JPH06213876A - Flaw detector for spiral seam joined steel pipe - Google Patents

Abstract

PURPOSE:To automatically detect a flaw on a joint seam of a spiral seam steel pipe. CONSTITUTION:A flaw detector comprises a path measuring means A for measuring paths SA, SB on A and B sides from a flaw detection gate and a shoulder echo from a supersonic flaw detector 1 and an averaging means B for additionally averages respective values wherein the paths SA, SB are all taken and measured with a constant interval and obtaining averaged path values SC, SD. It further comprises a comparison means C which compares the path values SC, SD with a dead zone value F, outputs a right going output or a left going output for moving a probe arm 1C toward right or left when SC-SD>F and SD-SC>F respectively, but does not output it when ¦SC-SD¦<=F, a moving output generating means D for outputting an output to an electromagnetic switch 5A or 5B and a probe arm moving mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to ultrasonic flaw detection of a weld seam portion of a spiral seam welded steel pipe by shoulder echo by ultrasonic waves from an ultrasonic probe (1A, 1B).
(HA or HB) to the flaw detection gate (GA, GB) is measured, and the ultrasonic transducer automatically detects the shoulder echo (HA or HB) inside the flaw detection gate (GA, GB). The present invention relates to a spiral seam welded steel pipe flaw detector equipped with a follow-up mechanism that moves a position.

[0002]

2. Description of the Related Art A shoulder echo (hereinafter referred to as a shoulder echo) which is an echo emitted from a flaw detection gate (GA, GB) and a shoulder portion (3B) of a welding seam portion (3C) by ultrasonic waves from an ultrasonic probe (1A, 1B) , "Shoulder echo"), and spiral seam welded steel pipe (hereinafter also simply referred to as "steel pipe")
There is known a spiral seam welded steel pipe flaw detector for performing ultrasonic flaw detection on the welded seam portion. A conventional ultrasonic flaw detector for a steel pipe will be described. FIG. 9 is a system diagram (partially perspective view) showing the relationship of the output configuration of the conventional ultrasonic inspection equipment for steel pipes.
Is. In FIG. 9, (1D) is a solenoid valve, (6) is a solenoid valve power supply, (1E) is a hydraulic cylinder, (4A) and (4B) are manual push buttons, and (1A) and (1B) are ultrasonic probes. Tactile (hereinafter simply referred to as "probe"), (1C) is a probe support arm (hereinafter simply referred to as "probe arm") holding the probes (1A) and (1B) , (2A) is steel pipe, (2) is steel pipe
(Spiral steel pipe material), (3A) is a continuous weld, (3C) is a weld seam, and (3) is a welding rod. Steel pipe (2A) is steel strip (2)
It is manufactured by spirally winding and shaping the steel sheet, and welding the spiral seam of the steel strip (2) by a submerged arc welding method.

The ultrasonic flaw detection of the welded seam (3c) is performed on both sides of the welded seam (3c) of the steel pipe (2A) moving in the axial direction and the circumferential direction at the time of manufacturing the spiral seam welded steel pipe. It is carried out by disposing the tentacles (1A) and (1B). At this time, it is necessary to position the probe (1A) and the probe (1B) at an equal distance from the welding seam (3c) for accurate measurement.

The probes (1A) and (1B) are welded seams (3C).
It is fixed to both ends of a probe arm (1C) that is movably arranged across the. Weld seam (3C) of continuous weld (3A) welded by submerged arc welding method
Since the slag covered with the flux (3F) used for A) is covered, the distances from the weld seam (3c) to the probes (1A) and (1B) cannot be visually located evenly. Therefore, conventionally, the ultrasonic flaw detector (1) shown in FIG.
Check the image of the flaw detection gate (GA or GB) and shoulder echo (HA or HB) of the CRT image so that the shoulder echo does not enter the flaw detection gate, that is, make sure that the path SA and SB are equal. , Probe arm (1
C) Move the probe arm (1C) by operating the manual switch (push button type switch) (hereinafter referred to as “switch”) (4A or 4B) to drive the moving mechanism, and move the welding seam (3c The distances from () to the probes (1A) and (1B) are equalized, and thus the flaw detection work is performed.

