JP2015004669A - Device and method for ultrasonic flaw detection of electro-resistance-welded tube and quality assurance method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device and a method for ultrasonic flaw detection of an electro-resistance-welded tube capable of accurately detecting a flaw by performing seam detection independently of reflection from a defect existing in a weld seam part, and provide a quality assurance method.SOLUTION: After welding an electro-resistance-welded tube, in a line in which a bead cutting machine, a seam detection unit for imaging a weld seam part, and a sensor head provided with an ultrasonic probe are arranged in this order, a bead position is calculated by installing a bead cutting position detection unit for detecting the bead position with respect to the bead cutting width just in front of or just behind the installation position of the sensor head, a seam position is calculated on the basis of a thermal image of the weld seam part, and a delay time required by the seam position for passage to the installation position of the bead cutting position detection unit is calculated. On the basis of these results, ultrasonic flaw detection for a defect of the weld seam part is performed while moving the sensor head by calculating the movement amount of the sensor head.

Description

  The present invention relates to an ultrasonic flaw detection apparatus and method, and a quality assurance method, for ultrasonic flaw detection of a welded seam of an electric resistance weld pipe.

  The process for producing an electric resistance welded tube is generally a process in which a steel plate is bent into a tubular shape and welded while pressing both left and right ends of the tubular shaped steel plate. In order to obtain good welding quality, after welding, the welded joint is subjected to ultrasonic flaw detection using an ultrasonic flaw detector, and further annealed (annealed) with a seam annealer (tempering the seam portion that has become hardened by welding) ) Will be made into a product.

  When ultrasonic flaw detection is performed on a welded seam portion of an electric resistance welded tube manufactured in such a manufacturing process, oblique flaw detection is usually used and is performed after cutting a weld bead or after a hydraulic pressure test. It is necessary to perform ultrasonic flaw detection after positioning the sensor head on which the ultrasonic probe is installed so that oblique angle ultrasonic waves are incident on a desired position. As for positioning, even in the seam annealer installed downstream of the ultrasonic flaw detector, in order to anneal the weld seam part pinpoint, it is necessary to perform the annealing process after correctly positioning the seam annealer on the weld seam part. is there.

  However, since the ERW pipe receives various forces on the production line, the weld seam portion is not necessarily located on the center line of the ultrasonic flaw detector or the seam annealer, and may be shifted left and right. Therefore, in order to position the ultrasonic probe directly above the weld seam portion, the temperature of the weld seam portion is measured by two radiation thermometers arranged across the weld seam portion of the ERW pipe, A technique is known in which a seam position is detected from a difference in measurement temperature (see Patent Document 1).

  In addition, as a technology to detect the seam position without using a radiant thermometer, based on the fact that the temper color of the weld seam part is the part where the heat input is most applied, the color tone change in the circumferential direction of the ERW pipe is measured. Detecting the position of the weld seam by detecting the position of the weld seam (see Patent Document 2), the brightness change of the weld seam taken by the camera, etc. A technique to consider (see Patent Documents 3 to 6) is known.

However, the technique disclosed in Patent Document 1 outputs a servo signal for welding seam tracking to a probe driving mechanism that drives the ultrasonic probe in the circumferential direction of the ERW pipe, thereby causing the ultrasonic probe to move. Since it is positioned right above the weld seam, it is necessary to integrate the radiation thermometer and the probe drive mechanism. Therefore, ultrasonic flaw detection is performed at a position where the temperature of the weld seam portion exceeds 100 ° C, and in order to improve flaw detection accuracy, an ultrasonic probe is brought close to the weld seam portion to attempt ultrasonic flaw detection. Then, the acoustic transmission medium (water) between the weld seam portion and the ultrasonic probe boils, and there is a problem that the weld seam portion cannot be ultrasonically detected.

  On the other hand, when the ultrasonic flaw detection is performed after the weld seam portion is cooled, the technique disclosed in Patent Document 1 measures the temperature of the weld seam portion with two radiation thermometers and servos for welding seam tracking. Since this is a method for outputting a signal, there is a problem that it cannot be applied in principle.

