JPH0236905B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention provides an ultrasonic flaw detector suitable for adjusting the time axis and flaw detection sensitivity of the flaw detector in field work in an ultrasonic flaw detector used for flaw detection testing of welded parts of welded structures. This invention relates to a test piece for adjustment. [Prior art] Generally, when applying ultrasonic flaw detection tests to welded parts of welded structures, the Japanese Industrial Standard JIS Z3060 "Ultrasonic flaw detection testing methods for steel welded parts and classification of test results" is often used. . Among these, to adjust the time axis and correct the origin of the ultrasonic flaw detector, use the A1 standard test piece TSB-A11 for ultrasonic flaw detection as shown in Figure 1 or the ultrasonic tilt as shown in Figure 2. A3 standard test piece STB for corner flaw detection
-A32, and also for creating echo height division lines and adjusting flaw detection sensitivity using distance amplitude characteristic curves.
Standard test piece STB-A2 or comparative test piece RB-4
It is stipulated that each should be used. In other words, STB-A11 has the shape and dimensions as shown in Figure 1a and b, and the test piece body 1' is made of rolled steel for welded structure, and the time axis adjustment for the vertical probe is installed. width 25mm, height 100mm,
Stepped part height 91mm for time axis adjustment for angle probe
A curved surface R100 mm is formed for measuring the incident point of the angle probe, for adjusting the time axis, and for correcting the time axis origin.The STB-A32 has the shape and dimensions as shown in Figure 2 a and b. A 45.5 mm height for adjusting the time axis for the angle probe and a curved surface R for measuring the time axis of 50 mm for incident point measurement are formed on the test piece body 2' of rolled steel for welded structures. . Furthermore, RB-4 is No. 1 depending on the thickness of the specimen.
~No.7 is used, and RB-4 No.13, RB-4 No.24 and RB with the shapes and dimensions shown in Figures 3, 4 and 5 are used for test specimens with a thickness of 100 mm or less. -4 No. 35 is used. This RB-4 No.
13, a standard hole 3 for flaw detection sensitivity adjustment of φ2.4 mm x 40 mm is formed at a position of 9.5 mm from one flaw detection surface of the parallel plane of the test piece body 3', and RB-4 No. φ3.2 at a position 9.5mm from the flaw detection surface of 4'
RB-4 No. 35 has a standard hole 4" mm x 40 mm with a diameter of 4.8 mm at a position 18.8 mm from the flaw detection surface of the test piece body 5'.
A standard hole 5" x 40mm is formed in each. On the other hand, special probes such as dual element probes and point focusing probes are used for precision testing of this type of flaw detection. In this case, to adjust the time axis and sensitivity of the flaw detector, use the above-mentioned STB-A11 or
In addition to STB-A32, a horizontal hole test piece 6 as shown in Figure 6, which was guided by the NDI202 subcommittee, is used. This test piece 6 has a diameter of 3 mm x 30 mm on the test piece body 6'.
Find 10 horizontal holes 6″ mm 4mm, longitudinal dimension 30
It is formed with a pitch of mm. However, when adjusting the time axis and flaw detection sensitivity of the flaw detector during field work, depending on the work environment, such as work at high places such as towers and tanks, narrow spaces, and remote work sites, these STB-A11, STB−
A32, RB-4 Nos. 1 to 33 to 5, and the horizontal hole test piece 6 may be difficult to carry in terms of weight and quantity, resulting in poor workability. [Object of the Invention] This invention has been made with the above points in mind, and each important dimension of STB-A1 and STB-A3 and each standard hole of RB-4 No. 1 to No. 3 are The purpose is to develop a formed test piece and improve workability in on-site work. [Structure of the Invention] In order to achieve the above object, in the test piece for adjusting an ultrasonic flaw detector of the present invention, an L-shaped test piece main body made of rolled steel for welded structure is provided with an ultrasonic wave in the thickness direction. Standard test piece STB-A1 for sonic flaw detection
Parallel first and second surfaces separated by a thickness equal to the time axis adjustment width for the vertical probe in the standard specimen STB-A1, and the oblique probe in the standard specimen STB-A1 perpendicular to the first and second surfaces. Parallel third and fourth surfaces separated by a thickness equal to the height of the stepped part for adjusting the time axis for children, and the first
~Standard test piece STB-A1 perpendicular to the fourth surface
parallel fifth and sixth surfaces separated by a thickness equal to the time axis adjustment height for the vertical probe in the vertical probe; The seventh surface is separated by a thickness equal to the time axis adjustment height for the angle probe in the standard test piece STB-A3 for sonic flaw detection, and the second surface is penetrated perpendicularly from the first surface to the second surface, respectively. The diameter and position from the third or fifth surface of the comparative specimen RB-4 No.
