KR870001259B1 - Steel piece inspection using electronic beam - Google Patents

Abstract

The method comprises detecting both internal and surface defects by an angle beam inspection on the surface layer of a specimen using a phased array probe. The projection on the surface of the estimated position of a defect located by the angle beam inspection is determined using the positional relation of the probe and the specimen, the incident angle of the ultrasonic beam, and the defect echo detecting time. Surface defects only are detected using a surface defect inspection apparatus.

Description

Inspection method of each piece using electronic scanning

1 shows a dead band of a conventional normal beam method.

2 shows the dead zone of inspection by each beam according to the present invention.

3 is a graph showing echo transmission changes of longitudinal and transverse sound pressure for incident angles and refraction angles.

4 shows an inspection area in inspection by an angle beam using a denomination according to the present invention.

5 is a schematic of a phased array probe.

6 (a), (b), (c) and (d) are diagrams illustrating the mode of adjustment of the ultrasonic beam by the normal array probe.

FIG. 7 is a graph illustrating the S / N ratio of the ø2 mm side pupil to the censor ultrasonic sonar diameter of angular steel pieces.

Figures 8 (a), (b) and (c) are diagrams illustrating the concept of electronic straight scan for each steel piece.

9 is a diagram illustrating an example of a circuit structure for performing an electronic linear scan.

10 (a), (b) and (c) are diagrams illustrating the concept of electronic fan-shaped scanning for each piece.

11 is a diagram for explaining an example of a circuit structure for performing an electronic fan scanning.

12 (a), (b), (c), and (d) are diagrams for explaining the comparison between the electron-shear scan and the combination of the electron-shear scan and the linear scan.

FIG. 13 is a diagram illustrating the relationship between device pitch and maximum beam angle of a normal array probe. FIG.

14 and 15 are diagrams illustrating an example of a melting chamber of the probe array for each steel piece.

16 is a diagram illustrating an information process and detection model for determining internal defects including subsurface defects.

Figure 17 is a diagram illustrating the principle of the discrimination process.

18 (a) and (b) are diagrams illustrating the incidence points of the ultrasonic beams.

19 is a diagram illustrating the determination of the point of incidence from the edge reverberation of a sample.

20 is a diagram for explaining types of surface defects.

21 is a diagram for explaining the combination of an electronic fan scan and a straight scan.

22 is a diagram illustrating the collection of detected defect information resulting from one defect.

Fig. 23 is a diagram for explaining the inspection area by the wheel type probe.

24 is a flowchart of a discrimination process.

25 is a diagram illustrating the concept of a discrimination process.

FIG. 26 is a diagram illustrating the arrangement of a wheeled probe. FIG.

The present invention relates to an ultrasonic inspection method for each piece of steel, which is used to detect internal defects including defects under the surface of a steel piece over the entire surface layer (depth: several tens of millimeters). The line system also detects effectively at high speed.

In the secondary conditioning industry of iron bars and steel bars, the process omission of manpower saving, energy saving, and cost reduction has been made more recently. Therefore, work cracking during cold forging caused by small inclusions and cracking during iron expansion cause various problems. In order to solve this problem, to detect the presence of small inclusions in terms of the quality of the outside smelting technology to prevent the removal and mixing of inclusions in pig iron and steel manufacturing and also to prevent their inclusion. The establishment of an inspection method has become essential.

As such an inspection method, an ultrasonic inspection method of a steel bar is known. In this method, a steel bar or a probe is rotated around the steel bar, and a focused ultrasonic beam is introduced into the sample. Similar inspection methods cannot be used for cast iron products because of their small diameters, and in the final stage, inspection over the entire circumference and length of the coiled product is impossible in the present state.

Inclusions of iron bars and steel bars that cause problems already exist at the raw material stage. Therefore, the quality of the product can be assured if the inclusions are detected at each steel sheet stage. In particular, in the case of barbed wire, ultrasonic inspection inside the steel sheet may be used as an internal inspection of the product. Introducing an internal inspection into the intermediate process can help to eliminate defective steel sheets in advance. Compared to the inspection in the product stage, the inspection in the intermediate process has an excellent effect because the sample length is short and the inspection efficiency is excellent. On the other hand, in order to secure reliability, high detection accuracy is required even for extremely small inclusions.