  Moreover, since the technique disclosed in Patent Document 2 affects the surface state of the cutting surface depending on the cutting state of the weld bead, actually, the temper color is stably detected on the production line of the ERW pipe. It is difficult.

  Further, in the techniques disclosed in Patent Documents 3 to 6, the center of the bead cutting portion is regarded as a weld seam portion. However, the center position of the weld seam portion is not necessarily the bead cutting portion depending on how the bead cutting tool hits. Since the width of the bead cutting portion is not limited to the center of each other and is about 10 mm, an error of several mm may occur. In the conventional ultrasonic inspection, the width of the ultrasonic beam is a few millimeters, and these methods are sufficient, but a small defect in the weld seam using a tandem method or a focused beam with a narrow beam intersection area. However, there is a problem that the accuracy is insufficient.

  Therefore, as a technique for solving these problems, a seam detection technique using an ultrasonic reflection signal from a defect in a weld seam portion (see Patent Document 7) or a weld seam portion of an electric-welded pipe is imaged with an infrared camera. A technique for detecting a seam position from a temperature distribution obtained in this manner and further correcting the seam position using an ultrasonic reflection signal from a defect present in a weld seam portion is disclosed (see Patent Document 8).

JP-A-61-107102 JP-A-6-201596 JP-A-1-302103 Japanese Patent Laid-Open No. 2-96602 JP-A-4-340403 JP-A-10-170228 JP 2011-227060 A JP 2009-222408 A

  However, the above technique has the following problems. That is, the techniques disclosed in Patent Documents 7 and 8 are both present in a weld seam portion obtained by electronically or mechanically scanning an ultrasonic beam in the pipe circumferential direction in the vicinity of the weld seam portion of the electric resistance welded tube. The true seam position is detected based on the reflected wave from the defect. In other words, the seam position cannot be calculated when there is no defect in the weld, and it cannot be guaranteed that the true seam position can be detected.

  In the present invention, in view of the problems of these prior arts, an ultrasonic inspection device and method of an electric-sewing tube capable of detecting a seam accurately without relying on reflection from a defect existing in a weld seam, and a quality thereof It is an object to provide a guarantee method.

  The above problems can be solved by the following invention.

[1] A seam detection unit that images a weld seam portion using a bead cutting machine, a thermal imaging camera, and an ultrasonic probe for ultrasonic inspection of defects in the weld seam portion after welding an electric resistance welded tube An ultrasonic flaw detection apparatus for an electric sewing tube in a line arranged in the order of a sensor head comprising:
A seam position calculator that calculates the seam position based on the thermal image captured by the seam detector; and
A bead cutting position detector that detects a bead position with respect to a bead cutting width, installed immediately before or after the installation position of the sensor head;
A delay unit that calculates a time required for the seam position calculated by the seam position calculation unit to pass to the installation position of the bead cutting position detection unit;
A movement amount calculation unit for calculating a movement amount based on the seam position calculated by the seam position calculation unit delayed by the time calculated by the delay unit and the bead position detected by the bead cutting position detection unit; ,
A sensor head driving unit that drives the sensor head by the movement amount calculated by the movement amount calculating unit;
An ultrasonic transmission / reception unit for performing ultrasonic transmission / reception with the sensor head driven by the sensor head driving unit;
An ultrasonic flaw detection apparatus for an electric-welded tube, comprising: an evaluation unit that receives a reflected ultrasonic signal from the ultrasonic transmission / reception unit and performs a quality evaluation as to whether or not a defect exists in the weld seam portion.

[2] In the ultrasonic flaw detection apparatus for an electric sewing tube according to [1] above,
The bead cutting position detector is
An ultrasonic flaw detection apparatus for an electric-welded tube, wherein a bead position is detected based on a change in emissivity using a thermal image type camera.

