JPS6020683B2 - Calibration method of ultrasonic dimension measuring device - Google Patents

Description

[Detailed description of the invention] The present invention relates to Sameshomanpo, an ultrasonic dimension measuring device.

In recent years, automatic measurement of the inner and outer diameters and wall thicknesses of various pipes over their entire length has become convenient by using ultrasonic dimension measuring devices.

The ultrasonic dimension measuring device is configured as follows, for example. That is, as shown in FIGS. 1 and 2, there are tubes to be measured (hereinafter referred to as
(simply referred to as "pipe") 1 Inlet 4a for inlet and outlet
and an outlet 4b are provided, and these inlets and outlets 4a and 4b' are sealed by appropriate sealing mechanisms 5a and 5b that can prevent leakage of water without interfering with the movement of the tube 1. The tube 1 has a spiral feeding loaf 6 installed before and after the rice cake 2.
... rotates around the shark's center and is sent toward the shark's center. The tank 2 is equipped with devices for keeping the water temperature in the tank uniform and constant, such as a temperature sensor 7 for water temperature measurement and a water circulation nozzle 8, as well as measurement probes 9a and 9b on both sides of the path of movement of the pipe 1. A slug 10a and a water temperature guarantee probe 10b are provided on both upper sides. Then, the measurement probe 9
When the ultrasonic waves emitted by a and gb are perpendicularly incident on the surface of tube 1, surface echoes S,,S2 and bottom echoes B,,B,2,
B, 3... and B illusion, &2, &3... occur.

The surface echoes S, , S2 are generated when the incident wave is reflected on the surface of the tube 1, and the bottom echoes B, . ,B2,B3・
. . , &, , B22, B23 . . . are generated when an incident wave entering the flesh of the tube 1 is reflected by the inner circumferential surface of the tube 1. Depending on the time interval between the oscillation pulse ○ on the measurement probe ga side and the surface echo S, the probe 9a and tube 1
The distance between W. is obtained, and the first bottom echo B. , and the second bottom echo B,2 determines the wall thickness T, on this side of the tube 1. Similarly, from the measuring probe 9b side, the distance W between the probe 9b and the tube 1 is
2 and the wall thickness T2 on this side of the tube 1. Assuming that the constant C corresponds to the probe spacing, the outer diameter ○D, wall thickness WT, and inner flea ID of the tube 1 are respectively OD-(W, 10W2) WT=T, ID=OD-(T, 10 T2).

Since this device measures dimensions based on the above principle, it is extremely sensitive to changes in water temperature.

Therefore, in order to keep the water temperature uniform throughout the tank, water is circulated according to the water circulation nozzle rule, and the water temperature horizontal probe force is used to keep the constant C constant even if the water temperature changes. This will automatically be corrected. By the way, in order to measure the dimensions of tubes that require extremely strict dimensional accuracy, such as Zircaloy fuel tubes for nuclear reactors, the dimensional accuracy of the test piece for measuring equipment must be high. It is extremely important not only to increase the dimensional accuracy of the test piece for normal use, but also to give sufficient consideration to the selection of the material of the test piece and the setting of processing conditions.

In other words, ``If the composition, processing degree, Q value, heat treatment conditions, etc. of the test piece are different from those of the object to be measured, the sound speed of the ultrasonic wave will differ, causing an error in the measurement results.
Currently, the Samesho method of ultrasonic dimension measuring equipment is ``at least the test piece is made of a material with the same composition as the object to be measured such as a pipe, and at least the processing degree of the object to be measured is
Test pieces were tested under the limited conditions of being processed with the same Q value and heat treatment conditions.

However, in actual dimension measurement work, it is extremely difficult to obtain a test piece and an object to be measured that have exactly the same composition, grain size, and processing degree.

For example, shark test pieces that are generally subjected to ultrasonic dimension measurements have standard parts for upper and lower limits of tolerance determined by the standard. In order to manufacture the standard parts for the upper and lower limits, the material that becomes the original tube of the test piece must have dimensions larger than the dimensions of the standard parts for the upper limit. Standard part and upper limit of the piece,
Naturally, the machining conditions and the machining degree are different between the workpiece and the workpiece, which should be within the lower limit tolerance. Conventionally, it has not been possible to quantitatively determine the extent to which this difference in working degree affects the specified dimension value.

Conventionally, the texture of the test piece and the object to be measured was
Qualitative determination was made using specular reflection pole mapping using lines.
As described above, when it is thought that a difference in dimensional indication value occurs due to the difference in processing degree of the test piece and the workpiece, the present invention determines the quantitative difference between the test piece and the workpiece and corrects the result. It concerns the shark-sho method of performing shark-sho.

