JP6238716B2 - Discrimination method and apparatus for surface defect depth of inspection object - Google Patents

Description

  The present invention relates to a method for discriminating a surface defect depth of an object to be inspected and a device for discriminating the depth of a surface defect present in a steel material or a steel bar.

Detects the presence or absence of defects (hereinafter collectively referred to as “surface defects”) on the surface of the object to be inspected, such as steel bars or steel slabs, which are metallic materials, and the depth of surface defects As a method for performing the inspection, in other words, a method for assuring the quality of the inspection object, a magnetic particle inspection method, an ultrasonic inspection method, and the like are known.
The magnetic particle flaw detection method is a wet inspection technology that detects a surface defect by observing the magnetic particle indication pattern formed on the surface of the object to be inspected. The ultrasonic flaw detection method uses ultrasonic waves to detect the object to be inspected. This is a technique for flaw detection on the surface and the inside of a wafer.

  As an ultrasonic flaw detection method, three techniques of “vertical flaw detection method”, “bevel angle flaw detection method”, and “surface flaw detection method” are generally used. Specifically, the vertical flaw detection method is a technique for flaw detection in the inspected body using ultrasonic waves that travel perpendicularly to the surface of the object to be inspected, and the oblique flaw detection method is for the surface of the object to be inspected. This is a technique for flaw-detecting an inspected body or the surface of an inspected object using ultrasonic waves that travel obliquely. The surface flaw detection method is a technique for flaw-detecting the surface of an inspection object using surface ultrasonic waves that propagate on the surface of the inspection object.

The above-mentioned magnetic particle inspection method and surface wave inspection method are used to guarantee the surface quality of the object to be inspected, and the vertical inspection method and the oblique inspection method are used to guarantee the internal quality of the object to be inspected. ing.
In this way, there are various flaw detection methods, but in order to accurately detect defects and defect depths existing on the surface of the object to be inspected and the surface under the skin, that is, in order to ensure the quality of the object to be inspected, Inspection of an object to be inspected that combines a plurality of flaw detection methods described above is performed.

Examples of inspection techniques for an object to be inspected by combining a plurality of flaw detection techniques include those disclosed in Patent Document 1 and Patent Document 2.
In Patent Document 1, a specimen such as a steel slab is flaw-detected by surface defect flaw detection, ultrasonic oblique flaw detection, and ultrasonic vertical internal flaw detection. For defects detected by flaw detection and defects detected by oblique flaw detection, defects whose depth of defect evaluation is shallower than the chamfering limit value are chamfered to the chamfering limit value of each defect rating position, When a defect is detected by vertical internal flaw detection, and for defects detected by oblique flaw detection whose depth of defect evaluation is deeper than the cut-off limit value, such as a steel slab that treats the test material as an internal defect material, etc. A pass / fail determination method for a test material is disclosed.

  In Patent Document 2, in a flaw detection method combining a plurality of nondestructive tests, an ultrasonic flaw detection test is performed by supplying a contact medium containing a permeation liquid between a flaw detection surface and a probe, and the permeation liquid A flaw detection method for detecting a defect indicating pattern by a permeating liquid after a required permeating liquid permeation time has elapsed from the supply of the contact medium containing the liquid is disclosed.

Japanese Patent Publication No. 6-77000 Japanese Examined Patent Publication No. 6-82118

  By the way, when inspecting an object to be inspected using the magnetic particle flaw detection method, a defect that originally exists in the object to be inspected is rarely detected. Also, when inspecting an object to be inspected using the ultrasonic flaw detection method, a location that is not a defect (for example, an ultrasonic wave reflected at a corner of a substantially square object to be inspected) is erroneously detected as a defect. In rare cases, the depth of a defect existing in the inspection object is erroneously detected.

When such erroneous detection occurs, it becomes impossible to ensure the quality of the object to be inspected. For example, the depth of surface defects may be detected as "deep" even though the surface defect depth of the object to be inspected is relatively shallow. Even though the surface defect depth of the object to be inspected is relatively deep, the depth of the surface defect may be detected as “shallow”.

However, if the surface defect is detected as “deep” despite being shallow, it can be shipped as a product by scraping the surface defect at the detected depth, and the front and rear ends of the object to be inspected. If it is inside, it can be shipped as a product by cutting the front and rear ends of the object to be inspected so as to ensure the weight of the product.
On the other hand, if a surface defect is detected as being "shallow" despite being deep, the surface defect will still exist (uncut) even if the surface defect is cut at the detected depth. In such a state, it is very difficult to ship as a product.

  By the way, the detected surface defects are automatically detected by a cutting device (trapping machine) such as a servo grinder or a milling cutter based on the position data of the detected surface defects in the surface defect removal process that is a subsequent process of the flaw detection process. Removed. The cutting device used in this surface defect removal process can remove (scratch) only surface defects at a shallow location (for example, about several mm) from the surface of the object to be inspected.