[3] A seam detection unit that images a weld seam portion using a bead cutting machine, a thermal imaging camera, and an ultrasonic probe for ultrasonic flaw detection of defects in the weld seam portion after welding an electric resistance welded tube A method for ultrasonic flaw detection of an electric sewing tube in a line arranged in the order of a sensor head comprising:
A bead cutting position detection unit that detects a bead position with respect to a bead cutting width immediately before or immediately after an installation position of the sensor head is installed,
Step 1 of capturing a thermal image of a weld seam portion with the seam detection unit;
Step 2 for calculating a seam position based on the captured thermal image;
Calculating a delay time required for the seam position calculated in step 2 to pass to the installation position of the bead cutting position detecting unit;
Step 4 of calculating the bead position in the bead cutting position detection unit;
Calculating a movement amount of the sensor head based on the bead position, the delay time, and the seam position;
Step 6 of moving the sensor head by the amount of movement;
After the step 6, there is a step 7 of ultrasonic flaw detection of defects in the weld seam with the sensor head.

[4] In the ultrasonic flaw detection method for an electric resistance welded tube according to [3] above,
The bead cutting position detector is
An ultrasonic testing method for an electric-welded tube, wherein a bead position is detected based on a change in emissivity using a thermal image type camera.

  [5] A quality assurance method characterized by performing a flaw detection on a weld seam portion using the ultrasonic flaw detection method for an electric resistance welded tube according to the above [3] or [4] and providing information on the result.

  ADVANTAGE OF THE INVENTION According to this invention, while detecting a seam without relying on the reflection from the defect which exists in a welding seam part, a flaw detection can be performed accurately, and quality assurance of a reliable ERW pipe is realizable.

It is a figure which shows the example of whole structure of the ultrasonic flaw detection apparatus of the electric sewing tube which concerns on this invention. It is a figure which shows the example of a processing flow which makes a sensor head track a welding seam. It is a figure which shows an example of the two-dimensional thermal image acquired with the thermal image camera. It is a figure which shows an example of the temperature distribution of a pipe peripheral direction. It is a figure explaining the method of calculating a seam position from temperature distribution. It is a figure explaining the method of calculating a bead peak position from temperature distribution. It is a figure explaining the method of calculating a more exact bead peak position from temperature distribution. It is a figure which shows the example of whole structure of the ultrasonic flaw detection apparatus of the ERW pipe which concerns on the Example of this invention.

  Embodiments of the present invention will be described below with reference to the drawings and mathematical expressions. FIG. 1 is a diagram showing an example of the entire configuration of an ultrasonic inspection device for an electric resistance tube according to the present invention.

  In the figure, 1 is a sensor head, 2 is a seam cooling unit, 3 is a seam detection unit, 4 is a seam position calculation unit, 5 is a bead cutting position detection unit, 6 is a bead cutting position calculation unit, 7 is a movement amount calculation unit, 8 represents a sensor head drive unit, 9 represents an ultrasonic transmission / reception unit, 10 represents an evaluation unit, and 11 represents a delay unit.

  The left and right ends of the steel sheet formed into a tubular shape by a roll are welded and joined by a welding machine, and the weld bead of the welded part is cut by a bead cutting machine to produce an electric resistance welded tube.

  The sensor head 1 equipped with an ultrasonic probe for ultrasonic flaw detection can be moved in the pipe circumferential direction of the electric sewing tube by the sensor head drive unit 8 so that the weld seam can be flaw detected.

  When the ultrasonic flaw detection method applied to the sensor head 1 is a water column ultrasonic method using water for acoustic coupling (local water immersion method) or a water film method, the closer the sensor position is to the weld seam, Boiling under the influence of heat of time, flaw detection becomes difficult.

  For this reason, when applying a flaw detection method that is affected by heat during welding, a seam cooling unit 2 is provided, and cooling is performed so that the seam temperature is about 100 degrees or less at the position where the sensor head 1 is installed. carry out. As the cooling method, water cooling by a laminar nozzle is the most effective. However, as long as the seam temperature is about 100 degrees or less at the position where the sensor head 1 is installed as described above, other means may be used.

  The seam detection unit 3 images the weld seam using a thermal image type camera. The captured image is sent to the seam position calculation unit 4, where the image is processed, and the position of the welding seam is calculated from the temperature distribution. The description of the bead cutting position detection unit 5 to the delay unit 11 will be made in the following description of the processing flow.

