JP2018179857A - Inspection method for periphery weld part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method of a periphery weld part capable of accurately and easily detecting a penetration failure which exist in a periphery weld part.SOLUTION: An inspection method of the invention comprises: a first step for stopping an inspected tube at a position where a periphery weld part of an inspected tube is deviated from a position on a radiation center CL of an X-ray source 412 to a longitudinal direction of the inspected tube by a deviation amount L, so that a pixel area corresponding to the periphery weld part P of the inspected tube P1 in the X-ray image generated by an X-ray image detector 413 becomes in an annular state; a second step for radiating an X-ray from the X-ray source to the inspected tube which has been stopped in the first step, for generating a first X-ray image which is an X-ray image by the X-ray image detector; and a third step for inspecting the periphery weld part of the inspected tube using the first X-ray image generated in the second step.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of inspecting a circumferential weld formed to connect ends of a plurality of tubes. In particular, the present invention relates to a method of inspecting a circumferential weld which can detect penetration defects present in the circumferential weld easily and accurately.

  Conventionally, as disclosed in Patent Document 1, a tube wound on a reel called coiled tubing is known. The coiled tubing is, for example, unwound from a reel at sea and dropped to a well such as a submarine oil field or a submarine gas field. Coiled tubing is used, for example, as an umbilical cable that functions as a control line that connects an offshore host facility and a subsea well. An umbilical cable contains an electric wire, a high pressure hydraulic hose, an optical cable, etc. inside.

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

As a defect of the circumferential welding part formed in the above long tubes, a penetration defect can be mentioned. The poor penetration is a defect in which the welding material does not sufficiently melt in between the ends of the pipe, and tends to occur on the inner surface of the circumferential weld of the small-thickness pipe at I groove (see FIG. 6 (b) described later).
If poor penetration occurs, the strength of the circumferential welds may decrease and it may become a starting point of cracking or fatigue failure due to stress concentration. Therefore, it is necessary to take measures such as performing circumferential welding again after cutting.

Here, an X-ray inspection apparatus is generally used to detect a defect present in a welded portion (see, for example, Patent Document 2).
The method described in Patent Document 2 has an X-ray source that has a radiation center extending in a direction substantially perpendicular to the longitudinal direction of the welded tube, and emits X-rays toward the welded tube; Inspect the weld of the weld tube using an X-ray examination machine provided with an X-ray image detector disposed at a position facing the radiation source and detecting an X-ray emitted from the X-ray source and transmitted through the weld tube It is a method. If the method described in Patent Document 2 is applied to inspection of a circumferential weld, it is considered that many defects present in the circumferential weld can be visualized.

  However, although there is no problem when inspecting welds where weld lines extend in the longitudinal direction of tubes, such as UO pipes and ERW pipes, long pipes manufactured by circumferential welding the ends of a plurality of pipes are produced. When inspecting a circumferential weld of a tube, X-rays are emitted from the direction substantially perpendicular to the longitudinal direction of the long tube toward the circumferential weld (that is, the circumferential weld is the radiation center of the X-ray source) In the state where it is located above, X-rays transmitted through the X-ray source side of the circumferential weld and X-rays transmitted through the X-ray image detector side of the circumferential weld are both X-rays. It will be detected overlapping (in the same position) by the image detector. For this reason, according to the examination of the present inventors, it was found that the penetration defect existing in the circumferential welds can not be clearly visualized and detection may not be performed accurately.

The above problem is that the X-ray transmitted through the X-ray source side of the circumferential weld and the X-ray transmitted through the X-ray image detector side of the circumferential weld overlap each other by the X-ray image detector. In the direction substantially perpendicular to the longitudinal direction of the long tube so that the X-rays transmitted through each part are detected at different positions of the X-ray image detector without overlapping, because it is caused by being detected. It is also conceivable to emit X-rays from an inclined direction toward the circumferential weld (that is, to tilt the radiation center of the X-ray source with respect to the direction substantially perpendicular to the longitudinal direction of the long tube).
However, as described above, if X-rays are emitted from the direction inclined with respect to the direction substantially perpendicular to the longitudinal direction of the long tube toward the circumferential welding portion, this occurs during casting of the base material and circumferential welding. For defects whose dimensions are important, such as void-like defects called obtainable porosity, as compared with the case where X-rays are emitted from the direction substantially perpendicular to the longitudinal direction of the long tube toward the circumferential weld, There is a possibility that the dimensions can not be evaluated accurately. Also, it is possible to switch between a state in which the radiation center of the X-ray source is in a direction substantially perpendicular to the longitudinal direction of the long tube and a state in which the radiation center is in a direction inclined to the substantially perpendicular direction. Although it is conceivable to provide a mechanism for tilting the X-ray source, there is a problem that the X-ray inspection machine becomes large and the cost increases and the maintainability deteriorates.

International Publication No. 1998/31499 Japanese Patent Application Laid-Open No. 58-117445

  An object of the present invention is to provide a method of inspecting a circumferential weld which can detect the penetration defect existing in the circumferential weld easily and accurately.

In order to solve the above problems, as a result of intensive investigations by the present inventors, it has been found that a conventional X-ray inspection machine (having a radiation center extending in a direction substantially perpendicular to the longitudinal direction of An X-ray source for emitting X-rays and a position opposite to the X-ray source across the examination tube, and detecting X-rays emitted from the X-ray source and transmitted through the examination tube; It has been found that, even if an X-ray inspection machine having an X-ray image detector for generating X.sub.X is used, the penetration defect existing in the circumferential weld can be accurately detected by devising the device. Specifically, it is as follows.
Although the ordinary X-ray inspection machine is used, the inspection tube is stopped at a position where the circumferential weld of the inspection tube deviates from the position on the radiation center of the X-ray source in the longitudinal direction of the inspection tube by a predetermined distance. By inspecting the circumferential weld at the stopped position, it is possible to make the pixel area corresponding to the circumferential weld in the X-ray image generated by the X-ray image detector annular. That is, the X-rays transmitted through the X-ray source side of the circumferential weld and the X-rays transmitted through the X-ray image detector side of the circumferential weld do not overlap, but the X-ray image detector differs. If the position of the circumferential weld is shifted from the position on the radiation center of the X-ray source as detected by the position, penetration defects existing in the circumferential weld can be relatively clearly visualized and the penetration defects can be detected accurately. I understand.

