JP5460149B2 - Steel pipe butt weld inner surface inspection apparatus and method - Google Patents

Description

  The present invention relates to a steel pipe butt welded portion inner surface inspection device (hereinafter referred to as an inner surface inspection device) that monitors a welding state from the inner surface of a steel pipe and searches for a defective portion in butt welding between a steel pipe and a steel pipe.

In the pipe laying work, the steel pipes manufactured at the factory are transported to the laying site, and the steel pipes and steel pipes are welded locally to extend the construction. Butt welding between steel pipes and steel pipes is a multi-layer weld if the thickness of the steel pipe does not end with one layer of welding. In multi-layer welding, there are a case where all the layers are welded on the spot without moving the steel pipe, and a case where welding is performed in a flow operation by dividing a welding work place into several layers.
In particular, the laying method, which is one of the methods for laying pipes in submarine pipelines, is a method selected when laying long-distance pipes, and is a method of laying on the sea floor while welding steel pipes on special laying ships. is there. The laid ship is provided with a plurality of welding stages and inspection stages, and other work stages as required, and are continuously welded and inspected. In other words, long-distance pipes are laid efficiently by dividing the work of multiple layers into a plurality of welding stages and using it as a flow work like a factory line including inspection and other work.

In order to guarantee the quality of steel pipe butt welds of submarine pipes welded by the laying ship construction method, visual inspection and radiation flaw detection methods are performed at the inspection stage after all of the multi-layer welding has been completed at multiple welding stages. We conduct non-destructive inspections by ultrasonic flaw detection methods, etc. to check for weld defects, and if defects are found, remove defects, repair welds by re-welding, and re-inspect .
If a weld defect occurs on the inner surface of the steel pipe, grind the welded part from the outer surface of the steel pipe until it reaches the defect with a grinder, etc., remove the defective part, and then weld the ground part again As a result, the welded portion is repaired, so that the time required for the grinding operation and the re-welding operation becomes longer than when the outer surface of the steel pipe is defective. In particular, if a defect occurs in the first layer welding, all the weld layers must be removed, which greatly affects not only the workability but also the productivity of pipe laying. There is a strong demand.
This is not limited to submarine piping, for example, pipes with thick steel pipes, such as land piping such as gas piping and water piping, piping for plant equipment, etc., and people and devices can be placed inside the steel pipe. This also applies to the case where the weld defect on the inner surface of the steel pipe cannot be repaired from the inside of the steel pipe.

  In this way, it is inefficient to repair the weld defect on the inner surface of the steel pipe from the outside of the steel pipe, so the welding condition on the inner surface of the steel pipe is monitored during welding, and a welder is installed to prevent the occurrence of weld defects based on the monitoring results. An automatic welding apparatus to be controlled has been proposed (for example, Patent Document 1). Such a welding apparatus includes an automatic welding machine and an inner surface monitoring device. In the inner surface inspection apparatus, there is described an example in which a laser sensor is disposed as a CCD camera for external monitoring, groove information detection means, and information detection means regarding the position of the molten material. However, this technique monitors the welding state during welding, and is not applicable to welding using a backing metal that is usually performed by butt welding of a pipeline or the like. In addition, only the status of welding during welding (situation of the backwater pool, etc.) is monitored, and the final welds are not inspected for weld defects, so inspection after the end of welding is indispensable and defects occur. The repair work cannot be completely eliminated. Therefore, it has not led to the productivity improvement of piping laying, such as a pipeline.

  By the way, inspection methods for defects opening on the surface of the welded portion include a visual inspection method by an operator, a penetrant inspection method, and a magnetic particle inspection method. These inspection methods are used in factories that weld steel materials such as steel pipes because of the need for proficiency for workers, the time required for inspections, and the fact that workers must be close to the inspection target part. In the production line, it is not so often adopted. Instead of these, a method for determining the presence or absence of defects by camera imaging (for example, Patent Document 2) or a light cutting method (when laser slit light projected onto an object is viewed from another direction, the laser slit light reflects the surface shape of the object. Defect determination method by measuring cross-sectional profile of welded part by measuring the surface shape of the object by photographing the contour line to be expressed with a CCD camera etc. (surface shape measuring method based on the principle of triangulation) (for example, patent document) 3) etc. are often adopted, and labor saving and automation of the welded portion inspection are achieved.

