JPH02263156A - Ultrasonic inspecting device - Google Patents

Abstract

PURPOSE:To calibrate the sensitivity to an echo level continuously by setting threshold values of different echo envelopes so that the number of defects at a threshold value set for a starting envelope is equal to the number of defects. CONSTITUTION:A master work 1 which faces a probe 2 is rotated by a rotating device 3 to generate a timing signal and an ultrasonic flaw detector 4 outputs analog signals of reflection echoes from the master work 1 from the start position to the end position of flaw detection, i.e. according to the angle of the rotation throughout one turn of the master work 1 in synchronism with the timing signal. The analog signals are inputted to a computer device 10 and digitized by an A/D converter 5 to display an echo envelope on a display 7, thereby setting a threshold value corresponding to the number of defects of the master work 1 as the echo envelope. Thus, when the threshold value is set, the inspection of a body 1' to be inspected, i.e. an actual product is started instead of the master work 1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic inspection device for water immersion flaw detection on a large number of specimens having the same shape by pulse reflection method, and in particular, the present invention relates to an ultrasonic inspection device for water immersion flaw detection on a large number of objects having the same shape. The present invention relates to an inspection device suitable for easily and steplessly performing calibration with a simple configuration.

[Conventional technology]

In order to ensure a certain level of product quality, during ultrasonic testing, we set pass/fail judgment values, echo level thresholds, and masterwork configuration (material, 2 dimensions).

Inspection conditions, including inspection criteria such as shape (shape, etc.), probe position, gain of the ultrasonic flaw detector, and flaw detection conditions such as Goo 1~ are determined depending on the various specimens, but these conditions The gain of the ultrasonic flaw detector is directly related to the pass/fail judgment value and threshold value, and it is necessary to keep it constant when inspecting many objects of the same shape in succession. Especially necessary. However, even if the same test equipment is used for testing, the gain can vary considerably due to, for example, contamination of the water being used, changes in temperature, or deterioration of the probe, so it is necessary to determine the cycle and calibrate the sensitivity. be.

Sensitivity calibration of conventional ultrasonic flaw detectors involves detecting reflected echoes using a master work or a sensitivity standard test piece made with the same material, dimensions, shape, etc., as the part to be inspected. This was done by changing the gain by turning the knob on the ultrasonic flaw detector so that the reflected echo level remained constant.

[Problem to be solved by the invention] For this reason, in conventional sensitivity calibration, the gain can only be adjusted stepwise and intermittently, and the sensitivity calibration can only be performed within that range, making it impossible to perform accurate sensitivity calibration. had.

In addition, when applying the conventional method of changing the gain so that the level of reflected echoes from the masterwork etc. is constant to automatic inspection, it is necessary to use the computer controller of the ultrasonic flaw detector, which requires a large amount of time. In addition, gain control was somewhat difficult, which caused problems.

SUMMARY OF THE INVENTION In view of the problems of the prior art mentioned above, an object of the present invention is to provide an ultrasonic inspection apparatus that can easily and steplessly calibrate the echo level sensitivity in an ultrasonic inspection apparatus with a simple configuration. shall be.

[Means to solve the problem]

In order to achieve the object described above, the ultrasonic testing apparatus of the present invention includes a moving device that relatively displaces a subject and a probe facing the subject over a certain distance, and a moving device that relatively displaces a subject and a probe facing the subject, and a moving device that moves a subject to the subject via the probe. An ultrasonic flaw detector comprising an ultrasonic flaw detector that transmits and receives ultrasonic pulses and outputs analog signals of reflected echoes from the object to be inspected, and a computer device that controls the moving device, captures the output signal of the ultrasonic flaw detector, and displays the data. In the sonic inspection apparatus, a master work having the same configuration as the test part of the test object and a known number of defects existing in the test part is replaced with the test object and placed so as to be movable relative to the probe. ,
a moving device that generates a timing signal corresponding to a relatively displaced position; an ultrasonic flaw detector that outputs an analog signal of a reflected echo from the master work during a certain distance of the relative displacement in synchronization with the timing signal; The peak value of each reflected echo output from the ultrasonic flaw detector is input and accumulated, and an echo envelope formed by the peak value of each accumulated reflected echo is set at a threshold corresponding to the number of defects in the master work. a computer device for setting and displaying different threshold values such that the number of defects at the threshold value is the same as the number of defects for echo envelopes with different echo levels obtained by measuring the master work with the same gain; It is structured as follows.