  Therefore, if the depth of the surface defect is set to cut deeply to the limit of the cutting device in order to avoid the above-mentioned “uncut residue”, the probability of leaving the surface defect is reduced. Further, it takes a long time to cut deep in the vicinity of the position where the surface defect exists, and the wear of the cutting blade may be increased. In addition, there is a problem that scraping failure due to increased wear of the cutting blade, and cost for replacing the worn cutting blade, which increases the manufacturing cost of the product.

In summary, the surface defect detected by the conventional inspection technology of the inspection object is simply cut with the cutting device, and the surface defect of the inspection object is accurately detected, and the surface defect is surely removed from the inspection object. It is unknown.
In order to avoid such an erroneous flaw detection result, it is also conceivable to inspect the object to be inspected by combining a plurality of inspection techniques as disclosed in Patent Document 1 and Patent Document 2.

However, Patent Document 1 and Patent Document 2 only disclose that two or more inspection technologies are used in combination, and two or more inspection technologies are allowed to cooperate in order to avoid the above-described erroneous detection. In addition, no technique for effectively operating is disclosed.
Therefore, in view of the above problems, the present invention provides a flaw detection result of the surface defect of the inspection object obtained by the magnetic particle flaw detection method and a flaw detection result of the surface defect depth of the inspection object obtained by the surface wave flaw detection method. The surface defect depth of the object to be inspected can be accurately and reliably discriminated by evaluating the depth of the surface defect of the object to be inspected. It is an object to provide a method and apparatus.

In order to achieve the above-described object, the present invention takes the following technical means.
The method for discriminating the surface defect depth of an object to be inspected according to the present invention detects a surface defect existing on the surface of the object to be inspected and / or the surface under the surface, and evaluates the depth of the surface defect of the object to be inspected. Te, a discriminating method of surface defect depth of the test subject to distinguish the depth of surface defects present in the object to be inspected, using a magnetic Konasagu scratch method, flaw detection surface defects of the object to be inspected, Using an ultrasonic flaw detection method in which the frequency of ultrasonic waves transmitted to the object to be inspected can be changed , the surface defect of the object to be inspected is detected and the depth of the surface defect is detected, By evaluating the combination of the case where the flaw is detected and the case where the flaw is not detected from the flaw detection result of the surface defect obtained by the magnetic particle flaw detection method and the flaw detection result of the surface defect obtained by the ultrasonic flaw detection method, absence of surface defects of the inspected, and discriminates the depth of the surface defect, the greater By examining the combination of the case where the reflected signal is received and the case where the reflected signal is not received when the measurement frequency is 5MHz, 2MHz and 1.5MHz from the surface defect inspection result obtained by the wave flaw detection method, In addition, it is characterized by discriminating into depth ranks classified according to the depth of surface defects .

The apparatus for discriminating the surface defect depth of an object to be inspected according to the present invention detects a surface defect existing on the surface and / or surface of the object to be inspected, and evaluates the depth of the surface defect of the object to be inspected. An apparatus for discriminating the surface defect depth of an object to be inspected for discriminating the depth of a surface defect existing in the object to be inspected, and for detecting the surface defect of the object to be inspected using a magnetic particle inspection method and means, prior SL using the ultrasonic flaw detection method is ultrasonic frequencies dispatched for inspection object is changeable, the depth of the surface defect while testing the surface defects of the object to be inspected Ultrasonic flaw detection means for detecting the surface flaw detection result obtained by the magnetic particle flaw detection means, and the case where a flaw is detected or not detected from the surface flaw detection result obtained by the ultrasonic flaw detection means to assess the combination, organic surface defects of the object to be inspected , And has a surface defect depth discrimination means for discriminating the depth of the surface defect, the said surface defect depth discrimination means, wherein the measuring frequency from the flaw detection results of the surface defect obtained by the ultrasonic flaw detection means 5MHz Discriminate flaws that have been inspected into depth ranks divided by the depth of surface defects by evaluating the combination of when reflected signals are received and not received at 2 MHz and 1.5 MHz It is comprised as follows.

  According to the method and apparatus for discriminating the surface defect depth of an inspection object according to the present invention, the inspection result of the surface defect of the inspection object obtained by the magnetic particle inspection method and the inspection obtained by the surface wave inspection method It is possible to accurately and reliably discriminate the depth of surface defects existing in the inspection object by evaluating the surface defect depth of the inspection object using the inspection result of the surface defect depth of the body. it can.

