JPH0731161B2 - Ultrasonic automatic flaw detector - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic ultrasonic flaw detector for steel plates that inspects defects existing inside a steel plate transported on a transport table using ultrasonic waves. It is a thing.

[Conventional technology]

Generally, an ultrasonic automatic flaw detector that automatically performs non-destructive inspection of a steel plate with a thickness of several mm to several tens of mm using an ultrasonic probe
There are two major flaw detection methods.

The first method is the method shown in FIG. 3, where (1) is the steel sheet to be inspected, (2) is an inside flaw detection mechanism for flaw detection in the central portion of the steel sheet, and (3) is the so-called edge of the steel sheet in the width direction. (3) requires two devices for both ends. (4) runs in the width direction of the steel plate,
This is a top / bottom flaw detection mechanism for flaw detection on the plate edges of the front and rear ends.

In this figure, I1 to I5 in (2) inside flaw detection mechanism represent a central flaw detection probe group, which is held by a probe holding mechanism (not shown) and has an appropriate pressure during flaw detection. Is pressed against the steel sheet to be tested, and the water of the contact medium is also sprayed at the same time. TB is a probe or probe group for top and bottom flaw detection, and E1 and E2 have a probe or probe group for edge flaw detection, which is similar to the probe for central flaw detection. It is held by a probe holding mechanism (not shown).

If the steel sheet is being conveyed in the direction of arrow (A),
When the tip of the steel plate (1) reaches the top flaw detection position where the probe TB is located, the steel plate is stopped and the probe holding mechanism is brought into contact with the air cylinder or the like, so that the top / bottom flaw detection mechanism (4) is While traveling in the plate width direction, the steel plate top is inspected for flaws. When the flaw detection of the top part is completed, the steel plate (1) is conveyed again in the direction of (A), and when the tip reaches just below the inside probe of I1 to I5, the inside probe holding mechanism (2) The center of the steel plate is inspected by contacting it with an air cylinder or the like. The flaw detection loci of the inside probe are indicated by SI1 to SI5 in FIG. Next, when the tip of the steel plate reaches directly below the edge probes E1 and E2, E1 and E2 are brought into contact with each other and flaw detection is performed on the plate side edge. The flaw detection loci of the edge probe are shown by SE1 and SE2 in FIG. 3, respectively. In the flaw detection method of FIG. 3, the flaw detection locus and the conveyance direction are the same except for the top end and the bottom end of the steel plate, which is generally called Y scanning flaw detection. The second method is the method shown in FIG.
In FIG. 4, (1) shows the steel plate to be inspected, (2) shows the inside flaw detection mechanism, and (3) shows the edge flaw detection mechanism.
Reference numeral 5 represents a probe or a probe group for central flaw detection.

In this figure, the steel plate (1) is conveyed in the direction of (A),
When the tip of the steel plate reaches directly below the probe I1 Steel plate (1)
Is stopped and all the probes I1 to I5 are in contact with the plate. Next, the inside flaw detection mechanism (2) self-propels in the direction of arrow (a), and when it reaches the upper plate edge in FIG.
Separate I1 to I5. In this method, flaws are detected in the direction perpendicular to the transport direction by the width W shown in FIG. 4 in one scan. After one scanning flaw detection, the steel sheet (1) is conveyed again in the direction of (a) by the distance W, and the probes I1 to I5 are again brought into contact with the steel sheet (1), and then the inside flaw detection mechanism is allowed to run by itself. After that, this operation is repeated to detect flaws in the steel sheet one after another in the direction orthogonal to the conveying direction.

Fig. 4 shows the state during the third flaw detection. SI1 to SI
Reference numeral 5 represents a flaw detection locus of the probes I1 to I5. This locus is orthogonal to the steel sheet conveyance direction (a), and this flaw detection method is generally called X-scan flaw detection.

In FIG. 3 and FIG. 4, the central flaw detection probe group is shown as five probe groups I1 to I5 for convenience.

Generally, the effective beam width for flaw detection is 10 for a single probe for steel plate flaw detection.
It is about 20 mm. Each probe group in FIGS. 3 and 4
The effective beam widths of I1 to I5 and TB, E1 and E2 are indicated by ω. Each probe group is composed of a single probe and, for example, a plurality of probes shown in FIG. 5 (4 probes in the example of FIG. 5).
Individual pieces) are attached to one probe holding mechanism (not shown), and act like one probe having a wide flaw detection effective beam width. In FIG. 5, effective flaw detection beam width L
The four contactors A1, A2, A3, A4 each having a width of 2 are arranged as shown in the figure, and these two sets are arranged as shown in the front and rear figures. It has one probe I1.

Even if each of the probe groups I1, I2, ... Is composed of a plurality of probes as shown in FIG.
The limit is about 100 mm. Now, assuming that the effective beam width L of each probe is L = 20 mm and one probe group is composed of four probes as shown in FIG. 5, ω = 20 mm × 4 = 80
mm.

When performing full-scale flaw detection on a steel sheet with a width of 4 m, the number of probe groups required by the Y flaw detection method shown in Fig. 3 is 4000 mm / 80 mm = 50 equations.