1, RB-4 No. 2, and RB-4 No. 3. The first, second, and third horizontal holes are formed to have the same diameter and position from the flaw detection surface as the standard holes for flaw detection sensitivity adjustment, respectively. . [Effects of the Invention] Therefore, according to the test piece for adjusting an ultrasonic flaw detector of the present invention, the test piece body has important dimensions of STB-A1, important dimensions of STB-A3, and RB-
4. Since horizontal holes corresponding to each of the standard holes No. 1 to No. 3 are formed, when adjusting the time axis and flaw detection sensitivity of the flaw detector using the standard probe, it is necessary to - Adjustment work can be carried out by carrying the A3, and when adjusting the time axis and flaw detection sensitivity of a flaw detector using a special probe, adjustment work can be carried out by carrying the relevant test piece and the horizontal hole test piece. This makes it possible to reduce the size and weight of the entire test piece required for these adjustments, making it extremely easy to carry to the site, and greatly improving workability. [Example] Next, this invention will be described in the seventh example showing one example.
This will be explained in detail with reference to the drawings below. First, FIG. 7 shows a test piece L for adjustment according to the present invention, and 7 shows a rolled steel material for welded structures, for example, SM50A.
The main body of the test piece is L-shaped. On the front and rear parallel planes of this main body 7, STB-A1
The first and second surfaces 7a and 7b having a thickness equal to the time axis adjustment width 25 mm of STB-A11 are on the upper and lower parallel planes of the main body 7.
The third and fourth surfaces 7c and 7d have a thickness equal to 91 mm,
On the left and right parallel planes of the main body 7, there are fifth and sixth holes with a thickness equal to the height of 100 mm for time axis adjustment of STB-A11.
Surfaces 7e and 7f are formed respectively, and the main body 7
On the right lower surface of , there is a surface 7c parallel to the third surface 7c.
The height for time axis adjustment of STB-A32 is 45.5 mm.
An eighth surface 7g is formed on the lower right side of the main body 7, parallel to the fifth surface 7e and spaced apart by a distance of 50 mm from the surface 7e.
A surface 7h is formed. Further, on the first surface 7a of the main body 7, RB-4 No.
The first, second, and third horizontal holes 8a, 8b, and 8c, which have the same diameter and position as the standard holes 3'', 4'', and 5'' for flaw detection sensitivity adjustment of No. 13, No. 24, and No. 35, are the second holes, respectively. The first horizontal hole 8a is formed to penetrate through the surface 7b.That is, the first horizontal hole 8a is formed from the third surface 7c, which is the flaw detection surface.
9.5mm, φ2.4mm x 25 at 20mm from 6th surface 7f
mm in size, the second horizontal hole 8b is the third hole which becomes the flaw detection surface.
The third horizontal hole 8c is located 9.5 mm from the surface 7c and 20 mm from the fifth surface 7e with a size of φ3.2 mm x 25 mm, and the third horizontal hole 8c is located 18.8 mm from the fifth surface 7e, which is the flaw detection surface, and 20 mm from the fourth surface 7d.
They are each formed at a position of mm with a size of φ4.8 mm x 25 mm. Here, the dimension of each horizontal hole 8a, 8b, 8c from a surface other than the flaw detection surface of 20 mm is set to such an extent that it will not be affected by reflected ultrasonic waves from each surface during adjustment. It is assumed that all the surfaces 7a to 7h of the test piece main body 7 have a surface roughness of ▽▽▽6S, and each dimensional accuracy is ±0.05 mm. Next, a method for adjusting a flaw detector using the embodiment described above will be explained. When using a standard probe - 1 Adjustment of the measurement range on the time axis (i) When using a vertical probe, depending on the measurement range, adjust the thickness direction of the specimen L that is less than 1/2 of the measurement range. Select dimensions 25mm, 50mm, and 100mm. For example, when adjusting the measurement range to 100 mm vertically, a thickness of 25 mm between the first and second surfaces 7a and 7b is used, and the ultrasonic wave is vertically incident from the first surface 7a with a vertical probe. The second bottom echo of the multiple reflection pattern on the cathode ray tube of the flaw detector is placed at the 25th scale in the center of the time axis scale, and the fourth bottom echo is placed at the 50th scale at the right end of the time axis scale. Adjust using the adjustment knob. (ii) When using an angle probe, there are cases where adjustment is made only with the angle angle probe, and cases where the angle angle probe is used after preliminary adjustment with a vertical probe.