It is the schematic which shows the discrimination apparatus of the surface defect depth of the to-be-inspected object which concerns on this invention. (A) is the schematic which shows the structure of the ultrasonic flaw detection means of the discrimination apparatus of the surface defect depth of a to-be-inspected object, (b) is the magnetic particle flaw detection means of the discrimination apparatus of the surface defect depth of a to-be-inspected object It is the schematic which shows the structure of these. It is a figure which shows the difference in the detection performance of the surface defect by the frequency (wavelength) of surface wave flaw detection. It is the figure which showed the relationship between the depth of a surface defect, and a depth rank. It is the schematic which shows the modification of the discrimination apparatus of the surface defect depth of the to-be-inspected object which concerns on this invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a discrimination device for surface defect depth of an object to be inspected according to the present invention will be described with reference to the drawings, and the present invention of a method for discriminating surface defect depth of an object to be inspected using the discrimination device Will be described with reference to the drawings.
The surface defect depth discrimination device 1 according to the present invention uses a magnetic particle inspection method to detect a surface defect K of the inspection subject W, and further uses an ultrasonic inspection method to detect a steel bar or The surface defect K of the inspection object W such as a steel material is detected, the depth of the surface defect K is detected, the depth of the surface defect K of the inspection object W is evaluated, and the inspection object W exists. This device discriminates the depth of the surface defect K.

In the present embodiment, defects existing on the surface and the surface of the inspected object W are collectively referred to as “surface defects K”.
FIG. 1 is a diagram showing a discrimination device 1 for the surface defect depth of an object to be inspected W according to the present invention. 2A is a diagram showing a configuration of the ultrasonic flaw detector 2 of the discrimination device 1 for the surface defect depth of the object W to be inspected, and FIG. 2B is a surface defect of the object W to be inspected. It is a figure which shows the structure of the magnetic particle flaw detection means 12 of the discrimination apparatus 1 of depth.

As shown in FIG. 1 and FIG. 2, the surface defect depth discrimination device 1 of the inspection subject W according to the present invention is installed in an inspection line for inspecting the inspection subject W. This inspection line includes a transport unit 20 (a pair of pinch rollers) that transports the object to be inspected W, and inspects the object to be inspected W transported by the transport unit 20 for the presence of surface defects K and the like. Do.
The discriminating apparatus 1 installed in the inspection line includes an ultrasonic flaw detector 2 provided upstream in the steel material conveying direction, a magnetic flaw detector 12 provided downstream thereof, and a surface obtained by the magnetic flaw detector 12. A surface defect that discriminates the presence / absence of the surface defect K and the depth of the surface defect K by using the flaw detection result of the defect K and the flaw detection result of the surface defect K obtained by the ultrasonic flaw detection means 2. Depth discriminating means 18.

In this way, by arranging the magnetic particle flaw detection means 12 after the ultrasonic flaw detection means 2, the contact medium used in the ultrasonic flaw detection means 2 remains on the surface of the object W to be measured a little, and the magnetic particle flaw detection is performed. The wettability of the magnetic powder L sprayed by the means 12 to the surface of the inspection object W is improved.
As shown in FIGS. 1 and 2 (a), the ultrasonic flaw detection means 2 uses a surface wave flaw detection method in which the frequency of ultrasonic waves sent to the object W to be inspected can be changed. The surface defect K of the inspection object W is detected and the depth of the surface defect K is detected.

The ultrasonic flaw detection means 2 includes a probe 4, a sensor head 3 including the probe 4, a sensor holder 5, and a holder support 6, an ultrasonic flaw detector 7, a signal recording processing unit 8, and a contact medium supply. The recovery unit 9, the air blower 10, and the air supply unit 11 are provided.
The sensor head 3 includes a probe 4, a sensor holder 5 that holds the probe 4, and a holder that supports the sensor holder 5 and abuts the probe 4 against the object W to be inspected. It is comprised with the support body 6. As shown in FIG.

  The probe 4 is composed of, for example, a piezoelectric element, and includes a sending unit that transmits ultrasonic waves (surface waves) propagating directly under the surface of the inspection object W being conveyed by the conveyance unit 20 and the inspection object W. It has a wave receiving part for receiving the ultrasonic wave reflected and returned by the surface defect K existing on the surface and the surface under the skin. The transmitting unit has a function of transmitting an ultrasonic wave (surface wave) having a predetermined frequency when a pulse current of a predetermined voltage is applied, and the receiving unit receives the reflected ultrasonic wave (reflected surface wave) and When a reflected surface wave is received, it has a function of generating a pulse current corresponding to the received reflected surface wave.

2A, the probe 4 comes into contact with the side surface of the object W to be inspected and a surface wave is generated in the circumferential direction of the object W indicated by the arrow. Is transmitted from the transmitting unit, and the ultrasonic wave reflected and returned by the surface defect K existing on the surface of the object to be inspected W and under the surface is received by the receiving unit.
In particular, the probe 4 in the ultrasonic flaw detector 2 of this embodiment is composed of two or more different types of piezoelectric elements, and has a plurality of frequencies (for example, f1 = 5 MHz, f2 = 2 MHz, f3 = 1.5 MHz). ) Surface wave can be transmitted.