As a specific method, at least the standard part of the test piece for shark measurement should be made of a material that has the same limit value as the object to be measured, or even if the standard part of the test piece for shark measurement and the object to be measured are not the same, This method corrects the difference in the dimension measurement instruction value corresponding to the deviation of the value. According to the inventors' research, there is a close relationship between the threshold value, which has recently been introduced as a quantitative analysis method for texture, and the ultrasonic sound velocity, that is, the difference in dimension indicated values. I found out something. The f value is the direction in which the crystal orientation of the object to be measured 11 is considered to be, as shown in FIG. The degree is shown in the formula below. 〆＝”Customer Kamida K
Evil? ) Sinocos 2 Nudbi Shonota' Poison 91 (Q,
〇Field n◇dQd〇.・--.

{1) {1} In the formula, 1 (Q,?): X-ray intensity at the forehead oblique angle Q, CI Here, the n value obtained by the formula {1' and the ultrasonic sound velocity (
The following describes the relationship between the dimensions (dimension measurement instructions).

For example, a Zircaloy nuclear fuel cladding tube 2 whose main component is zirconium, which is composed of steel-tight hexagonal crystals 13, has a phys- ical slope in the direction perpendicular to the (0002) plane (c-axis direction) as shown in Fig. 4. The sound speed is the farthest at corner 8, and as the slope falls from the c-axis direction, the sound speed gradually decreases. Therefore, the ultrasonic sound velocity (dimensional measurement instruction value) varies depending on the degree of aggregation in the c-axis direction, that is, the texture representing the integrated concentration of single crystals. For example, judging from the pole figure shown in Figure 7, the accumulated concentration on the (0002) plane of the Zircaloy cladding tube is 8
It reaches its maximum near =30o, and the speed of sound passing around this area is the fastest. Next, FIG. 5 shows the relationship between the null value and the ultrasonic sound velocity (dimensional measurement instruction value) for Zircaloy with a thickness of 1 mm.

In Fig. 5, the Na value on the horizontal axis is (0) in the ultrasonic irradiation direction.
002) is a quantitative representation of the orientation of the crystal planes, and the vertical axis indicates the ultrasonic dimension measurement instruction value. For example, if the value is 0.55, the dimension measurement instruction value is 10.0, and if the value is 0.45, the dimension measurement instruction value is 10.10. If the dimensional value changes by 0.1, the dimensional value will change by 1%.Generally, in the case of Zircaloy nuclear fuel cladding, the (0
002) is approximately 0.6±0.05. Next, the Q value, which has a large effect on the crystal texture in the Zircaloy coated steel pipe, will be described.

The Q value is a parameter indicating processing conditions, and its degree is shown in the formula below. (2) In the formula: Wall thickness before processing, t: Wall thickness after processing do: Inner diameter before processing, d: Inner diameter after processing Figure 6 shows Zirca with 98% zirconium.

This shows the relationship between the final value and the Q value for .
As shown in FIG. 6, as the Q value increases, the NA value increases. That is, as the Q value becomes larger, the c-axis of the crystal becomes a texture that is accumulated in the radial direction of the tube (r-direction shown in FIG. 3). As mentioned above, the relationship between the Q value, that is, the processing conditions and the final value, the N value and the ultrasonic sound velocity (dimension measurement instruction value)
It was found that there is a correlation between the two.

As a result, when performing ultrasonic dimension measurement, it is sufficient to make the n values of the shark test piece and the object to be measured the same, and even if they are not the same, it is sufficient to correct the difference in dimension indicated values corresponding to the f value difference. This significantly improves the accuracy of shark alignment, and the effect is significant.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing the ultrasonic dimension measuring device during tube dimension measurement and the pulse waveform obtained from it, Fig. 2 is a side sectional view of the same device, and Fig. 3 shows the crystal orientation of the object to be measured. Stereo projection diagram, Figure 4 is a diagram showing the crystal orientation of Zircaloy nuclear fuel cladding, Figure 5 is a diagram showing an example of the relationship between Zircaloy's f value and dimension measurement instruction value, and Figure 6 is a diagram showing Zircaloy's crystal orientation. Diagram 7 showing an example of the relationship between f value and Q value
The figure is a diagram showing the texture of a Zircaloy nuclear fuel cladding tube using the pole projection method. 12... Zircaloy nuclear fuel cladding tube, 13...
... Steel-tight hexagonal crystal. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure T

Claims (1)

[Claims] 1. When measuring dimensions using ultrasonic waves, use a calibration test piece made of the same material as the object to be measured, and if the f value between the object to be measured and the calibration test piece is the same, the If there is a difference in the f-values,
A method for calibrating an ultrasonic dimension measuring device, characterized in that the calibration method is carried out by correcting a dimension measurement instruction value corresponding to the degree of the difference.