3, the closing member 421 includes two members 42 a and 42 b, but is not limited thereto, and three members are provided as long as they are a plurality of members that can be opened and closed in the radial direction. It is also possible to constitute from the above members.

  When the X-ray inspection apparatus main body 41 inspects the girth weld PW of the long tube P1 (that is, when the X-ray is emitted from the X-ray source 412), the control device 5 performs the operations shown in FIGS. As shown in b), the X-ray leakage suppression mechanism 42 is driven such that the plurality of members 42a and 42b constituting the closing member 421 are in the radially closed position. In other words, when a driving device such as an air cylinder included in the X-ray leakage suppression mechanism 42 is driven by a control signal from the control device 5, the plurality of members 42 a and 42 b are in the radially closed position. Then, as shown in FIGS. 3A and 3B, when the plurality of members 42a and 42b are in the radially closed position, the radial dimension L1 of the opening 421a of the closing member 421 is determined by the X-ray inspection. The radial dimension L2 (the radial dimension of the opening 410 of the sleeve 41b, see FIG. 3C) is smaller than the radial dimension L2 of the entrance side and the exit side of the apparatus main body 41. Accordingly, a part of the opening of the X-ray inspection apparatus main body 41 (a part of the opening 410 of the sleeve 41b) is closed by the closing member 421 (the plurality of members 42a and 42b). Also, when the plurality of members 42a and 42b are in the radially closed position, the radial dimension L1 of the opening 421a of the closing member 421 is substantially the same as the radial dimension of the long pipe P1 other than the circumferential weld PW. It is. Accordingly, the gap between the opening 421a of the closing member 421 and the long pipe P1 is eliminated or becomes extremely small. For this reason, after the plurality of members 42a and 42b reach the radially closed position, if the circumferential weld PW of the long tube P1 is inspected by the X-ray inspection apparatus main body 41, the opening of the X-ray inspection apparatus main body 41 can be determined. It is possible to suppress leakage of X-rays from the portion (the opening 410 of the sleeve 41b) to the outside.

  On the other hand, the control device 5 terminates the inspection of the circumferential weld P1 of the long tube P1 by the X-ray inspection device main body 41 (that is, the X-ray emission from the X-ray source 412 stops), and the transport device 1 When the long tube P1 is conveyed, as shown in FIGS. 3C and 3D, X-ray leakage is performed so that the plurality of members 42a and 42b forming the closing member 421 are at radially open positions. The suppression mechanism 32 is driven. Then, as shown in FIGS. 3C and 3D, when the plurality of members 42a and 42b are at the positions opened in the radial direction, the closing member 421 does not interfere with the circumferential weld PW of the long pipe P1. Position. In the present embodiment, the plurality of members 42a and 42b constituting the closing member 421 are located radially outward from the sleeve 41b. For this reason, even if the long pipe P1 is transported after the X-ray inspection in the X-ray inspection apparatus main body 41 is completed, there is no possibility that the circumferential welded portion PW of the long pipe P1 interferes with the closing member 421, and the transport is performed. Does not cause any problems.

  In order to further suppress the leakage of X-rays, as shown in FIG. 1, a pair of X-ray leakage suppression mechanisms 42A having the same configuration as that of the X-ray leakage suppression mechanism 42 is mounted in the housing 41a. preferable. The X-ray leakage suppression mechanism 42A is attached to the sleeve 41b provided on the upstream side in the transport direction of the long tube P1 of the pair of sleeves 41b in the vicinity of the opening 410 on the downstream side thereof. The sleeve 41b provided on the downstream side in the transport direction of P1 is attached near the opening 410 on the upstream side.

  The peripheral welding portion PW of the long pipe P1 is inspected by the X-ray inspection device 4 described above, and when it is determined that the peripheral welding portion PW is normal, the control device 5 controls the transport device 1 and the winding device 3 to operate. By driving, the long tube P <b> 1 is conveyed and wound on the reel 31.

  On the other hand, when the X-ray inspection device 4 determines that the circumferential weld PW of the long pipe P1 is defective, the welding device 2 and the X-ray inspection device 4 Since they can be moved separately, the control device 5 does not drive the transport device 1 and the winding device 3 in the reverse direction (without transporting the long tube P1 in the reverse direction), and uses the welding device 2 to move the long tube P1. It is possible to form the girth weld PW again on the shank P1 and to inspect the girth weld PW formed again by the X-ray inspection device 4. A specific operation example of the control device 5 when it is determined that the circumferential weld PW of the long pipe P1 is defective will be described later.