However, in the defect presence / absence determination method based on camera imaging, the presence / absence of a weld surface opening can be determined, but the depth of the weld surface opening cannot be measured. Moreover, the defect determination method by the cross-sectional profile measurement of the welding part by an optical cutting method cannot measure the length of a welding surface opening part, unless several cross-sectional profiles are used. Recently, a method for determining the presence or absence of a defect in a weld bead by comparing a thinned image with a plurality of parallel line patterns and a reference thinned image has also been proposed (for example, Patent Document 4). However, even in the method of Patent Document 4, the number of line pattern generations that can be incorporated into an actual measurement apparatus is limited, and the effect of reducing the measurement time is limited.
As described above, inspection of steel pipe butt welds in the laying ship construction method is generally performed from the outside of the steel pipe by visual inspection on the outer surface of the weld and radiation inspection or ultrasonic inspection inside the weld. . This is because internal clamps and other devices used for welding are placed inside the steel pipe, and it is not possible for humans to enter the inside of the steel pipe that is being welded in the flow operation to perform inspections such as visual inspection. This is to hinder the entire piping laying work such as moving a device such as a null clamp or interrupting the welding work, thereby deteriorating the laying work efficiency.

JP 2000-153356 A JP-A-60-135705 JP 2008-267836 A JP 2008-216199 A

As mentioned above, even if welding technology such as a device that welds based on the monitoring results of the welding status is innovated, inspection of the welded part is essential, and the improvement in welding technology has increased the welding speed and inspection efficiency. We must try to improve it. In addition, non-destructive inspection such as the radiation inspection method and ultrasonic inspection method from the outside of the steel pipe, such as the inspection method of the steel pipe butt weld in the laying ship construction method, found defects opening in the weld surface on the inner surface of the steel pipe. There is a possibility that it may be impossible or mistakenly determined as a defect, causing serious accidents after laying, or performing unnecessary repairs to deteriorate work efficiency.
In steel pipe butt welding, including the laying ship method, the construction environment, interference with peripheral devices such as internal clamps and backing metal, and time constraints to maintain the productivity of flow work are taken into account. Therefore, monitoring and detection of welded portion defects on the inner surface side of the steel pipe are required.

An object of the present invention is to improve the detection accuracy of a welded portion defect on the inner surface side of a steel pipe and improve the monitoring / detection speed in butt welding of steel pipes.
In particular, with the aim of applying to the laid ship method, etc., we will improve the detection accuracy of defects opening on the welded part surface on the inner surface of the steel pipe, and achieve the inspection time and welding that match the time required for the specialized welding In order to shorten the time required for welding work including the repair of defects, an object of the present invention is to provide an inner surface inspection method for a steel pipe butt weld and an inspection device that embodies the method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a wide-field imaging device (meaning a wider field of view than a measurement and measurement device described later) when inspecting a weld from the inner surface of the steel pipe. Perform macroscopic observation to identify the defect part and the length of the defect (defects are generally long in the welding direction, that is, the circumferential direction of the steel pipe), and then microscopically observe only the extracted defect part using a shape measuring device. The depth of the defect portion is grasped, and harmful surface defects are determined and extracted from the grasped length and depth of the defect. As a result, it has been found that the defect detection accuracy can be increased while increasing the defect detection speed, and the present invention has been made.