The present invention has been completed based on the above findings of the present inventors.
That is, to solve the above problems, the present invention has an X-ray source which has a radiation center extending in a direction substantially perpendicular to the longitudinal direction of the inspection tube, and emits X-rays toward the inspection tube. An X-ray image disposed at a position facing the X-ray source across the inspection tube, detecting an X-ray emitted from the X-ray source and transmitted through the inspection tube to generate an X-ray image; A method of inspecting a circumferential weld of a tube to be inspected using an X-ray inspection machine comprising a detector, the method comprising the following first to third steps.
(1) First step: The circumferential weld portion of the inspection tube is on the radiation center of the X-ray source so that the pixel region corresponding to the circumferential weld portion of the inspection tube in the X-ray image is annular. The inspection pipe is stopped at a position deviated from the position in the longitudinal direction of the inspection pipe.
(2) Second step: The X-ray source emits X-rays to the tube to be inspected stopped in the first step, and the X-ray image detector detects the first X-ray image as the X-ray image Generate
(3) Third step: The circumferential welded portion of the inspection tube is inspected using the first X-ray image generated in the second step.

According to the inspection method of the circumferential welding portion according to the present invention, by executing the first and second steps,
A first X-ray image is generated in which a pixel area corresponding to a circumferential weld portion of the inspection tube is annular. That is, the X-rays transmitted through the X-ray source side of the circumferential weld and the X-rays transmitted through the X-ray image detector side of the circumferential weld do not overlap, but the X-ray image detector differs. The first X-ray image detected and generated at the position is obtained. Accordingly, in the third step, the penetration defects can be detected with high accuracy using the first X-ray image in which the penetration defects present in the circumferential weld are relatively clearly visualized.
Further, according to the present invention, since it is only necessary to shift the position of the circumferential weld from the position on the radiation center of the X-ray source using a conventional X-ray inspection machine, it is possible to easily detect penetration defects.

The amount of displacement of the circumferential welds necessary for the pixel area corresponding to the circumferential welds of the examination tube in the X-ray image (first X-ray image) to be annular is determined by the dimensions of the examination tube and circumferential welds It can be approximately obtained by geometrical calculation using the positional relationship between the inspection tube and the X-ray source.
Specifically, the separation distance between the X-ray source and the outer surface of the inspection tube on the side facing the X-ray source is H, the outer diameter of the inspection tube is OD, and the width of the circumferential weld In the first step, the displacement amount L from the position on the radiation center of the X-ray source in the first step satisfies the following equation (1) in the first step: If the inspection tube is stopped, it is possible to make the pixel area corresponding to the circumferential weld portion of the inspection tube in the first X-ray image annular.
L> W (2H + OD) / 2 OD (1)

In the above-mentioned preferred method, "the width of the circumferential weld" means the dimension of the circumferential weld along the longitudinal direction of the tube to be inspected.
In the above equation (1), the separation distance H between the X-ray source and the outer surface of the inspection tube on the side facing the X-ray source, the outer diameter OD of the inspection tube and the width W of the circumferential weld are design values It is possible to easily calculate the lower limit value (the value on the right side of Formula (1)) of the displacement amount L of the circumferential welding portion.
If the circumferential welds are shifted too much, a single X-ray transmitted through the X-ray source side of the circumferential welds and a single X-ray transmitted through the X-ray image detector side of the circumferential welds There is a possibility that the X-ray image detector can not detect simultaneously. For this reason, according to the dimensions of the X-ray image detector (dimensions along the longitudinal direction of the inspection tube), deviation of the circumferential welds so that each X-ray can be simultaneously detected by a single X-ray image detector. The upper limit of the amount L may be determined.

  Preferably, in the inspection method of a circumferential weld according to the present invention, a fourth step of stopping the tube under inspection such that the circumferential weld of the tube under inspection is at a position on the radiation center of the X-ray source; An X-ray source emits X-rays to the inspection tube stopped in the fourth step, and the X-ray image detector generates a second X-ray image as the X-ray image; And a sixth step of inspecting a circumferential weld of the inspected tube using the second X-ray image generated by the fifth step. And in the said 3rd step, the penetration defect which exists in the circumferential welding part of the said to-be-inspected tube is detected using the said 1st X-ray image, and the said to-be-tested | inspected using the said 2nd X-ray image in the said 6th step. Defects other than penetration defects present in circumferential welds of tubes are detected.

According to the above-mentioned preferred method, by performing the fourth and fifth steps, the second X generated by emitting X-rays from the direction substantially perpendicular to the longitudinal direction of the inspected tube toward the circumferential welding portion A line image is obtained. Therefore, in the sixth step, by using the second X-ray image, it is possible to detect defects (e.g., porosity, etc.) other than penetration defects present in the circumferential welded portion of the inspected tube in a state of high dimensional accuracy. is there.
According to the above preferable method, it is necessary to provide a mechanism or the like for tilting the X-ray source in the case of detecting penetration defects (third step) and in the case of detecting defects other than penetration defects (sixth step). There is no possibility that the cost increase and the maintenance performance will be deteriorated due to the large scale of the X-ray inspection machine.
In the preferred method described above, the fourth to sixth steps do not necessarily have to be performed after the first to third steps, and the first to third steps may be performed after the fourth to sixth steps have been performed first. It is also possible to It is also possible to execute the third and sixth steps after performing the first, second, fourth and fifth steps first (generating the first X-ray image and the second X-ray image first). It is.

  According to the inspection method of the circumferential welding portion according to the present invention, it is possible to easily and accurately detect the penetration failure existing in the circumferential welding portion.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows typically schematic structure of the manufacturing equipment of the elongate tube which applies the inspection method of the circumference welding part which concerns on one Embodiment of this invention. It is a figure which shows typically schematic structure of the X-ray-inspection machine which the X-ray-inspection apparatus main body shown in FIG. 1 comprises. It is a figure which shows typically schematic structure of the X-ray leak suppression mechanism shown in FIG. In the inspection method of the circumferential welding part which concerns on one Embodiment of this invention, it is explanatory drawing explaining the determination method of the shift | offset | difference amount of a circumferential welding part. In the inspection method of the circumference welding part concerning one embodiment of the present invention, it is an explanatory view explaining the relation between the 1st-3rd step, and the 4th-6th steps. It is a figure which shows the example of the X-ray image produced | generated by the X-ray-image detector shown in FIG. 1 about a normal material and a defect material. It is a figure which shows an example of the method of automatically determining the presence or absence of a penetration defect. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs. It is a top view explaining the motion of the welding apparatus and X-ray-inspection apparatus by the procedure which the control apparatus shown in FIG. 1 performs.