  Hereinafter, a method for inspecting a girth weld PW according to an embodiment of the present invention will be described with reference to FIGS. 4 to 7 as appropriate. As described above, the method of inspecting the girth weld PW according to the present embodiment uses the X-ray inspection machine 41c including the X-ray source 412 and the X-ray image detector 413, as a long tube that is a tube to be inspected. This is a method for inspecting the girth weld PW of P1, and executes the following first to fourth steps. However, in the method of inspecting the girth weld PW according to the present embodiment, it is not necessary to always execute all of the first to fourth steps, and only the first step may be executed as described later.

<First step>
FIG. 4 is a diagram schematically showing a state before and after the rotation of the X-ray inspection machine 41c in the method of inspecting the girth weld PW according to the present embodiment. In FIG. 4, the X-ray source 412 of the X-ray inspection apparatus 41c before rotation is denoted by reference numeral 412a, and the X-ray image detector 413 is denoted by reference numeral 413a to distinguish the X-ray inspection apparatus 41c before and after rotation. It is attached. The X-ray source 412 included in the rotated X-ray inspection apparatus 41c is denoted by reference numeral 412b, and the X-ray image detector 413 is denoted by reference numeral 413b. The same applies to FIGS. 6 and 7 described later.
In the first step, the long pipe P1 including the circumferential weld PW is used by using the X-ray inspection apparatus 41c (the X-ray source 412a and the X-ray image detector 413a) at the initial position (position before rotation) shown in FIG. Is generated. The X-ray source 412a and the X-ray image detector 413a at the initial position correspond to the X-ray source 412 and the X-ray image detector 413 indicated by solid lines in FIG. 2B, respectively. Then, the image processing device 414 performs image processing on the generated first X-ray image to extract the first defect area in the pixel area corresponding to the girth weld PW, and calculates the size of the first defect area.

FIG. 5 is an explanatory diagram illustrating the contents of the image processing performed by the image processing device 414. FIG. 5A is a diagram schematically illustrating an example of a first X-ray image. FIG. 5B is a diagram illustrating a pixel region (hereinafter, a candidate region) corresponding to a defect F from which the first defect region FA is extracted. FIG. 5C is an enlarged view schematically showing an example of the first defect area FA. The X direction shown in FIG. 5 indicates a direction corresponding to the longitudinal direction of the long tube P1. The Y direction indicates a direction corresponding to the radial direction of the long tube P1. The same applies to the X direction and the Y direction shown in FIG.
As illustrated in FIG. 5, the image processing device 414 performs image processing on the first X-ray image illustrated in FIG. 5A, and corresponds to a girth weld PW as illustrated in FIG. 5B. A pixel region having a higher density (brighter) than the surrounding pixel region is extracted as a candidate region in the pixel region to be processed. In the example illustrated in FIG. 5B, a candidate area including the pixel areas F1, F2, and F3 is extracted. Next, as shown in FIG. 5C, the image processing device 414 determines, for example, half or more of the density peak value of the pixels constituting the candidate area in the extracted candidate area (FIG. 5B). A pixel area having a density is extracted as a first defective area FA. In the examples shown in FIGS. 5B and 5C, the pixel area F1 has a density peak value, the pixel area F2 has a density equal to or more than half the density peak value, and the pixel area F3 has a density peak value. Therefore, the pixel areas F1 and F2 are extracted as the first defective area FA. Then, the image processing device 414 calculates the area of the extracted first defect area FA, and calculates the equivalent circle diameter as the dimension of the first defect area FA based on the area of the first defect area FA. That is, assuming that the area of the first defect area FA is S, the circle equivalent diameter R of the first defect area FA is calculated by the following equation (1).
R = (4S / π) ^1/2 (1)
The equivalent circle diameter R may be calculated in pixel units, or may be calculated in actual size by obtaining the correspondence between pixels and actual size in advance and storing it in the image processing device 414. .
As described above, this first step is executed at a plurality of predetermined positions (three positions at 60 ° pitch in the example shown in FIG. 2B).