  In addition, by using the inner surface inspection system based on the above knowledge and inspecting immediately after the first layer welding is completed, the first layer weld can be repaired immediately after the discovery of harmful surface defects, greatly increasing the repair time for defects. Can be shortened. Repairing harmful surface defects on the inner surface of the steel pipe in the first layer welding after completion of the first layer welding means repairing harmful surface defects from the outer surface of the steel pipe to the inner surface of the steel pipe after all the multi-layer welding is completed. This is because the amount of grinding and re-welding of the welded portion can be reduced as compared with the method of performing this, so that the time required for repairing the weld defect can be shortened.

The gist of the present invention is as follows.
(1) A steel pipe welded part inner surface inspection device for inspecting butt welds between steel pipes from inside the steel pipe, and a shape measuring device capable of measuring the defect depth of the welded portion, and a wide field of view can be photographed from the shape measuring device. Each having at least one imaging device and an illumination device capable of illuminating the imaging field of view of the imaging device, and having a sensor moving mechanism capable of moving these devices along the circumferential direction of the steel pipe;
The sensor moving mechanism includes a guide rail disposed along the circumferential direction of the inner surface of the steel pipe and a turning device that travels on the guide rail, and the shape measuring device, the imaging device, and the lighting device are included in the turning device. Installed,
Further, the sensor moving mechanism has a constant distance holding mechanism that can hold the distance between the shape measuring device, the imaging device, the lighting device, and the welded portion constant,
Based on a photographed image of the welded part photographed by the imaging device, the presence or absence of a defect in the welded part is determined, and when there is a defect, the shape measuring device measures the shape of the defect. Steel pipe butt weld inner surface inspection equipment.

(2 ) The sensor moving mechanism is configured by a hollow rotary stage that can rotate in the circumferential direction inside the steel pipe, and the shape measuring device, the imaging device, and the illumination device are fixed to the hollow rotary stage. (1) The steel pipe butt-welded inner surface inspection device according to (1).

( 3 ) The illuminating device is arranged to be symmetric with respect to the welded portion, and each illuminating device illuminates the welded portion at an incident angle of 10 ° to 30 ° (1) Or the steel pipe butt-weld part inner surface inspection apparatus as described in (2) .

( 4 ) The steel pipe butt welded portion inner surface inspection device according to any one of (1) to ( 3 ), characterized in that it has a detachable device connected to an internal clamp device used for steel pipe butt welding.

( 5 ) A steel pipe inner surface weld inspection method for inspecting butt welds of steel pipes from the inside of the steel pipe using the steel pipe inner surface weld inspection apparatus according to (1), wherein the welding is taken by the imaging device. Process the image information of the part, determine the presence or absence of defects in the weld, determine the position and length of the defect if there is a defect, and then determine the shape based on the determined defect position The shape measurement information obtained by measuring the shape of the defect with a measuring device is processed to determine the depth of the defect, and from the determined length and depth of the defect, it is determined whether it is a harmful surface defect. A method for inspecting the inner surface of a steel pipe butt weld.

( 6 ) The method for determining whether the surface defect is harmful or not is characterized in that the length and depth of the determined defect are compared with a predetermined threshold value to determine the harmful surface defect ( 5). The method for inspecting the inner surface of a butt welded portion of steel pipe as described in)

( 7 ) A method for inspecting a welded inner surface of a steel pipe using the steel pipe welded part inner surface inspection apparatus according to (1) above, wherein the butt welded portion of the steel pipes is inspected from inside the steel pipe. Process the captured image information of the welded portion photographed by the apparatus, determine the presence or absence of a defect in the welded portion, and if there is a defect, determine the defect position and the defect length, and then determine Based on the position of the defect, the shape measurement information obtained by measuring the shape of the defect is processed by the shape measuring device to determine the depth of the defect, and from the determined length and depth of the defect, whether it is a harmful surface defect or not. A method for inspecting the inner surface of a butt welded portion of a steel pipe, comprising: determining whether or not a harmful surface defect exists and repairing the harmful surface defect portion.