  As shown in FIG. 3, for example, when a surface defect K having a depth of 0.2 mm is to be detected, if an ultrasonic wave having a frequency of 5 MHz is used, the surface wave propagation region is narrow and the surface has a depth of 0.2 mm. It is easy to detect the defect K. On the other hand, if the surface defect K is detected using an ultrasonic wave having a frequency of 2 MHz, the surface wave propagation region is wide and it is difficult to detect the surface defect K having a depth of 0.2 mm.

  Table 1 shows the difference in detection performance depending on the frequency (wavelength) of the above-described ultrasonic wave (surface wave).

As shown in Table 1, since the ultrasonic energy is concentrated to about one wavelength of the surface layer as a characteristic of the surface wave, the reflected wave intensity is related to the depth of the surface defect K, and therefore, has different frequencies (wavelengths). Surface waves are used. Therefore, the depth information of the surface defect K can be obtained. In addition, the depth to be distinguished can be changed by properly using surface waves having different frequencies.
As described above, since the depth of the surface defect K that can be detected differs depending on the frequency, the frequency can be switched in this embodiment.

The sensor holder 5 is, for example, a box-shaped housing having a substantially cubic shape and opened downward, and is supported by a holder support 6.
The sensor holder 5 supplies the probe 4 with the above-described probe 4 and a contact medium that transmits ultrasonic waves between the probe 4 and the object W to be inspected. And a contact medium recovery pipe for recovering the supplied contact medium from the probe 4.

  The ultrasonic flaw detector 7 is connected to a probe 4 provided in the sensor head 3, and selectively applies a pulse current of a predetermined voltage to one of two types of piezoelectric elements that function as a sending unit of the probe 4. Is output. Further, the ultrasonic flaw detector 7 receives a pulse current generated when the two types of piezoelectric elements receive the reflected surface wave and acts as a wave receiving unit, and receives the reflected surface wave in the signal recording processing unit 8 described later. It is output as a signal. By adjusting the pulse current with the ultrasonic flaw detector 7, the surface wave propagating to the surface of the inspection subject W can be sent to the probe 4.

  The signal recording processing unit 8 is connected to the ultrasonic flaw detector 7, receives the reflected surface wave signal output from the ultrasonic flaw detector 7, and based on the received reflected surface wave signal, the reflected surface wave ( Echo) arrival time, that is, the depth of the surface defect K is calculated. The flaw detection result of the depth of the surface defect K calculated by the signal recording processing unit 8 is sent to the surface defect depth discrimination means 18 described later.

The contact medium supply / recovery unit 9 supplies the contact medium used by the probe 4 of the sensor head 3 to the probe 4 through the contact medium supply pipe of the sensor holder 5 and also passes through the contact medium recovery pipe of the sensor holder 5. The contact medium is collected from the probe 4 and is connected to the contact medium supply pipe and the contact medium collection pipe of the sensor holder 5.
As shown in FIG. 2A, the air blower 10 is a means for removing contact medium and the like remaining on the side surface of the object W to be inspected. The air blower 10 is arranged on the side surface of the inspection object W on which the sensor head 3 is arranged, on the downstream side in the material passing direction, which is away from the sensor head 3 by a predetermined distance. A substantially rectangular parallelepiped housing having substantially the same width, a plurality of air nozzles extending in the longitudinal direction of the housing and projecting in the direction opposite to the material passing direction, and an air inlet (not shown). The

  On the other hand, as shown in FIG. 1 and FIG. 2B, the magnetic particle flaw detector 12 includes a magnetic powder liquid spraying unit 13 that sprays the magnetic powder liquid L onto the surface of the object W being transported by the transport unit 20, and this A magnetizer 14 that magnetizes the inspected object W on the downstream side of the magnetic powder dispersion unit 13, an illuminating unit 15 that illuminates the surface of the inspected object W on the downstream side of the magnetizer 14, and fluorescence by the illuminating unit 15. The imaging unit 16 that images the emitted magnetic powder pattern and the image analysis unit 17 that analyzes the image captured by the imaging unit 16 and detects the surface defect K are included.

The magnetic powder liquid spraying unit 13 sprays a test liquid L containing magnetic powder (iron powder with a phosphor attached) to the surface of the inspection object W with a spray nozzle.
The magnetizer 14 includes, for example, two sets of electromagnets in which a coil is wound around a U-shaped magnetic body, and an object to be inspected is formed between a pair of tip portions (pole portions) of each U-shaped magnetic body. An AC current is applied to the coil close to W, and a magnetic field is applied to the surface of the object to be inspected W positioned between both pole portions. When the surface defect K exists in the inspected object W to which the magnetic field is applied by the magnetizer 14, a magnetic field leaked in the vicinity of the surface defect K is present, so that a stronger magnetic field is generated than the portion without the surface defect K, Magnetic powder containing the phosphor aggregates in the vicinity of the surface defect K at a high density, and a pattern of magnetic powder corresponding to the state of the surface defect K appears.