Hereinafter, the inspection tube according to an embodiment of the present invention is a long pipe such as a coiled tubing etc. with reference to the attached drawings as appropriate, and is applied to a manufacturing facility of this long pipe. An example case will be described. First, the entire configuration of the manufacturing facility will be described.
FIG. 1: is a top view which shows typically schematic structure of the manufacturing equipment of the elongate pipe which applies the inspection method of the circumferential welding part which concerns on this embodiment.
As shown in FIG. 1, the manufacturing equipment (hereinafter simply referred to as “manufacturing equipment”) 100 for a long tube according to the present embodiment includes a conveying device 1, a welding device 2, a winding device 3, and an X And a line inspection device 4. In addition, the manufacturing facility 100 according to the present embodiment includes the control device 5 that controls the operations of the conveying device 1, the welding device 2, the winding device 3, and the X-ray inspection device 4. Furthermore, the manufacturing equipment 100 which concerns on this embodiment is provided with the carrying-in stand 6 in which several pipe | tube P was mounted.

  In the manufacturing facility 100 according to the present embodiment, as a preferable configuration, the welding device 2 and the X-ray inspection device 4 can be moved along the transport device 1 separately from each other. 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 (longitudinal direction of the pipe P). Specifically, for example, the welding device 2 and the X-ray inspection device 4 are each attached to a driving device (not shown) such as an air cylinder, and wheels (not shown) are respectively attached to the lower portion. There is. Moreover, the rail (not shown) is provided in the floor surface along the conveyance direction of the pipe | tube P. As shown in FIG. By driving the drive device by the control device 5, the welding device 2 and the X-ray inspection device 4 can be moved independently of each other along the transport device 1 with their respective wheels rolling on the rail It is done. Therefore, as described later, when it is determined by the X-ray inspection apparatus 4 that the circumferential welded portion is defective, it is not necessary to drive the conveying device 1 and the winding device 3 in the opposite direction. In addition, for example, if the separation distance between welding device 2 and X-ray inspection device 4 is adjusted according to the length of pipe P to which circumferential welding is performed and the distance is set to be substantially equal to the length of pipe P, the welding device It is also possible to conduct the circumferential welding by 2 and the inspection of the circumferential welded portion by the X-ray inspection apparatus 4 in parallel to enhance the manufacturing efficiency.

  The pipe P of the present embodiment is, for example, a stainless steel pipe, and preferably a long pipe P1 formed by subjecting the pipe P to circumferential welding by the welding device 2 is used as an umbilical cable. It is called a stainless steel pipe. The pipe P may be a welded tube or a seamless pipe.

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

The conveyance 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 of the welding device 2 in the conveyance direction (X direction) of the pipe P so as to clamp 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) from the position where the pipe P is carried in from the loading table 6 to the winding device 3. The V roller supports the pipe P from below and rotates along with the transport of the pipe P in the longitudinal direction.
With the above configuration, the tube P before being welded by the welding device 2 and the long tube P1 before being wound around the reel 31 by the winding device 3 are driven by the side clamp roller 11 in the longitudinal direction. The long pipe P1 which has been applied and wound around the reel 31 by the winding device 3 is given a driving force in the longitudinal direction by the winding device 3 and is conveyed in the longitudinal direction.
Note that, in the present embodiment, the configuration has been described in which the conveyance device 1 includes the side clamp roller 11 for applying the driving force and the V roller 12 that only follows the drive force without applying the driving force. It is not a thing. As the transfer device, for example, instead of the side clamp roller 11, a pusher that pushes the pipe P from the upstream side to the downstream side in the transport direction is adopted, and various configurations are adopted as long as the plurality of pipes P can be transported in the longitudinal direction It is possible.

The welding device 2 is disposed along the conveying 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 the long pipe P1.
The welding device 2 of the present embodiment includes a circumferential welding machine (circumferential welding machine) 21 and a pair of gripping devices disposed along the conveyance direction of the pipe P (longitudinal direction of the pipe P) with the circumferential welding machine 21 interposed therebetween. And 22. The welding device 2 of the present embodiment also includes a cooling device (not shown). As a method of cooling the cooling device, for example, forced air cooling can be exemplified.

  The control device 5 stops the operation of the transfer device 1 and the winding device 3 at the timing when the end of each tube P arrives at the arrangement position of the circumferential welder 21 and drives each gripping device 22. Thereby, each gripping device 22 grips the end of each tube P. That is, the tip end of the pipe P located on the upstream side in the transport direction is gripped by the gripping device 22 disposed on the upstream side in the transport direction of the pipe P, and on the downstream side in the transport direction with the gripping device 22 disposed on the downstream side The rear end portion of the positioned pipe P (long pipe P1) is gripped. And each holding | grip apparatus 22 adjusts the position of each pipe | tube P so that the axial center of each pipe | tube P may correspond. Next, the control device 5 drives the circumferential welding machine 21 and the circumferential welding machine 21 performs circumferential welding on the end portions of the pipes P whose positions are adjusted. Finally, the control device 5 drives the cooling device, and the cooling device cools the formed circumferential weld portion PW. After cooling of the circumferential welds PW is completed, the control device 5 releases the gripping by the gripping devices 22, drives the transport device 1 and the winding device 3, and transports the long pipe P1.

The winding device 3 is disposed downstream of the welding device 2 in the transport direction of the pipe P (the long pipe P1) along the transport device 1. The winding device 3 is a device driven by the control device 5 and configured to wind the long pipe P1 transported by the transport device 1 around the reel 31.
Specifically, the winding device 3 of the present embodiment has a rotation mechanism (not shown) for rotating the reel 31 around its central axis and a movement mechanism (for moving the reel 31 in the central axial 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 rotation mechanism and moving the reel 31 by the movement mechanism.

The X-ray inspection apparatus 4 is an apparatus for performing the inspection method of the circumferential weld portion 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 transfer device 1. The X-ray inspection apparatus 4 is driven by the control device 5 and inspects the circumferential weld portion PW of the long pipe P1.
In control device 5, the circumferential welding portion PW of long tube P1 formed by welding device 2 is located at the position where X-ray inspection apparatus 4 is disposed (specifically, the position where X-rays are emitted by X-ray source 412 described later) The long pipe P1 is stopped by stopping the operation of the conveying device 1 and the winding device 3 at the timing when the vehicle 1 arrives at the X-ray inspection apparatus 4.

