JPH09229910A - Method for ultrasonic angle beam flaw detection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable discrimination of a flaw occurring near a welding uranami bead (penetration), relating to super sonic angle beam flaw detection method for welding part. SOLUTION: Relating to the angle flaw detection method of ultrasonic flaw detection test, a sight field angle 10 wherein resolution between adjacent flaws 4 is maximum is selected. Then, a peak position 102 of echo height of the flow 4 is detected, and a closing point of the beam path of an ultrasonic probe 1 corresponding to the peak value 102 and a scan line 9 of the ultrasonic probe 1 is judged to be a flaw position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for ultrasonic angle beam inspection of a weld.

[0002]

2. Description of the Related Art Ultrasonic bevel flaw detection is a method for nondestructive inspection of welded portions.

In the ultrasonic oblique-angle flaw detection method, as shown in FIG. 5, ultrasonic waves are made incident on a welded portion 8 from a probe 1 at a predetermined refraction angle 2, and the beam path of a reflection echo from a flaw 4 or a backside wave 6 is made. This is a method for evaluating the position and size of flaws and back waves by measuring the height of the echo and echo.

The positions of the flaw 4 and the back wave 6 are determined by the ultrasonic probe 1.
The beam path from the incident point 3 to the flaw reflection echo 5 and the backside reflection echo 7 is calculated by the refraction angle 2. When the probe 1 is moved in the direction (Y) at right angles to the welded portion 8,
The positions of the flaw reflection echo 5 and the backside reflection echo 7 are calculated on the scanning line 9 corresponding to the position of the probe 1 to obtain a sectional image of one welding section. Then, by performing flaw detection continuously in the direction of the welded portion 8, a plane image (C scope) and a sectional image (B scope) of the welded portion are obtained.

As an example of a method for imaging the ultrasonic wave reflection information, as in the method disclosed in Japanese Patent Laid-Open No. 4-366671 (hereinafter referred to as the conventional method), the position coordinate (X , Y) and the echo height information of the reflection echo in the gate are displayed continuously in the direction of the weld.
In the conventional method, as shown in FIG. 7, a flaw detection gate 19 is provided in the inspection range in synchronization with the transmission pulse 20, and the reflected echo existing in this gate is detected, and as shown in FIG. Position coordinates (X, Y) of 1 and echo height 5, 7
Is continuously displayed in the direction of the weld.

[0006]

In the conventional method, as shown in FIG. 7, a flaw detection gate 19 is provided in the inspection target range,
Although the echo existing in the gate is detected, if a plurality of echoes exist in the gate, there is a problem that only the information of one of the flaw reflection echo 5 and the back side reflection echo 7 can be obtained. is there.

Further, in the conventional method, as shown in FIG. 8, since it is an imaging method showing the relationship between the probe position coordinates (X, Y) and the echo height, the beam path direction corresponding to the flaw position is obtained. There is a problem that the information of is not obtained.

In the flaw detection of the welded portion, assuming that all the data of the beam path and the height of the reflected echoes of a plurality of reflected echoes can be collected within the range to be inspected, the position of the flaw of one welding cross section is shown in FIG. As described above, it can be expressed as being on the scanning line having the predetermined refraction angle 2 of the probe 1. Usually, even with one flaw, the flaw is detected by a plurality of scanning lines because of the spread of the beam of the probe. Data is continuously collected in the direction of the welded portion 8 and the data shown in FIG.
When the flaw 4 is imaged from the direction of arrow C or arrow B shown in FIG. 6, a plan view (C scope) or a sectional view (B scope) as shown in FIG. 6 can be obtained.

However, when these images are viewed, when the flaw 4 and the back wave 6 in FIG. 5 are present close to each other, a group of the flaw reflection echo 5 and a group of the back wave reflection echo 7 are displayed in an overlapping manner. Therefore, there is a problem that it is difficult to distinguish the flaw 4 and the back wave 6 from each other.

The present invention has been made to solve the above problems, and an object thereof is to separate adjacent flaws and form an image.