Compared to non-destructive inspection such as radiation flaw detection and ultrasonic flaw detection from the outside of the steel pipe according to the present invention, the weld surface on the inner surface of the steel pipe can be directly inspected. In addition to improving the accuracy of detecting defects to be detected, the inspection speed can also be improved. As a result, the inspection of the steel pipe inner surface of the steel pipe butt weld can be carried out immediately after the completion of the first layer welding, and when a welding defect is detected, the inspection is performed after the completion of all layers of the multi-layer welding. In comparison, the amount of grinding and re-welding of the weld can be reduced, and the time required for repairing the weld defect can be greatly reduced.
In addition, unnecessary repair work due to false detection can be avoided, and it can be presented as data that guarantees that there are no defects opening on the welded surface on the inner surface of the steel pipe, significantly improving the productivity of pipe laying such as pipelines. Can be made.

The conceptual diagram which shows the example (example of a guide rail system) of embodiment of the welding part inner surface inspection method by this invention. Schematic of an example of a welded part inner surface inspection device (equipped with one turning device). FIG. 2A is a view of a cross section perpendicular to the tube axis of the steel pipe as an example of the guide rail system. FIG.2 (b) is the figure which looked at the cross section of the example of a guide rail system of the pipe axis direction of a steel pipe. FIG.2 (c) is the figure which looked at the cross section perpendicular | vertical to the pipe axis of a steel pipe in the example of a hollow rotary stage system. FIG.2 (d) is the figure which looked at the cross section of the example of a hollow rotary stage system of the pipe axis direction of a steel pipe. The figure which shows the irradiation conditions of an illuminating device. Schematic of the constant distance holding mechanism to the steel pipe inner wall surface. Schematic of an example of a welded part inner surface inspection device (equipped with four turning devices). Fig.5 (a) is the figure which looked at the cross section perpendicular | vertical to the pipe axis of a steel pipe. FIG.5 (b) is the figure which looked at the cross section of the pipe axis direction of the steel pipe.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a conceptual diagram showing an example of an embodiment of a welded part inner surface inspection method according to the present invention.
In the butt welding of the steel pipe 2a and the steel pipe 2b in the laying ship construction method or the like, the steel pipe 2a and the steel pipe 2b are usually clamped by the internal clamp device 4 and several layers from the first layer or the first layer are welded. After the first layer welding is finished, the clamps of the steel pipe 2a and the steel pipe 2b are released and used for clamping the steel pipe to be welded next, so that the internal clamp device 4 is held inside the steel pipe. The inner surface inspection apparatus 1 according to the present invention may be attached to the internal clamp apparatus 4. Of course, the inner surface inspection apparatus may be arranged alone. The inner surface inspection device 1 includes an attachment / detachment device 6 so that it can be easily fixed to the internal clamp device skid portion 5. When the inner surface inspection device 1 is moved to the inspection target welded portion 3, it is carried out by moving the internal clamp device 4, and is incorporated in the swivel device 15 of the inner surface inspection device 1 for more accurate positioning. It can be performed by a fine movement function in the tube axis direction (not shown). Of course, if the internal clamp device 4 has a fine movement function, it can also be performed. There is no particular problem no matter what function is used as long as the inner surface inspection device can be precisely aligned.

  Outside the inner surface inspection device 1, there is a sensor moving mechanism for positioning the inner surface inspection device 1 inserted into the steel pipe and for controlling the positions of sensors (illumination device 12, imaging device 13, shape measuring device 14). A control device 7 that controls the operation and operations such as imaging and shape measurement, an imaging information processing device 8 that processes information from the imaging device 13, a shape information processing device 9 that processes information from the shape measuring device, A central inspection management device 10 that determines harmful surface defects from defect shape information, defect position information, and the like processed by these information processing devices is arranged to process a series of information. The central inspection management device 10 has an image recording function for recording original images and image processed images of the imaging device 13 and the shape measuring device 14, and also includes a display device 11, and the obtained image (real time It is also possible for humans to monitor inspection information and the like. There is no need to be particular about this configuration for information processing systems. It only needs to be able to process information (signals) from the imaging device and shape measuring device, which are sensors mounted on the inner surface inspection device, to recognize defects and determine harmful surface defects, and to control the device based on the defect information. .