In the present embodiment, as a preferable configuration, the second to fourth steps described later are executed only when the circle equivalent diameter R of the first defect area FA calculated in the first step is within a predetermined reference range. . On the other hand, when the circle equivalent diameter R of the first defect area FA calculated in the first step is out of the reference range, the second to fourth steps described below are not performed, and the first calculated in the first step. The equivalent circle diameter R of the one defect area FA is determined as the equivalent circle diameter R of the first defect area FA.
As the above-mentioned “reference range”, the calculated circle equivalent diameter R of the first defect area FA is a predetermined criterion for determining the quality of the girth weld PW (for example, a circle having a thickness of 10% of the wall thickness of the long pipe P1). It is sufficient to appropriately determine a range (for example, a circle equivalent diameter of 3% or more and 30% or less of the wall thickness of the long tube P1) in which it is clear whether the difference is equal to or larger than the equivalent diameter regardless of the correction. .
Specifically, for example, the reference range determined above is stored in the image processing device 414 in advance, and whether or not the circle equivalent diameter R of the first defect area FA calculated by the image processing device 414 is within the reference range is determined. It is possible to adopt a configuration in which the image processing device 414 automatically determines whether the above is the case or not and the image processing device 414 automatically determines whether to execute the second to fourth steps.
Alternatively, it is also possible to adopt a configuration in which the operation of the image processing device 414 is temporarily stopped after executing the first step. Then, the first X-ray image as shown in FIG. 5A is displayed on a monitor of the image processing device 414, and the operator views the displayed first X-ray image, and the image is calculated by the image processing device 414. It is also possible to visually determine whether or not the circle equivalent diameter R of the first defect area FA is within the reference range. When the operator visually determines that the circle-equivalent diameter R of the first defect area FA is within the reference range, for example, the operator performs a button operation for executing the second to fourth steps. It is also possible to adopt a configuration in which the image processing device 414 restarts the operation and executes the second to fourth steps.

<Second step>
In the second step, as shown in FIG. 4, after rotating the X-ray inspection device 41c from the initial position around the circumferential direction of the long tube P1 by a predetermined angle β, the rotated X-ray inspection device 41c (X A second X-ray image of the long tube P1 including the girth weld PW is generated using the radiation source 412b and the X-ray image detector 413b). Note that the lower limit of the angle β is preferably set to an angle such that the movement amount of the second X-ray image (movement amount of the visual field) with respect to the first X-ray image is equal to or larger than the size of the defect F to be detected. The upper limit of the angle β is preferably set to 角度 of the viewing angle α of the X-ray inspection apparatus 41c (30 ° in the present embodiment because the viewing angle α is about 60 °).

  Then, the image processing device 414 performs image processing on the generated second X-ray image to extract a second defect area FB corresponding to the first defect area FA in a pixel area corresponding to the girth weld PW. The details of the image processing performed on the second X-ray image to extract the second defective area FB are the same as the details of the image processing performed on the first X-ray image described above with reference to FIG. Description is omitted.

<Third step>
FIG. 6 is an explanatory diagram illustrating the contents of the third step of the method for inspecting the girth weld PW according to the present embodiment. FIG. 6A is a diagram schematically showing a state in which the defect F exists on the X-ray source side (upper side in the example shown in FIG. 6A) of the circumferential weld PW, and FIG. FIG. 6 is a diagram schematically showing an example of a first X-ray image generated in the state shown in FIG. 6A, and FIG. 6C is generated in the state shown in FIG. It is a figure which shows the example of a 2nd X-ray image typically. FIG. 6D is a diagram schematically illustrating a state in which the defect F is present at a position on the X-ray image detector side (the lower side in the example illustrated in FIG. 6D) of the circumferential weld PW, FIG. 6E is a diagram schematically showing an example of the first X-ray image generated in the state shown in FIG. 6D, and FIG. 6F is a view showing the state in the state shown in FIG. It is a figure which shows typically the example of the 2nd X-ray image generated at the time.
In the third step, the position of the first defect area FA in the first X-ray image generated in the first step and the position of the second defect area FB in the second X-ray image generated in the second step are determined by the image processing device 414. Are compared, the moving direction of the second defect area FB with respect to the first defect area FA is determined. Specifically, when the defect F exists in a portion above the girth weld PW, the position of the first defect area FA in the first X-ray image shown in FIG. By comparing the position of the second defect area FB in the second X-ray image shown, it is determined that the moving direction of the second defect area FB with respect to the first defect area FA is the left direction in the drawing. Further, when the defect F exists in the lower part of the girth weld PW, the position of the first defect area FA in the first X-ray image shown in FIG. 6E and the position of the first defect area FA shown in FIG. By comparing the position of the second defect area FB in the 2X-ray image with the position of the second defect area FB, it is determined that the moving direction of the second defect area FB with respect to the first defect area FA is the right direction in the drawing.