[For production]

First, a master work is prepared that has the same material, dimensions, shape, etc. as the part to be inspected of the test object, and the number of defects present in the part to be inspected is known, and the master work is moved relative to the probe using a moving device. let At this time, the moving device generates a timing signal corresponding to the relatively displaced position.

The ultrasonic flaw detector outputs an analog signal of a reflected echo from the master work during a certain distance during which the master work and the probe are relatively displaced in synchronization with the timing signal. The output analog signal is input to a computer device, where it is digitized, and the digital value and the flaw detection position of the timing signal are stored in a memory as a pair. The echo envelope formed by the peak value of the accumulated digital values is displayed graphically, and a threshold value corresponding to the number of defects in the master work is set. This threshold value becomes the pass/fail judgment value, and the pass/fail of the actual product to be tested is subsequently judged. However, due to changes in flaw detection conditions and the properties of ultrasonic waves, it is necessary to determine the cycle and calibrate the sensitivity.In this case, when setting the echo envelope and threshold value using the master work, When echo envelopes are displayed graphically with the same gain as the gain of , the echo levels of both echo envelopes are not necessarily at the same level, and echo envelopes with different peak values may be formed.

The method of sensitivity calibration in this case is to set the threshold value for this different echo envelope so that the number of defects at the threshold value set for the original echo envelope is the same as the number of defects. Based on this sensitivity-calibrated threshold value, the pass/fail determination of the actual product to be tested is performed again.

〔Example〕

One embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the figure, 1 is a master work having a test part 1a made of the same material, 2 dimensions, shape, etc. as the test part (circumferential welded part) 1'a of the test object 1' which is the actual product. The number of defects in the part to be inspected 1a is known.a2 is a probe placed opposite to the master work 1; 3 is a rotating device on which the master work 1 (or the object 1') is placed rotatably; Then, by rotating the master work 1 (or the subject 1'), the subject part 1. a (or 1'a) and the probe 2 are displaced relative to each other, and at the same time, the rotating device 3 generates a predetermined timing signal corresponding to the relatively displaced position.

4 transmits and receives ultrasonic pulses to and from the master work 1 via the probe 2 in synchronization with the timing signal, and during a certain distance of relative displacement (one rotation in this example), reflected echoes from the master work 1 are generated. This is an ultrasonic flaw detector that outputs an analog signal. 5 is an A/D converter that inputs and digitizes the peak value of a plurality of reflected echoes output from the ultrasonic flaw detector 4, for example, 1,000 points per rotation; 6 is an A/D converter; 7 is a display that stores the data of the peak value re-digitized by the device 5 and the flaw detection position based on the timing signal; 7 is a display that displays the echo envelope formed by the data stored in the memory 6; Displays the threshold set on the echo envelope. 8 is the keyboard, 9 is the CPU, 10 is the A/D
Converter 5, memory 6, display 7, keyboard 8
, a CPU 9, etc.

When the master work 1 facing the probe 2 is rotated by the rotating device 3, the timing signal is generated at the same time as the rotation, and the ultrasonic flaw detector 4 outputs the flaw detection from the start position to the end in synchronization with the timing signal. The master work 1 outputs analog signals of a plurality of reflected echoes (for example, 1,000 points) according to the position, that is, the frontal rotation angle of one rotation of the master work 1. The analog signal is input to the computer device 10 and digitized by the A/D converter 5, and the digital value is stored in the memory 6 in pairs with the flaw detection position signal. The accumulated data is
The echo envelope formed by the peak value of the reflected echo is displayed on the display 7, and a threshold value corresponding to the number of defects in the master work 1 is set on the echo envelope.

