KR102307685B1 - Evaluating method of steel and evaluating apparatus of steel - Google Patents

Abstract

According to an embodiment of the present invention, a metal material evaluation method includes the following steps of: preparing a specimen from a metal material; forming a swollen part on the surface of the specimen; detecting the height (HdB) and width (LdB) of the swollen part; and deriving the depth (Ddl) and size (Ldl) of an interposed material located in the specimen, using the detected height (HdB) and width (LdB) of the swollen part. Therefore, according to an embodiment of the present invention, through the metal material evaluation method and a metal material evaluation apparatus, there can be an effect of improving reliability in determining whether a defect is caused by an interposed material, during the machining of a metal material. Accordingly, the metal material, which is expected to be defective during the machining, can be prevented from being shipped to customers.

Description

The evaluation method of a metal material, and the evaluation apparatus of a metal material TECHNICAL FIELD

The present invention relates to a method for evaluating a metallic material and an apparatus for evaluating a metallic material, and more particularly, to a metallic material evaluation method and a metallic material evaluation apparatus capable of evaluating whether a metallic material can be shipped.

The cast steel manufactured by solidifying the molten steel is shipped to the customer through the rolling process. And the plate material shipped to the customer (hereinafter, rolled material) is processed by bending or tapping to become a final product.

On the other hand, the rolled material shipped to the customer is a product with no defects on its surface. However, when a customer performs processing to manufacture a final product such as an automobile, defects such as holes or holes are generated on the surface. And, defects tend to occur mainly in difficult machining or machining areas with a lot of deformation.

Defects appearing by processing in this way are due to non-metallic inclusions existing inside the rolled material shipped to the customer. And, the closer the position of the inclusions in the rolling material to the surface of the rolling material, the larger the size of the inclusions, the greater the possibility that defects will occur. Further, the greater the number of inclusions close to the surface of the rolling material, the greater the number of defects.

Therefore, when the rolled material is manufactured, it is necessary to determine in advance the possibility of surface defects caused by non-metallic inclusions. However, the conventional method for evaluating a rolled material has a problem in that the depth of the non-metallic inclusions inside the specimen cannot be detected. Accordingly, when determining the possibility of occurrence of surface defects due to non-metallic inclusions by such an evaluation method, there is a problem in that reliability thereof is lowered.

Korean Patent 1746990

The present invention provides a method for evaluating a metal material and an apparatus for evaluating a metal material, which can more accurately predict the depth and size of inclusions.

The present invention provides a method for evaluating a metal material and an apparatus for evaluating a metal material, which can more accurately predict whether or not defects caused by inclusions occur during processing of a manufactured metal material.

A method for evaluating a metal material according to an embodiment of the present invention includes a process of preparing a specimen from a metal material to be evaluated; forming an inflated portion on the surface of the specimen; The process of detecting the height (H _dB ) and width (L _{dB) of the inflated portion;} and a process of deriving a _{depth (D dI} ) and a size (L _dI ) of an inclusion in the specimen by using the detected height (H _dB ) and width (L _{dB ) of the inflated portion.}

The process of detecting the height (H _dB ) and width (L _dB ) of the inflatable part is to transmit and receive light with respect to the specimen, and the height (H _dB ) and width (L _dB ) of the inflatable part in an indirect way using optical data It includes the process of calculating

The process of deriving the depth (D _dI ) of the inclusions is the ratio (T _d ) of the width (L _{dB ) to the height (H dB} ) of the inclusions, the ratio (T _d ) of the inclusions using the ratio (T d ). It includes the process of deriving (D _{dI ).}

The process of deriving _{the depth (D dI} ) of the inclusions using the ratio (T _d ) of the inflated part is to prepare a depth derivation model having _{model depths (DM} ) data according to the model _{ratios (T M ) and} , the model ratio (T _M ) to the ratio (T _d ) of the inflated portion to the selected model ratio (T _M ) The model depth (D _M ) for the depth of the inclusion (D _dI ) It includes the process of deriving do.

