JPS60244843A - Reference gauge for radiographic testing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radiographic testing machine, and more particularly to a gauge for a radiographic testing machine used to accurately detect the position and size of a defect existing within an inspected body. .

[Technical Background of the Invention] Radiographic testing that utilizes the transparency of radiation is used as a non-destructive inspection device that measures the position and dimensions of defects existing inside an inspected object without cutting the inspected object. There is a chance.

When using such a radiographic testing machine to measure the position and size of defects in the thickness direction parallel to the surface included in the connection part of a steel plate, the steel plate 1 is usually measured as shown in Fig. 1(a). A radiation film marker 3 such as a wire made of a heavy metal film such as tungsten or lead is attached to the lower surface of the position where the defect 2 is estimated to exist, and a radiation sensitive material is attached to the lower side of the radiation film marker 3. A radiation film 4 is placed. Then, the steel plate 1 is irradiated with radiation 7 such as X-rays from the radiation [6] at a predetermined inclination angle θ with respect to the center line 5 including the radiation film marker 3. As a result, an image 8 of the radiation film marker 3 and an image 9 of the defect 2 are generated on the radiation film 4, as shown in FIG. 1(b).

Next, as shown in FIG. 2(a), the radiation source 6 is centered at $1.
5 to the opposite side of FIG. 1(a) and irradiates the steel plate 1 with radiation 7. As a result, as shown in FIG. 2(b), an image 9 of the defect 2 is formed on the radiation film 4 at a position opposite to that of FIG. 1(b) with respect to the image 8 of the radiation film marker 3. As shown in FIG. 3, the moving distance of the radiation source 6 is calculated, and the distance from the radiation source 6 to the radiation film 4 is F. When the moving distance of the image 9 of the defect 2 is d, the distance (depth) h of the defect 2 in the steel plate 1 from the lower surface is determined by the following equation by simple geometric considerations.

h=d F/ (D+d)・・・・・・・・・■Also,
When the defect 2 exists in the thickness direction of the steel plate 1, Fig. 4 (a
), when the radiation source 6 irradiates the steel plate 1 with the radiation 7 at a predetermined inclination angle θ, the height of the defect 2 appears on the radiation film 4 as shown in FIG. 4(b). A defect 2 6110 having a length W corresponding to the width H in the direction is generated. In this case, assuming that the distance between the radiation source 6 and the steel plate 1 is sufficiently large, the actual width H of the defect 2 in the steel plate 1 is approximately determined by the formula (2).

H ratio w/ tan θ...■ [Problems with the background art] However, the radiation transmission tester configured as described above has the following problems.

That is, as shown in FIG. 1, the position (distance 11 from the lower surface) of the defect 2 in the steel plate 1 is expressed as
, the distance F to the radiation film 4, and the movement path wid of the image 9 of the defect 2 between the two radiation films 4.
In this method, the measurement accuracy of the defect position is determined by each distance, F.

It depends on the measurement accuracy of d. However, since measuring each of the distances with high accuracy requires a great deal of effort and is actually very difficult, the measuring method shown in FIG. 1 is not practical.

Also, the width H in the height direction of the defect 2 in the steel plate 1 shown in FIG.
In the method of measuring , there is no problem if the defect 2 is accurately oriented in the thickness direction of the steel plate 1 as shown in Figure 4, but if, for example, insufficient penetration occurs at the joint of the steel plate 1, etc. When the direction of the defect 2 is diagonal as shown in FIG. 5, an image 11 due to the diagonal defect 2 is generated on the radiation film 4 as shown in FIG. In this case, it is not possible to determine in which direction the dimensions of the image 11 of the defect 2 should be measured, so this measurement method is also not practical.

In particular, when the object to be inspected is not a steel plate but has a curved surface such as a cylindrical steel pipe 12 as shown in FIG. angle θ
Therefore, when radiation 7 is irradiated from radiation source 6, the seventh
When a plurality of defects 13a, 13b exist along the annular connecting portion of the steel pipe 12 as shown in FIGS.
, 14b is the defect 13a as shown in FIG. 7(C).
, 13b, the shape of the image changes greatly depending on the circumferential position where the images are located. From these images 14a and 14b, the steel pipe 12
It is very difficult to calculate the exact positions and dimensions of the defects 13a and '13b that exist within the wafer. Furthermore, if the object to be inspected is not cylindrical like the steel pipe 12 but has an arbitrary shape with no regularity, the position of the defect can be determined from the image on the radiation film 4.

