JPS60142249A - Surface echo gate method in ultrasonic flaw detection - Google Patents

Abstract

PURPOSE:To generate at a correct time a flaw detecting gate which is not influenced by a curvature and unevenness of the surface of a material to be inspected, by forming a flaw detecting gate of one of two probes for constituting one pair, at the time when a detecting surface echo of the other probe has exceeded a prescribed value. CONSTITUTION:A defective echo in flaw detecting gates 14G-17G is detected by transmitting ultrasonic beams 14a-17a to a material to be inspected 1 from probes 14-17 for constituting a pair of two pieces, placed in an axis symmetry, rotating a rotary mechanism of a probe device by a local water dipping method. At a flaw detection start point of a channel (CH) A, an ultrasonic pulse is transmitted from the probe 14 by generation of a trigger pulse, and a part of said pulse is reflected by the surface of a material to be inspected 1 and received by the probe 16. A part of other pulse invades the inside of the material to be inspected 1, reflected by a defect and received by the probe 14. When a receiving time of the probe 16 is set as a reference time of a start point of the flaw detecting gate 14G of the CH A, the flaw detecting gate 14G is opened without being influenced by a curvature of the surface of the material. Other CHs B-C are also the same.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface echocat method in ultrasonic flaw detection, and is capable of generating a flaw detection cat at the correct time without being affected by the curvature or unevenness of the surface of a target phase.

When performing ultrasonic flaw detection using the vertical method, the probe 2 is placed perpendicularly to the material to be inspected as shown in Fig. When an ultrasonic beam is transmitted in the past, as shown in Figure 2, the transmitted wave T is followed by a surface echo S, a defective part: I - F, and a bottom echo B, j-1, which are detected in the flaw detection cage G. Defect 4 is determined based on the defect echo f.

Therefore, the gate width Gu of the flaw detection gate G is a time width corresponding to the thickness of the test object 44 or the depth at which flaw detection is required due to the material mechanics of the test material, and the setting of the flaw detection gate IG is as follows. The starting point of the flaw detection case G can be defined based on this, since four surface echoes S of the human heart can be obtained in one minute using the vertical method. However, in the oblique flaw detection method, the surface echo S misses to the opposite side 11 as shown in Figure 3, so it is reduced by almost 1%. In addition, in the angle method, it is often necessary to detect flaws from just below the surface, and the flaw detection gate G
It is necessary to match the starting point exactly to the surface. In this case, if the surface of the material to be inspected 1 is a very smooth plane, the ultrasonic waves transmitted from the probe 2 can be Since the time it takes for the ultrasonic waves to reach is constant, it is possible to transmit the ultrasonic waves and open the flaw detection cage G after a certain period of time has elapsed. This is called the fixed gate method, and is already commonly installed in commercially available flaw detectors. However, if the surface of the material 1 to be tested has curvature or unevenness, the distance between the probe 2 and the material surface is
It becomes very difficult to keep l constant. For example, in ultrasonic flaw detection of a 1:1 marine propeller, the surface of the test material 1 has a curvature, so when applying the angle angle flaw detection method, there was a problem as mentioned above. .

The present invention was provided for the purpose of solving the problems of the previous ijL, and its features are as follows: 2. When the probe is placed almost axially symmetrically within the water level, and one probe is in a position where the inside of the material to be inspected is detected using the pulse echo method, the ultra-convex signal transmitted by that one probe is detected. The surface echo of the wave beat is detected by the other probe, and the time when the surface echo exceeds a certain threshold value is used as a reference point to detect the flaw detection case for the one probe in the flaw detection state. It is at the point where it generates 1-.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
Figures 6 and 6 show a four-probe type probe rotation device using the local water immersion method used for ultrasonic flaw detection of marine propellers.
Reference numeral 5 denotes a support plate that is provided so as to be scannable in the X-axis and Y-axis directions.A water tank 6 that is movable over the test material 2 is provided on the lower side of the support plate 5. A tentacle rotation mechanism 7 is arranged, and water 8 is supplied inside the mechanism. The probe rotation mechanism 7 includes a cylindrical rotating shaft 12 rotatably held in a bearing case 11 of a support plate 5'' via bearings 9 and 10, and a probe mounted on the lower end of this rotating shaft 12. Child boulder-1
3, and the probe holder 13 has 90 holes in the circumferential direction.
Four oblique angle probes 14 to 17 are installed at a pitch of .degree. Although the probes 14 to 17 are arranged so as to be able to detect flaws in a range of 20 degrees from the surface of the test material 1 at a pitch of 31111, the present invention is not limited thereto. Each probe 14-1
For example, 7 is an ultrasonic beam 14a-1 with a refraction angle θ of 45°.
The beam diameter of 1a is 9.2++II, and as shown in FIG. 7, each of the super wave bees A14a to 17a has a depth of 2.
5.7.5.12.5、I7、5 Dragon's position intersects with the center of rotation, so that the distance from the center of rotation changes slightly. Therefore, when the probes 14 to I7 are rotated, the probes 14G to 17
If an echo within G is received, the flaw detection area becomes a bead-shaped area (shaded area 3) as shown in FIG. 7, and echoes of defects within this range can be captured. Anal V
A motor for driving the probe rotation mechanism 7 and a rotary encoder 19 for detecting the rotation angle of the probe rotation mechanism 7 are mounted on the support plate 5. It is connected to the rotary shaft 12 via a rotary transmission mechanism 20.21.22 indicates each probe-7-14 of the probe rotation mechanism 7.
This is a Surinozo ring for transmitting and receiving ultrasonic signals to and from 17.