In the depth derivation model, as the model ratio T _M increases, the model depth D _M may have a tendency to increase.

The process of deriving the size of the inclusions (L _dI ) includes: calculating the _{volume (V dB} ) of the inflatable part using the _{height (H dB} ) and the width (L _{dB) of the inflatable part;} The process of deriving _{the size (L dI} ) of the inclusion using the volume (V _{dB) of the inflated portion; includes.}

The process of deriving _{the size (L dI} ) of the inclusion using the volume (V _dB ) of the inflated part is to prepare a size derivation model having model sizes (L _{M ) data according to the model volumes (V M ),} includes the step of deriving the model volume (V _M) of the model size (L _M) for the model volume (V _M) selected in case the volume (V _dB) of said bulge in the size of the inclusions (L _dI) .

The size derivation model may have a tendency for the model size (L _{M ) to increase as the model volume (V M ) increases.}

A method for evaluating a metal material according to an embodiment of the present invention includes a process of preparing a specimen from a metal material to be evaluated; forming an inflated portion on the surface of the specimen; irradiating light to the specimen; receiving light reflected from the surface of the specimen; and a process of detecting a _{height (H dB} ) and a width (L _dB ) of the inflated portion by using the intensity of the received light.

The process of detecting the height (H _dB ) and the width (L _dB ) of the inflated part may include a process of graphing the intensity of the reflected light along the extension direction of the specimen surface; identifying, on the graph, a peak indicating a change in intensity of light reflected from the inflated portion; Using the identified peak, the process of detecting the _{height (H dB} ) and the width (L _{dB) of the inflated portion; includes.}

In identifying the peak, on the graph, an intensity of light exceeding a reference intensity, which is an intensity of light reflected from the surface of the specimen on which the bulge is not formed, is identified as a peak.

The process of detecting the height (H _dB ) of the inflated part includes a process of detecting the _{height (H dB} ) of the inflated part using the maximum intensity of the peak.

The process of detecting the width (L _dB) the bulging portion is, by using the area of the peak detects the bulge width (L _dB) portion.

_{The process of detecting the width (L dB} ) of the inflated portion using the area of the peak may include: forming a virtual circle having the area of the peak; calculating a diameter of the virtual circle; Let the diameter be the width (L _dB ) of the inflated portion.

and deriving _{the depth (D dI} ) and size (L _dI ) of the inclusions in the specimen by using the height (H _dB ) and the width (L _{dB ) of the inflated portion.}

Using the depth (D _dI ) and the size (L _dI ) of the inclusions, it includes a process of evaluating whether shipment is possible with respect to the metal material serving as the base material of the specimen.

The process of deriving the depth and size of each of the plurality of inclusions respectively corresponding to the plurality of bulges and evaluating whether to ship the defect-inducing inclusions, among the depths and sizes of the plurality of inclusions, is less than or equal to the reference depth and greater than or equal to the reference size A process of deriving the number of; Calculating a ratio of the defect-causing inclusions with respect to all of the plurality of inclusions; and when the ratio of the defect-inducing inclusions is less than or equal to the reference ratio, evaluating the metal material as normal for shipment.

An apparatus for evaluating a metal material according to an embodiment of the present invention includes: an inflated part generator for generating a bulged part on a surface of a specimen in an electrolytic manner; a bulging part detector irradiating light to the specimen and detecting the bulging part by using the intensity of light reflected from the specimen; and an inclusion predictor for predicting inclusions in the specimen corresponding to the inflated portion and calculating information on the inclusions.

The bulge detector may include: a light source for generating light; and an optical system that irradiates the generated light to the surface of the specimen, receives the light reflected from the surface of the specimen, and is horizontally movable along the extension direction of the surface of the specimen.

The light source may generate white light.

The bulge detector includes a detector that generates a graph to continuously show the intensity of light by using the light data received from the optical system.