FIG. 3 is an explanatory view showing the positional relationship between the probe arm and the probe. The probe arm (1C) is fixed to the piston rod of a reciprocating hydraulic cylinder (1E), and reciprocates in the right or left direction shown in FIG. 3 by switching the port of the solenoid valve (1D). The solenoid valve (1D) port is a solenoid valve
Switch (4A or 4B) connected to solenoid (1D)
Press to switch. In FIG. 9, since the switches (4A, 4B) are not pressed, the cylinder (1E) is stopped. When the switch (4A) is pressed, the probe arm (1C) moves to the right from the position in the drawing of FIG. 3, while when the switch (4B) is pressed, it moves from the same position to the left. ( Less than,
"Prior art").

[0006]

However, the above-mentioned prior art has the following problems. The flaw detection by the conventional ultrasonic flaw detector shown in the prior art is performed by the probe arm (1C).
This is a so-called semi-automatic flaw detection in which the movement of is done by a manual switch. That is, the waveforms of flaw detection gate (GA or GB) and shoulder echo (HA or HB) displayed on the CRT screen of the ultrasonic flaw detector (1) are compared by switching the screen to the A side or B side, and comparing Every time there is a difference between (SA) and (SB), manually operate the switches (4A, 4B) so that the travel distance values (SA) and (SB) become equal. 1E) is driven to move the probes (1A and 1B) to the left or right. Such semi-automatic flaw detection is inconvenient and inaccurate.

The spiral seam steel pipe is formed by connecting coils of steel strips having a standard width and forming a spiral shape. However, when there is a difference in width between the coils of the steel strips, the spiral seam steel pipe has a spiral shape for the purpose of ensuring a product standard diameter. Welding seam (3C) and probe arm (1C) where the spiral welding position changes and ultrasonic flaw detection is attempted to change the spiral modeling angle of the
The relative position of the probe (1A) and (1B) changes, the difference between the roadway distance values (SA) and (SB) occurs, and the flaw detection gate (G
Shoulder echo (HA or HB) enters into (A or GB) and flaw detection cannot be performed.

Further, in particular, in the case of a steel strip made of a hot strip mill rolled material, it is general that there is a large difference in width between the steel strips at the points where the seams intersect. Is used as a material without cutting in the width direction), the probe arm (1C) (probe (1A
And 1B)} must be moved significantly.

Therefore, an object of the present invention is to set a preset allowable value of the probe (1A, 1B) and a dead zone when performing automatic ultrasonic flaw detection on the weld seam (3C) of the spiral seam steel pipe (2A). Value (F) signal, set the output time value (T) corresponding to the movement range value, and output right (UA) and left (left) for moving the probe arm (1C). An object of the present invention is to provide a spiral seam welded steel pipe flaw detector equipped with an automatic tracking mechanism capable of controlling the output (UB).

[0010]