[0011]

[Means for Solving the Problems] As means for solving the above problems, in the oblique angle flaw detection method of an ultrasonic flaw detection test,
Select a viewing angle that maximizes the resolution of adjacent flaws, detect the peak value of the echo height of the flaws, and scan the ultrasonic probe beam path corresponding to this peak value. It is an ultrasonic oblique angle flaw detection method characterized in that an intersection with a line is determined as a flaw position.

According to the above-mentioned means, in the bevel flaw detection method of the ultrasonic flaw detection test, the distribution map of the height of the reflection echo from the flaw is obtained, and the field of view that maximizes the resolution of the neighboring flaws in this distribution chart. The selection of the corners has the effect of improving the resolution of flaws and facilitating the discrimination of flaws. Also, by detecting the peak value of the echo height of the flaw and setting the intersection of the beam path and the scanning line corresponding to this peak value as the flaw position, the flaw position can be accurately evaluated. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to FIG. Welded portion 8 where flaw 4 and back wave 6 are present close to each other
When flaw detection is performed with the oblique probe 1, there are reflection echoes such as a flaw reflection echo 5 and a backside reflection echo 7 in each scanning line 9 of the probe 1, and a cross-sectional view of the welded portion 8 can be obtained.

In this sectional view, in order to improve the resolution of the flaw 4 and the back wave 6, the following (1) shown in FIG.
It is desirable to set the viewing angle 10 in the direction having the relation of formula. The optimum value of the viewing angle 10 is the direction in which the resolution of the flaw reflection echo 5 becomes maximum in the distribution map of the reflection echo height viewed from the view direction.

Further, the peak position W1 of the echo height 102 and the scan line L1 having the maximum echo height 102 at the peak position W1 in the distribution map of the reflection echo height are found, and the intersection 4 is marked. The position of the flaw 4 can be accurately specified by grading the position of the flaw 4.

FIG. 2 is a block diagram of an ultrasonic oblique flaw detection method according to the present invention. In FIG. 2, an ultrasonic flaw detector 12 that transmits and receives ultrasonic waves using the bevel probe 1, and a maximum echo height detection circuit 13, which is a circuit that processes the output of the ultrasonic flaw detector 12, Echo height sharpness calculation circuit 1
4, a visual field direction and visual field range setting circuit 15, a flaw position evaluation circuit 16, an image display circuit 17, and a probe position detection circuit 18.

The flaw detection data of each scanning line 9 is obtained from the ultrasonic flaw detector 12, and the probe 1 corresponding to the scanning line 9 is obtained.
The position of is obtained by the probe position detection circuit 18.

The calculation range of the beam path for obtaining the echo height distribution map is the visual field direction and visual field range setting circuit 1.
Set by 5. Maximum echo height detection circuit 13
Detects the maximum echo height when the flaw detection data is viewed from the visual field direction, and obtains the echo height distribution map in the time axis direction.

The echo height sharpness calculation circuit 14 calculates the sharpness of the echo height distribution map.

The sharpness of the echo height distribution map is judged by the width of the echo width 101 in the echo height distribution map of FIG. 1, and the maximum resolution is obtained when this width is the narrowest. .

As a method of calculating the sharpness, there is also a method using the echo height 103 at the valley of the peak value of the two echo heights in the echo height distribution chart of FIG.

The flaw position evaluation circuit 16 detects the peak value of the echo height distribution map and determines the peak position value (W) of the beam path.
In 1), the scan line with the maximum echo height (L
1) Find out and grade the intersection as the position of the flaw.

The image display circuit 17 is a circuit for displaying the position of the flaw 4 and the echo height 102 of the flaw 4.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to FIG. As an example, for a butt welded portion 8 of a steel plate having a plate thickness of 19 mm, a frequency of 5 MHz and a transducer size of 10 ×
A case will be described where flaw detection is performed using the probe 1 having a refraction angle of 70 degrees and a diameter of 10 mm.

A flaw 4 in the path of the ultrasonic wave propagating through the welded portion 8
Is present, it is reflected there and follows the path opposite to the incident path and is received by the probe 1. It is assumed that the scanning pitch of the probe 1 is 1 mm and the scanning line 9 for flaw detection is parallel to the refraction angle 2.

Since the beam from the ultrasonic probe 1 has a beam divergence instead of a straight line, a reflected echo can be obtained even in the scanning line 9 where the flaw 4 does not actually exist.