In either case, R50mm of STB-A32,
Use the specified method using a height of 45.5 mm. The measurement range in this case is limited to STB-A1, but in many cases STB-
A3 is sufficient. -2 Adjustment of flaw detection sensitivity First, in the test room, as shown in Figure 8a, a standard hole 3'' is flaw detected using an RB-4 No. 13 with an angle probe 9 (refraction angle 70° in the figure). Then, on the cathode ray tube, we created an echo height division line based on the distance-amplitude characteristic curve, ie, H line, as shown in Figure b, and furthermore, the echo height of standard hole 3'' was
Adjust the gain to match the line (80%) and use this as the flaw detection sensitivity. Record the reading Ho (d _B ) on the scale of the gain knob at this time. Next, without changing the reading Ho on the scale of the gain knob, set the 9th
As shown in Figure a, the first horizontal hole 8a of the test piece L is flaw-detected from the third surface 7c using the above-mentioned bevel probe 9 using the direct method. Adjust the gain knob so that the echo height at this time matches the H line (80%), and read the scale of this gain knob as H (d _B ).
Record. Furthermore, the difference in the scale reading of the gain knob for the H line between the echo height of the standard hole 3'' of RB-4 No. 13 and the echo height of the first horizontal hole 8a of the test piece 7 △H (d _B ) = H - Ho Then, in the field work, using the test piece 7, the gain is adjusted so that the echo height of the first horizontal hole 8a matches the H line, and then the scale of the gain knob is adjusted to △H. (d _B ) and this is taken as the flaw detection sensitivity.In other words, by changing the scale of the gain knob by △H (d _B ),
This is equivalent to adjusting the flaw detection sensitivity using RB-4 No.13. For example, as shown in the table, RB-4 No.13
If the gain knob reading Ho is -40.5d _B and the gain knob reading H by the first horizontal hole 8a of the test piece 7 is -39.0d _B , the difference △H is +1.5d _B
This means that the flaw detection sensitivity can be adjusted by increasing the scale of the gain knob _{by 1.5dB} during field work.

[Table] In addition, the flaw detection sensitivity is checked by checking whether the echo height due to the first horizontal hole 8a of the test piece L is higher than the H line by ΔH, that is, by 1.5 _dB . In addition, to adjust and check the flaw detection sensitivity,
This is usually done before the start of the test, every hour thereafter, and after the end of the test. In addition, the above case is when the thickness of the test piece is 25 mm or less, but the thickness of the test piece is between 25 mm and 50 mm.
mm, 50mm to 100mm as above,
Difference △H in the scale of the gain knob between RB-4 No. 24 and the second horizontal hole 8b of the test piece L, RB-4 No.
This can be done by finding the difference △H in the scale of the gain knob between No. 3 and the third horizontal hole 8c of the test piece L, and the table above shows Ho, H, and △H in this case.
Also listed. When using a special probe In this case, the use of a side hole comparison test piece 10 as shown in FIG. 10 in place of the above-mentioned side hole test piece 6 is approved by the Nondestructive Testing Association. Here, R is the focusing range and T is the plate thickness. Therefore, based on the guidelines of the Non-destructive Inspection Association, a horizontal hole test piece 11 for on-site use as shown in FIG. 11 is prepared. i.e. thickness 30mm, height 40
mm, length 150mm test piece main body 11', horizontal holes 11'' of φ3mm x 30mm are made at the positions of 8mm, 16mm, and 32mm from the top flaw detection surface and the dimensions from the right side are 40mm, 70mm, and 100mm, respectively. -1 Adjustment of the measurement range on the time axis (i) When using a vertical probe, as in (i) of -1.
Select 25mm and 100mm. (ii) When using an angle probe First, we will explain how to find the beam path when a horizontal hole is detected using an angle probe. That is, as shown in FIG. 12, the bevel probe 12 is placed at position A on the flaw detection surface of the horizontal hole test piece 11 to detect flaws in the side hole 11 ₀₁ '', and the bevel probe 12 is scanned to detect echoes. Fix the probe 12 when the height reaches its maximum, and probe 1 from the right end surface of the test piece 11 at this time.
Measure dimension Y ₁ up to 2. Next, place the probe 12 at position B and
₀₂ '' and measure the dimension Y ₂ when the echo height reaches its maximum. Note that measurements of these dimensions Y ₁ and Y ₂ are carried out by fixing a steel scale etc. on the detection surface. Here Then, the incident point P of the angle probe 12 is
Using the similar relationship between the positions of the horizontal holes 11 ₀₁ ″ and 11 ₀₂ ″ in Fig. 12 and the position of the probe 12, (1)
It can be determined by the formula. In addition,
D ₀₁ , D ₀₂ are each horizontal hole 11 ₀₁ ″, 1 from the flaw detection surface.