  A series of inspection flows are as follows, for example. First, the steel pipe butt inner surface inspection device 1 is controlled by an external control device 7 and arranged at a steel pipe butt weld part to be inspected, and inspection is started from the steel pipe inner surface. First, macro observation is performed by the imaging device 13, and information (or signal) obtained there is transmitted to the imaging information processing device 8, where processing (image processing, etc.) is performed, and defect position information, length information, and as necessary. To extract width information. This is transmitted to the central inspection management device 10 to determine whether or not a detailed inspection is required. If a detailed inspection is necessary, it is fed back to the control device 7 and the shape measuring device 14 is controlled based on the position information of the defect. Operate and measure shape. The shape information obtained by the shape measuring device 14 is transmitted to the shape information processing device 9, where it is processed (image processing or the like) to extract the shape information of the defect. This is transmitted to the central inspection management apparatus 10 and integrated with the defect information based on the previously obtained imaging information to determine whether it is a harmful surface defect. The determination result, the defect shape information, and a captured image as necessary may be displayed on the display device (monitor) 11, and the human system determination may be intervened when the operator confirms the result.

  As a method for determining harmful surface defects, for example, there are methods in which the length and depth of a defect exceed a previously assumed threshold value, or a method for determining a harmful surface defect when it falls within a previously assumed range. The central inspection management apparatus (for example, PC) may be flexibly dealt with so that the determination method can be selected according to the target defect.

FIG. 2 shows an example of the inner surface inspection apparatus 1. FIG. 2A is a view of a cross section perpendicular to the tube axis of a steel pipe of a guide rail system (a system in which a turning device equipped with a sensor travels on a guide rail as a sensor moving mechanism). FIG.2 (b) is the figure which looked at the cross section of the pipe-axis direction of the steel pipe of a guide rail system.
The inner surface inspection apparatus 1 includes an illuminating device 12 that illuminates a region to be inspected, an imaging device 13 that images a welded portion to be inspected with a wide field of view, a shape measuring device 14 that measures the surface shape of the extracted defective portion, Is the example comprised by the guide rail 16 for the turning apparatus 15 to move along a steel pipe inner surface.
FIG.2 (c) is the figure which looked at the cross section perpendicular | vertical to the tube axis | shaft of the steel pipe of a hollow rotary stage system (method in which the hollow rotary stage which fixed the sensor rotates inside a steel pipe as a sensor moving mechanism). FIG.2 (d) is the figure which looked at the cross section of the pipe axis direction of the steel pipe of a hollow rotation stage system. In this inner surface inspection apparatus 1, an illumination device 12, an imaging device 13, and a shape measuring device 14 are fixed to a ring-shaped hollow rotary stage 24 having an outer shape smaller than the inner diameter of a steel pipe, and the hollow rotary stage 24 is further rotated. In this example, the motor 25 is used.
The following description will be based on the guide rail system. Of course, the sensor moving mechanism is not necessarily limited to these methods as long as the sensors can be positioned.

  In the case where the inner surface inspection device 1 is of a type attached to an internal clamp device, a method in which the turning device 15 travels on the guide rail 16 is given as an example. In this system, the vicinity of the center of the cross section of the pipe is hollow, and the cables 23 for power supply and control of the internal clamp device 4 can be passed, and these cables 23 obstruct the turning operation of the inner surface inspection apparatus 1. Can be prevented.