The X-ray inspection apparatus 4 includes an X-ray inspection apparatus main body 41, and an X-ray leakage suppression mechanism 42 attached in the vicinity of the opening on the entry side and the exit side of the X-ray inspection apparatus main body 41. In the X-ray inspection apparatus main body 41, the long pipe P1 is an opening on the entrance side (upstream side in the conveyance direction of the long pipe P1) and the exit side (downstream side in the conveyance direction of the long pipe P1) of the X-ray inspection apparatus main body 41 The outer circumferential weld portion PW of the long pipe P1 is inspected in a state where it protrudes outside from the above. While the X-ray inspection apparatus main body 41 is inspecting the circumferential welded portion PW of the long pipe P1, the X-ray leakage suppression mechanism 42 is externally exposed from the entrance and exit openings of the X-ray inspection apparatus main body 41. Control the leakage of x-rays to
Hereinafter, the 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 is provided with a housing 41a, a pair of sleeves 41b respectively provided on the inlet side and the outlet side of the housing 41a and communicating with the housing 41a, and the inside of the housing 41a. And an X-ray inspection machine 41c disposed in This X-ray inspection machine 41c is an X-ray inspection machine used to execute the inspection method of the circumferential weld portion PW according to one embodiment of the present invention. The X-ray inspection apparatus main body 41 welds the circumference of the long pipe P1 by the X-ray inspection machine 41c in a state where the long pipe P1 is inserted into the X-ray inspection machine 41c and the sleeves 41b arranged in the housing 41a. Check part PW.

FIG. 2 is a view schematically showing a schematic configuration of an X-ray inspection machine 41c included in the X-ray inspection apparatus main body 41. As shown in FIG. Fig.2 (a) is a perspective view, FIG.2 (b) is the front view seen from the longitudinal direction of long pipe P1, FIG.2 (c) was seen from the direction orthogonal to the longitudinal direction of long pipe P1 It shows a side view. In FIG. 2B, illustration of the image processing apparatus is omitted, and in FIG. 2C, illustration of the rotation mechanism unit and the image processing apparatus is omitted.
As shown in FIG. 2, the X-ray inspection machine 41 c 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 circumferential direction of the long tube P1, and an inner ring member 411B rotatably attached to the outer ring member 411A with respect to the outer ring member 411A. Equipped with

  The X-ray source 412 is a device having a radiation center CL extending in a direction substantially perpendicular to the longitudinal direction of the long tube P1 which is an inspection tube, and emitting X-rays toward the long tube P1. The X-ray source 412 emits X-rays from the radiation point C to a substantially conical area centered on the radiation center CL. 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 when the inner ring member 411B rotates with respect to the outer ring member 411A. As shown in FIG. 2 (b), the X-ray source 412 repeatedly rotates and stops, and X-rays are generated at a plurality of predetermined positions (three locations at a 60.degree. Pitch in the example shown in FIG. 2 (b)). Radiate.

  The X-ray image detector 413 is disposed at a position facing the X-ray source 412 across the long tube P1, and detects X-rays emitted from the X-ray source 412 and transmitted through the long tube P1. An apparatus for generating an image, for example, a flat panel detector (FPD) is preferably 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 rotates with respect to the outer ring member 411A to be integrated with the X-ray source 412 (long tube P1 While maintaining the state of facing the X-ray source 412).

  The image processing device 414 is a device that displays the X-ray image generated by the X-ray image detector 413 on a monitor, performs image processing on the X-ray image, and inspects the circumferential weld portion PW of the long pipe P1. The image processing apparatus 414 includes, for example, a general-purpose personal computer in which a program for executing predetermined image processing is installed.

FIG. 3 is a view schematically showing a schematic configuration of the X-ray leakage suppression mechanism 42. As shown in FIG. 3 (a) is a front view showing the state of the X-ray leakage suppression mechanism 42 when the circumferential welded portion PW of the long tube P1 is inspected by the X-ray inspection apparatus main body 41, and FIG. 3 (b) is FIG. The bb arrow sectional view of (a) is shown. FIG. 3C shows the state of the X-ray leakage suppression mechanism 42 at the time when the long pipe P1 is transported by the transport device 1 when the inspection of the circumferential weld portion PW of the long tube P1 is completed by the X-ray inspection apparatus main body 41. FIG. 3 (d) is a cross-sectional view taken along the line dd in FIG. 3 (c).
As described above, the X-ray leakage suppression mechanism 42 is attached in the vicinity of the entrance and exit openings of the X-ray inspection apparatus main body 41. Specifically, the X-ray leakage suppression mechanism 42 is attached near the substantially circular opening 410 of the pair of sleeves 41 b of the X-ray inspection apparatus main body 41. More specifically, the X-ray leakage suppression mechanism 42 is in the vicinity of the opening 410 on the upstream side of the sleeve 41b provided on the upstream side in the transport direction of the long tube P1 among the pair of sleeves 41b. With respect to a sleeve 41b attached and provided on the downstream side of the long pipe P1 in the transport direction, the sleeve 41b is attached in the vicinity of the opening 410 on the downstream side. The X-ray leak suppression mechanisms 42 attached to the entrance side and the exit side of the X-ray inspection apparatus main body 41 have the same configuration, so only one X-ray leak suppression mechanism 42 will be described here.

The X-ray leakage prevention mechanism 42 includes a closing member 421. The closing member 421 is composed of a plurality of members (two half members 42a and 42b divided in the example shown in FIG. 3) which can be opened and closed in the radial direction (the radial direction of the long pipe P1). , 42b in the radially closed position (the states of FIGS. 3A and 3B), a substantially circular opening 421a through which the long pipe P1 is inserted is formed inside. Specifically, the members 42a and 42b are attached to a drive device (not shown) such as an air cylinder, and by driving the drive device, the members 42a and 42b extend in the radial direction (FIG. 3). In the example shown in (1), it is possible to open and close (advance and retract) in the vertical direction. The members 42a and 42b that constitute the closing member 421 are made of, for example, stainless steel.
In the example shown in FIG. 3, the respective members 42a and 42b can be opened and closed in the vertical direction, but the present invention is not limited thereto. The radial direction of the long pipe P1 (in the longitudinal direction of the long pipe P1 As long as it is the orthogonal direction), it is also possible to make it a member that can be opened and closed in other directions such as the horizontal direction. Further, in the example shown in FIG. 3, the closing member 421 is composed of two members 42 a and 42 b, but the invention is not limited to this, and three closing members can be used as long as they are plural members which can be opened and closed in the radial direction. It is also possible to constitute from the above members.