The illumination unit 15 is an ultraviolet lamp or the like that irradiates the magnetic powder pattern generated by the magnetic flux leaked in the vicinity of the surface defect K with ultraviolet rays, and a light source with less luminance unevenness is used.
The imaging unit 16 images the fluorescence emitted from the magnetic powder containing the phosphor attached in the vicinity of the surface defect K of the inspection object W, and the captured image is supplied to the image analysis unit 17. For example, a line sensor camera or the like is used for the imaging unit 16.

The image analysis unit 17 analyzes the surface image of the inspection object W imaged by the imaging unit 16 and determines the presence or absence of the surface defect K of the inspection object W. The flaw detection result of the surface defect K analyzed by the image analysis unit 17 is sent to the surface defect depth discrimination means 18 described later. Further, the flaw detection result of the surface defect K obtained by the ultrasonic flaw detection means 2 is also sent to the surface defect depth discrimination means 18 described later.
The surface defect depth discriminating means 18 is based on the surface defect K detection result obtained by the ultrasonic flaw detection means 2 and the surface defect K flaw detection result obtained by the magnetic particle flaw detection means 12. The presence / absence of the defect K and the depth of the surface defect K are identified and discriminated.

The surface defect depth discrimination means 18 is connected to the signal recording processing section 8 of the ultrasonic flaw detection means 2 and also connected to the image analysis section 17 of the magnetic particle flaw detection means 12.
As shown in Table 2, the surface defect depth discriminating means 18 can detect the depth of any surface defect K existing on the surface of the object W to be inspected and the surface of the surface to be inspected.
When the pattern 1 of Table 2 is seen, the surface defect K of the to-be-inspected object W is detected in the magnetic particle flaw detector 12. Further, in the ultrasonic flaw detection means 2, even when flaw detection is performed with the frequency of the ultrasonic wave being f1, or when flaw detection is performed by switching the frequency of the ultrasonic wave to f2 (f1> f2), the surface defect K of the inspection object W is detected. The depth of is detected. In the case of such a detection result, the shape of the surface defect K present in the inspection object W is identified as a surface defect K that is open on the surface of the inspection object W and has a deep wrinkle depth.

  Next, looking at the pattern 2 in Table 1, the magnetic particle flaw detector 12 detects the surface defect K of the object W to be inspected. Further, in the ultrasonic flaw detection means 2, the depth of the surface defect K of the inspection object W is detected only when flaw detection is performed with the frequency of the ultrasonic wave being f1. In the case of such a detection result, the shape of the surface defect K existing in the inspection object W is identified as the surface defect K that is open on the surface of the inspection object W and has a shallow wrinkle depth.

  When the pattern 3 of Table 2 is seen, the surface defect K of the to-be-inspected object W is detected in the magnetic particle flaw detector 12. On the other hand, in the ultrasonic flaw detection means 2, the depth of the surface defect K of the object W to be inspected is not detected at any ultrasonic frequency. In the case of such a detection result, the shape of the surface defect K present in the inspection object W is identified as the surface defect K that is open on the surface of the inspection object W and has a very shallow wrinkle depth.

Looking at the pattern 4 in Table 2, the magnetic particle flaw detector 12 does not detect the surface defect K of the object W, and the ultrasonic flaw detector 2 does not detect even if the ultrasonic frequency is f1. Even when the ultrasonic frequency is switched to f2 (f1> f2) and the flaw detection is performed, the depth of the surface defect K of the inspected object W is detected.
In the case of such a detection result, the shape of the surface defect K present in the inspection object W is identified as the surface defect K that is closed on the surface of the inspection object W and has a deep wrinkle depth.

  When looking at the pattern 5 in Table 2, the magnetic particle flaw detector 12 does not detect the surface defect K of the object W, and the ultrasonic flaw detector 2 detects flaws with the frequency of the ultrasonic wave set to f1. Only the depth of the surface defect K of the inspection object W is detected. In the case of such a detection result, the shape of the surface defect K present in the inspection object W is identified as the surface defect K that is closed on the surface of the inspection object W and has a shallow wrinkle depth.

  When the pattern 6 of Table 2 is seen, the surface defect K of the to-be-inspected object W is not detected in the magnetic particle flaw detection means 12, and the ultrasonic flaw detection means 2 performs flaw detection with the ultrasonic frequency set to f2. Only the depth of the surface defect K of the inspection object W is detected. In the case of such a detection result, the shape of the surface defect K present in the inspection object W is identified as the surface defect K that is closed on the surface of the inspection object W and has a deep wrinkle depth.

As described above, the surface defect depth discriminating means 18 which is a feature of the present invention is obtained by combining and verifying the results obtained by a plurality of flaw detection means (magnetic particle flaw detection means 12 and ultrasonic flaw detection means 2). Any surface defect K present in the inspection subject W and the depth of the surface defect K can be discriminated.
For example, even if the surface defect K is detected by the magnetic particle flaw detection means 12, the surface defect K does not actually exist. Conversely, even if the surface defect K is not detected, the surface defect K actually exists. In some cases, erroneous detection of the surface defect K can be reduced by referring to the flaw detection result obtained by the ultrasonic flaw detection means 2 at that time.