The inclusion predictor may include: an inclusion depth derivation unit in which a depth derivation model for deriving the depth of the inclusion using the detected inflated unit is stored; and an inclusion size derivation unit in which a size derivation model for deriving the size of the inclusions is stored using the detected inflated unit.

According to the method for evaluating a metal material and an apparatus for evaluating a metal material according to an embodiment of the present invention, the depth of the inclusion and the size of the inclusion may be derived. And, using the derived depth and size of the inclusions, it is predicted whether or not a defect will occur during processing of the metal material.

Accordingly, there is an effect of improving the reliability of determining whether a defect is generated due to an inclusion during processing of a metal material. Accordingly, it is possible to prevent the metal material, which is to be defective during processing, from being shipped to the customer.

In addition, without directly or actually measuring the depth and size of the inclusions, the bulge is artificially generated, and the depth and size of the inclusion are indirectly derived using the height and width of the bulge. This method has the advantage of being fast over methods of directly or actually measuring the depth and size of the inclusions.

1 is a flowchart illustrating a method for evaluating a metal material according to an embodiment of the present invention.
2 is a block diagram conceptually illustrating an apparatus for evaluating a metal material according to an embodiment of the present invention.
3 is a view conceptually illustrating a blower generator for forming a blowout part on a surface of a specimen in order to evaluate a metal material by a method according to an embodiment of the present invention.
4 and 5 are diagrams conceptually illustrating a process in which an inflated portion is formed on a surface of a specimen.
6 is a photograph taken of the surface of the specimen on which the inflated portion is formed by the method according to the embodiment of the present invention.
Figure 7 (a) is a diagram conceptually showing the inflated part detector according to an embodiment of the present invention.
FIG. 7(b) is a graph illustrating optical data obtained by using the swelling part detector of FIG. 7(a).
FIG. 8 is a conceptual shape of a bulge having a height and a length detected using optical data obtained using a bulge detector according to an embodiment of the present invention.
9 is a flowchart illustrating a method of deriving a depth and length of an inclusion by a method according to an embodiment of the present invention.
10 exemplarily illustrates a depth derivation model for deriving a depth of an inclusion by a method according to an embodiment of the present invention.
11 exemplarily shows a size derivation model for deriving the size of inclusions by a method according to an embodiment of the present invention.
12A is a photograph taken using a scanning electron microscope from the upper side of the surface of the specimen on which the inflated portion B is formed.
(b) of FIG. 12 is a photograph observed for the cut cross-section obtained by cutting (E'-E'') the 'E' region in which the inflated portion (B) is formed in the first extending direction of the specimen in FIG. 12 (a). am.
_{13 is a graph showing a size (L dI} ) and a depth (D _dI ) of an inclusion derived by a method according to an embodiment of the present invention on one coordinate.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art will be completely It is provided to inform you. The drawings may be exaggerated in order to explain the embodiments of the present invention, and like reference numerals in the drawings refer to like elements.

1 is a flowchart illustrating a method for evaluating a metal material according to an embodiment of the present invention. 2 is a block diagram conceptually illustrating an apparatus for evaluating a metal material according to an embodiment of the present invention.

Referring to FIG. 1 , the evaluation method of a metal material according to an embodiment of the present invention includes a process of generating a blister on the surface of a specimen (S10), _{and detecting the height (H dB} ) and width (L _dB ) of the swollen portion. Process (S20), using the height (H _dB ) and width (L _dB ) of the detected bulge, the depth at which non-metallic inclusions are located inside the specimen (hereinafter, the inclusion depth (D _dI )) and the size of the inclusions (L _dI ) It includes a process of deriving (S30), a process of evaluating a metal material serving as a base material of the specimen (S40) using the _{derived depth (D dI} ) and the size (L _{dI ) of the inclusions.}

Referring to FIG. 2 , the metal material evaluation device generates or forms a bloated part on the surface of the specimen (S10), the bloated part generator 100, and the height (H _dB ) and width (L _dB ) of the bloated part formed on the surface of the specimen is detected. (S20) using the bulge detector 200, the height (H _dB ) and the width (L _dB ) of the bulge detected by the bulge detector 200, the depth (D _dI ) and the size of the inclusions (L) _dI ) The inclusion predictor 300 for deriving or predicting, using the derived depth of the inclusion (D _dI ) and the size of the inclusion (L _dI ), an evaluation unit 400 for evaluating the metal material as the base material for the specimen do.