The turning device 15 can start, stop, and adjust the speed from the outside of the steel pipe by the operation of the control device 7.
The imaging device 13 and the shape measuring device 14 maintain a certain angle and a certain distance to the inner surface of the steel pipe on the swivel device 15 so that the welded portion can be photographed and measured by these devices. Fixed. It is desirable that these angles and distances can be varied from the outside of the steel pipe by the operation of the control device 7. As an example of the imaging device 13, there is a CCD camera that is equipped with an autofocus function or that can adjust the focus by an operation from the control device 7.

As an example of the shape measuring apparatus 14, there is a measurement sensor by a light cutting method. In this case, the line laser oscillation unit and the light receiving unit may be integrated or separated, but it is desirable that the laser oscillation intensity and the light receiving sensitivity can be adjusted.
The illuminating device 12 is arranged at a line-symmetrical position with the welding line as the center, and can illuminate at least a range to be imaged by the imaging device among the welded portions (inspected portions) one side at a time or simultaneously. In the example of FIG. 2, two lighting devices are used, but they may be integrated. However, as shown in FIG. 3 as illumination conditions, the illumination device 12 is a swivel device 15 so that the illumination device 12 can illuminate under an inclination angle 19 (θ) formed by the illumination device and the inner wall surface of the steel pipe between 10 ° and 30 °. It is desirable to be fixed on top. In addition, it is desirable that the lighting device 12 can variably control the distance 17 in the tube axis direction, the distance 18 in the center direction of the tube cross section, and the inclination angle 19 from the outside of the steel pipe by the operation of the control device 7.

  The illuminating device 12, the imaging device 13, and the shape measuring device 14 on the turning device 15 must be kept constant even while turning the distance to the inspection target weld. An example of a constant distance holding mechanism for this purpose is shown in FIG. The swivel device 15 is divided into an upper part 15 a and a lower part 15 b and connected by a spring 20. An arm 21 for maintaining a constant distance to the inner wall surface of the steel pipe is attached to the upper part 15a of the turning device, and the ball bearing 22 at the tip of the arm is always in contact with the inner wall surface of the steel pipe by the extension force of the spring 20. For this reason, even if the inner wall surface of the steel pipe is dented inside the pipe cross section or bulges outside the pipe cross section, and there is a deformed portion, the distance between the upper part 15a of the turning device and the inner wall surface of the steel pipe is always constant due to the expansion and contraction of the spring 20. The distance to the steel pipe inner wall surface of the apparatus 12, the imaging apparatus 13, and the shape measuring apparatus 14 is also kept constant. The movement in the tube axis direction and the tube circumferential direction is not restricted by the ball bearing 22 at the tip of the arm.

A method for defect inspection will be described.
As described above, macroscopic observation is performed by the imaging device, and defect part extraction and defect length (defects are generally long in the welding direction, that is, the circumferential direction of the steel pipe) are measured. As described above, imaging is performed in a batch with a wide-field imaging device such as a CCD camera. The obtained image signal is sent to the picked-up image information processing apparatus 8 for image processing. Image processing emphasizes the shadow of the welded portion illuminated by the lighting device, and determines the presence or absence of a defect. If it is determined that there is a defect, the defect length is also measured. Although the defect length may be measured with a shape measuring device, welding defects usually tend to occur in the welding direction (in this case, the circumferential direction of the steel pipe). Is efficient.

  Next, when a defective part is specified by image processing using an imaging device image, the shape measuring device is moved to that position and the depth is measured in order to measure the defect depth. As described above, the light cutting method is desirable for a non-contact type sensor because it is compact but has good measurement accuracy and high measurement speed. The light cutting method itself is a known technique, and there are many examples used for measuring the shape of the weld bead. Patent document 4 is also an example of this. The information obtained by the shape measuring device is sent to the shape measuring image shape information processing device 9 to perform image processing and measure the depth of the defect.

  The defect position information and defect length information obtained by the picked-up image information processing apparatus 8 and the defect depth information obtained by the shape measurement image shape information processing apparatus 9 are sent to the central inspection management apparatus 10. Determine harmful surface defects. The method for determining harmful surface defects depends on the conditions required for piping such as pipelines and cannot be uniquely determined here. For example, those exceeding a predetermined length and depth can be determined as harmful surface defects. In any case, it is desirable that these harmful surface defect determination methods are incorporated in the central inspection management apparatus 10 in advance and can be determined in real time.