The depth to the center of 1 ₀₂ ″, Y ₀₁ , Y ₀₂ is the depth from the right end surface of test piece 6 to the center of each horizontal hole 11 ₀₁ ″, 11
This is _{the dimension to the center of the probe 12} . The angle of refraction is at position A
Since it can be determined by the average refraction angle θ of the refraction angle θ ₀₁ at position B and the refraction angle θ ₀₂ at position B, the refraction angles θ ₀₁ and θ ₀₂ are determined by equations (2) and (3), respectively, and (4) Find the refraction angle θ using the formula. θ ₀₁ = tan ^-1 (Y ₁ +P〓) - Y ₀₁ /D ₀₁ ...(2) θ ₀₂ =tan ^-1 (Y ₂ +P〓) - Y ₀₂ /D ₀₂ ...(3) θ = θ ₀₁ + θ ₀₂ /2...(4) Therefore, by using this refraction angle θ, from the angle probe 12 to the side hole 11 ₀₁ ″,
The beam path length W ₀ J ₁ , W ₀₂ up to 11 ₀₂ ″ is (5)
It is determined by the formula and formula (6). W ₀₁ = D ₀₁ /COSθ−1.5 …(5) W ₀₂ =D ₀₂ /COSθ−1.5 …(6) First, preliminary adjustment of the time axis with the vertical probe is performed using the test piece L, and the measurement range is The thickness direction dimensions of 91 mm and 45.5 mm are selected according to the requirements. For example, when adjusting a transverse wave of 125 mm, the 91 mm propagation time of the longitudinal wave (sound velocity 5900 m/s) corresponds to the 50 mm propagation time of the transverse wave (sound wave 3230 m/s), so Dimension between surfaces 7c and 7d 91
As shown in FIG. 13a, vertical flaw detection is performed using the vertical probe 13 from the third surface 7c. Then, the multiple reflection pattern at this time is displayed on the cathode ray tube, and the pulse position of the first bottom echo is placed on the 20th scale of the time axis scale, and the pulse position of the second bottom echo is placed on the 40th scale, as shown in Figure b. Adjust using the knob and sound velocity adjustment knob. At this time,
Since the first bottom echo corresponds to the beam path length of the transverse wave of 50 mm, the maximum 50 scale is 125 mm, completing the preliminary adjustment. Next, the horizontal hole test piece 11 and the oblique probe 12 are used to adjust the zero point of the time axis. That is, as shown in FIG. 14a, the horizontal hole 11 ₀₁ ″ of the test piece 11 was detected using the angle probe 12, and
When the echo height reaches the maximum, the probe 12 is fixed, and the zero point of the time axis is adjusted so that the rise of this echo matches the beam path length W ₀₁ determined by equation (5). Next, the horizontal hole 11 ₀₂ ″ is detected with the probe 12, the beam path length W ₀₂ u on the cathode ray tube when the echo height reaches the maximum is measured, and the beam path length W ₀₂ obtained by equation (6) and Compare. If the difference in beam path length △W ₀ = W ₀₂ u−W ₀₂ at this time is within ±0.5 mm,
Considering that the zero point adjustment mentioned above was done correctly, ±0.5
If it exceeds mm, perform zero point adjustment again. -2 Adjustment of flaw detection sensitivity In this case, basically use the same method as in case -2. That is, first, using the horizontal hole test piece 6 shown in Fig. 6 in the test room, each horizontal hole 6'' is flaw-detected to create an H line, and the echo height when the horizontal hole 6'' with a depth D = 8 mm is detected. Adjust the gain so that it matches the H line, and record the reading H ₀ (d _B ) on the scale of the gain knob at this time, and use this as the flaw detection sensitivity. Next, inspect the side hole 11'' of the field side hole test piece 11 with D = 8 mm, adjust the gain so that the echo height matches the H line, and record the reading H (d _B ) on the scale of the gain knob. Then, in the field, D=8 of the side hole test piece 11.