[Means for Solving the Problems] The present invention is arranged so as to be movable across a welded seam portion (3C) of a spiral seam welded steel pipe (2A) formed by spirally winding a steel strip and forming the welded seam. The probe arm (1C) and the probe arm (1C) are fixed to both ends, and the welding seam portion (3C) is sandwiched between the spiral seam welded steel pipe (2A). Ultrasonic probe (1A, 1B), a moving mechanism for moving the probe arm (1C), the ultrasonic wave from the ultrasonic probe (1A, 1B) the welding seam portion ( 3C) shoulder part (3B)
Shoulder echo (HA, HB) and flaw detection gate (G
(A, GB) and an ultrasonic flaw detector (1) capable of displaying on the screen, the probe arm (1C) is moved by the moving mechanism, and the shoulder echo (HA, HB) is moved to the flaw detection gate (GA). , GB)
A spiral seam welded steel pipe flaw detector for flaw detection without entering inside, shoulder echo (HA, HB) input from the ultrasonic probe (1A, 1B) and the ultrasonic flaw detector (1). And based on the flaw detection gate (GA, GB), from the shoulder echo (HA, HB) to the flaw detection gate (GA, GB)
Up to the road distance value (SA, SB) for measuring the road distance value (A) and the road distance value (S) input from the road distance measuring means (A).
(A, SB) is measured at constant time intervals and averaged by means (B) for adding and averaging, the roadway distance values (SC, SD) averaged by the averaging means (B) and a predetermined dead zone. To move the probe arm (1C) when the difference between the averaged distance values (SC) and (SD) deviates from the dead zone value (F) by comparing the value (F). Comparison processing means (C) for outputting the selection signal (UA, UB), and an electromagnetic switch (5A, 5B) provided for driving the moving mechanism of the probe arm (1C), , The selection signal (UA, U) inputted from the comparison processing means (C).
B) is converted to a moving output, and the electromagnetic switch (5A) or (5B)
And a movement output generating means (D) for driving the probe arm (1C) to move the probe arm (1C).

[0011]

In order to achieve the above object, in the present invention,
An ultrasonic flaw detector that obtains a flaw detection gate and shoulder echo and the signal values of these are input, and the path length (SA) and B on the A side of the weld seam from the flaw detection gate and shoulder echo are input.
Distance measuring means for measuring the side distance (SB), and the side distance (S
A) and B side road length (SB) are all taken in and the respective values measured at fixed time intervals are added and averaged to obtain the averaged road length value.
(SC and SD) is compared with the averaging means to obtain the roadway distance values (SC and SD) and the dead zone value (F). When SC-SD> F, the probe arm is moved to the right. Output going (UA), when SD-SC> F, it moves the probe arm to the left, outputting left going output (UB), and when | SC-SD | ≤F, The comparison processing means that does not output to the slave arm, the moving output generating means that outputs the right going output (UA) and the left going output (UB) for selecting the output to the right going electromagnetic switch and the left going electromagnetic switch, and the electromagnetic output Equipped with a probe arm movement mechanism such as a valve, in ultrasonic flaw detection work of continuous welded parts of spiral seam welded steel pipe, the flaw detection mechanism portion such as ultrasonic probe is automatically operated so that shoulder echo does not enter the flaw detection gate. Control.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a system diagram showing one embodiment of the spiral seam welded steel pipe flaw detector of the present invention. A seam tracking configuration according to the present invention will be described with reference to FIG. In FIG. 1, (1) is an ultrasonic flaw detector, (A) is a path measuring means, (B) is an averaging processing means, (C) is a comparison processing means, and (D) is a movement output generating means. FIG. 2 is a system diagram (partial perspective view) showing the relationship of the output configuration of the ultrasonic flaw detector of the present invention. 5A is a right-going electromagnetic switch, 5B is a left-going electromagnetic switch, and UA is a right-going electromagnetic switch. Output, UB indicates output to the left. In FIG. 2, parts substantially the same as or corresponding to those in FIG. 9 showing the conventional example are denoted by the same reference numerals as those in FIG.

As shown in FIG. 1, the probes (1A) and (1B)
Input the flaw detection signal (ultrasonic wave) to the ultrasonic flaw detector (1),
The flaw detection gate (GA, GB) and shoulder echo (HA, HB) in the flaw detection signal are input to the road distance measuring means (A). In the road distance measuring means (A), the probe (1A) detects the flaw detection gate (GA) and the shoulder echo (HA) road distance (SA), and the probe (1B) detects the flaw detection gate (GB). Generates data that measures shoulder echo (HB) road length (SB).

The averaging processing means (B) receives the road distance values (SA) and (SB) and averages the data for the respective road distances (SC) and (SD) by measuring at regular intervals. .