In the above configuration, during flaw detection, the probe rotation mechanism 7 is rotated φ), and ultrasonic beams 14a to 17a are transmitted from each probe 14 to 17 to the material to be inspected l while the probe rotation mechanism 7 is rotated (φ). J
Detecting defective echoes in the HI streets 14G to 17, etc., and cutting off the defect 111. In this case, as shown in FIG.
The starting point of ~17G is based on the time when the surface of the specimen l, that is, the center of the ultrasonic pulse I, reaches the surface of the specimen phase l at j゛11 ((I'-), and It is defined by adding the delay time ΔF of flaw detection case 1.
l1ll for each probe 14-17 according to 146-17G
'The deepest flaw is detected.

However, since the material to be tested has a surface with a gentle curve and slope, probes 14 to 17
ML on the surface of Pu1 Covera! 1jJ varies depending on the location
In order to do this, the fixed chi 1 force type ゛ζ on the Y floor is detected by the operation probe 14. The defect echo is transmitted from the flaw detection cage 14G to the outer hole 1. ``(If not detected, j, L is the size of the defect detected by the probe 15, and the accuracy of estimating the size of the C1 defect. There is a problem in which a t-situation occurs.

Therefore, a bar processing system as shown in FIG. 8 was installed after the probes 14 to 17. (The flaw detection cage is defined according to the procedure shown in the figure. In Fig. 8, 23 to 26 are pulsers, 27 to 30 are lenghers, and signal processing units 1, 35 to 31, including 31 to 3<cg analysis peak holders, 38 is a flaw detection lead.
(Generation circuit “Otogorera 4 corresponding to probes 14 to 17
-J-yan;j (sufficient &J is provided. 39 is timing -J site 1-!-ra, which generates various timings such as flaw detection interval and trigger pulse.

Figure 9 shows a tights chart for four channel flaw detection.

7IO (;l, With the output pulse of the rotary encoder 19 of 10 hits, the time equivalent to 2 of this is allocated to the four nayan faults in order, and they are sent to the flaw detection ink hull~!] and ■・]' and 1. Not shown in II to 44.The operating Q monthly η capacity of the flaw detection fault generation circuits 35 to 38 is 8-c, n-.+1.C.
---A, l)--・11 are the same, so below, details will be explained based on the group A-C.

At the starting point of the flaw detection interface 41, a pulse 1 is generated, and in response to this, an ultrasonic pulse is transmitted from the probe 14. -181 of this ultrasonic pulse
; is reflected by the surface of the test material 1, and the probe iQJ, which is placed almost axially symmetrically with the probe ('-14), is
: j'16 -I surface with 16 width -Im ml
- It is received as ru. In addition, the other part of the ultrasonic pulse is transmitted to C (1 (and if there is a defect, it is reflected as a defect echo 1-F) of the test material 1). Received by Kaya Tensei 1.1 (Detection (A ”j to 4
6). The time when you receive the surface d]-5 at 1 mo 1 Zhuangzi I6 is a must-see! (JJ Re (Detector Detective C47) before the time when the defective echo F is received at 1/l) Also, an ultrasonic pulse is transmitted from the probe I4 and is received by the probe 16 as a surface echo S. The time it takes for the flaw detection to be detected depends on the distance between the probe and the surface of the material to be tested.
By using the reference time of the opening ζ1 point of G and U2, it is possible to open the flaw detection gate 14 from an appropriate time without being affected by the curve 1 of the shrine surface. ,4)
3 has a fixed delay gate to perform a minute XBI of the intercostal space from the time when the surface echo is received until the opening of the flaw detection case 1.
-About No Yanel^-(Ha, haha O8 [!c,, Chano Furu O, C, O's gon] caused a long delay■, blasphemy 111
7 (, the flaw detection hole -1 as shown in Fig. 7 is set
'JJ is performing f5 processing such as peak baud month N on the signal detected in the cell phone.