Based on the moving direction determined as described above, the image processing device 414 determines that the defect F corresponding to the first defect area FA is located above (the X-ray source side) and below (the X-ray source) the circumferential weld PW. It is possible to determine which of the parts on the image detector side) is the defect.
Note that, for example, a plurality of first defect areas FA and a plurality of second defect areas FB may be extracted because a plurality of defects F exist in the circumferential weld PW. In this case, the determination as to which second defect area FB corresponds to which first defect area FA is based on, for example, feature amounts such as the shapes and densities of the first defect area FA and the second defect area FB. By performing pattern matching, it is possible to determine that a combination of the first defect area FA and the second defect area FB having the highest matching score is a defect area corresponding to each other.

<Fourth step>
FIG. 7 is an explanatory diagram illustrating the contents of the fourth step of the method for inspecting the girth weld PW according to the present embodiment.
The magnification of the defect F detected by the X-ray image detector 413 is determined by a value obtained by dividing the distance between the X-ray source 412 and the X-ray image detector 413 by the distance between the X-ray source 412 and the defect F. As shown in FIG. 7, the distance between the X-ray source 412 and the lower surface of the long tube P1 is H1, the distance between the lower surface of the long tube P1 and the X-ray image detector 413 is H2, and the length of the long tube P1 is Assuming that the outer diameter is OD, when the defect F exists below the circumferential weld PW (on the side of the X-ray image detector 413), the magnification of the defect F is approximately expressed by (H1 + H2) / H1. Is done. On the other hand, when the defect F exists at a position above the girth weld PW (on the side of the X-ray source 412), the magnification of the defect F is approximately represented by (H1 + H2) / (H1-OD). For this reason, even if the defect F has the same size (equivalent circle diameter) in actuality, when it exists in the upper part of the girth welded portion PW, the X-rays are present more than in the lower part. The dimension (the circle equivalent diameter R in the first X-ray image) detected by the image detector 413 increases by H1 / (H1-OD) times.
Therefore, if the defect F is present in the lower part of the girth weld PW and the circle equivalent diameter R of the first defect area FA is not to be corrected (correction coefficient = 1), the defect F becomes a girth weld. If it exists in the area above the PW, the correction coefficient is set to (H1−OD) / H1, and the circle equivalent diameter R of the first defect area FA is multiplied, so that the correction coefficient is equal regardless of the area where the defect F exists. The size of the defect F can be calculated.

For this reason, in the fourth step, a correction coefficient corresponding to a portion where the defect F corresponding to the first defect area FA exists is determined based on the determination result in the third step. In the example shown in FIG. 7, when it is determined in the third step that the defect F corresponding to the first defect area FA exists in the lower part of the girth weld PW, the correction coefficient is set to 1. In addition, when it is determined in the third step that the defect F corresponding to the first defect area FA exists in a portion above the girth weld PW, the correction coefficient is determined to be (H1−OD) / H1.
Then, the determined correction coefficient is multiplied by the circle equivalent diameter R of the first defect area FA, and the result of the multiplication is determined as the circle equivalent diameter R of the first defect area FA.
The image processing apparatus 414 according to the present embodiment is configured such that the circle equivalent diameter R determined as described above is equal to or greater than a predetermined criterion for determining the quality of the girth welded portion (for example, 10% of the wall thickness of the long pipe P1). For example, it is determined that the girth weld PW is defective, and if it is less than the criterion, it is determined that the girth weld PW is normal.