On the other hand, in the X flaw detection method of Fig. 4, if the number of probe groups is 5 as it is in Fig. 4, W = 5 x 80 mm = 400 mm, and a length of 400 mm can be spread over the entire width of the steel plate in one scan. It is possible to detect flaws, and by repeating the number of scans, it is possible to detect flaws across the entire width and length of the steel sheet with a few probe groups.

The present invention relates to an X-scan flaw detector, which is an automatic ultrasonic flaw detector for steel plates, which performs flaw detection by scanning a probe group in the plate width direction.

As shown in FIG. 4, a conventional X-scan flaw detector detects two edges of a steel plate by two edge flaw detection mechanisms, and the inside flaw detection mechanism repeatedly scans the plate length by W in the plate width direction. I will inspect the central part of. In this method, as shown in FIG. 6, when the tip of the steel plate (1) first comes to the position of the edge flaw detection mechanism (3) and stops, the edge flaw detection mechanism control unit (6) causes the probes E1 and E2 to move. Then, as the steel plate travels in the direction of arrow (a), the edge capturing sensor (not shown) follows the edge of the plate to detect the edges of both edges. Next, when the tip of the steel plate (1) comes to the position of the inside flaw detection mechanism (2) and stops, the inside flaw detection mechanism (2), which has reached the standby position (2 ') by the inside flaw detection mechanism control unit (5), moves to the steel plate. It is moved to the top, and each probe I1 ... Im ... In is brought into contact with it. At that time, in order to make sure that each probe is in contact with the steel plate, the contact control is performed at a certain distance D, which is a sum of the control allowance d1 and the allowance d2 for lateral displacement and skew of the steel plate, beyond the end of the steel plate. To be done. When each probe completes contact with the plate, the inside flaw detection mechanism (2) runs in the direction of arrow (a) to detect flaws in the central portion of the steel sheet. After that, each time the inside flaw detection mechanism repeats running between both edges of the steel sheet. In addition, the probe contact plate and plate separation control will be implemented in consideration of the above margin values.

[Problems to be Solved by the Invention]

Since the conventional automatic ultrasonic flaw detector for steel plates by the X-scan method is configured as described above, it is necessary for the probe of the inside flaw detection mechanism to contact the steel plate with a certain margin at the start of flaw detection. There was a dead band in the strip, and if there was skew in the steel strip, it would lead to a further increase. The above-mentioned margin is also required when the probe separates at the end of flaw detection, and each time the inside flaw detection mechanism moves in the plate width direction, an undetected region remains at the plate edge each time the contact plate and plate separation are repeated. There was a problem.

The present invention has been made to solve the above problems, and an object of the present invention is to obtain an ultrasonic automatic flaw detector for steel plates that can reduce the dead zone at the plate edge.

[Means for Solving the Problems]

The ultrasonic automatic flaw detection system for steel sheets according to the present invention provides the control section of the inside flaw detection mechanism with position information that the edge flaw detection mechanism located upstream of the inside flaw detection mechanism along the transport line traces the edge portion of the steel sheet. In this way, by accurately knowing the position of the plate edge at the probe position of the inside flaw detection mechanism, the margin distance from the plate edge at the probe contact plate and plate separation can be minimized. is there. Further, by dividing the plurality of probe holding mechanisms in the inside flaw detection mechanism into several groups and controlling them, the unflawed area is reduced even when the steel sheet is skewed.

[Action]

The X-scan automatic ultrasonic flaw detector for steel plates according to the present invention controls the position of the inside flaw detection mechanism, the contact plate of the probe, and the plate separation timing by using the plate edge copying information of the edge flaw detection mechanism. The undetected area in the edge portion of the steel sheet is extremely small.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, (1) is a steel sheet to be inspected, (2) and (2 ') are inside flaw detection mechanisms for flaw detection in the central portion of the steel sheet, I1 ... Im ... I
n is an inside probe, (3) is an edge flaw detection mechanism for flaw detection on the plate edge in the width direction of the steel plate, E1 and E2 are edge probes,
(5) is an inside flaw detection mechanism control unit, (6) is an edge flaw detection mechanism control unit, and (7) is an inside flaw detection mechanism control unit that receives edge detection mechanism position information from the edge detection mechanism control unit (6). It is an interface circuit for transmitting to 5).