Here, the inclusion predictor 300 uses the height (H _dB ) and the width (L _dB ) of the bulge detected by the bulge detector 200 to derive the depth (D _dI ) of the inclusion depth derivation unit 310 ) and an inclusion size deriving unit 320 for deriving the size of the inclusion _{(L dI ).}

First, with reference to FIGS. 3 to 6 , a method of forming an inflated portion on the surface of a specimen will be described.

3 is a diagram conceptually illustrating an inflating unit generator according to an embodiment of the present invention. 4 and 5 are diagrams conceptually illustrating a process in which an inflated portion is formed on a surface of a specimen. 6 is a photograph taken of the surface of the specimen on which the inflated portion is formed by the method according to the embodiment of the present invention.

The swelling part generator 100 may be a device for forming the puffing part by artificially infiltrating hydrogen into the specimen through an electrochemical reaction. As shown in FIG. 3 , the inflated part generator 100 is a water tank 110 having an internal space, a power supply unit 120 for supplying power to the specimen 20 and the conductor 30 charged into the water tank 110 . ), a power supply line 130 for connecting the power supply unit 120 and the specimen 20 and the conductor 30, respectively.

The specimen 20 may be prepared by cutting from the base material to be evaluated. Here, the base material may be a plate material (hereinafter, a rolled material) obtained by rolling a cast slab by solidifying molten steel. That is, the specimen 20 may be prepared by cutting a rolled material to a predetermined size. Of course, the specimen 20 is not limited to the rolled material, and may be provided by cutting a part of the cast steel, which is a plate material before rolling. Hereinafter, for convenience of explanation, the cast steel and the rolled material serving as the base material of the specimen 20 will be collectively referred to as 'metal material'.

The metal material serving as the base material of the specimen 20, ie, a cast steel or a rolled material, may be carbon steel having a component composition as shown in Table 1 below. In other words, the specimen 20 may be carbon steel having the component composition shown in Table 1 below. Of course, the specimen 20 is not limited to carbon steel, and may be variously changed according to the steel type of the metal material to be evaluated.

division C Mn Cu Cr N P S weight% 0.002 0.15 0.06 0.03 0.002 0.01 0.005

The specimen 20 may have a plate shape having a surface 21 having a predetermined area. More specifically, the specimen 20 includes a first surface 21a that is a surface 21 having a predetermined area and a second surface 21b that is a surface facing the first surface 21a and has a predetermined area. The branches may have a plate shape. Hereinafter, for convenience of description, the alignment direction of the first surface 21a and the second surface 21b of the specimen 20 is defined as the thickness direction (Z-axis direction) of the specimen 20 .

The specimen 20 according to the embodiment has first and second surfaces 21a, 21b) each is provided to have an area of 100mm * 100mm, but the first and second surfaces 21a, 21b) Each area is not limited to the above-mentioned area and can be changed to various areas.

The conductor 30 may be an inert metal or a noble metal, for example, an alloy including Ir and Ti. The conductor 30 may be provided in the shape of a plate having a predetermined area.

When the specimen 20 and the conductor 30 are prepared, the specimen 20 and the conductor 30 are immersed in the aqueous solution 14 in the water tank 110 as shown in FIG. 3 . At this time, one of the first surface 21a and the second surface 21b of the specimen 20, for example, the first surface 21a is immersed to face the conductor 30 .