  FIG. 2 is a diagram illustrating an example of a processing flow for causing the sensor head to follow the welding seam. First, in Step 01, a thermal image of a welding seam is acquired. A two-dimensional thermal image is obtained by imaging the periphery of the weld seam with the thermal image type camera of the seam detection unit 3. FIG. 3 is a diagram illustrating an example of a two-dimensional thermal image acquired by the thermal image camera. A weld seam having a higher temperature than the surroundings can be confirmed in the central portion.

  Next, in Step 02, the seam position is calculated. The two-dimensional thermal image obtained in Step 01 is sent to the seam position calculation unit 4 and the seam position is calculated based on the two-dimensional thermal image. First, the temperature distribution in the tube circumferential direction is calculated from the obtained two-dimensional thermal image. FIG. 4 is a diagram illustrating an example of a temperature distribution in the pipe circumferential direction. Pixels in the tube circumferential direction are plotted on the horizontal axis and temperature is plotted on the vertical axis, and a bifurcated temperature distribution having a low temperature portion at the center of the seam can be confirmed.

  FIG. 5 is a diagram illustrating a method for calculating the seam position from the temperature distribution. Set the threshold temperature θt for the temperature distribution, determine the two locations that cross θt from the temperature distribution of the weld seam, and then the midpoint of the two locations (Xa, Xb) that cross the threshold θt (the axial direction of the ERW pipe) The seam position calculation unit 4 calculates the X coordinate Xc) of the weld seam portion in the direction perpendicular to the welding seam position Xc of the ERW pipe when it passes through the place where the seam detection unit 3 is installed. . Specifically, Xc is calculated based on equation (1).

  In this case, the threshold value θt may be a fixed value or a value determined at a certain ratio with reference to the peak value of the temperature distribution. Further, it is desirable to obtain the temperature distribution of the weld seam at a plurality of positions in the longitudinal direction of the ERW pipe and to average these values (as shown in the averaging range at the right end of FIG. 3). By doing so, it is possible to reduce the influence of fluctuations in the thermal image due to noise from the welder and steam generated in the seam cooling section, and therefore the accuracy of the calculated seam position can be further increased.

  Next, the bead cutting position is calculated by the seam position calculation unit 4 from the thermal image shown in FIG. In the temperature distribution diagram obtained from the thermal image, the temperature decreases near the center of the seam. The bead-cut position is more specular than the cut periphery and the emissivity is different from the periphery.

  When a temperature distribution is calculated from a thermal image using infrared rays, a valley portion is generated at the center as shown in FIG. A range that is affected by the emissivity due to the mirror state of the bead cutting portion is extracted from the temperature distribution, and the bead cutting position is calculated.

  A specific bead cutting position calculation method will be described with reference to FIGS. 6 and 7. FIG. 6 is a diagram for explaining a method for calculating the bead peak position from the temperature distribution. FIG. 7 is a diagram for explaining a method of calculating a more accurate bead peak position from the temperature distribution.

First, by using Xc calculated by the equation (1), a position X _p1 having a maximum value peak is calculated in a range where the tube circumferential direction position X is smaller than Xc (FIG. 6). Subsequently, curve fitting is performed within a range of several points before and after the calculated X _p1 to calculate an accurate peak position. For example, as shown in FIG. 7, five points before and after are extracted, a curve that can be fitted with a quadratic function using the least square method is obtained, and a position X _m1 that is the maximum value of this curve is calculated. Further, in the same procedure, even in the range where the pipe circumferential position X is larger than Xc, first, the position X _p2 that is the maximum position peak is calculated, and then the true maximum position X _m2 is used by using several points before and after that. Is calculated.

By performing the above calculation in the seam position calculation unit 4, the bead cutting positions _Xm1 , _Xm2 and the seam position Xc can be calculated.

In Step 03, the delay time is calculated and sent to the movement amount calculation unit. The bead cutting positions X _m1 and X _m2 and the seam position Xc calculated by the seam position calculation unit 4 are the time Td required to pass through the position where the bead cutting position detection unit 5 is installed based on the pipe forming speed by the delay unit 11. The calculated amount is delayed by Td and sent to the movement amount calculation unit 7.