Fig. 1 shows that the tip of the steel plate to be inspected (1) stops at the position of the edge flaw detection mechanism (3) and the edge probes E1 and E2 come into contact with each other, and then the steel sheet is conveyed again to detect edges on both sides. Meanwhile, the state is shown in which the tip end is stopped at the position of the inside flaw detection mechanism (2). In this figure, when the tip of the steel plate enters the inside flaw detection position, the inside flaw detection mechanism (2 ') in the standby state is the flaw detection start position (2) by the inside flaw detection mechanism control unit (5). Set to state. On the other hand, in the process of flaw detection of both edge portions of the steel plate by the edge flaw detection mechanism (3), the position signal P as a result of the edge flaw detection mechanism (3) operating by scanning while detecting the edge of the steel sheet is the edge flaw detection mechanism control unit. After being detected by (6) and then shifted by the distance T between the edge flaw detection mechanism (3) and the inside flaw detection mechanism (2) by the interface circuit (7), the inside flaw detection mechanism control unit (5) It is transmitted and input as signal P '. The position signal P'is information indicating the position of the steel plate end at the location of the inside flaw detection mechanism (2), and the inside flaw detection mechanism control unit (5) uses this information to detect the inside flaw detection regardless of the lateral deviation or skew of the steel sheet. By setting the mechanism, it is possible to bring the probes I1 ... Im ... In into contact with each other so that the dead zone D of the edge portion is minimized. Thereafter, as shown in FIG. 4, the inside flaw detection mechanism (2) performs flaw detection on the steel plate (1) to be inspected while repeating widthwise scanning, and at each scanning, the edge flaw detection mechanism control unit (6) as described above. ), It is possible to control the contact plate operation at the plate edge of the inside probe so that the dead zone is minimized.

On the other hand, in Fig. 2, the steel plate to be inspected (1) is the transfer standard of the transfer line.
The inside flaw detection mechanism (2) and each probe I1 ... Im ... In of the so-called oblique traveling, which is conveyed in an oblique state rather than traveling parallel to the RL as in the normal case The relationship is illustrated. In the conventional ultrasonic automatic flaw detector for steel plates by X scanning, each probe I1 ... Im ... In is brought into contact with and separated from the inside flaw detection mechanism controller (5) at the same time. Therefore, when the steel sheet is in the skewed state, even if one of the probe rows (I1 side in FIG. 2) can reduce the dead zone, the other dead zone (In side in FIG. 2) has a large dead zone D. Will remain. Therefore, in the configuration of FIG. 2 related to the present invention, the probe groups are I1 ... Im and Im + 1.
It is divided into two groups, In, and its control unit is also divided into (5a) and (5b) to operate. As a result, as shown in the figure, the probe group I1 ... Im can be flaw-detected along the flaw-trajectory SIa, and the probe group Im + 1 ... In can be flaw-detected along the flaw-trajectory SIb. It will be smaller than before. It is also clear that if the number of subdivided groups is increased, it can be made smaller.

Up to this point, the operation when the inside probe is brought into contact with the plate has been mainly described above, but the dead zone at the end of the steel plate can be reduced by controlling with the same purpose even when the plate is separated. it can.

〔The invention's effect〕

As described above, according to the present invention, the edge flaw detection mechanism on the upstream side of conveyance transmits a position signal for flaw detection along the plate edge of the steel sheet to the inside flaw detection mechanism on the downstream side of conveyance, thereby It is possible to accurately know the position of the edge portion when the inside flaw detection mechanism detects the central portion of the
Since the inside probe is brought into contact with and removed from the plate based on the information of the position signal, there is an effect that the undetected region at the edge of the steel plate can be reduced.

In addition, the inside probe group is divided into several groups in the plate length direction, and each group is individually contacted and separated to further reduce the undetected area even for skewed steel plates. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the structure and operation of an X-scan type automatic ultrasonic flaw detector for steel plates according to an embodiment of the present invention.
FIG. 3 is an explanatory view showing another additional function included in the present invention, FIGS. 3 and 4 are views showing the configuration and operation of a conventional ultrasonic automatic flaw detector for steel plates, and FIG. 5 is one probe. FIG. 6 is a view showing the arrangement row of the probe groups housed in the holding mechanism, and FIG. 6 shows a conventional X-scan type ultrasonic automatic flaw detection apparatus for steel plates for comparison with the embodiment according to the present invention in FIG. It is a block diagram. In the figure, (1) is a steel sheet to be inspected, (2) is an inside flaw detection mechanism, (3) is an edge flaw detection mechanism, (4) is a top / bottom flaw detection mechanism, (5) is an inside flaw detection mechanism control unit,
(6) is an edge flaw detection mechanism controller, and (7) is an interface circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An X-scan ultrasonic automatic flaw detector for a steel sheet, which detects a flaw by scanning a steel sheet in a direction perpendicular to the conveying direction of the steel sheet, wherein the steel sheet is installed on the upstream side of the conveying line in the width direction of the steel sheet. An edge flaw detection mechanism that detects flaws on both sides of the plate, an inside flaw detection mechanism that is installed on the downstream side of the transport line to detect the central portion of the steel sheet, and an edge flaw detection mechanism that scans the edge of the steel sheet in order to constantly detect the edge of the steel sheet. And a means for determining a flaw detection start position or an end position of the inside flaw detection mechanism according to a locus moved while moving a plurality of probe holding mechanisms in the inside flaw detection mechanism to a plate end of the edge flaw detection mechanism. When the central plate is contacted or separated at the start of flaw detection or at the end of flaw detection based on the traced trajectory, the plurality of probe holding mechanisms are divided into several groups in the length direction of the steel plate, or the contact plate or Ultrasonic automatic inspection apparatus being characterized in that so as to plate.