  3 (a), ((when the X-ray is emitted from the X-ray source 412), when the circumferential weld portion PW of the long tube P1 is inspected by the X-ray inspection apparatus main body 41. 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. That is, by driving a driving device such as an air cylinder provided in the X-ray leakage suppression mechanism 42 by a control signal from the control device 5, the plurality of members 42a and 42b are in the radially closed position. And, 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 X-ray inspection It is smaller than the radial dimension L2 (the radial dimension of the opening 410 of the sleeve 41b, see FIG. 3C) of the opening on the entry side and the exit side of the device 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 (a plurality of members 42a and 42b). 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 other than the circumferential welded portion PW of the long pipe P1. It is. Accordingly, the gap between the opening 421a of the closing member 421 and the long pipe P1 disappears or becomes extremely small. Therefore, if the circumferential weld portion PW of the long pipe P1 is inspected by the X-ray inspection apparatus main body 41 after the plurality of members 42a and 42b reach the radially closed position, the opening of the X-ray inspection apparatus main body 41 It is possible to suppress the 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 ends the inspection of the circumferential welded portion PW of the long tube P1 by the X-ray inspection apparatus main body 41 (that is, the radiation of X-rays from the X-ray source 412 stops) When the long pipe P1 is transported, as shown in FIGS. 3C and 3D, the X-ray leaks so that the plurality of members 42a and 42b constituting the closing member 421 are in the radially opened position. The suppression mechanism 32 is driven. And as shown in FIG.3 (c), (d), when it exists in the position which several members 42a and 42b opened in radial direction, the obstruction member 421 does not interfere in the circumferential welding part PW of the elongate pipe P1. It is in position. In the present embodiment, the plurality of members 42 a and 42 b constituting the closing member 421 are positioned radially outward of the sleeve 41 b. Therefore, even when 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 part PW of the long pipe P1 interferes with the closing member 421 There is no hindrance to

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

When the circumferential welded portion PW of the long pipe P1 is inspected by the X-ray inspection apparatus 4 described above and the circumferential welded portion PW is determined to be normal, the control device 5 performs the conveyance device 1 and the winding device 3 By driving, the long pipe P1 is transported and taken up on the reel 31.
On the other hand, when it is determined by the X-ray inspection apparatus 4 that the circumferential welded portion PW of the long pipe P1 is defective, the welding apparatus 2 and the X-ray inspection apparatus 4 are mutually connected along the transport apparatus 1 as described above. As it is separately movable, the control device 5 does not drive the conveying device 1 and the winding device 3 in the reverse direction (without conveying the long pipe P1 in the reverse direction), and the welding device 2 is long It is possible to form the circumferential weld portion PW again on the elongated pipe P1 and inspect the circumferential weld portion PW formed again by the X-ray inspection apparatus 4. A specific operation example of the control device 5 when it is determined that the circumferential welded portion PW of the long pipe P1 is defective will be described later.
In addition, when it is automatically determined by the X-ray inspection apparatus 4 whether or not the circumferential welded portion PW of the long pipe P1 is defective, the determination result is automatically transmitted to the control device 5, thereby the control device 5 can execute an operation according to the determination result. In addition, when the operator determines whether or not the circumferential welded portion PW of the long pipe P1 is defective using the X-ray inspection apparatus 4, the operator inputs the determination result to the control device 5 Then, the control device 5 can execute an operation according to the determination result.

  Hereinafter, the inspection method of perimeter welding part PW concerning one embodiment of the present invention is explained, also referring to Drawing 4-Drawing 7 suitably. As described above, the inspection method of the circumferential weld portion PW according to the present embodiment uses the X-ray inspection machine 41 c including the X-ray source 412 and the X-ray image detector 413 to measure the long pipe P1. This is a method of inspecting the circumferential welding portion PW, and executes the following first to third steps. Further, in the present embodiment, the following fourth to sixth steps are also executed as a preferable method.

<First step>
In the first step, as shown in FIG. 2C, at the position where the circumferential welded portion PW of the long tube P1 is shifted in the longitudinal direction of the long tube P1 from the position on the radiation center CL of the X-ray source 412, Stop the long pipe P1. Specifically, the control device 5 stops the operation of the conveying device 1 and the winding device 3 so that the circumferential welding portion PW stops at a position deviated from the position on the radiation center CL by the shift amount L.
The shift amount L is determined so that the pixel region corresponding to the circumferential weld portion PW of the long tube P1 in the X-ray image generated by the X-ray image detector 413 has an annular shape. The method of determining the deviation amount L will be specifically described below with reference to FIG.

FIG. 4 is an explanatory view for explaining the method of determining the displacement amount L of the circumferential weld portion PW in the inspection method of the circumferential weld portion PW according to the present embodiment. As shown in FIG. 4, in the present embodiment, when determining the displacement amount L of the circumferential weld portion PW, the outer diameter of the circumferential weld portion PW is the outer diameter of the long pipe P1 (per It is assumed that the thickness of the long pipe P1 is zero, as well as assuming that it is equal to the outer diameter OD of the part other than the part PW. Even if this assumption is made, a large error does not occur in the calculation result of the shift amount L necessary for the pixel region corresponding to the circumferential weld portion PW of the long tube P1 in the X-ray image to be annular.
As shown in FIG. 4, among the X-rays radiated from the radiation point C of the X-ray source 412, the X-rays transmitted through the outer surface of the circumferential weld part PW on the X-ray source 412 side are straight lines LU1 and LU2. The X-ray which exists in the divided range and transmits the outer surface of the circumferential weld portion PW on the X-ray image detector 413 side is present in the range divided by the straight line LL1 and the straight line LL2. In order for the pixel region corresponding to the circumferential weld portion PW of the long tube P1 in the X-ray image generated by the X-ray image detector 413 to be annular, the outer surface of the circumferential weld portion PW on the X-ray source 412 side is transmitted. It is sufficient that X-rays to be transmitted do not overlap with X-rays transmitted through the outer surface of the circumferential weld portion PW on the X-ray image detector 413 side. For that purpose, when an angle formed by the straight line LU2 and the radiation center CL is θ1, and an angle formed by the straight line LL1 and the radiation center CL is θ2, it suffices to satisfy θ1> θ2. Therefore, the following equation (A) should be satisfied.
tan θ1> tan θ2 (A)