The aqueous solution 14 is an electrolyte for causing an electrochemical reaction, and the aqueous solution 14 may include, for example, NaCl, NH ₄ SCN, and water. More specifically, with respect to the entire aqueous solution 14, 1 wt% to 10 wt% _{of NaCl, NH 4} SCN is included 1/10 to 1/7 of NaCl, and the remainder may be water. At this time, it is more preferable that NaCl is 2 wt% to 5 wt% with respect to the entire aqueous solution. In addition, the temperature of the aqueous solution 14 is adjusted to 0 ℃ to 30 ℃, more preferably 15 ℃ to 30 ℃.

When the specimen 20 and the conductor 30 are immersed in the aqueous solution 14 in the water tank 110, the power supply line 130 is connected to the specimen 20 and the conductor 30, respectively, and then power is applied. That is, a current is applied with the specimen 20 as a negative electrode (-) and the conductor 30 as a positive electrode (+). At this time, the applied current is 5A/m ² to 120A/m ² , preferably 20A/m ² to 40A/m ² .

On the other hand, when the current is as small as less than ^{5A/m 2 or large to exceed 120A/m 2} , the inflated portion may not be formed even if there is an inclusion in the specimen 20 .

When an electric current flows through each of the specimen 20 and the conductor 30, an electrochemical reaction, in other words, an electrolysis reaction, between the specimen 20, the conductor 30 and the aqueous solution 14 occurs, resulting in the generation of hydrogen, that is, H ⁺ ions. occurs (see Scheme 1).

Scheme 1) NaCl + NH ₄ SCN + H ₂ O --> Na ⁺ + Cl ^- + NH ₃ H ₂ O + (SCN) ^- + H ⁺

The generated H ⁺ ions are adsorbed to the surface of the specimen 20, which is the negative electrode (−), and then penetrated or injected into the specimen 20 as shown in FIGS. 4 and 5 . At this time, ^{most of the generated H +} ions are absorbed on the surface 21 of the specimen 20 facing the conductor 30 , that is, the first surface 21a, and then penetrate into the specimen 20 . ^{That is, most of the H +} ions generated from the outside of the specimen 20 are moved to pass through the first surface 21a of the specimen 20 and penetrate into the interior of the specimen 20 .

When the penetrating H ⁺ ions reach the surface of the non-metallic inclusion (hereinafter, the inclusion (I)) inside the specimen 20 while moving, as shown in FIGS. 4 (a) and 5 (a) As such, it is no longer penetrated or moved and is accumulated on the surface of the inclusion (I). ^{At this time, as H +} ions accumulated on the surface of the inclusion (I) are combined, molecular hydrogen gas (hereinafter, hydrogen (H ₂ ) gas) is formed. That is, hydrogen gas is formed around the inclusion I or between the surface of the inclusion I and the specimen 20 . And, as the gap between the inclusion I and the specimen 20 gradually widens due to the increase in hydrogen gas, a portion of the surface of the inclusion I and the specimen 20 are separated. By this separation, a void G is formed between the surface of the inclusion I and the specimen 20 as shown in FIGS. 4 (b) and 5 (b), and the void (G) is hydrogen gas. As the amount increases, it expands.

The void G is generated when the separation between the surface of the inclusion I and the specimen 20 occurs inside the specimen 20 as described above. At this time, among the surfaces of the inclusions (I), the surface ^{facing the direction (solid arrows in FIGS. 4 and 5) through which H +} ions penetrate or the surface of the inclusions (I) facing the first surface 21a is the specimen 20 ) can be separated from

And as shown in FIGS. 4 and 5 , the surface of the specimen 20 swells by the void G generated inside the specimen 20 in this way. That is, the surface of the specimen 20 is inflated to protrude by the void G generated inside the specimen 20, which is called an inflated portion (B). At this time, among the first and second surfaces 21a and 21b that are the surface 21 of the specimen 20 , the inflated portion B is generated as a surface in a direction relatively close to the inclusion I.