Conventionally, a regular beam method using a double crystal probe is known as an ultrasonic inspection method for each steel piece. In this method, internal defects in each steel piece can be detected, but subsurface defects cannot be detected. When each piece is machined into a product, inclusions that cause work cracks are often present in the surface layer. Therefore, it is necessary to establish an inspection method for detecting internal defects including surface defects. An ultrasonic detection method for each steel piece using mechanical scanning is also known. This method is inadequate due to the high speed operation requiring high speed movement of the probe.

SUMMARY OF THE INVENTION In view of the above problems of the prior art, an object of the present invention is to provide an ultrasonic inspection method of a angular steel piece which can be efficiently detected internal defects, including surface defects of each steel piece.

It is another object of the present invention to provide an ultrasonic inspection method of each steel piece in which the presence of a defect can be detected accurately at each steel piece step.

It is still another object of the present invention to provide an ultrasonic inspection method for each steel piece using an electron straight scan, an electron fan scan, or a combination of an electron fan scan and a straight scan.

It is still another object of the present invention to provide an ultrasonic inspection method for each steel piece which can distinguish internal defects and subsurface defects from surface defects by erasing information according to the inspection.

It is yet another object of the present invention to provide an ultrasonic inspection method for angular strips, in which the angular strips can be inspected over the inside and the entire surface layer at high speed in an on-line system.

Referring to the test method in detail as an embodiment of the present invention.

First, the start of the inspection by the square beam in the present invention will be described.

In order to check the internal defects of each steel piece, a regular beam technique has been commonly used as described above. However, as is clear from FIG. 1, this method allows the ultrasonic wave S transmitted from the probe 1 to the angular piece 2 to generate the reflection reflection S ₁ at the incident surface and generate the reflection reflection B ₁ at the low surface. This has several disadvantages in that the adjacent surface area becomes a dead zone. In contrast, when the inspection by the angle beam is used as shown in FIG. 2, the reflection reflection S ₁ of the ultrasonic wave S coming from the incident surface remains substantially, but the reflection direction S ₂ from the transverse surface of the angular strip ₂ is downward. Therefore, the deadband based on reflection does not occur on the transverse surface. If inspection by angular beam is used and the transverse surface adjacent to the incident surface is to be the inspection area, inspection of each steel piece from the surface to the inside is possible without deadband.

The basic principle of the present invention is to inspect the inside of the transverse surface layer and the angle steel piece adjacent to the incident surface by using the inspection by the angle beam.

Secondly, the examination area following the use of the intra-sectal denomination and the examination by the intra-denomination angular beam should be described.

The reasons for using sect are as follows.

As evident from Fig. 3, when the shear wave is used for the inspection by the angle beam, the echo transmission of the sound pressure is small at the refraction angle of less than 34 °, so the echo transmission of the sound pressure is performed when the inspection is performed at the refraction angle in the range of 30 ° to 40 °. If the refraction angle in the range of 50 ° to 65 ° is used, which is sensitive depending on the shape of the incident surface and the small error in adjusting the angle of incidence, and the echo transmission of sound pressure does not change much, the area below the horizontal surface adjacent to the incident surface is geometrically Several drawbacks arise from the fact that they cannot be inspected. In contrast, when transverse waves are used, the echo transmission change of sound pressure depending on the refraction angle is relatively small and continuous. In view of this advantage, sects are introduced.

The effective inspection area for the fan-shaped scan using the angular beam inspection method should be described. Due to the large refraction angle, the transverse wave is also introduced to the angular section at a considerably high level (see Figure 3), and the S / N ratio adjacent to the transverse surface is reduced by the transverse reflection, and the refraction angle is up to about 50 °. Limited. That is, as shown in FIG. 4, the inspection area is limited to the surface layer side at the lower half of the transverse surface of the angular strip 2.