To the comparison processing means (C), added averaged data {path length values (SC) and (SD)} and dead zone set value (F) are input. Then, in this comparison processing means (C), the {road distance value (SC), (SD)} is compared with the dead zone value (F), and SC-SD> F
When, SD-SC> F, the probe arm (1C) is moved to the left. When SD-SC> F, the probe arm (1C) is moved to the right in Fig. 1. Left-going output signal
(UB) is output and no signal is output when | SC−SD | ≦ F.

In the moving output generating means (D), the right going output (UA) or the left going output (UB) is inputted from the comparison processing means (C), and the right going electromagnetic switch (switch) (5A) or The drive signal of the electromagnetic switch (switch) (5B) to the left is output. Drive the electromagnetic switch (switch) (5A) to the right or the electromagnetic switch (switch) (5B) to the left to drive the probe arm.
The moving mechanism of (1C) is driven. That is, output is made to the solenoid valve (1D), and at the solenoid valve (1D), the movement output is hydraulic cylinder 1E.
Is converted into a driving signal.

Next, the inspection gate (G) of the spiral steel pipe (2A)
A, GB) and shoulder echo (HA, HB) signal generation are explained. In the manufacturing process of spiral steel pipe (2A), online ultrasonic flaw detection is common, and the equipment used for ultrasonic flaw detection is A side probe (1A) and B side probe ( 1B), a pair or a plurality of pairs, an ultrasonic flaw detector (1), and a shielded cable for connecting the devices for exchanging signals and the like between the devices. A CRT device is attached to the ultrasonic flaw detector (1), and the CRT device includes a flaw detection gate (GA, GB) and a shoulder echo (H
The image of the signal wave of (A, HB) is displayed. When there is a welding defect, the waveform of the defect signal is output to the flaw detection gate, at the same time an alarm such as a buzzer is sounded, and the defect signal is recorded if necessary. These devices are publicly known products on the market, and are used to detect flaws (GA, GB) and shoulder echoes from the ultrasonic flaw detector.
The signal wave of (HA, HB) can be easily extracted.

Next, the relationship between the flaw detection gate and the shoulder echo will be described with reference to FIGS. FIG. 3 shows the principle of a generally used ultrasonic flaw detection method. The steel pipe (2A) is shown in cross section. The probe (1A) is placed at the symmetrical position (A side) of this welded portion (3A), and the probe (1B) is placed at (B side). Ultrasonic waves are incident on the shoulder (3B) from the tentacles (1A, 1B). The probe arm (1C) is
B) is fixed and both probes are located in symmetrical positions.
Move by hydraulic cylinder (1E).

FIG. 4 is a waveform diagram showing flaw detection gates and shoulder echoes obtained from both the probes (1A, 1B). A
The shoulder echo (HA) is obtained with the waveform of the probe (1A) on the side, and the path length (SA) is obtained between the probe and the flaw detection gate set in advance. Similarly, the road length (SB) is obtained on the B side.
If the weld has a defect such as slag inclusion, a signal is input to the flaw detection gate. The process up to this point is the general ultrasonic flaw detection method shown in the prior art.

FIG. 5 shows the above-mentioned road length (S
FIG. 6 is a waveform diagram showing the principle of extracting and processing the signals A) and (SB). The road lengths (SA) and (SB) are measured at regular time intervals (n), and the average value (SC, SD) of each is calculated according to the following formula. {S (A-1) + S (A-2) ... + S (A-n)} / n = SC {S (B-1) + S (B-2) ... + S (B-n )} / N = SD Next, the difference between the average road distance values (SC) and (SD) and the dead zone value (F) are compared to control (+) or (-).

Next, the operation of FIG. 1 will be described with reference to the flow chart shown in FIG. Step 12 as shown in FIG.
The road distance measuring means (A) calculates the road distance values (SA) and (SB), and the averaging processing means (B) calculates
The road distance values (SC) and (SD) calculated as the average value for each (n) are output to the comparison processing means.

In step 13, the difference between the preset dead zone value (F) and the road distance values (SC) and (SD) is compared.