Once the threshold value is set, the actual product to be inspected 1' is inspected instead of the master work 1, and pass/fail judgment is made based on the threshold value. However, when restarting the test after a certain period of time has elapsed, or after a large number of tests have been performed even on objects with the same shape, the test conditions in the test equipment may change due to water contamination, probe deterioration, etc. However, the gain of the ultrasonic flaw detector 4 is likely to change, so it is necessary to determine the cycle and calibrate the sensitivity.

As a sensitivity calibration method, the master work 1 is used again, and the echo envelope is graphically displayed on the display 7 with the same gain as the gain for the echo envelope obtained initially. However, as shown in FIG. 2, if the initially obtained echo envelope is a, echo envelopes with different echo levels are formed on the display 7 due to changes in the test conditions, etc., and the echo envelopes a, The echo levels of b may not necessarily be at the same level.

If the echo levels of echo envelopes a and b are different in this way, the known number of defects between the rotation angle m - n at the threshold value A set for echo envelope a and the number of defects in echo envelope The threshold value B is set for the echo envelope so that the values are the same. Once the threshold value B is set, the actual product to be inspected 1' is inspected again, and a pass/fail determination is made based on the threshold value B. In this case, the threshold value B is the second
As shown in the figure, the echo level is lower than threshold A, but the sensitivity has been calibrated in response to changes in inspection conditions, etc., and the actual product test object 1' was tested at threshold A. You can obtain the same test results as the results.

As described above, the sensitivity calibration of the echo level can be steplessly and accurately shifted to one corresponding to the inspection conditions in that case, and a highly accurate pass/fail judgment value can be obtained.

In the above embodiment, the master work 1 or the test object 1 having the test parts 1a, l'a such as circumferential welds
' is rotated by the rotating device 3, but the present invention is not limited to this, and can be similarly applied to detecting flaws in a straight welded part of a fixed length on a flat material. Of course, in that case, the moving device 3 would be used instead of the rotating device 3.

〔Effect of the invention〕

Since the present invention is configured as described above, it is possible to easily and steplessly calibrate the sensitivity of the echo level in an ultrasonic inspection device with a simple configuration, and to improve the accuracy for the subject. This has the effect of allowing accurate pass/fail judgments to be made.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing one embodiment of the ultrasonic testing device of the present invention, and Fig. 2 shows an example of data displayed graphically on the display of the device shown in Fig. 1, and explains the sensitivity calibration method. This is a diagram for use. 1... Master work, 1'... Actual product subject, l
a, l'a...Test part, 2...Probe, 3...Rotating device (moving device), 4...Ultrasonic flaw detector, 10...
- Computer equipment.

Claims (1)

[Claims] 1. A moving device that relatively displaces a subject and a probe facing the subject over a certain distance, and transmitting and receiving ultrasonic pulses to and from the subject via the probe and receiving analog signals of reflected echoes from the subject. In an ultrasonic inspection apparatus comprising an ultrasonic flaw detector that outputs an output, and a computer device that controls the moving device, captures the output signal of the ultrasonic flaw detector, and displays the data, the configuration is the same as that of the test part of the test object. and a moving device that replaces a master work with a known number of defects existing in the test part as the test object, places it so that it can be displaced relative to the probe, and generates a timing signal corresponding to the position of the relative displacement. and an ultrasonic flaw detector that outputs analog signals of reflected echoes from the master work during a certain distance of relative displacement in synchronization with the timing signal, and a peak value of each reflected echo output from the ultrasonic flaw detector. is input and accumulated, and a threshold corresponding to the number of defects in the master work is set on the echo envelope formed by the peak value of each accumulated reflected echo, and the master work is measured with the same gain. a computer device that sets and displays different threshold values for which the number of defects at the threshold value is the same as the number of defects for echo envelopes of different obtained echo levels;
An ultrasonic inspection device characterized by having the following configuration.