  As described above, according to the method for inspecting a girth welded portion PW according to the present embodiment, the first to third steps are executed, and the first to third steps are extracted using the X-ray inspection machine 41c at the initial position. It is possible to determine which one of the defect area FA is the defect F existing in the part on the X-ray source 412 side and the part on the X-ray image detector 413 side of the circumferential weld PW of the long pipe P1. is there. Therefore, the distance (H1 or H1−OD) between the X-ray source 412 and the defect F, and the magnification of the defect F detected by the X-ray image detector 413 can be calculated. Accordingly, in the fourth step, a correction coefficient (corresponding to the distance between the X-ray source 412 and the defect F) corresponding to the portion where the defect F exists can be determined, and the first correction coefficient is determined using the determined correction coefficient. By correcting the circle-equivalent diameter R of the defect area FA, the circle-equivalent diameter R, which is the size of the defect F, can be accurately calculated regardless of the location where the defect F exists.

  In this embodiment, the case where the initial position of the X-ray inspection device 41c is at the position indicated by the solid line in FIG. 2B has been described as an example, but the initial position of the X-ray detection device 41c is shown in FIG. The same applies to any one of the three 60 ° pitches shown in b).

  When it is determined that the circumferential weld PW of the long pipe P1 is defective by the above-described method for inspecting the circumferential weld PW according to the present embodiment, as described above, the welding device 2 and the X-ray inspection device 4 are used. The control device 5 can execute the following first to sixth procedures as a preferred embodiment, since they can be moved separately from each other along the transport device 1. Hereinafter, the first to sixth procedures executed by the control device 5 will be described with reference to FIGS. 8 to 14 are plan views illustrating movements of the welding device 2 and the X-ray inspection device 4 according to the first to sixth procedures executed by the control device. For convenience, illustration of the transport device 1 is omitted. are doing.

<First procedure>
When the X-ray inspection device 4 at the initial position indicated by the broken line in FIG. 8 determines that the circumferential weld PW of the long tube P1 is defective, the control device 5 sets the X-ray inspection device 4 to the long tube P1. To the downstream side in the transport direction. The amount of movement of the X-ray inspection apparatus 4 does not hinder the cutting operation of the circumferential welding portion PW determined to be defective, and furthermore, the welding apparatus 2 is moved in the transport direction of the long pipe P1 in a second procedure described later. It is preferable that the welding apparatus 2 be set so as not to interfere with the X-ray inspection apparatus 4 when the apparatus is moved downstream.
After the X-ray inspection apparatus 4 moves, as shown in FIG. 9, the circumferential weld PW determined to be defective may be cut. The cutting of the circumferential weld PW can be manually performed by an operator using, for example, a portable cutting machine installed on the downstream side of the welding device 2.
In addition, it is preferable that the end face of the long pipe P1 after cutting is subjected to deburring, polishing, or the like, so that circumferential welding can be easily performed in a third procedure described later. Deburring and polishing of the end face of the long pipe P1 can be manually performed by an operator using, for example, a portable bevel / chamfering machine installed on the downstream side of the welding device 2.

<Second procedure>
Next, as shown in FIG. 10, the control device 5 controls the welding device in the initial position indicated by the broken line to the cutting position of the long pipe P1 after the circumferential welding portion PW determined to be defective is cut. 2 is moved to the downstream side in the transport direction of the long tube P1.

<Third procedure>
Next, as shown in FIG. 11, the control device 5 drives the welding device 2 to perform the circumferential welding again on the cut portion of the long pipe P1 by the welding device 2 to form the circumferential weld portion PW.
According to the first to third procedures described above, it is necessary to drive the transport device 1 and the winding device 3 (see FIG. 1) in the reverse direction to transport the long pipe P1 in the reverse direction (upstream side). There is no. Instead of transporting the long tube P1 in the reverse direction, the X-ray inspection device 4 and the welding device 2 are moved in the normal transport direction of the long tube P1.

<Fourth procedure>
Next, as shown in FIG. 12, the control device 5 moves the welding device 2 to the upstream side in the transport direction of the long pipe P1. At this time, it is preferable to move the welding device 2 to the initial position (the position shown in FIG. 8). Accordingly, even if the X-ray inspection device 4 is moved in a fifth procedure described later, the welding device 2 does not interfere with the X-ray inspection device 4.

<Fifth procedure>
Next, as shown in FIG. 13, the control device 5 moves the X-ray inspection device 4 to the upstream side in the transport direction of the long tube P1 up to the re-formed circumferential weld PW of the long tube P1. That is, the X-ray inspection apparatus 4 is moved to the initial position (the position indicated by the broken line in FIG. 8).
Note that the fourth procedure and the fifth procedure may be executed simultaneously unless the moving speed of the X-ray inspection apparatus 4 is higher and there is no trouble such that the welding apparatus 2 and the X-ray inspection apparatus 4 interfere with each other. It is possible.