  It is preferable that the operator can recognize the determination result of the harmful surface defect through the display device 11 or the like. This leads to the next action to be taken and leads to an improvement in productivity of pipe laying work such as a pipeline.

  An increase in the speed of the harmful surface defect determination process, which is an important part of the pipe inner surface inspection method, directly leads to an increase in the inspection speed. Therefore, as in the present invention, the defect search is assigned to a relatively wide-field imaging device such as a CCD camera, and after the defect is extracted and the position is specified, the shape measuring device is assigned to the detailed analysis, thereby reducing the inspection time. It became possible to shorten significantly.

  By arranging a plurality of swiveling devices in one pipe inner surface inspection device and operating them simultaneously, the inspection time can be further shortened. FIG. 5 shows an example in which four swiveling devices are mounted. In this case, since one swivel device only needs to share 1/4 of the entire circumference of the pipe, the inspection time is also shortened to approximately 1/4. Therefore, the inspection speed can be set according to the workability of laying a pipe or the like.

As shown in FIG. 1, the inner surface inspection of the first layer welded part of actual pipe butt welding was performed by the inner surface inspection device attached to the internal clamp device, and the inspection accuracy and inspection speed were verified.
The target inspection accuracy is the same detection capability as the radiation penetration test or the ultrasonic flaw detection test from the outside of the pipe currently being implemented, and defects exceeding 0.5 mm are detected as harmful surface defects.
Test conditions: Butt welding of 750A piping was performed, and after the first layer welding, the entire circumference of the welded portion was inspected with an inner surface inspection device, and the inspection time was measured. At this time, the entire circumference was first inspected by the shape measuring device to accurately grasp the position and size of the heel, and then the entire periphery was inspected by the imaging device + the shape measuring device as described above. Welding speed was higher than usual so that defects were likely to occur.

Test results:
(1) Measurement using only a shape measuring device (light cutting method) In order to determine a defect exceeding 0.5 mm, it is necessary to measure at a pitch of at least 0.5 mm. Therefore, it took about 185 seconds for the entire circumference inspection. Two defects were detected on the entire circumference, both of which were 1 mm.
(2) Measurement by the inspection method according to the present invention The field of image captured by the imaging device was 30 mm × 30 mm, which is sufficiently capable of detecting a 0.5 mm defect in a prior offline confirmation test. In order to increase defect detection accuracy, imaging was performed at a pitch of 15 mm so as to provide a 50% overlap between the images.
As a result, it took 75 seconds for the entire circumference inspection with the imaging apparatus. Two defects could be confirmed by the image processing of this imaging device, and both were the same as those detected by the shape measuring device.
The time measured by the shape measuring device for these two wrinkles was 1 second or less including the moving time.
From the above results, it was confirmed that in the butt welding of steel pipes, it is possible to ensure sufficient inspection accuracy with the inner surface inspection method and apparatus according to the present invention immediately after the first layer welding.

  The present invention can be used in butt welding of pipes such as pipelines. In particular, by applying to flow-laying pipe construction such as the laying ship construction method, high inspection accuracy, fast inspection speed, and inspection immediately after the first layer welding have the effect of shortening the defect repair time, and in the future We are convinced that this will contribute to the improvement of the reliability of pipelines and the like that support the energy situation and the significant improvement in laying productivity.