As described above, in order to inspect the angular flakes over the entire length using the inspection method by the angular beam, the ultrasonic beam must be injected at a high speed. In this case, the scanning system is classified into mechanical scanning and electron scanning. Electron scanning is preferable from various viewpoints, such as high-speed scanning, directivity, and accuracy of evaluating defect locations as described later.

The principle of electron scanning is explained as follows.

Referring to FIG. 5, the steady-array probe consists of a plurality of elements 3 arranged on a substrate 4 and a coating 5 is formed on the surface of the elements 3. The shape of the ultrasonic beam irradiated from the probe is adjusted by adjusting the start wave in each element 3 using the same time delay control circuit for all elements at the time of transmission and reception. If the delay time is properly fixed, the beam S may be deflected as shown in Figure 6 (b) or focused as shown in Figure 6 (c), or as shown in Figure 6 (d). And deflect freely to form the beam contour.

When such a probe is injected in an electron scanning system, the characteristics of the electron scanning (linear or fan-shaped scan) are summarized as follows.

(I) high speed scanning

High speed scanning is easier than machine scanning.

(II) sensitive orientation

In a phased array probe, multiple devices are operated simultaneously so that the devices correspond to a single transducer with a large overall width and have a sensitive orientation.

(III) dynamic binding

As described above, for a normal array probe, a predetermined amount of delay time is provided to the transmitting and receiving wave signals, whereby the beam can be focused on a concave transducer or a transducer with a lance in a similar manner, and the inspection resolution is high. It can be performed as. In this state, the focusing distance can be freely fixed, so that the accuracy of detecting small defects and also the accuracy of defect position evaluation can be improved by focusing on the inspection area of the sample. FIG. 7 shows, for example, the correlation between the ultrasonic beam diameter and the S / N ratio of the ø2 mm side pupil during inspection of each steel piece.

(IV) Ultrasonic beams can be injected by a processed probe, so that a large inspection area can be obtained using one probe.

The comparison between the electron linear scan and the electron fan scan using the normal array probe having the above characteristics is as follows.

When the electron linear scanning is performed, the probe 1 is fixed in a predetermined state, and the ultrasonic beam S is displaced in parallel as shown in Figs. 8 (a), (b) and (c), and the adjacent transverse Inspection of the surface layer side is performed. An example of the scanning circuit required for such a process is shown in FIG.

A normal array probe consisting of 64 elements in total will consist of 16 elements in a set. The probe 1 and the transmitting / receiving device 6 are added to the delay circuit 7 as described above and connected via the relay circuit 8, and the ultrasonic beam is connected to the transmitting or receiving state by a conversion switch. When converted, it is scanned.

When the electronic fan scanning is performed, the probe 1 is adjusted to a predetermined state in a similar manner, and then the ultrasonic beam S is applied to the incident surface as shown in Figs. 10 (a,) (b) and (c). The inspection is performed on the surface layer side of the deflected and adjacent half surface lower half portion. An example of the scanning circuit required for such a process is shown in FIG. In the total division, the probe 1 consisting of 32 elements and the transmission / reception device 6 are connected through the delay circuit 7 in a one-to-one correspondence. The adjustment of the delay time according to the delay circuit 7 changes continuously, whereby the inclination of the ultrasonic beam changes and scanning is performed in the beam deflection.

Further, a feature of the present invention is that the combination of the electronic fan scanning and the electron linear scanning is based on the reasons described below.

Comparing the electron linear scanning with the electronic fan scanning, the latter eliminates the former defect as described below.

(I) In electron linear scanning, the total number of elements increases because the elements in the transmission or reception state are discontinuously displaced, and thus the probe becomes huge.

(II) The conversion requires a large number of delays, but the delay life is short.

(III) Since the elements in the transmission or reception state are displaced continuously, the transmission / reception unit (T / R unit) and each element do not correspond to 1-to-1 correspondence, which makes it difficult to adjust the sensitivity change.