Furthermore, the surface defect depth discriminating means 18 which is a feature of the present invention has a function of discriminating the surface defects K into depth ranks classified according to their depths based on the flaw detection result in the ultrasonic flaw detection means 2. Is provided. With this function, the reliability of the depth of the detected surface defect K can be increased, and the surface defect K can be distinguished more satisfactorily.
The depth rank obtained by the surface defect depth discrimination means 18 is calculated on the basis of the reflected signal intensity by the signal recording processing unit 8 of the ultrasonic flaw detection means 2, and the frequency of the emitted ultrasonic wave and The depth of the surface defect K (surface defect) is estimated and ranked based on the received signal strength.

In this embodiment, a relatively shallow surface defect K having a depth of 0.5 mm or less is defined as “depth rank 1”, and a surface defect K having a depth in the range of 0.5 to 1.0 mm is defined as “depth rank 1”. 2 ”, a relatively deep surface defect K having a depth of 1.0 mm or more is defined as“ depth rank 3 ”, and the depth of the surface defect K is discriminated (classified).
Specifically, when flaw detection of the surface defect K is performed, when the frequency of the transmitted ultrasonic wave is 5 MHz, the intensity of the reflected signal received is equal to or higher than a preset threshold, and the transmitted ultrasonic wave When the frequency of the sound wave is 1.5 MHz and 2 MHz, the depth of the detected surface defect K is discriminated to “depth rank 1” when the received reflected signal intensity is less than a preset threshold value. .

In other words, the reflected signal intensity is received only when the transmitted ultrasonic frequency is 5 MHz, or the reflected signal is not received at all transmitted frequencies (5 MHz, 2 MHz, and 1.5 MHz). When the surface defect K is not detected, the depth of the detected surface defect K is discriminated to “depth rank 1”.
Next, when the frequency of the transmitted ultrasonic wave is 2 MHz, when the reflected signal intensity received is equal to or higher than a preset threshold, and when the frequency of the transmitted ultrasonic wave is 1.5 MHz, the received wave When the reflected signal intensity to be detected is less than a preset threshold value, the depth of the detected surface defect K is discriminated to “depth rank 2”.

In other words, when the frequency of the transmitted ultrasonic wave is 1.5 MHz, the reflected signal is not received, and when the frequency of the transmitted ultrasonic wave is 5 MHz and 2 MHz, the reflected signal intensity is received. In this case, the depth of the detected surface defect K is discriminated to “depth rank 2”.
Further, a surface defect is detected when a reflected signal is received at all the frequencies of the transmitted ultrasonic waves (5 MHz, 2 MHz, 1.5 MHz) and the reflected signal intensity is equal to or lower than a preset threshold value. The depth of K is also distinguished into “depth rank 2”.

Further, when the frequency of the transmitted ultrasonic wave is 1.5 MHz and the intensity of the reflected signal received is equal to or higher than a preset threshold, the depth of the surface defect K to be detected is expressed as “depth rank 3 To discriminate.
In other words, when the reflected signal is not received when the transmitted ultrasonic frequency is 5 MHz and 2 MHz, and when the reflected signal intensity is received when the transmitted ultrasonic frequency is 1.5 MHz. Further, the depth of the detected surface defect K is discriminated into “depth rank 3”.

Further, a surface defect is detected when a reflected signal is received at all the frequencies of the transmitted ultrasonic waves (5 MHz, 2 MHz, 1.5 MHz) and the reflected signal intensity is equal to or higher than a preset threshold value. The depth of K is also distinguished into “depth rank 3”.
And things other than the above-mentioned depth ranks 1-3 are discriminated as "outside the depth rank".
As described above, the depth of the surface defect K detected by the ultrasonic flaw detector 2 is classified according to the depth of the surface defect K based on the flaw detection result of the surface defect K obtained by the ultrasonic flaw detector 2. Distinguish to a given depth rank.

Next, the result of discriminating the depth of the surface defect K using the above-described depth rank will be described with reference to the drawings.
FIG. 4 shows that the surface defect K detected by the magnetic particle flaw detector 12 is subjected to ultrasonic flaw detection, and the detected surface flaw K based on the reflected signal intensity at each frequency obtained by the ultrasonic flaw detector 2. It is a figure which shows the result of having discriminate | determined the depth of this by the surface defect depth discrimination means 18. FIG. The vertical axis shown in FIG. 4 indicates the depth rank of the distinguished surface defect K, and the horizontal axis indicates the result of actually measuring the depth of the surface defect K.

