JPS613008A - Measurement of width - Google Patents

Abstract

PURPOSE:To facilitate measurement of the width of an object, by obtaining the height of a scattered wave echo at each end of an object for measurement by the use of an ultrasonic beam. CONSTITUTION:When an ultrasonic beam is projected from a probe 4 toward an internal defect 2, there are produced a scattered wave echo 6 at the upper end 5 of the defect 2 and a scattered wave echo 8 at the lowe end 7 of the defect 2. The narrower the width of the defect 2, the smaller the height of the echo 6, and the larger the height of the echo 8. The wider the width of the defect 2, the larger the height of the echo 6, and the smaller the height of the echo 8. Accordingly, various widths for the internal defect 2 of a test specimen 1 are set, and an echo height ratio is obtained from a given formula on the basis of echo heights corresponding to the set defect widths, whereby correlation between echo height ratios and defect widths is obtained. This correlation exists independently of the material of the specimen 1 or the height of the internal defect 2. Accordingly, a defect width is readily obtained from the correlation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for measuring a width dimension, and particularly to a method for measuring a width dimension using ultrasonic flaw detection.

[Background of the invention]

There are various methods such as using a measuring instrument to measure the width of an object that has a substantially constant width from one end to the other. It is not easy to measure this width when the object is an internal defect in a structure, or an object placed in a fluid flowing through a pipe or the like.

For example, when the object to be measured is an internal defect, the width dimension, that is, the defect width, is generally measured by cutting the structure and observing the macro cross section of the cut surface. There are problems listed below that make it necessary to rely on destructive inspection.

(1) It is not possible to measure products that are actually used.

■ It is not possible to carry out 100% inspection.

(6) It takes a lot of effort and time to measure the defect width.

In addition, if the object to be measured is an object placed in a fluid, it is necessary to destroy the pipe body etc. that houses the fluid, which ultimately leads to the above problems (1) to (3). I have almost the same problem.

[Purpose of the invention]

The present invention has been made in view of the actual situation in the prior art, and its purpose is to easily measure the width dimension of an object to be measured without destroying the object containing the object. The purpose of the present invention is to provide a method for measuring width dimensions that is possible.

[Summary of the invention]

In order to achieve this objective, the present invention focuses on nondestructive testing using ultrasonic flaw detection, and projects an ultrasonic beam in a direction that includes one end and the other end of an object to be measured, such as an internal defect. A first scattered wave echo at the one end and a second scattered wave echo at the other end.
A configuration in which a scattered wave echo is generated, a ratio between an echo height of the first scattered wave echo and an echo height of a second scattered wave echo is determined, and the width dimension of the object to be measured is measured using this ratio as an evaluation index. It's Nishide.

[Embodiments of the invention]

An example of the width measurement method of the present invention is shown in Figs.
This will be explained based on FIG.

FIGS. 1 to 6 are explanatory diagrams illustrating preparatory work that can be performed prior to actual measurement work. In Figure 1,
1 is a test specimen, for example, material 5 with a plate thickness T of 50+1llK.
Made of 0kg high tensile strength steel.

Reference numeral 2 denotes an object to be measured, that is, an internal defect formed on this test piece 1, and the distance l from the flaw detection surface 6 is, for example, 25 m, and the defect height 8 is 10 m. Note that t is the width dimension of the internal defect 2, that is, the defect width, and the internal defect 2 is formed so that the direction of the defect width is parallel to the testing surface B. Reference numeral 4 denotes a probe for projecting an ultrasonic beam onto the internal defect 2, which is disposed on the flaw detection surface 3 and is configured to make the ultrasonic wave incident perpendicularly to the flaw detection surface 6, using a known probe (not shown). It is connected to a display means such as an oscilloscope or a pulse reflection A-Shub display type ultrasonic flaw detector, and to a calculation means such as a microcomputer.

In the state shown in FIG. 1, when an ultrasonic beam is projected from the probe 4 toward the internal defect 2 at a frequency of, for example, 5 MHz, as shown in FIG.
A first scattered wave F-6 is generated at an end, for example, the upper end 5, and a second scattered wave F-8 is generated at a second end, for example, the lower end 7.

If we pay attention to the first scattered wave echo 6 and the second scattered wave echo 8 obtained in this way, we can see that the defect a! of the internal defect 2 is a!
There is a relationship that the narrower t, the smaller the echo height hl of the first scattered wave F-6 at the upper end 5, and the larger the echo height hl of the second scattered wave echo 8 at the lower end 7; , as the defect width t increases, the first scattered wave F-6
The f-height hl of becomes larger, and the second scattered wave echo 8
The relationship is such that the echo height h2 becomes smaller.

Therefore, the defect width t of the internal defect 2 in the test specimen 1 is set to various values, and the echo height hI + '! corresponding to these defect widths t is set. 2, and based on the hI and h2, the following formula, By (d B )
-20lop 10 (-”) When the echo height ratio Hr is calculated using a calculation means such as a microcomputer, the correlation between the echo height ratio Hr and the defect width t illustrated in FIG. 6 can be obtained. Such a correlation is stored in a storage unit such as a micro combinator (not shown), for example.