(IV) Since the movement of the point of incidence of the ultrasonic wave is large, the refraction angle changes depending on the surface nonuniformity of the angular steel piece, and the accuracy of the defect position evaluation is reduced.

On the other hand, the electron fan scanning is displaced due to the deflection of the ultrasonic beam S as shown in Fig. 12 (I) of the incident surface of the angular steel piece 2.

In order to eliminate the above-mentioned drawbacks of the electronic fan scanning, the present invention combines the linear scanning with the electronic fan scanning. As shown in Figs. 12 (b), (c), and (d), the transmitting / receiving element is displaced corresponding to the non-beam angle, and accordingly, the change of the incident point is suppressed to the minimum, and the combined scanning method is the electronic fan type. Scanning is less affected by the incident surface and the accuracy of defect localization can be improved.

The probe adjusting method for combining the electronic fan scan and the electron linear scan having the above characteristics is described as follows. If the maximum inclination angle of the ultrasonic beam S is assumed to be ± θ ₀ , the vibrating element pitch d required to prevent the occurrence of grate projections in the normal array probe is expressed as follows.

Is the wavelength in the ultrasonic transmission medium.

In order to increase the tilt angle of the ultrasonic beam S when λ is constant, the device pitch d must be reduced. (The relationship between the element width and the maximum beam tilt angle θ ₀ is shown in Figs. 13 (a) and (b). Therefore, device width should be reduced.

The following two methods are proposed to adjust the probe using the above features.

(1) One method is a method that is located at a predetermined distance from the sample surface in a plane perpendicular to the axial direction of each steel piece and adjusted parallel to the plane of incidence. In this case, the width of each element of the probe decreases and the number of divisions increases. The feature of this method is that the two transverse surfaces adjacent to the incident surface can be investigated because of the large maximum beam angle.

(2) In another method, the probe is similarly positioned at a defined distance from the sample surface in a plane perpendicular to the axial direction of each steel piece, and is inclined to be adjusted with respect to the incident surface by the angle of incidence to form a center of deflection scanning. Way.

The feature of this method is that the absolute value of the beam angle is small and therefore the maximum delay time is reduced. Since the absolute value of the beam angle is small, the width of each probe element can be increased.

14 and 15 show an example of the arrangement state application of the probe 1 to the angular steel piece (2). In the example of FIG. 14, one probe 1 is arranged in parallel with each surface of the square steel piece 2. As shown in FIG. That is, one probe 1 examines the lower half of the two transverse surfaces adjacent to the incident surface in the angular flat 2 as shown in the drawing, and thus the four probes 1 are angular slabs 2 Examine the entire surface layer. In another embodiment of FIG. 15, two probes 1 are arranged at defined angles with respect to the respective surfaces of the steel strip 2.

That is, one probe 1 inspects the lower half of the transverse surface adjacent to the incident surface in the angular steel piece 2 as can be seen in the drawing. Thus, eight probes 1 are angular steel piece 2 The entire surface layer of is examined. In other arrangements, high-speed inspection over the entire surface of each steel sheet is possible with an on-line system. The process of determining the subsurface defects in each steel piece is explained as follows. According to the present invention, according to the irradiation by each beam combining the combination of the electron fan and the linear scan, each steel piece as a sample can be inspected at high speed and accurately to detect the internal defect including the lower surface defect. Can be. When the surface layer of each steel piece is inspected, not only subsurface defects but also surface cracks are detected, whereby the test results include information on detection according to the surface defect test. However, surface cracks can be removed by finishing work or grinding work in the steel machine process, so there is no problem in the secondary process operation of the product. Therefore, it is necessary to detect only internal bonds (usually including subsurface defects) without surface cracks.

In order to detect internal defects, the surface defect inspection results may be erased as previously described in the ultrasonic examination results of the angle beams of the steel pieces from the inside. Various methods for inspecting surface defects are described in the following table along with their detectability.

Since the detection of surface defects is different in various methods for surface defect inspection, the detection characteristic of internal defects depends on which method for surface defect inspection is combined with the internal defect inspection.