  As shown in FIG. 4, based on the reflected signal intensity corresponding to depth rank 1 received when flaws are detected on the surface and the surface of the inspected body W at each frequency (5 MHz, 2 MHz, and 1.5 MHz). The flaw detection results obtained are distinguished on the horizontal axis indicating depth rank 1 (marked with ◆). Similarly, the flaw detection result obtained based on the reflected signal intensity corresponding to the depth rank 2 that is received when flaw detection is performed on the surface and the subsurface of the test subject W at each frequency is the depth rank 2. Discriminated on the horizontal axis shown (▲). Similarly, the flaw detection results obtained based on the reflected signal intensity corresponding to the depth rank 3 received when flaws are detected on the surface and the subsurface of the test subject W at each frequency are the depth rank 3 Discriminated on the horizontal axis (marked with ●).

  Here, looking at the flaw detection result A discriminated in FIG. 4, the flaw detection result A has a reflection intensity corresponding to the depth rank 2, and is discriminated to the depth rank 2 from the reflection intensity. Depth rank 2 is estimated as a surface defect K having a depth in the range of 0.5 to 1.0 mm. On the other hand, when the depth of the surface defect K is detected by actually measuring the wrinkle depth, the depth of the surface defect K is detected as about 0.8 mm with respect to the flaw detection result A. That is, in the flaw detection result A, the depth of the surface defect K and the depth rank are the same (successful discrimination).

The results determined as successful in this way are distributed in the vicinity of the diagonal line connecting the origin and the upper right in FIG. 4, and the region surrounded by the broken line in FIG.
On the other hand, when looking at the identified flaw detection result B (the one-dot chain line in FIG. 4), this flaw detection result B is the one where the actual surface defect K has a shallow depth (about 0.55 mm). The reflection intensity corresponding to the depth rank 3 (a relatively deep surface defect K of 1.0 mm or more) is obtained, and this is the case where the wrinkle depth does not match the depth rank.

In the case of the flaw detection result B, the reflection intensity corresponding to the depth rank 3 is obtained in spite of the shallow wrinkles, and therefore, it is identified as “over discrimination”, that is, wrinkles deeper than the actual wrinkle depth. there is a possibility. The flaw detection results plotted in the area above the diagonal line connecting the origin and the upper right in FIG.
Further, looking at the detected flaw detection result C (solid line in FIG. 4), this flaw detection result C shows that the actual surface defect K has a deep depth (about 1.2 mm). The reflection intensity corresponding to rank 2 (depth in the range of 0.5 mm to 1.0 mm) is obtained, and the ridge depth does not match the depth rank.

In the case of the flaw detection result C, the reflection intensity corresponding to the depth rank 2 is obtained in spite of the deep flaw, so that “false discrimination”, that is, a flaw that is shallower than the actual flaw depth may be identified. There is. The flaw detection results plotted in the area below the diagonal line connecting the origin and the upper right in FIG.
That is, “false discrimination” and “overdiscrimination” are problems in inspecting the inspected object W. “Over-discrimination” is detected as deep even though the surface defect K is shallow, and although it is a problem, the surface defect K (surface defect) existing on the surface of the inspected object W can be removed. On the other hand, “misidentification” is detected as shallow even though the surface defect K is deep, and the cutting depth set when removing the surface defect K present on the surface of the inspection object W is shallow. There is a possibility that the surface defect K cannot be removed. Therefore, the surface defect K detected as “false discrimination” may be dealt with so as to succeed in the discrimination by reinspecting the surface defect K.

  As described above, according to the discrimination apparatus 1 for the surface defect depth of the inspection subject W according to the present invention, the flaw detection result obtained by the magnetic particle flaw detection means 12 and the flaw detection result obtained by the ultrasonic flaw detection means 2 are used. As shown in FIG. 4, it can be seen that most inspection results of ultrasonic flaw detection belong to “successful discrimination”, and the depth of the surface defect K of the object W to be inspected is highly probable. It is possible to discriminate.

As described in detail above, when using the discrimination device 1 for the surface defect depth of the inspection object W according to the present embodiment, the depth of the surface defect K based on the signal waveform obtained by the ultrasonic flaw detection means 2. In addition to detecting the depth, the depth rank is obtained by the surface defect depth discrimination means 18.
When the “depth of the surface defect K” matches the “depth rank”, it can be considered that the depth of the surface defect K is accurately obtained.

Thus, by accurately identifying the surface defect K, it is possible to efficiently and reliably remove the surface defect K in a subsequent process. Furthermore, it leads to cost reduction such as improvement of product productivity and reduction of the number of times of replacing the replacement blade of the cutting apparatus.
[Modification]
Next, a modified example of the surface defect depth discrimination device 1 according to the present invention will be described with reference to the drawings.

  As shown in FIG. 5, a modification of the surface defect depth discrimination device 1 according to the present invention is a discrimination device according to the present invention in which the arrangement positions of the magnetic particle flaw detection means 12 and the ultrasonic flaw detection means 2 are described above. It is very different from 1. That is, in this modification, the magnetic particle flaw detection means 12 is disposed on the upstream side of the inspection line, and the ultrasonic flaw detection means 2 is disposed on the downstream side of the magnetic particle flaw detection means 12. Is different.