Here, as shown in FIG. 4, the distance between the X-ray source 412 (radiation point C of the X-ray source 412) and the outer surface of the long tube P1 opposite to the X-ray source 412 is H. Assuming that the outer diameter of the pipe P1 is OD and the width of the circumferential weld PW is W, geometrically
tan θ1 = (L−W / 2) / H (B)
tan θ 2 = (L + W / 2) / (H + OD) (C)
Is true.
As described above, in order to make the pixel region corresponding to the circumferential weld portion PW of the long tube P1 in the X-ray image be annular, it is sufficient to satisfy the equation (A). Substituting (B), substituting the expression (C) into the right side of the expression (A) and organizing, the following expression (1) is established.
L> W (2H + OD) / 2 OD (1)

In the present embodiment, in the first step, the long length is such that the displacement amount L from the position on the radiation center CL of the X-ray source of the circumferential weld portion PW of the long tube P1 satisfies the above equation (1). Stop the pipe P1.
In the above equation (1), the separation distance H between the X-ray source 412 and the outer surface of the long tube P1 facing the X-ray source 412, the outer diameter OD of the long tube P1 and the width W of the circumferential weld portion PW Since each design value can be used, it is possible to easily calculate the lower limit value (the value on the right side of Formula (1)) of the displacement amount L of the circumferential weld portion PW.
When the circumferential welding portion PW is shifted too much, X-rays transmitted through the portion on the X-ray source 412 side of the circumferential welding portion PW and X-rays transmitted through the portion on the X-ray image detector 413 side of the circumferential welding portion PW May not be detected simultaneously by a single X-ray image detector 413. For this reason, circumferential welding is performed so that each X-ray can be simultaneously detected by a single X-ray image detector 413 according to the dimensions of the X-ray image detector 413 (dimensions along the longitudinal direction of the long tube P1). The upper limit value of the deviation amount L of the part PW may be determined.

For example, assuming that H = 192.4 mm, OD = 15.3 mm, W = 3 mm, the above equation (1) is L> 39.2 mm.
Therefore, for example, by setting L = 50 mm, the above equation (1) is satisfied, and the shift amount L does not increase excessively, so X transmitted through the portion on the X-ray source 412 side of the circumferential weld part PW. A single X-ray image detector 413 can simultaneously detect a ray and an X-ray transmitted through a portion on the X-ray image detector 413 side of the circumferential weld portion PW.

Second step
In the second step, the X-ray source 412 emits X-rays to the long tube P1 stopped in the first step, and the X-ray image detector 413 generates a first X-ray image which is an X-ray image.
In the present embodiment, the second step is performed at a plurality of predetermined positions (three positions at a pitch of 60 ° in the example shown in FIG. 2B) to generate a plurality of first X-ray images. Be done.

<Third step>
In the third step, the circumferential welds PW of the long pipe P1 are inspected using the plurality of first X-ray images generated in the second step. Specifically, in the present embodiment, the penetration defects present in the circumferential welded portion PW of the long pipe P1 are detected using each first X-ray image. Specific contents of the method of detecting the penetration failure will be described later.

<4th step>
FIG. 5 is an explanatory view illustrating the relationship between the first to third steps and the fourth to sixth steps in the inspection method of the circumferential weld portion PW according to the present embodiment.
In the fourth step of the present embodiment, the long tube P1 is stopped so that the circumferential weld portion PW of the long tube P1 is located on the radiation center CL of the X-ray source 412. Specifically, as shown in FIG. 5A, the control device 5 drives the conveying device 1 and the winding device 3 so that the circumferential weld portion PW is on the radiation center CL in the first to third steps. To convey the long tube P1 stopped at a position deviated from the position of L by the displacement amount L so that the circumferential weld part PW stops at a position on the radiation center CL of the X-ray source 412 The operation of the removing device 3 is stopped.

<Fifth step>
In the fifth step, the X-ray source 412 emits X-rays to the long tube P1 stopped in the fourth step, and the X-ray image detector 413 generates a second X-ray image which is an X-ray image.
In the present embodiment, the fifth step is performed at a plurality of predetermined positions (three positions at a pitch of 60 ° in the example shown in FIG. 2B) to generate a plurality of second X-ray images. Be done.

<6th step>
In the sixth step, the circumferential welds PW of the long pipe P1 are inspected using the plurality of second X-ray images generated in the fifth step. Specifically, in the present embodiment, defects (for example, porosity and the like) other than the penetration defects present in the circumferential welded portion PW of the long pipe P1 are detected using each second X-ray image. In order to detect defects other than penetration defects such as porosity, for example, the image processing device 414 performs image processing on each second X-ray image to extract a pixel region having a pixel density different from that of the surroundings as a defect region. Just do it. And it is possible to judge the quality of perimeter welding part PW according to the size of the area of the extracted defective field.

The fourth to sixth steps do not necessarily need to be performed after the first to third steps, and the first to third steps may be performed after the fourth to sixth steps are performed first. It is.
It is also possible to execute the third and sixth steps after performing the first, second, fourth and fifth steps first (generating the first X-ray image and the second X-ray image first). It is.

  Further, as shown in FIG. 5B, a pair of X-ray sources 412A and 412B are disposed as the X-ray source 412 along the longitudinal direction of the long tube P1, and one X-ray source 412A is used to It is also possible to perform the first to third steps and perform the fourth to sixth steps using the other X-ray source 412B. That is, the radiation center CL of one X-ray source 412A and the radiation center CL of the other X-ray source 412B are determined along the longitudinal direction of the long tube P1 so as to satisfy the above equation (1) The pair of X-ray sources 412A and 412B are arranged in a state of being mutually shifted by the set amount of deviation L. And in the example shown in Drawing 5 (b), in the state where long tube P1 is stopped so that circumference welding part PW of long tube P1 may become a position on radiation center CL of X-ray source 412B of another side. The first to third steps can be performed using one X-ray source 412A, and the fourth to sixth steps can be performed using the other X-ray source 412B. In the example shown in FIG. 5B, since it is necessary to dispose a pair of X-ray sources 412A and 412B as the X-ray source 412, there is a disadvantage that the cost is increased as compared with the example shown in FIG. However, it is not necessary to convey the long pipe P1 and change the position of the circumferential welding portion PW between the case where the first to third steps are performed and the case where the fourth to sixth steps are performed. Compared to the example shown in FIG. 5A, the inspection time is reduced.