The information processing method for discriminating the lower surface defect is basically performed by erasing the information 2 from the information 1 as shown in FIG. However, the ultrasound inspection by the angle beam includes various factors to reduce the accuracy of the defect location evaluation, so that the information (1) is less reliable than the defect location information (information 2) based on the surface defect inspection, and the information (1) The error region of the defect position evaluation in is large. Therefore, a simple cut will cause an error.

표시의 위치에 있음을 나타낸다. 만일 이와같은 정보가 정정되지 않고 공정이 진행되면 각개의 결함이 별도로 존재하고 표면하부 결함의 존재를 나타내는 정보(1)는 잔유하게 된다. 즉 표면결함(15)면이 실제로 존재하더라도 이것은 표면하부결함으로서 보이게 된다.Referring to FIG. 17, the surface defect 15 is actually present, the information 1 indicates that the defect position detected by the ultrasonic inspection by the angle beam is at the position of the mark ◎, and the information 2 is different. The surface defect position detected by the surface defect inspection device

Indicates the position of the mark. If such information is not corrected and the process proceeds, each defect is present separately and the information 1 indicating the presence of subsurface defects remains. In other words, even if the surface defect 15 surface actually exists, this is seen as a subsurface defect.

In order to eliminate such inaccurate defects in which the surface defects are regarded as subsurface defects, a predetermined area in which the introduced information 1 is deleted can be supplied to the information 2. The extent of the area supplied to the information 2 is determined by the accuracy of the information 1, and the accuracy is considerably affected by the ultrasonic beam diameter (small diameter, i.e. a focused state) and the shape of the incident surface. . (The nonuniformity of the incident surface changes the angle of refraction so that the point of incidence does not change much, and the incident surface is preferably flat.)

표시)에 대하여 정방형의 강철폭 방향으로 폭 ±△H의 범위내에 있고, 전체 검사영역(δ)이 깊이방향 즉 일점쇄선으로 도시된 영역에 있게되면 정보(1)은 소거된다. 이와같이하여 정보(2)에 일정영역을 제공으로써 정보(1)이 표면 결함이라고 결정되는 것이다.The area supplied to the information 2 is shown by a dashed-dotted line in FIG. 17 and must be larger than the defect position evaluation error area of the information 1 (shown by the broken line). If information (1) is a surface defect evaluation position (

Information 1 is erased when it is in the range of width ± DELTA H in the square steel width direction and the entire inspection area δ is in the depth direction, that is, the area shown by the dashed-dotted line. In this way, by providing a certain area for the information 2, it is determined that the information 1 is a surface defect.

Clearing the inspection information by the angle beam in the width ± ΔH in the width direction of the angular strip 2 makes an inaccurate determination that the substantial detection of the subsurface defects in the area is not regarded as a subsurface defect. To reduce the likelihood of such contradictions, the width of DELTA H should be reduced. In other words, the introduction of a scanning system with high accuracy of defect location evaluation is preferable for inspection by square beams.

Straight line scans are significantly affected by the non-uniformity of the sample shape and, therefore, inferiority to the fan-shaped scans in the accuracy of defect location evaluation. Therefore, fan-shaped injections are desirable. Of course, it is most preferable to combine fan and linear scanning. This is because the change in position of the incident point is minimized.

The following two methods are used together to improve the accuracy of flaw location evaluation in the combination of flat scan and straight scan.

One method is to enter ultrasonic waves from the center of the surface, which is considered to be least affected by the nonuniformity of the incident surface. In such a configuration, even if there is a nonuniformity on the surface of the angular steel piece 2, the state of the surface center portion is approximately the same as that of the flat surface as shown in Figs. 18 (a) and (b).

Another method is to measure the angle of incidence rising to the maximum reflection by detecting the reflection from the corner portion so as to correct the appearance change of the refraction angle (So-S) caused by the inclination of the incidence surface shown in FIG. . The inclination of the incidence surface is evaluated from the value of the incidence angle, and the incidence angle is corrected so that the beam is within the area to be irradiated.