  In order to track the seam position, the seam detection unit 3 is preferably close to the sensor head 1. If there is a distance from the seam detection unit 3 to the sensor head 1, there is a possibility that the steel pipe cannot be tracked with high accuracy due to torsion of the steel pipe.

  However, for example, when the water column ultrasonic method (local water immersion method) using water as an acoustic binder is applied as the ultrasonic flaw detection method as described above, when the seam temperature is high, the water boils and bubbles are generated. Occurs, and transmission and reception of ultrasonic waves are hindered. Therefore, the seam cooling part 2 for cooling the seam must be installed upstream of the sensor head 1. In the seam detection after the seam cooling, the temperature distribution has changed due to the cooling, and the seam position Xc cannot be calculated accurately.

  Accordingly, the seam detection unit 3, the seam cooling unit 2, and the sensor head 1 must be installed in this order from the upstream side, and the positions of the sensor head 1 and the seam detection unit 3 are necessarily separated from each other. Therefore, in the present invention, even if the positions of the sensor head 1 and the seam detection unit 3 are separated and the seam position is displaced in the pipe circumferential direction, the sensor head 1 can follow the seam position with high accuracy. ing.

  The present inventor can calculate the bead cutting width based on the change in the emissivity between the bead-cut portion and the other portion using the thermal image in the vicinity of the sensor head, and the bead position relative to the bead cutting width, that is, the bead. It was noted that the bead position relative to the cutting width can be calculated. This is because the emissivity is low in the bead-cut portion, and the temperature of the bead-cut portion is apparently lower than that in the non-bead-cut portion (the central valley portion in FIG. 4 is the bead-cut portion). Is equivalent).

  In the present invention, the seam detection unit 3 is installed on the upstream side, and a bead cutting position detection unit 5 that newly detects a bead position is installed immediately before or after the sensor head 1 installed downstream of the seam cooling unit 2. .

In Step 04, the bead position in the bead cutting position detection unit is calculated and sent to the movement amount calculation unit. That is, based on the information obtained by the bead cutting position detection unit 5, bead positions X _s1 and X _s2 with respect to the bead cutting width at the position where the bead cutting position detection unit 5 is installed are calculated, and these values are calculated. Delivered to the movement amount calculation unit 7.

When a thermal image type camera is used in the bead cutting position detection unit 5 similarly to the seam detection unit 3 described above, the bead cutting position calculation unit 6 and the seam position calculation unit 4 use the obtained temperature information. Similar operations (X _p1 and X _p2 and The same calculation as X _m1 and X _m2 ) is performed to calculate the bead position. In detecting the bead cutting position, the bead position may be calculated using another method (optical method, shape measurement, etc.) different from the above.

  Next, in Step 05, the movement amount calculation unit calculates the movement amount D. The movement amount calculation unit 7 calculates the movement amount in the sensor head driving unit 8 that moves the sensor head 1 in the pipe circumferential direction. In the movement amount calculation unit 7, first, based on the information from the seam position calculation unit 4 sent after being delayed and the information sent from the bead cutting position calculation unit 6, Expressions (2) and (3) The seam position Xpos in the pipe circumferential direction is calculated using the equation.

  In Step 06, the sensor head driving unit 8 drives the sensor head 1 to follow the ultrasonic flaw detection sensor 1 by the tracking movement amount D in the tube circumferential direction so that the seam position Xpos approaches the preset target value Xd. The follow-up movement amount at this time is as shown in equation (4).

  By operating the sensor head 1 in the pipe circumferential direction in this way, the sensor head 1 can reliably follow the weld seam, and accurate ultrasonic flaw detection and reliable quality assurance of the weld seam are possible.

  Although not specified in the processing flow of FIG. 2, when the sensor head 1 is able to reliably follow the weld seam (at the end of Step 06), the ultrasonic flaw detector installed on the sensor head 1 is super An ultrasonic transmission / reception command is issued from the ultrasonic transmission / reception unit 9 to perform ultrasonic flaw detection. The ultrasonic signal reflected from the weld seam is sent from the ultrasonic transmission / reception unit 9 to the evaluation unit 10, and after the signal processing, quality evaluation is performed to determine whether or not there is a defect in the weld seam. Is provided by displaying and recording. Thus, reliable quality assurance is achieved by the present invention.