For example, the first surface 21a of the specimen 20 is disposed to face the conductor 30, and the inclusion I is on the second surface 21b of the specimen 20 as shown in FIG. 4(a). In comparison, when positioned close to the first surface 21a, the inflated portion B may be formed on the first surface 21a of the specimen 20 as shown in FIG. 4B. In addition, in this case, H ⁺ ions pass through the first surface 21a from the outside of the specimen 20 and then move and penetrate into the specimen 20 (solid arrows in (a) and (b) of FIG. 4 ). ), since the inflated portion B is formed to protrude outward from the first surface 21a of the specimen 20, the ^{direction in which the H +} ions permeate and the direction in which the inflated portion B protrudes are opposite to each other. can

As another example, when the inclusion (I) is located closer to the second surface (21b) than the first surface (21a) of the specimen (20) as shown in FIG. It may be formed on the second surface 21b of the specimen 20 as shown in (b). In addition, in this case, H ⁺ ions pass through the first surface 21a from the outside of the specimen 20 and then move and penetrate into the specimen 20 (solid lines in (a) and (b) of FIG. 5) , since the swollen portion B is formed to protrude outward from the second surface 21a of the specimen 20, the ^{direction in which the H +} ions permeate and the direction in which the inflated portion B protrudes are the same. can

And in this way, when ^{the penetration direction of H +} ions and the protrusion formation direction of the inflated portion B are the same, the inclusion I moves a predetermined distance from its initial position (dashed line I in FIG. 5 (b)) ( FIG. 5 ( The solid line I) of b) may be At this time, the inclusion (I) may be moved a predetermined distance in the thickness direction of the specimen (20).

As shown in FIG. 6 , a plurality of such inflated portions B may be formed, and a plurality of first and second surfaces 21a and 21b of the specimen 20 may be formed. In addition, the inflated portion (B) may be formed in large amount as the number of inclusions (I) present in the specimen 20 increases.

Hereinafter, in the specimen 20 in which the swollen portion B is generated on the surface 21 , the actual height and width of the swollen portion B and the actual depth and size of the inclusion I will be described. And, here will be described by referring to the actual height of the bulging portion (B) to H _B, L _B refers to the actual width of the explanation, and the actual depth of the inclusions (I) D _I, the physical size L _I.

4 and 5, the height (HB) of the inflated portion ( _B ) is, based on the thickness direction of the specimen 20, the inflated portion (B) is formed from the surface of the specimen 20 ( B) may mean the length to the uppermost surface. Further, it is possible to sense the length of the extending direction of the bulge portion (B) the width (L _B) is, the specimen (20) surface 21 of the first surface (21a) or the second surface (21b) of example , when the surface 21 of the specimen 20 has a rectangular shape extending in the first extension direction (X-axis direction) and the second extension direction (Y-axis direction) orthogonal to the first extension direction (see FIG. 6 ) and the width (L _B) of the swelling portion (B), the first is the length of the first extended direction and the second extending direction of any one of the extending direction. At this time, as the basis of the extension direction for example, the first extending direction of the specimen 20, the width (L _B) of the swelling portion (B) bulging portion (B) the length between the opposite ends of.

In addition, the inclusion (I) the size (L _I) is, the specimen (20) surface (21) extending in a first extending direction (X axis direction) direction of a and the second of the extension direction (Y-axis), any one of is the length in the extension direction. At this time, based on the extension direction of the specimen 20, for example, the first extension direction, the length between both ends of the inclusion I is the size L _{I of the inclusion I.}

Here, each of the width of the inflated portion and the size of the inclusions is equally defined as the length between both ends in the extension direction of the specimen. However, for convenience of explanation, as described above, in the inflated portion, the length in the extension direction of the specimen is named as the 'width' of the inflated portion, and in the inclusion, the length in the extension direction of the specimen is the 'size' of the inclusion. named as

The depth D _I of the inclusion I may be a distance from the surface 21 of the specimen 20 on which the inflated portion B is formed to the inclusion I. An accurate description of the depth (D _I ) of the inclusion (I) will be described later.