In step 14, when (SC)-(SD)> (F), the rightward output (UA) is selected and the rightward electromagnetic switch (5
Output signal to A) (step 15). (SD)-(SC)> (F)
If it is, go to step 16 and select the output to the left (UB) and output the signal to the electromagnetic switch to the left (5B) (step 1
7). If | SC-SD | ≦ F, proceed to step 18 and do not output the signal to move the probe arm (1C) (step
19).

FIG. 6 is a system diagram showing the control equipment configuration of the device of the present invention in association with the prior art (prior art). Conventionally,
The ultrasonic flaw detector for spiral seam welded steel pipes consisted of a flaw detector, a control unit and an indoor operation panel (including the probe and cable), and the operation for flaw detection was a manual operation using push buttons. On the other hand, the present invention utilizes conventional equipment, and further includes a path measurement unit, an I / O unit,
Also, a personal computer, CRT and keyboard attached to it will be installed. For this reason, part of the signal transfer unit was modified for the conventional equipment.

FIG. 7 shows a CRT display example of the embodiment shown in FIG.
The set value is displayed on the CRT screen. Offset (d) and offset (e) have irregular irregularities on both end faces of the weld seam continuously, so smooth measurement is performed.Therefore, the size of the weld seam (3C) depends on the thickness of the steel strip (2). Determine and enter the values on the A and B sides with.

The dead zone value (F) is a predetermined dead zone value (F) in consideration of the offset (E). That is, the steel pipe for flaw detection (2A)
The thickness of the probe arm (1C) allows the probe arm (1C) to move in response to the distance from both probes (1A, 1B) to the shoulder (3B) of the weld (3A) determined by the unique characteristics of the probe. In order to prevent hunting, set a range of not responding by several percent.

The error counter indicates the road length value (SC) and (S
In the counter for measurement error such as measurement error during averaging in (D), if an error that exceeds the set value occurs, the output goes to the right (U
A), Abnormal processing is performed to stop output to the left (UB). When the measurement error falls within the set count, the error processing is automatically canceled.

The road lengths (SC) and (SD) after the averaging process are (a),
It is displayed numerically in (b). (C) is the road length value (S
The difference between (C) and (SD) is displayed with the numerical values of (+) and (-). The moving direction is lit up and displayed by the arrow in FIG. The recalibration can be re-set with one touch by using a push button separately provided when the probe is brought into a better condition by manual switching during the operation. The fact that this operation has been performed is displayed.

Next, using the apparatus of the present invention, ultrasonic flaw detection of the spiral seam welded steel pipe was carried out at the time of its manufacture. The manufacturing conditions of the spiral seam welded steel pipe (2A) were as follows. Steel strip (2) thickness 9.0mm, width 1380mm, steel pipe diameter 800mm
, Forming angle 47 ° 39 ', steel pipe (2
A) is manufactured. The setting values are: Offset (d): 3 mm, Offset (e): 0 mm, Dead zone: 10%, Error counter: 10 times, when the probe (1A) (a): 105 mm,
(B) of the probe (1B): 98 mm, difference between the road distance (SC) and (SD)
(C): 7 mm, the welded joint of the steel strip (2) is
A) and becomes about 30 times for several minutes before and after passing the ultrasonic flaw detection position,
The solenoid valve (1D) operates and shoulder echo is detected at the flaw detection gate (G).
Two regular defects were detected without (H) entering. It was confirmed that the other parts had solenoid valve actuation 4 to 5 times within several minutes, and that ultrasonic flaw detection work could be performed normally.

[0030]

As described above, according to the present invention, in ultrasonic flaw detection work of a continuous welded portion of a spiral seam welded steel pipe, flaw detection of an ultrasonic probe or the like is performed so that shoulder echo does not enter the flaw detection gate. The mechanical part can be automatically controlled, and the accuracy and work efficiency of ultrasonic flaw detection are improved, thus providing industrially useful effects.