Adjust the gain to match the echo height to the H line when detecting the horizontal hole 11" of mm, and further change the scale of the gain knob by the difference in scale reading △H (d _B ) = H - H ₀ , This adjusts the flaw detection sensitivity. Also, in the same way, D = 16 for the horizontal hole test piece 6.
mm, D = 32mm side hole 6″ and side hole test piece 11
The flaw detection sensitivity is adjusted according to the thickness of the specimen using the difference in flaw detection sensitivity between the 16 mm and 32 mm horizontal holes 11".Furthermore, the flaw detection sensitivity is checked using the horizontal holes 11" of the horizontal hole test piece 11. This is done by checking whether the echo height obtained by changing by ΔH (d _B ) with respect to the H line is obtained. Therefore, according to the above embodiment, the test piece main body 7 of the test piece L has a width of 25 mm, a height of 100 mm, and a stepped part height of 91 mm, which are important dimensions of STB-A11.
A thickness dimension equal to mm is formed, and RB-4 No. 1, No. 2, No. 33, 4,
The diameter of each standard hole 3″, 4″, 5″ in 5.
Since horizontal holes 8a, 8b, and 8c are formed at the same positions, the time axis and flaw detection sensitivity of the flaw detector using the standard probe can be adjusted between the test piece L and STB.
This can be done by carrying the STB-A32 with the test piece L weighing 1.3 kg.
A11, STB-A32 and RB-4 No.1-3
The weight can be reduced to about 1/20 compared to the conventional method using 3 to 5, making it extremely easy to carry to the site and greatly improving work efficiency. Furthermore, the test piece main body 7 of the test piece L has not only the above-mentioned dimensions but also a thickness dimension equal to the height of 45.5 mm, which is an important dimension of STB-A32. The time axis and flaw detection sensitivity can be adjusted by carrying the test piece L and the horizontal hole test piece 11. Furthermore, this side hole test piece 11 has been newly developed for on-site use and has been miniaturized. This makes on-site work easier.

[Brief explanation of drawings]

Figures 1, 2, 3, 4, 5, and 6 are STB-A1, STB-A3, and RB, respectively.
-4No.1, RB-4No.2, RB-No.3 and the horizontal hole test piece are shown respectively, and each a is a plan view,
Each b is a front view, the drawings from FIG.
Figures 8 and 9 show the flaw detection sensitivity adjustment, Figure 8 a and b are a front view of the flaw detection situation with RB-4 No. 1, and a characteristic diagram of the beam path and echo height in the cathode ray tube. a and b are a front view of the flaw detection situation using the test piece and a characteristic diagram of the beam path and echo height in the cathode ray tube;
Figures 10a and b are a plan view and a front view of a horizontal hole test piece according to the guidelines of the Nondestructive Testing Association, Figure 11a
and b are a plan view and a front view of the horizontal hole test piece for field use, Fig. 12 is an explanatory front view at the time of beam path calculation, and Fig. 13 a and b are front views of the flaw detection status of the test piece during time axis preliminary adjustment. and characteristic diagram of beam path and echo height in a cathode ray tube, 1st
Figures 4a and 4b are a front view of the flaw detection status of the horizontal hole test piece during zero point adjustment on the time axis, and a characteristic diagram of the beam path length and echo height in the cathode ray tube. 1...STB-A1, 3...RB-4No.1, 4...RB-
4No.2, 5...RB-4No.3, L...Adjustment test piece,
7...Test piece body, 7a, 7b, 7c, 7d, 7
e, 7f...first, second, third, fourth, fifth, sixth
Surface, 8a, 8b, 8c...first, second, and third horizontal holes.

Claims (1)

[Scope of Claims] 1. An L-shaped test piece body made of rolled steel for welded structures is provided with a vertical probe in the standard test piece STB-A1 for ultrasonic flaw detection in the thickness direction of the test piece body. Parallel first and second surfaces separated by a thickness equal to the time axis adjustment width, and the standard test piece STB perpendicular to the first and second surfaces.
- Parallel third and fourth surfaces separated by a thickness equal to the height of the stepped part for time axis adjustment for the angle probe in A1, and perpendicular to the first to fourth surfaces, respectively, and the standard test. A parallel fifth, separated by a thickness equal to the height for time axis adjustment for the vertical transducer in one STB-A1;
a sixth surface, and a standard test piece for ultrasonic flaw detection STB-A3 parallel to the third or fifth surface and from the third or fifth surface;
a seventh surface spaced apart by a thickness equal to the height for time axis adjustment for the angle probe; The position from the 5th side is the comparative test piece RB-4 No.1, RB-4 No.2, RB
-4 First, second, and third horizontal holes having the same diameter and position from the detection surface as the respective standard holes for flaw detection sensitivity adjustment of No. 3, and an adjustment test for an ultrasonic flaw detector characterized by forming: Piece.