  If there is the next seam tracking in Step 07, the process returns to Step 01 and the series of processes is repeated. Then, when there is no next seam tracking, the process ends.

  The embodiments of the present invention will be described below with reference to the drawings and mathematical expressions. FIG. 8 is a diagram showing an example of the entire configuration of the ultrasonic testing equipment for an electric resistance tube according to an embodiment of the present invention. The entire configuration of the embodiment shown in FIG. 8 is in accordance with the contents described in the mode for carrying out the invention. The reference numerals 1 to 11 in the figure are the same as those in FIG. Reference numeral 12 denotes a seam detector height position adjusting mechanism, reference numeral 13 denotes a seam tracking control device, and reference numeral 14 denotes a speed detector. Similarly, a PO roll not shown in FIG. 1 represents a pull-out roll. In the production of welded pipes, steel plates are gradually formed into a tubular shape with a forming roll installed upstream from the welder, and both ends of the steel plates are welded together with a welder to produce steel pipes. The role of pushing out in the pipe making direction while forming a steel pipe welded by a welding machine into a predetermined cross-sectional shape is a pull-out roll.

  The seam tracking control device 13 includes a seam position calculation unit 4, a delay unit 11, a movement amount calculation unit 7, and a bead cutting position calculation unit 6. Based on the image information obtained by the seam detection unit 3 and the bead cutting position detection unit 5, the seam position in the circumferential direction at the position where the bead cutting position detection unit 5 is installed is calculated. Then, the sensor head 1 is subjected to follow-up control in the tube circumferential direction by the sensor head driving unit 8 so that the seam position is within the sensitivity range of the ultrasonic probe installed in the sensor head 1.

  In this embodiment, a seam detection unit 3 for measuring the true seam position with respect to the bead cutting unit is installed immediately after the bead cutting machine, and the bead cutting position detection unit 5 is tied to the sensor head 1 on the downstream side. installed. The seam detection unit 3 adjusts the outer diameter size of the electric sewing tube to be formed, which is transmitted from the operation information database (not shown) so that the image can be always captured at a predetermined focus position in accordance with the outer diameter size of the electric sewing tube. Based on this, the height adjustment with respect to the ERW pipe is performed by the seam detection unit height position adjustment mechanism 12.

  In order to cause the sensor head 1 to follow the seam, in this embodiment, based on information obtained by the seam detection unit 3 installed immediately after the bead cutting machine and the bead cutting position detection unit 5 entangled with the sensor head 1. The true seam position at the position of the sensor head 1 was calculated.

  The seam detection unit 3 is used to capture an image of the welded seam, and the captured image is sent to the seam position calculation unit 4, and the temperature distribution obtained by image processing is divided into two locations (Xa, Xb) as the welding seam position Xc of the ERW pipe when the seam detection section 3 is placed at the midpoint (the X coordinate of the welding seam section with respect to the direction perpendicular to the axial direction of the ERW pipe) The seam position calculation unit 4 calculates. Specifically, as shown in FIG. 5, Xc is calculated based on the equation (1).

Further, using the Xc calculated by the equation (1), a position X _p1 that is the maximum value peak is calculated in a range where the tube circumferential direction position X is smaller than Xc (FIG. 6). Subsequently, curve fitting is performed within a range of several points before and after the calculated X _p1 to calculate an accurate peak position.

For example, as shown in FIG. 7, five points before and after are extracted, a curve that can be fitted with a quadratic function is obtained using the least square method, and a position X _m1 that is the maximum value of this curve is calculated. Further, in the same procedure, even in the range where the tube circumferential position X is larger than Xc, first, the position X _{p2 at} which the maximum value peak is obtained is calculated, and then the true position X _m2 is determined by using several points before and after that. calculate.

By performing the above-described calculation by the seam position calculation unit 4, the bead cutting positions X _m1 and X _m2 and the seam position Xc are calculated. Then, the time Δt required for the seam position measured based on the speed information obtained from the speed detector 14 by the delay unit 11 to reach the position of the bead cutting position detection unit 5 is calculated, and only the delay time Δt is calculated. The bead cutting positions X _m1 and X _m2 and the seam position Xc are sent to the movement amount calculation unit 7 over a delay time.