[Brief description of drawings]

FIG. 1 is a system diagram showing one embodiment of a spiral seam welded steel pipe flaw detector of the present invention.

FIG. 2 is a system diagram (partial perspective view) showing the relationship of the output configuration of an ultrasonic flaw detector for steel pipes.

FIG. 3 is an explanatory diagram showing a positional relationship between a probe arm and a probe.

FIG. 4 is a waveform diagram showing flaw detection gates and shoulder echoes obtained from both probes.

FIG. 5 is a waveform diagram showing the principle of extracting and processing a road length signal in the device of the present invention.

FIG. 6 is a system diagram showing a control device configuration of the device of the present invention in correspondence with a conventional example.

FIG. 7 is a diagram showing an example of CRT display in the embodiment of FIG.

FIG. 8 is a flowchart illustrating an ultrasonic flaw detection process of the present invention.

FIG. 9 is a system diagram (partially perspective view) showing the relationship of the output configuration of a conventional ultrasonic testing apparatus for steel pipes.

[Explanation of symbols]

 1 Ultrasonic flaw detector 1A Probe (A side) 1B Probe (B side) 1C Probe support arm 1D Solenoid valve 1E Hydraulic cylinder 2 Steel strip 2A Spiral seam welded steel pipe 3 Welding rod 3A Welding part 3B Welding shoulder Part 3C Weld seam 3F Welding flux 4 Push button type switch 4A Push button to the right 4B Push button to the left 5A Electromagnetic switch to the right 5B Electromagnetic switch to the left 6 Solenoid valve power supply A Path measurement means B Averaging processing means C Comparison processing Means D Moving output generation means F Dead band value G Flaw detection gate GA Flaw detection gate (A side) GB Flaw detection gate (B side) H Shoulder echo HA Shoulder echo (A side) HB Shoulder echo (B side) S Path SA Flaw detection gate (GA ) And shoulder echo (HA) route SB flaw detection gate (GB) and shoulder echo (HB) route SC route (SA) averaged route SD route (SB) averaged route T Output time Value UA Right output UB Left Can output.

Claims (1)

[Claims] 1. A welded seam portion of a spiral seam welded steel pipe (2A) formed by spirally winding a steel strip and forming the welded seam.
Probe arm (1C) movably arranged across (3C)
And fixed to both ends of the probe arm (1C), the ultrasonic probe (1A, 1B) arranged on the spiral seam welded steel pipe (2A) with the weld seam portion (3C) interposed therebetween. ), A moving mechanism for moving the probe arm (1C), and ultrasonic waves from the ultrasonic probe (1A, 1B) from the shoulder portion (3B) of the welding seam portion (3C). Shoulder echo
(HA, HB) and an ultrasonic flaw detector (1) capable of displaying flaw detection gates (GA, GB) on the screen.The probe arm (1C) is moved by the moving mechanism to generate a shoulder echo ( HA,
HB) is a spiral seam welded steel pipe flaw detector for flaw detection without entering the flaw detection gate (GA, GB), wherein the ultrasonic probe (1A, 1B) and the ultrasonic flaw detector (1)
Based on the shoulder echo (HA, HB) and flaw detection gate (GA, GB) input from
Road distance (SA, SB) from B) to the flaw detection gate (GA, GB)
And a averaging processing means (B) for measuring the road distance values (SA, SB) input from the road distance measuring means (A) at regular intervals and averaging them. ), And the road length value (S
(C, SD) and a predetermined dead zone value (F), and when the difference between the averaged distance values (SC) and (SD) deviates from the dead zone value (F), the probe Comparison processing means (C) for outputting a selection signal (UA, UB) for moving the arm (1C), and an electromagnetic wave provided for driving the moving mechanism of the probe arm (1C). Switch (5A, 5B) and the comparison processing means
For converting the selection signal (UA, UB) input from (C) into a movement output and driving the electromagnetic switch (5A) or (5B) to move the probe arm (1C). Moving output generation means
(D), and a spiral seam welded steel pipe flaw detector.