Hereinafter, the detection method of the penetration defect in the above-mentioned 3rd step is explained concretely.
FIG. 6 shows an X-ray image detector for a normal long pipe (normal material) P1 having no defect in the circumferential weld part PW and a long pipe (defective material) P1 having a penetration defect in the circumferential weld part PW. It is a figure which shows the example of the X-ray image produced | generated by 413. FIG. 6 (a) is a schematic cross-sectional view of a normal material, FIG. 6 (b) is a schematic cross-sectional view of a defective material, FIG. 6 (c) is an example of a second X-ray image of the normal material, and FIG. 6 shows an example of the second X-ray image of the defective material, FIG. 6 (e) shows an example of the first X-ray image of the normal material, and FIG. 6 (f) shows an example of the first X-ray image of the defective material. In each of the X-ray images shown in FIG. 6C to FIG. 6F, a pixel region with a large amount of X-ray transmission is displayed dark (having a small pixel density close to black), and X-ray transmission A small amount of pixel area is displayed bright (having a large pixel density close to white).
As shown in FIG. 6 (b), the penetration failure is a failure in which the welding material does not sufficiently penetrate between the ends of the pipe. The circumferential weld portion PW where the penetration defect exists has less weld material compared to the circumferential weld portion PW of the normal material shown in FIG. 6A, so the penetration defect is more pronounced than the circumferential weld portion PW of the normal material. It is believed that the amount of X-ray transmission through the existing area increases. In the example shown in FIG. 6 (b), a penetration failure occurs on the upper side of the cross section, but the lower side is normal. As described above, normally, the penetration failure does not occur over the entire circumference of the circumferential weld portion PW, but occurs in part of the circumferential direction.

  However, the second X-ray images shown in FIGS. 6C and 6D are the X-rays transmitted through the portion of the circumferential weld portion PW on the X-ray source 412 side and the X-ray image detector 413 side of the circumferential weld portion PW. All of the X-rays transmitted through the region are X-ray images generated by being overlapped (at the same position) by the X-ray image detector 413. Therefore, even if the second X-ray image of the normal material shown in FIG. 6C and the second X-ray image of the defective material shown in FIG. 6D are compared, the difference between the two can not be clearly distinguished. Poor penetration can not be detected accurately.

  On the other hand, in the inspection method of circumferential welding part PW which concerns on this embodiment, as above-mentioned, the penetration defect which exists in circumferential welding part PW of long pipe P1 is detected using a 1st X-ray image. As shown in FIGS. 6E and 6F, in the first X-ray image, the pixel region corresponding to the circumferential weld portion PW is annular. That is, in the first X-ray image, the X-ray transmitted through the portion of the circumferential weld portion PW on the X-ray source 412 side and the X-ray transmitted through the portion on the X-ray image detector 413 side of the circumferential weld portion PW are heavy It is an X-ray image detected and generated at different positions of the X-ray image detector 413. Therefore, when the first X-ray image of the normal material shown in FIG. 6 (e) and the first X-ray image of the defective material shown in FIG. 6 (f) are compared, the penetration defect of the defective material shown in FIG. Can be relatively clearly visualized (in the annular pixel area shown in FIG. 6 (f), the partially darkened portion indicated by the arrow is a portion where the poor appearance occurs), and the poor penetration can be detected with high accuracy. is there. Specifically, the operator visually checks the first X-ray image displayed on the monitor included in the image processing device 414 to determine the presence or absence of the penetration defect, and the circumferential weld portion PW is determined according to the presence or absence of the penetration defect. It is possible to determine the quality.

The image processing apparatus 414 can also automatically determine the presence or absence of a penetration defect, instead of or in addition to the visual determination of the worker.
FIG. 7 is a diagram showing an example of a method of automatically determining the presence or absence of penetration failure. FIG. 7 (a) shows an example of a normal material, and FIG. 7 (b) shows an example of a defective material in which a penetration defect exists in the circumferential weld portion PW. As shown in FIG. 7, in order to automatically determine the presence or absence of penetration failure, for example, in a predetermined area including the circumferential weld portion PW (an area surrounded by a broken line in the first X-ray image shown on the left side of FIG. A pixel area having a large pixel density exceeding the threshold value is extracted, and the extracted pixel area (the hatched area shown in the right side of FIG. 7) is set as a pixel area corresponding to the circumferential weld portion PW. In the case of the defective material shown in FIG. 7 (b), the pixel density becomes smaller (darker) in the portion where the penetration defect exists, and therefore the pixel corresponding to the circumferentially welded portion PW without exceeding the predetermined threshold value It can be expected not to be extracted as a region. Therefore, for example, compared with the area S1 of the pixel region corresponding to the circumferential weld portion PW in the case of the normal material shown in FIG. 7A, the circumferential weld portion PW in the case of the defective material shown in FIG. It is considered that the area S2 of the corresponding pixel area is reduced. Therefore, it is possible to automatically determine the presence or absence of the penetration failure according to the size of the area of the pixel region corresponding to the circumferential weld portion PW.

As described above, according to the inspection method of the circumferential welding portion PW according to the present embodiment, the pixel region corresponding to the circumferential welding portion PW of the long pipe P1 is obtained by executing the first and second steps. An annular first X-ray image is generated. That is, the X-rays transmitted through the portion at the X-ray source 412 side of the circumferential welding portion PW and the X-rays transmitted by the portion at the X-ray image detector 413 side of the circumferential welding portion PW do not overlap The first X-ray image detected and generated at different positions of the detector 413 is obtained. Therefore, in the third step, the penetration defects can be detected with high accuracy using the first X-ray image in which the penetration defects present in the circumferential weld part PW are relatively clearly visualized.
Further, according to the inspection method of the circumferential welding portion PW according to the present embodiment, the position of the circumferential welding portion PW is only shifted from the position on the radiation center CL of the X-ray source 412 using the normal X-ray inspection machine 41c. Can easily detect penetration defects.
Furthermore, according to the inspection method of the circumferential welding portion PW according to the present embodiment, the fourth and fifth steps are performed to direct the circumferential welding portion PW from a direction substantially perpendicular to the longitudinal direction of the long pipe P1. A second x-ray image generated by emitting x-rays is obtained. Therefore, in the sixth step, by using the second X-ray image, it is possible to detect defects (for example, porosity, etc.) other than penetration defects existing in the circumferential welded portion PW of the long pipe P1 in a state of good dimensional accuracy. It is possible. According to the present embodiment, it is necessary to provide a mechanism or the like for tilting the X-ray source 412 in the case of detecting penetration defects (third step) and in the case of detecting defects other than penetration defects (sixth step). There is no possibility that the cost increase and the maintenance performance will be deteriorated due to the X-ray inspection machine 41c becoming large-scaled.