The beam path of the ultrasonic wave on each scanning line 9 can be converted into a distance, and the starting point (S1) for calculating the ultrasonic data in the set visual field direction is determined by the following equation.

Calculation start point (S1) = y · cos (θ1) + a θ1: viewing angle y: probe distance a: constant In addition, the end point (S2) of calculation of flaw detection data is expressed by the above equation. Determined by changing the constant. The start point (S1) and end point (S2) of the calculation are set so as to satisfy the inspection target range of the welded portion 8.

The flaw detection data of each scanning line 9 is calculated in the visual field direction to obtain a distribution chart of the echo height 102.

When this calculation is performed by changing the visual field direction, the visual field angle 10 that maximizes the resolution of the flaw 4 can be obtained in the distribution chart of the echo height 102, and this angle has the highest resolution of the flaw 4. The viewing angle is 10. Usually, the optimum viewing angle (θ1) is qualitatively expressed by the following equation.

Optimum viewing angle (θ1) = 90 degrees−Refraction angle (1) If the refraction angle 2 of the probe 1 is 70 degrees, the optimum viewing angle 10 is 20 degrees, but the flaw 4 It is necessary to determine the optimum viewing angle 10 in accordance with the inclination of the sound field and the sound field of the ultrasonic wave.

In each scanning line 9, flaw detection data of the A-scope consisting of the beam path and the echo height is collected as a digital value.

The position of the flaw 4 is evaluated as the intersection of W1 of the beam path having the maximum added value and L1 of the scanning line 9 having the maximum echo height 102 at the position corresponding to this beam path.

Although the flaw imaging method for one welding cross section has been described above, by scanning the ultrasonic probe 1 in the direction of the welded portion 8 and repeating the same procedure, as shown in FIG. Images of a plan view (C scope) and a sectional view (B scope) continuous in the direction of the welded portion 8 can be obtained. Further, FIG. 4 shows an example in which the relationship between the beam path length and the echo height distribution diagram is continuously imaged in the welding portion direction. 4 is different from the conventional method shown in FIG. 8 in that all the information on the echo height and the beam path length of the flaw reflection echo 5 and the backside reflection echo 7 included in the scanning line of the probe is included in the image, No flaws were overlooked, and it became easier to separate and identify the backside and flaws of the weld.

[0035]

According to the ultrasonic bevel flaw detection method of the present invention,
It is possible to image a flaw in the welded portion with high resolution, and it is possible to discriminate a shape echo reflected by a back wave or extraneous portion of the welded portion and a flaw reflection echo reflected by the welded flaw.

By accurately displaying the position and size of the flaw with an image, the flaw can be easily identified and the reliability of the inspection can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an ultrasonic oblique angle flaw detection method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a processing flow of an embodiment of the present invention.

FIG. 3 is a diagram showing an image display according to an embodiment of the present invention.

FIG. 4 is a diagram showing an image display result according to an embodiment of the present invention.

FIG. 5 is a diagram showing a conventional ultrasonic oblique angle flaw detection method.

FIG. 6 is a diagram showing an image display result of a conventional method.

FIG. 7 is a diagram showing a reflection echo detection gate of a conventional method.

FIG. 8 is a diagram showing test results of a conventional method.

[Explanation of symbols]

 1 probe 2 refraction angle 3 incident point 4 flaw 5 flaw reflection echo 6 back wave 7 back wave reflection echo 8 weld 9 scanning line 10 viewing angle 11 probe position 12 ultrasonic flaw detector 13 maximum echo height Detection circuit 14 Echo height sharpness calculation circuit 15 Field-of-view direction and field-of-view range setting circuit 16 Flaw position evaluation circuit 17 Image display circuit 18 Probe position detection circuit 19 Flaw detection gate 20 Transmission pulse 101 Echo width 102 Echo height It

Claims (1)

[Claims] 1. A bevel flaw detection method for ultrasonic flaw detection testing, comprising:
Select a viewing angle that maximizes the resolution of adjacent flaws, detect the peak value of the echo height of the flaws, and scan the ultrasonic probe beam path corresponding to this peak value. An ultrasonic bevel flaw detection method, characterized in that an intersection with a line is determined as a flaw position.