In the movement amount calculation unit 7, the bead cutting positions X _m1 and X _m2 and the seam position Xc sent from the seam position calculation unit 4, and X _s1 and X _s2 sent from the bead cutting position calculation unit 6. From (2) and (3), the seam position Xpos is calculated. The flaw detection is performed while performing the seam tracking by controlling the sensor head driving unit 8 so that the seam position Xpos is always at the center of the field of view of the bead cutting position detection unit 5.

  According to the present embodiment, seam detection can be performed without relying on reflection from a defect existing in the weld seam portion, and flaw detection can be performed with high accuracy, and reliable quality assurance of the ERW pipe has been realized.

DESCRIPTION OF SYMBOLS 1 Sensor head 2 Seam cooling part 3 Seam detection part 4 Seam position calculation part 5 Bead cutting position detection part 6 Bead cutting position calculation part 7 Movement amount calculation part 8 Sensor head drive part 9 Ultrasonic transmission / reception part 10 Evaluation part 11 Delay part 12 Seam detector height position adjustment mechanism 13 Seam tracking control device 14 Speed detector

Claims (5)

Equipped with a bead cutting machine, a seam detection unit that images the weld seam using a thermal imaging camera, and an ultrasonic probe for ultrasonic inspection of defects in the weld seam after welding the ERW tube An ultrasonic flaw detection apparatus for an electric sewing tube in a line arranged in the order of the sensor head,
A seam position calculator that calculates the seam position based on the thermal image captured by the seam detector; and
A bead cutting position detector that detects a bead position with respect to a bead cutting width, installed immediately before or after the installation position of the sensor head;
A delay unit that calculates a time required for the seam position calculated by the seam position calculation unit to pass to the installation position of the bead cutting position detection unit;
A movement amount calculation unit for calculating a movement amount based on the seam position calculated by the seam position calculation unit delayed by the time calculated by the delay unit and the bead position detected by the bead cutting position detection unit; ,
A sensor head driving unit that drives the sensor head by the movement amount calculated by the movement amount calculating unit;
An ultrasonic flaw detection apparatus for an electric-welded tube, comprising: an evaluation unit that receives a reflected ultrasonic signal from the ultrasonic transmission / reception unit and performs a quality evaluation as to whether or not a defect exists in the weld seam portion. In the ultrasonic flaw detection apparatus of the electric sewing tube according to claim 1,
The bead cutting position detector is
An ultrasonic flaw detection apparatus for an electric-welded tube, wherein a bead position is detected based on a change in emissivity using a thermal image type camera. Equipped with a bead cutting machine, a seam detection unit that images the weld seam using a thermal imaging camera, and an ultrasonic probe for ultrasonic inspection of defects in the weld seam after welding the ERW tube A method for ultrasonic flaw detection of an electric sewing tube in a line arranged in the order of a sensor head,
A bead cutting position detection unit that detects a bead position with respect to a bead cutting width immediately before or immediately after an installation position of the sensor head is installed,
Step 1 of capturing a thermal image of a weld seam portion with the seam detection unit;
Step 2 for calculating a seam position based on the captured thermal image;
Calculating a delay time required for the seam position calculated in step 2 to pass to the installation position of the bead cutting position detecting unit;
Step 4 of calculating the bead position in the bead cutting position detection unit;
Calculating a movement amount of the sensor head based on the bead position, the delay time, and the seam position;
Step 6 of moving the sensor head by the amount of movement;
After the step 6, there is a step 7 of ultrasonic flaw detection of defects in the weld seam with the sensor head. In the ultrasonic testing method of the electric sewing tube according to claim 3,
The bead cutting position detector is
An ultrasonic testing method for an electric-welded tube, wherein a bead position is detected based on a change in emissivity using a thermal image type camera. 5. A quality assurance method, comprising: flaw detection of a weld seam portion using the ultrasonic flaw detection method for an electric resistance welded tube according to claim 3 or 4;