Referring to the surface defect inspection apparatus for detecting the surface 15 is as follows.

The surface defect inspection method includes a magnet particle (self-supporting) test method, an eddy current inspection method, a surface wave inspection method, an optical inspection method, and an apparatus suitable for each method is known. The detection capability of the device differs according to various surface defect inspection methods and types of defects. The detection capabilities of the various inspection methods for the various types of surface defects shown in FIG. 20 are shown in the above table. In Fig. 20, the numeral 15a indicates a crack, 15b indicates a scab, and 15c indicates a scratch.

As can be seen from the table, all kinds of surface defects detected using the inspection method by the square beam can be detected using the surface examination, but defects except the crack 15a can be detected using the independent inspection. Can't. However, in the surface wave inspection, when one surface defect is found, further wave propagation from the defect point is significantly reduced. Therefore, in the case where a large number of surface defects exist, the surface examination cannot detect the surface defects.

As described above, various surface defect inspection methods have both advantages and disadvantages. The discrimination of surface defects (15) and subsurface defects depends on how the various methods are combined for inspection by the square beam.

An information process for discriminating surface layer defects from surface defects in the case of using a normal array apparatus for inspection by a square beam and using a surface wave inspection apparatus and a self-standing inspection apparatus for surface defect inspection will be described as follows.

The data processing method for inspection by square beams is explained.

Referring to FIG. 21, the inspection area by the normal array device is irradiated by combining fan-shaped and linear scanning in eight steps from the bottom edge as a reference point. If there are echoes above the preset echo level (limit value) for each stage in the inspection area, the stage number, echo height, detection time, and axial position of the square strip 2 corresponding to the maximum echo are shown in FIG. It is taken as inspection data as one. The defect projection evaluation position on the angular steel piece is evaluated from the refraction angle and the detection time, and the evaluated position is converted into position information in the width direction of the angular steel piece divided by a constant pitch. The data is collected in the light of defect continuity in the axial direction of each steel piece 2, and information on the number of defects, the point of occurrence of defects (axial direction), the defect length (axial direction) and the position in the width direction is finally determined.

In FIG. 21, the inspection gate 16 in the inspection region has a sufficient length to ensure inspection from the surface in consideration of the passage change caused by the deformation of the specimen 2. However, the inspection gate region is limited in the corner portion so as not to detect the edge echo.

FIG. 22 shows a cross section of the angular steel piece 2, where the number 17 indicates the position of the detected defect and the number 18 indicates the projection evaluation position information of the defect. 22 (b) shows the projection surface matrix of the square steel pieces 2. P ₁ represents the pitch of the scanning step, and P ₂ represents the axial inspection pitch of each steel piece. The projection evaluation position information 18 of the defect is collected in the matrix. If the information 18 does not continue more than twice in the axial direction of each steel piece, it is determined as noise 19 and does not become defect information. If the information 18 continues more than twice, it is processed into defect information 20. That is, the detected defect 17 is surrounded by a dark line in FIG. 22 (b), and becomes information having a starting point 21 and a depth of (1).

Although a combination of a sector scan and a linear scan by an electronic scanning type inspection apparatus has been described as an example, a similar process by a straight scan or a sector scan can be performed. For example, although the inspection area is inspected in eight steps, the inspection is performed more closely as the number of steps is increased, and a constant pitch division in the width direction of the tetragonal steel piece can be performed more finely during projection onto the surface, thereby improving discrimination. Is sure.

The data processing method in surface defect inspection is described as follows.

As shown in FIG. 23, the wheel-type probe 22 is used for surface and inspection. In this case, the inspection area is the surface 24 opposite the adjacent transverse surface 22 and the surface in contact with the probe and the edge 25. The gate is used in the inspection area in detail, ie surface and edges. For the reverberation height, the detection time, and the axial position of the tetragonal steel strips, the maximum reflections at or above the maximum limit at the edge gate portion 25 and the maximum reflections at the edge gate portion 25 are the maximum reflections at the first gate 23 and the second gate 24, respectively. Is taken as the inspection data. The defect evaluation position in the axial direction of each steel piece is evaluated from the detection time in a similar manner to the data collection in the inspection by each beam, and the evaluation position is converted to the position information in the axial direction of each steel piece when divided into a certain pitch. do. Taking into account the continuity of each steel piece in the axial direction, information on the number of defects, the starting point of the defect (axial direction), the defect length (axial direction) and the width direction position is determined.