  When it is determined that the circumferential welded portion PW of the long pipe P1 is defective by the inspection method of the circumferential welded portion PW according to the present embodiment described above (a determination is made that the first to third steps are defective) Or when it is determined that the fourth to sixth steps are defective), as described above, the welding device 2 and the X-ray inspection device 4 can be moved separately along the transport device 1 Therefore, the control device 5 can execute the following first to sixth procedures as a preferred embodiment. Hereinafter, first to sixth procedures executed by the control device 5 will be described with reference to FIGS. 8 to 13 as appropriate. 8 to 14 are plan views for explaining the movement of the welding device 2 and the X-ray inspection device 4 according to the first to sixth procedures executed by the control device, and the illustration of the conveying device 1 is omitted for convenience. doing.

<First step>
When it is determined by the X-ray inspection apparatus 4 at the initial position shown by the broken line in FIG. 8 that the circumferential welded part PW of the long pipe P1 is defective, the control device 5 operates the X-ray inspection apparatus 4 as the long pipe P1. Move to the downstream side of the transport direction of. The moving amount of the X-ray inspection apparatus 4 does not disturb the cutting operation of the circumferential welding portion PW determined to be defective, and further, in the second procedure described later, the welding device 2 moves in the conveyance direction of the long pipe P1. It is preferable to set so that the welding apparatus 2 does not interfere with the X-ray inspection apparatus 4 when it is moved downstream.
After the X-ray inspection apparatus 4 has moved, as shown in FIG. 9, the circumferential weld portion PW determined to be defective may be cut. The cutting of the circumferential welding portion PW can be performed manually by an operator using, for example, a portable cutting machine installed downstream of the welding device 2.
The end face of the long pipe P1 after cutting is preferably deburred, polished or the like to facilitate circumferential welding in a third procedure described later. An operator can manually perform deburring and polishing of the end face of the long pipe P1 using, for example, a portable beveling / chamfering machine installed on the downstream side of the welding device 2.

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

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

<The 4th procedure>
Next, as shown in FIG. 12, the control device 5 moves the welding device 2 upstream 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). Thereby, the welding device 2 does not interfere with the X-ray inspection apparatus 4 even if the X-ray inspection apparatus 4 is moved in a fifth procedure described later.

<Fifth step>
Next, as shown in FIG. 13, the control device 5 moves the X-ray inspection apparatus 4 upstream in the transport direction of the long pipe P <b> 1 to the circumferential weld part PW formed again of the long pipe P1. That is, the X-ray inspection apparatus 4 is moved to the initial position (the position shown by the broken line in FIG. 8).
The fourth and fifth procedures may be simultaneously performed as long as the moving speed of the X-ray inspection apparatus 4 is larger and there is no problem that the welding apparatus 2 and the X-ray inspection apparatus 4 interfere with each other. It is possible.

<Sixth procedure>
Finally, the control device 5 drives the X-ray inspection device 4 to inspect the re-formed circumferentially welded portion PW of the long tube P1 by the X-ray inspection device 4.
Also in the fourth to sixth procedures described above, it is not necessary to convey the long pipe P1.
That is, by performing the above-described first to sixth procedures, the welding device can be operated without driving the conveying device 1 and the winding device 3 in the reverse direction (without conveying the long pipe P1 in the reverse direction). The circumferential welded portion PW can be formed again on the long pipe P1 in 2 and the circumferential welded portion PW formed again by the X-ray inspection apparatus 4 can be inspected. For this reason, it is possible to suppress the occurrence of the outer surface wrinkles and the deterioration of the strength caused by conveying the long pipe P1 in the reverse direction.

  As a result of performing the above-described first to sixth procedures, when it is determined that the circumferential weld portion PW formed again is normal, the control device 5 drives the transport device 2 and the winding device 3, The long pipe P1 is transported and taken up by the reel 31. On the other hand, when it is determined that the circumferential weld portion PW formed again is defective, the above-described first to sixth procedures are repeatedly executed.

DESCRIPTION OF SYMBOLS 1 ... Transport 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 machine 412, 412A, 412B · · · X-ray source 413 · · · X-ray image detector 42 · · · X-ray leakage suppression mechanism 100 · · · Long pipe manufacturing equipment P · · · P1 ... Inspected tube (long tube)
PW: Perimeter weld L: Deviation amount

Claims (3)

An X-ray source having a radiation center extending in a direction substantially perpendicular to the longitudinal direction of the inspection tube and emitting X-rays toward the inspection tube; and the X-ray source sandwiching the inspection tube An X-ray examination machine provided with an X-ray image detector disposed at an opposite position and detecting an X-ray emitted from the X-ray source and transmitted through the inspection tube to generate an X-ray image; A method of inspecting a circumferential weld of an inspection tube,
The circumferential weld portion of the tube under test is positioned from the position on the radiation center of the X-ray source so that the pixel region corresponding to the circumferential weld portion of the tube under inspection in the X-ray image becomes annular. A first step of stopping the inspection tube at a position shifted in the longitudinal direction;
A second step of emitting X-rays from the X-ray source to the inspection tube stopped in the first step, and generating a first X-ray image which is the X-ray image by the X-ray image detector; ,
A third step of inspecting a circumferential weld of the inspected tube using the first X-ray image generated in the second step;
A method of inspecting a circumferential weld, comprising: When the separation distance between the X-ray source and the outer surface of the inspection tube on the side facing the X-ray source is H, the outer diameter of the inspection tube is OD, and the width of the circumferential weld is W In the first step, the tube to be inspected is stopped so that the displacement L from the position on the radiation center of the X-ray source of the circumferential weld of the tube to be inspected satisfies the following equation (1) Let
A method of inspecting a circumferential weld according to claim 1, characterized in that.
L> W (2H + OD) / 2 OD (1) A fourth step of stopping the tube to be inspected so that a circumferential weld of the tube to be inspected is at a position on a radiation center of the X-ray source;
A fifth step of emitting an X-ray from the X-ray source to the inspection tube stopped in the fourth step, and generating a second X-ray image which is the X-ray image by the X-ray image detector; ,
A sixth step of inspecting a circumferential weld of the inspected tube using the second X-ray image generated in the fifth step;
Further include
In the third step, a penetration defect existing in a circumferential weld portion of the inspected tube is detected using the first X-ray image,
In the sixth step, a defect other than a penetration defect existing in a circumferential weld of the inspected tube is detected using the second X-ray image,
The inspection method of the girth weld according to claim 1 or 2 characterized by things.