The parts other than the arrangement position of the modification of the discrimination device 1 for the surface defect depth of the object W to be inspected are substantially the same as the discrimination device 1 of the present invention described above (see FIG. 1).
In addition, since the other structure in this modification and the effect to show | play are substantially the same as the discrimination apparatus 1 and the discrimination method of this invention mentioned above, the description is abbreviate | omitted.
As described above, according to the discrimination method of the surface defect depth of the inspection object W and the apparatus 1 of the present invention, the flaw detection result of the surface defect K of the inspection object W obtained by the magnetic particle inspection method, and the surface Using the flaw detection result of the surface defect of the inspection object W obtained by the wave flaw detection method, the depth of the surface defect K of the inspection object W is evaluated, and the surface defect K existing in the inspection object W is evaluated. The depth can be discriminated accurately and reliably.

The embodiment disclosed this time should be considered as illustrative in all points and not restrictive.
For example, in the present embodiment, the depth rank has been described as being divided into three, but the number of depth ranks may be changed as appropriate according to the flaw detection method of the inspection subject W to be inspected. .
In the present embodiment, the changeable ultrasonic frequency is 1.5 MHz, 2 MHz, 5 MHz.
In the case of three types of z, an example is described. However, the frequency of the ultrasonic wave that can be changed may be appropriately selected depending on the depth of the surface defect K to be discriminated, and the number of frequencies to be used is two or more. If there is, it does not specifically limit.

  In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

1 Discriminating device 2 Ultrasonic flaw detection means (surface wave flaw detection means)
DESCRIPTION OF SYMBOLS 3 Sensor head 4 Probe 5 Sensor holder 6 Holder support body 7 Ultrasonic flaw detector 8 Signal recording process part 9 Contact medium supply collection | recovery part 10 Air blower 11 Air supply part 12 Magnetic particle flaw detection means 13 Magnetic powder dispersion | spreading part 14 Magnetizer 15 Illumination Section 16 Imaging section 17 Image analysis section 18 Surface defect depth discrimination means 20 Transport section L Magnetic powder liquid K Surface defect (surface defect)
W Inspected object

Claims (2)

A surface defect that exists on the surface and / or under the surface of the inspection object is detected, and the depth of the surface defect of the inspection object is evaluated to discriminate the depth of the surface defect that exists on the inspection object. A method for discriminating the surface defect depth of an inspection object,
Using magnetic Konasagu scratch method, flaw detection surface defects of the object to be inspected,
Using an ultrasonic flaw detection method in which the frequency of ultrasonic waves transmitted to the object to be inspected can be changed , the surface defect of the object to be inspected is detected and the depth of the surface defect is detected,
By evaluating the combination of the case where the flaw is detected and the case where the flaw is not detected from the flaw detection result of the surface defect obtained by the magnetic particle flaw detection method and the flaw detection result of the surface defect obtained by the ultrasonic flaw detection method, Discriminate the presence or absence of surface defects in the inspection object and the depth of surface defects ,
From the flaw detection result of the surface defect obtained by the ultrasonic flaw detection method, by evaluating the combination of the case where the reflected signal is received and the case where the reflected signal is not received when the measurement frequency is 5 MHz, 2 MHz and 1.5 MHz, the flawed surface A method for discriminating a surface defect depth of an object to be inspected, characterized by discriminating defects into depth ranks classified according to the depth of surface defects. A surface defect that exists on the surface and / or under the surface of the inspection object is detected, and the depth of the surface defect of the inspection object is evaluated to discriminate the depth of the surface defect that exists on the inspection object. A discrimination device for the surface defect depth of an inspection object,
Magnetic particle flaw detection means for flaw detection of surface defects of the object to be inspected using a magnetic particle flaw detection method,
Before SL using the ultrasonic flaw detection method in which the ultrasonic frequency is changeable dispatched for the test subject, to detect the depth of the surface defect while testing the surface defects of the object to be inspected Ultrasonic flaw detection means,
By evaluating the combination of the case where the flaw is detected and the case where the flaw is not detected from the flaw detection result of the surface defect obtained by the magnetic particle flaw detection means and the flaw detection result of the surface defect obtained by the ultrasonic flaw detection means, A surface defect depth discriminating means for discriminating the presence / absence of a surface defect in the inspection object and the depth of the surface defect ;
The surface defect depth discrimination means is a combination of a case where a reflected signal is received and a case where a reflected signal is not received when the measurement frequency is 5 MHz, 2 MHz and 1.5 MHz from the surface defect inspection result obtained by the ultrasonic inspection means. A device for discriminating the surface defect depth of an object to be inspected, which is configured to discriminate the surface defects detected by evaluation into depth ranks classified according to the depth of the surface defects. .