The above-mentioned correlation is for internal defect 2 of test specimen 1 having the above-mentioned material, plate thickness T, etc., but almost the same correlation as shown in FIG. 6 is for the material of specimen 1. , the plate thickness T1, the distance to the internal defect 2, 11, the defect height of the internal defect 2, 8, and the frequency. In other words, by obtaining one correlation shown in FIG.
etc., to obtain the echo height AI + h2 as described above.
You can start the actual measurement work described below without having to go through the work of obtaining .

FIGS. 4 to 7 are explanatory diagrams illustrating actual measurement work. As mentioned above, the echo height ratio H illustrated in FIG.
With the correlation between r and defect width t set in advance, the fourth F1! As shown in J, the probe 4 is placed on the flaw detection surface 6 of the structure 9 that may contain the internal defect 2 to be measured, and the ultrasonic beam 10 is projected. In this case, when the internal defect 2 exists in the structure 9,
As shown in FIG. 5, in a display means such as an oscilloscope (not shown), in addition to the echo reflected by the bottom surface of the structure 9 (echo height E), scattered wave echoes due to the internal defect 2 are obtained. At this time, when the direction of the ultrasonic beam 10 and the direction including the upper end 5 and lower end 7 of the internal defect 2 match, the first Both the scattered wave echo 6 and the second scattered wave echo 8 at the lower end 7 are obtained, but if it is assumed that they do not match as illustrated in FIG. 4, the structure as shown in FIG. Besides the echo reflected by the bottom surface of 9, only one echo is obtained.

In such a case, as shown in FIG. 6, use a probe 4 that allows the ultrasonic beam 10 to enter the flaw detection surface at an oblique angle, and move the probe 4 over the flaw detection surface 3. move it.

Then, as shown in FIG. 7, the first scattered wave F-6 (echo height 7s+) at the upper end 5 of the internal defect 2 and the second scattered wave at the lower end 7 are displayed by a display means such as an Otsushiroshoob (not shown). When echo 8 (echo height A2) is obtained, the direction of the ultrasonic beam 10 projected from the probe 4 and the direction including the upper end 5 and lower end 7 of the internal defect 2 match, Based on hI+hz obtained at this time, a calculation means such as a microcomputer (not shown) performs the calculation for determining the echo height ratio Hr, that is, hI Hr (d B ) -201o110 (-7g).

In addition, if the internal defect 2 of the structure 9 is as shown in FIG. Since the echo height hI, A2 can be obtained, the above-mentioned Hr can be calculated without using the probe 4 which is incident at an oblique angle.

If the Hr obtained in this way is, for example, 5 (dB), then #! From the correlation illustrated in FIG. 3, the defect fat of the internal defect 2 is determined to be 20 μm.

In the embodiment in which the measurement is performed as described above, it is possible to easily and accurately measure the defect lit of the internal defect 2 included in the structure 9 without destroying the structure 9 in any way. can.

In addition, in the above embodiment, the internal defect 2 inherent in the structure 9
Although the example of measuring the defect width t of a fluid is shown, the width dimension of an object placed in a fluid can be measured in substantially the same manner without destroying the tube body or the like.

[Effect of idea]

As described above, the width measurement method of the present invention uses ultrasonic flaw detection to determine the echo heights of scattered wave echoes at the first end and second end of the object to be measured. Since the configuration uses the ratio of the echo heights of This produces the effects listed below.

(1) It is possible to measure products that are actually used.

■ 100% inspection can be carried out.

(6) The number of steps required for measurement work can be minimized.

[Brief explanation of the drawing]

Figures 1 to 7 are explanatory diagrams showing one embodiment of the width dimension measuring method of the present invention, and in particular, Figures 1 to 6 illustrate preparatory work performed prior to the actual measurement work. 1st
The figure is a cross-sectional view of the main part showing the state in which the probe is placed on the test specimen.
Fig. 2 is a sectional view of the main part showing the state in which the ultrasonic beam is projected, Fig. 6 is an explanatory diagram showing the relationship between the echo height ratio and the defect width obtained by the projection of the ultrasonic beam, and Figs. Figure 7 shows an example of actual measurement work, Figure 4 is a sectional view of the main part showing the state in which the probe is placed in a structure containing an internal defect, and Figure 5 is a cross-sectional view of the main part in the state shown in Figure 4. A waveform diagram showing the obtained scattered wave echo, Fig. 6 is a cross-sectional view of the main part showing the state in which the ultrasonic beam is projected in a direction including the upper and lower ends of the internal defect, and Fig. 7 is shown in Fig. 6. FIG. 3 is a waveform diagram showing scattered wave echoes obtained in the state. 1... Test specimen, 2... Internal defect (object to be measured), 3
...Flaw detection surface, 4...Probe, 5...Top end (first
), 6... first scattered wave echo, 7... lower end (second end), 8... second scattered wave echo, 9...
...Structure, 10...Ultrasonic beam. Fig. 1 Section 2 Section 3 Defect width t (ILm) Section 4 ------------------------j71-14 Oni 6 Fig. '111 Fig. 5 House 7 Time

Claims (1)

[Claims] In a method for measuring the width dimension of an object to be measured which has a substantially constant width dimension from one end to the other end, an ultrasonic beam is projected in a direction including the one end and the other end of the object to be measured. to generate a first scattered wave echo at the one end and a second scattered wave echo at the other end, and an echo height of the first scattered wave echo and an echo height of the second scattered wave echo. A method for measuring a width dimension, characterized in that the width dimension is measured using the ratio as an evaluation index.