When describing the independent inspection data using the independence inspection apparatus, the information format is similar to the collected information of the inspection by the square beam, and the surface wave inspection is used.

In order to discriminate the surface defect information from the information in the inspection by the square beam and the information in the surface defect inspection, the surface defect information supplied with a certain area as described above is erased from the collection information in the inspection by the square beam. Used as surface defect area information. A block diagram of such a process is shown in FIG.

The surface defect area information includes surface wave inspection, self-supporting inspection, or both of the position information in the width direction of the surface defect collection information in the width direction, several expanded blocks divided in the width direction of each steel piece, the origin of the defect, and extended by several tens of millimeters. The defect length in the area is included.

25 shows the concept of the discriminating process of the present invention. As can be seen from the figure, inaccurate detection in which surface defects are treated as subsurface defects is prevented by combining surface wave inspection and independence inspection.

Probe arrangements for inspection by angle beams over the entire surface have already been described. The arrangement of the wheel-type probe in the inspection over the entire surface will be described with reference to FIG. Two probes 27 are included in the wheel-type probe 26, and two wheel-type probes 22 face each other. Of course, the sample moves in the axial direction.

In the embodiment of the present invention described above, a phased array device, a surface wave inspection device, and a self-supporting inspection device are combined, whereby surface defects can be discriminated from subsurface defects. In addition, surface defects can be detected without failure compared to surface defect inspection alone. In particular, in the self-supporting inspection method, the low detection ability of the edge portion defect can be supplemented by the inspection information on the edge portion in the surface wave inspection.

The present invention is not limited to the above embodiments. The sample may be a major phase, in which case an arrayed probe such as the one described in Japanese Patent Application No. 58-3198 may be used, and the surface layer and the surface inspection may be performed simultaneously to determine a defect. .

Claims (4)

In the method of inspecting each piece of steel, in which an electron scanning array probe is used for ultrasonic inspection, an array probe in which the electron scanning is a straight scan is positioned at a prescribed distance from the surface of the steel piece in a plane perpendicular to the axial direction of each steel piece. A method for inspecting each piece of steel, set at an angle defined for the surface, wherein each piece is inspected in the inner and surface layers using a linear scanning array probe. In the method of inspecting each piece of steel in which an electron scanning array probe is used for ultrasonic inspection, the array type probe in which the electron scanning is a fan-shaped scan is positioned at a predetermined distance from the surface of the steel piece in a plane perpendicular to the axial direction of each steel piece. A method for inspecting each piece of steel, characterized by being set at an angle defined for the surface, wherein each piece is inspected in the inner and surface layers using a flat-array array probe. In the inspection method of each piece using the electron scanning array type probe for ultrasonic inspection, the array type probe in which the electron scanning combination of the red line scan and the fan-shaped scan is defined from the surface of the piece in the plane perpendicular to the axial direction of each piece. A method of inspecting each piece of steel, characterized in that it is placed at a distance and is set at an angle defined for the surface of the piece of steel, and each piece of steel is inspected in the inner and surface layers using a combination array probe of straight and flat scanning. Performing inspection by each beam on the surface layer of the sample using a normal array probe; Determining a defect evaluation position when projected onto the surface of the sample by an operation process from the positional relationship between the probe and the sample, the incident angle of the ultrasonic wave, and the defect reflection detection time; Detecting only a surface defect using a surface defect inspection apparatus and determining a prescribed region of the defect position; Detecting only a lower surface defect based on erasing the latter defect area information from the former defect evaluation position information; Detection method of the lower surface defects by the ultrasonic test, characterized in that consisting of.

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