<Sixth procedure>
Lastly, the control device 5 drives the X-ray inspection device 4 to inspect the re-formed circumferential weld PW of the long pipe P1 by the X-ray inspection device 4.
Also in the fourth to sixth procedures described above, there is no need to transport the long tube P1.
That is, by performing the above-described first to sixth procedures, the welding device can be driven without driving the transport device 1 and the winding device 3 in the reverse direction (without transporting the long pipe P1 in the reverse direction). 2, it is possible to form a girth weld PW again on the long pipe P1 and to inspect the girth weld PW formed again by the X-ray inspection device 4. For this reason, generation | occurrence | production of the external surface flaw and deterioration of intensity | strength resulting from conveying the long pipe P1 in a reverse direction can be suppressed.

  As a result of executing the first to sixth procedures, when it is determined that the re-formed girth weld PW is normal, the control device 5 drives the transport device 2 and the winding device 3 by The long tube P <b> 1 is conveyed and wound on a reel 31. On the other hand, if it is determined that the re-formed girth weld PW is defective, the above-described first to sixth procedures are repeatedly executed.

DESCRIPTION OF SYMBOLS 1 ... Conveying apparatus 2 ... Welding apparatus 3 ... Winding apparatus 4 ... X-ray inspection apparatus 5 ... Control apparatus 31 ... Reel 41 ... X-ray inspection apparatus main body 41c ... X-ray inspection machines 412, 412a, 412b ... X-ray sources 413, 413a, 413b ... X-ray image detector 42 ... X-ray leakage suppression mechanism 100 ... Manufacturing equipment P for long pipes ..Tube P1 ... Inspection tube (long tube)
PW: circumferential weld F: defect FA: first defect area FB: second defect area

Claims (3)

An X-ray source that emits X-rays from the direction substantially perpendicular to the longitudinal direction of the tube to be inspected toward the tube to be inspected, and an X-ray source disposed at a position facing the X-ray source with the tube to be inspected interposed therebetween; An X-ray image detector for detecting an X-ray radiated from the X-ray source and transmitting through the tube to be inspected to generate an X-ray image; A method of testing,
A first X-ray image of the pipe to be inspected including the girth weld is generated by using the X-ray inspection machine at the initial position, and the generated first X-ray image is subjected to image processing so that the girth weld is formed on the girth weld. A first step of extracting a first defective area in a corresponding pixel area and calculating a size of the first defective area;
After rotating the X-ray inspection machine from the initial position by a predetermined angle around the circumferential direction of the pipe to be inspected, the X-ray inspection apparatus after the rotation is used to inspect the pipe to be inspected including the circumferential welded portion. 2nd step of generating a 2X-ray image and performing image processing on the generated 2nd X-ray image to extract a second defect area corresponding to the first defect area in a pixel area corresponding to the girth welded portion When,
By comparing the position of the first defect area in the first X-ray image generated in the first step with the position of the second defect area in the second X-ray image generated in the second step, The direction of movement of the second defect area with respect to the first defect area is determined, and a defect corresponding to the first defect area is determined based on the determined direction of movement. A third step of determining which part of the parts on the X-ray image detector side is a defect;
Based on the determination result of the third step, a correction coefficient corresponding to a portion where a defect corresponding to the first defect area exists is determined, and the determined correction coefficient is calculated in the first step. A fourth step of multiplying the dimension of the first defect area and determining the result of the multiplication as the dimension of the first defect area;
A method for inspecting girth welds, comprising:   2. The method according to claim 1, wherein, in the first step, an area of the first defect area is calculated, and a circle-equivalent diameter is calculated as a dimension of the first defect area based on the area of the first defect area. Inspection method for girth welds described. Performing the second step, the third step, and the fourth step only when the size of the first defect area calculated in the first step is within a predetermined reference range;
If the size of the first defect area calculated in the first step is outside the reference range, the second step, the third step, and the fourth step are not performed, and the first step is performed in the first step. The method according to claim 1 or 2, wherein the calculated size of the first defect area is determined as the size of the first defect area.