DESCRIPTION OF SYMBOLS 1 Steel pipe butt weld part inner surface inspection apparatus 2a Steel pipe 2b Steel pipe 3 Welded part to be inspected (first layer welded part)
DESCRIPTION OF SYMBOLS 4 Internal clamp apparatus 5 Internal clamp apparatus Skid part 6 Attachment / detachment apparatus 7 Control apparatus 8 Imaging information processing apparatus 9 Shape information processing apparatus 10 Central inspection management apparatus 11 Display apparatus 12 Illumination apparatus 13 Imaging apparatus 14 Shape measurement apparatus 15 Turning apparatus 15a Swivel upper part 15b Swivel lower part 16 Guide rail 17 Distance X in the tube axis direction from the weld line to be inspected
18 Distance Z from the inner surface of the steel pipe to the center of the pipe cross section
19 Inclination angle θ between lighting by lighting device and inner wall of steel pipe
20 Spring 21 Arm 22 Ball bearing 23 Cable for inner clamp device 24 Motor driven hollow rotary stage 25 Motor

Claims (7)

A steel pipe welded inner surface inspection device for inspecting butt welds between steel pipes from inside the steel pipe, a shape measuring device capable of measuring the defect depth of the welded portion, and an imaging device capable of photographing a wide field of view from the shape measuring device, And at least one illumination device that can illuminate the field of view of the imaging device, and a sensor moving mechanism that can move these devices along the circumferential direction of the steel pipe,
The sensor moving mechanism includes a guide rail disposed along the circumferential direction of the inner surface of the steel pipe and a turning device that travels on the guide rail, and the shape measuring device, the imaging device, and the lighting device are included in the turning device. Installed,
Further, the sensor moving mechanism has a constant distance holding mechanism that can hold the distance between the shape measuring device, the imaging device, the lighting device, and the welded portion constant,
Based on the photographed image of the welded portion taken by the imaging device, the presence or absence of a defect in the welded portion is determined. If there is a defect, the shape measuring device measures the shape of the defect and inspects it. A steel pipe welded part inner surface inspection device characterized by that.
The sensor moving mechanism is configured by a hollow rotary stage that can rotate inside a steel pipe in a circumferential direction, and the shape measuring device, the imaging device, and the illumination device are fixed to the hollow rotary stage. The steel pipe butt weld inner surface inspection device according to claim 1.
The lighting device is arranged so as to be symmetrical with respect to the weld, each of the lighting device, to claim 1 or 2, characterized in that illuminated with an incident angle of 10 ° to 30 ° with respect to the weld The steel pipe inner surface welding inspection apparatus as described.
The steel pipe inner surface welding inspection apparatus according to any one of claims 1 to 3, further comprising an attachment / detachment device connected to an internal clamp device used for steel pipe butt welding.
A steel pipe inner surface weld inspection method for inspecting a butt weld of steel pipes from the inside of the steel pipe using the steel pipe inner surface weld inspection device according to claim 1,
Process the captured image information of the welded portion imaged by the imaging device, determine the presence or absence of a defect in the welded portion, if there is a defect, determine the defect position and the defect length, Determine the depth of the defect by processing the shape measurement information obtained by measuring the shape of the defect with the shape measurement device based on the determined defect position,
A method for inspecting a welded portion on the inner surface of a steel pipe, wherein it is determined from the determined length and depth of the defect whether or not it is a harmful surface defect.
Method of determining whether the harmful surface defects, the length and depth of the defects described above decision, according to claim 5, characterized in that to determine the harmful surface defects by comparing with a predetermined threshold value Steel pipe inner surface welded part inspection method.
A steel pipe inner surface weld inspection method for inspecting butt welds of steel pipes from the inside of the steel pipe using the steel pipe weld inner surface inspection device according to claim 1,
After the first layer welding, the captured image information of the welded part imaged by the imaging device is processed, the presence / absence of a defect in the welded part is determined, and if there is a defect, the defect position and the defect length are determined. Next, the shape measurement information obtained by measuring the shape of the defect with the shape measuring device based on the determined defect position is processed to determine the depth of the defect, and the length and depth of the determined defect are determined. From the above, it is determined whether or not a harmful surface defect exists, and when the harmful surface defect exists, the harmful surface defect part is repaired.

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