It is almost impossible to calculate the dimensions.

[Object of the Invention] The present invention has been made based on the above circumstances, and its purpose is to inspect objects even if the surface is formed into a curved surface, such as a steel pipe. It is an object of the present invention to provide a reference gauge for a radiographic testing machine that enables accurate and easy measurement of the position and size of internal defects.

[Summary of the Invention] The reference gauge for a radiation transmission testing machine of the present invention is inserted between an object to be inspected and a radiation-sensitive material of a radiation transmission testing machine, and is inserted into a flexible plate-shaped support object. A plurality of first bar-shaped heavy metal markers are embedded in the thickness direction of this plate-shaped support object, and a plurality of second bar-shaped heavy metal markers are embedded in a direction perpendicular to the thickness direction.

[Embodiments of the invention] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 8(a) is a plan view showing a part of the reference gauge for a radiographic testing machine according to the embodiment, and FIG. 8(b) is an elevational view. In the figure, reference numeral 21 denotes a band-shaped supporting object having a rectangular cross section with a width A and a thickness B, and this band-shaped supporting object 21 is made of a flexible rubber magnet. Then, in the longitudinal direction of the band-shaped support object 21, first markers 22 formed in a rod shape made of heavy metal that absorb radiation having a length B that penetrates the band-shaped support object 21 in the thickness direction are arranged at regular intervals C. A number of them are buried. Also, in the same longitudinal direction,
A plurality of second markers 23 made of the same material as the first marker 22 are buried at equal intervals C in a direction perpendicular to the thickness direction, that is, in the width direction. Note that the length E of the second marker 23 is set shorter than the width A of the band-shaped support object 21. Incidentally, the above-mentioned length is set to a value E' which is longer than the length E for every five pieces for position detection. The above-mentioned dimensions of the reference gauge (hereinafter abbreviated as reference gauge) 24 for a radiation transmission tester according to the embodiment are, for example,
A=15sn, B=5M, C=2Otu, E=6
mm, E' = 10 mm.

The reference gauge 24 is used as shown in FIGS. 9(a) and 9(b) when measuring the position and size of a defect existing in a joint of a steel pipe using an irradiation test machine. That is, when there is an annular defect 26 extending from the inner circumferential surface to the outer circumference due to insufficient weld penetration inside the annular connection part 25 of the steel pipe 12, the band-shaped reference gauge 24 of the embodiment is replaced with the annular connection part 2.
It is attached to the outer peripheral surface of the steel pipe 12 adjacent to the steel pipe 5. Note that since the band-shaped support object 21 is made of a rubber magnet, the steel pipe 1
It can be easily attached to 2. Further, a spacer 27 made of a rubber magnet and having the same shape as the reference gauge 24 is attached on the opposite side of the reference gauge 24 with the connecting portion 25 in between. A radiation film 4 is attached to the outer peripheral surfaces of the reference gauge 24 and the spacer 27. Note that the spacer 27 maintains the position of the radiation film 4 parallel to the outer peripheral surface of the steel pipe 12.

In this state, the direction of each first marker 22 of the reference gauge 24 coincides with the radial direction of the steel pipe 12, and the direction of each second marker 23 coincides with the axial direction.

Then, when the radiation source 6 irradiates the steel pipe 12 with the radiation 7 at the angle of inclination θ as shown in FIG. 6, the radiation film 4
On the top, as shown in FIG. 10, there is an image 28 of the outer boundary line of the annular defect 26, and an image 28 of the outer boundary line of the annular defect 26, and an image 28 of the inner circumferential surface of the tube 12).
An image 29 of , a polyimage 30 of each first marker 22 and a polyimage 31 of each second marker 23 are generated. The radiation 17 is not inclined in the circumferential direction of the steel pipe 12 as shown in FIG. 9(a), and the second markers 23 are arranged in the axial direction. The polygonal image 31 becomes parallel to the axis 32 of the steel pipe 12. while each first
Since the markers 22 are arranged in the circumferential direction of the steel pipe 12, the direction θ1 and length B1 of each fi 130 of each first marker 22 differ depending on the circumferential position (angle) as shown in FIG. . However, since the actual length B and direction of the first marker 22 are known, this position F
It is possible to easily determine the actual dimension (depth) L of the annular defect 26 at . That is, the distance from the position F to the intersection G of the parallel line of the image 30 of the first marker 22 and the image 29 of the inner boundary line at this position is the dimension (depth) Ll of the annular defect 26 on the radiation film 4. Become. Therefore, the actual dimensions can be determined by simple proportional calculation using the formula (2).