It should be noted that the following method was used only for the channel. Namely, as shown in Fig. When trying to perform flaw detection with the Vino, the starting point of the flaw detection gate to the channel is longer than the time at which the ultrasonic pulse transmitted from the probe 14 reaches the surface of the test material l): (0,4
2μS) or ♀. For this purpose, as shown in FIG. 1O, the distance MII between the probe 16 and the surface of the specimen 1 is
j! C is slightly smaller than that of the probe 14 (0,7
+n+n) or shorter.

For example, this example has a
m'(, 111 angle is 45°(j Tokara, β
To 7 IC': 0.7 m++ Nishi-Kori is the 11th;! 14 Show - 3' J: '+ Search I ↓ It seems that some gates are generated.

As an experimental example of flaw detection on a material with curves and 1 points, fixed °
- The case of the Toka type is shown in FIG. 11, and the surface knee 1 according to the present invention is shown in FIG.
- Gu 1 - The case of the method is shown in Figure 1Z, and these 4J
Techniques that appeared in Exploration Game I: Exploring the peak value of J-;-
There are two flaw detection patterns on the prong i L at the L axis of 4 at 7 points. IQ Sao, j,
It has horizontal hole-shaped defects 1, 1, 1, and 2 with a center of 16.5 and a diameter of 16.5, and the flaw detection locations are 1) and 0. In the case of the fixed gate force type, the starting point of the gate is set at point P (li + I node 7), and the horizontal hole-like defect on the surface of point P can be detected by channel 8. However, at point 0, 14 As the surface curvature l:met, the distance between the two probes l and the material surface becomes longer, and as shown in FIG. 11, defects can no longer be detected with an amplitude of 1=min.

On the other hand, in the present invention, since the starting point of the flaw detection gate is automatically determined based on the surface echo fp, the starting point of the flaw detection gate is automatically determined based on the surface echo. J horizontal hole-like defect P1. +72 or the same swing I failure has been detected.

From this, the surface echo Ri-F method of the present invention is adopted6. From 2, the parameters such as the size of the defect and the 73ν size of the ultra-fine frame tin device of P1'' are determined by I[, , (r(+
Recognize 1, urinari, pu1. J Bella's product %J'
It can be said that there is a large effect on the ifλ redundancy.

As detailed in the Examples below, according to the present invention, 2 +t
Place the probes of I, I-group in the water tank for local water immersion with a diameter of approximately φ111.
Illusion (place 7), one probe F + J!
1. The surface echo of the ultrasonic beam transmitted from the power probe 1 was detected by the external force probe t, and the surface echo exceeded a certain threshold. Since the flaw detection gate is generated for the above-mentioned force probe in the flaw detection state based on the time, the flaw detection gate 1 can be generated at 4° due to the influence of the curvature and unevenness of the surface of the test material. The surface of the Z-Peller has a curvature of (11+A), which is extremely high for hot water exploration.

[Brief explanation of the drawing]

No. 11
Part 1, Figure 4 is a view of the frame (not shown), Figure 51 is a 1JJi side view showing an embodiment of the present invention,
Figure 6 is the bottom of the same section, Figure 1 is a diagram showing depth flaw detection of the same LSI, Figure 1 is a diagram of the processing system for the Tsuro J Doshin Shinsei processing system,
Figure 9 is the same time chart 1, Figure 10 is the layout of the same probe, and Figure 11 is the flaw detection pattern using the fixed goo 1~ method.
(aLl: P point, b is 0 point)], Fig. 12 is a small diagram of the deepening pattern by the surface Foucauldian method ((a) is P point, (h) is u point), and Fig. 13 is a small diagram. Diagram C shows the materials to be tested. ■ Material to be tested, 6 Water tank, 7 Detector: 3) (Flaw detection gate generation circuit. Patent applicant: Kobeso Co., Ltd. 614, Figure 8, Figure 10)

Claims (1)

[Claims] 1. A set of two probes are arranged almost axially symmetrically in a water tank for local water immersion, and one probe is in a condition to detect flaws inside the specimen material using the pulse echo method. , 5. The surface echo of the ultrasonic beam transmitted from one probe is detected by the other probe, and the surface finish is calculated based on the time when the ultrasonic beam exceeds a certain threshold. , a surface echo gate method in super-right fatigue testing, characterized in that a flaw detection gate is generated for the one of the probes in the flaw detection shape I.