L=LIB/B1...... ■Note that the circumferential position of position G on the steel pipe 12 in the actual annular defect 2G can be easily determined by confirming the position of the image 31 of the second marker 23. It is possible to

In this way, the reference gauge 24 has the first and second markers 22, 23 embedded therein in a predetermined direction and length.
is attached to the outer circumferential surface of the steel pipe 12 adjacent to the annular connecting portion 25 by the attraction force of a magnet, and each first
And a second marker 22, 23 is exposed on the same radiation film 4 together with the annular defect 26 which is present in the circumferential direction in the connection part 25. And the actual first and second
Determine the relationship between the position of the marker 22.23 and the first dimension in the direction and the position of the image 30.31 on the radiation film 4 and the second dimension in the direction, and use that relationship to detect the annular defect 2 on the radiation film.
The actual position and dimensions on the steel pipe 12 are calculated from the image 6. Therefore, since these calculation procedures can be performed by simple proportional calculations as described above, the annular defect 2
Even if the defect has a complicated shape like No. 6, its position and dimensions can be measured accurately and easily.

Further, it is not necessary to accurately measure each distance, d, and F, unlike the conventional testing machines shown in FIGS. 1 and 2.

Furthermore, there is no need to accurately measure the inclination angle θ as shown in FIG. Therefore, the time required for measurement can be shortened.
Measurement work efficiency can be improved.

Furthermore, since only one radiation film 4 is used for one measurement, it is also possible to reduce the cost required for measurement.

Note that the present invention is not limited to the embodiments described above. In the examples, the reference gauge of the present invention was used to detect the annular defect 26 existing in the joint 25 of the steel pipe 12, but it can also be applied to other objects to be inspected that have curved surfaces. .

[Effects of the Invention] As explained above, according to the present invention, by using a reference gauge for a radiographic testing machine in which a plurality of first and second markers that are orthogonal to each other are embedded, the surface of a steel pipe or the like can be Even if the object to be inspected has a curved surface, the position and size of defects existing inside the object can be precisely and easily measured.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing the measurement procedure when measuring defects using a conventional radiographic testing machine, and Figures 4 and 5 are also diagrams showing the measuring procedure when measuring defects using a conventional radiographic testing machine. Figures 6 and 7 are diagrams for explaining defect measurement of steel pipes using a conventional radiographic testing machine, and Figure 8 (
a) is a plan view showing a part of a reference gauge for a radiographic testing machine according to an embodiment of the present invention, FIG. 9(b) is an elevational view showing the same reference gauge, and FIG. FIG. 10 is a diagram showing a radiation transmission tester, and FIG. 10 is a diagram showing a radiation film. 1... Steel plate, 2.13a, 13b... Defect, 4...
・Radiation film, 6... Radiation source, 7... Radiation, 8°9.10.11.14a, 14b, 28.29°30.31... Image, 12... Steel pipe, 21... - Band-shaped support object, 22... first marker, 23... second
marker, 24... reference gauge, 25... connecting portion, 26... annular defect, 27... spacer. Applicant's agent Patent attorney Takehiko Suzue Figure 1 l! Figure 2 (a) (a) Figure 3

Claims (1)

[Claims] In a radiation transmission testing machine that detects defects existing in the inspected object by inserting an object to be inspected between a radiation source and a radiation-sensitive material, the object is inserted between the object to be inspected and the radiation-sensitive material. a flexible plate-shaped support object; a plurality of first heavy metal rod-shaped markers embedded in the thickness direction of the plate-shaped support object; 1. A reference gauge for a radiographic testing machine, comprising a plurality of second heavy metal rod-shaped markers embedded in a right angle direction.