Test pieces (20) depth to the inclusion (I) position from the surface (21) (D _I) and their size in height of the bulging portion (B) which is in accordance with the (L _I), to form (H _B) and width (L _B) may be different. That is, the height of the inclusion (I) depth (D _I) is deep more bulging portions (B) the height (H _B) is low and, conversely the inclusions (I) depth (D _I) is, the lower inflation unit (B) of the ( H _B ) can be high. Since the void G is generated around the inclusion I, the depth D _I of the inclusion I is low so that when it is located close to the surface 21 of the specimen 20, the surface 21 of the specimen 20 ) may be because the expansion force of the air gap (G) transferred to it strongly affects it. Further, the width (L of inclusions (I) the size (L _I) is larger bulge portion (B) the width (L _B) is large, the inclusions (I) the size (L _I) is smaller the swelling portion (B) of the _B ) can be small. This is because, since the void G is generated around the inclusion I, as the size L _I of the inclusion I increases, the size of the void G in the extension direction of the specimen 20 increases. have.

On the other hand, as shown in (b) of FIG. 4 , when ^{the permeation direction of H +} ions and the direction of protrusion formation of the bulging part B are opposite, the inclusion I may not move when the bulging part B is formed. have. However, as described above, when ^{the penetration direction of H +} ions and the protrusion formation direction of the swollen portion B are the same as in FIG. It can be moved a predetermined distance in the direction Thus, in defining the depth (D _I) of the inclusions (I), the specimen (20) before forming the bulge portion (B) to the surface or the specimen 20 inclusions (I, before a gap (G) formed in the ) is preferably defined as the separation distance between the initial position and the surface 21 of the specimen 20 on which the inflated portion B is formed.

For a more detailed description, the void G is defined as follows. The void G formed in the specimen 20 may be formed around the inclusion I or at least a portion of the inclusion I. Accordingly, an interface (hereinafter, an interface GF) is generated between the specimen 20 and the void G, and the void G may be described as a space partitioned by the interface GF. Accordingly, the interface GF forming the void G is a surface relatively close to the first surface 21a of the specimen 20 (hereinafter, the first interface GF ₁ ) with the inclusion I interposed therebetween. and a surface close to the second surface 21b (hereinafter, a second interface GF ₂ ).

Reflecting this and explaining the depth of the inclusions _{again (D I} ), among the first interface (GF ₁ ) and the second interface (GF ₂ ), the interface that is relatively far from the surface 21 on which the inflated part (B) is formed and The separation distance between the surfaces 21 of the specimen 20 on which the inflated portion B is formed may be defined as _{the depth D I of the inclusions I.}

More specifically, as shown in FIG. 4 , the first surface that is the surface 21 of the specimen 20 facing the conductor 30 so that the inflated portion B protrudes in the opposite direction to the permeation direction of ^{H + ions.} When the inflated portion B is formed in 21a, the depth D _I of the inclusion I is between the first surface 21a of the specimen 20 and the second interface GF _{2 of the void G.} It could be a distance. As another example, as shown in FIG. 5 ^{, the inflated portion B protrudes in the same direction as the permeation direction of H +} ions, the surface opposite to the first surface 21a of the specimen 20 facing the conductor 30 When the inflated portion B is formed on the second surface 21b, the depth D _{I of the inclusion I is the first interface GF 1} of the void G from the second surface 21b of the specimen 20 ) may be the distance between them.

Embodiment, the depth (D _I) of the inclusions (I) by using the width (L _B) of the specimen (20) surface bulging portion height of (B) (H _B) and inflation portion (B) formed at the 21 and Derive or predict the magnitude L _{I .} That is, without directly measuring the depth (D _I ) and size (L _{I ) of the inclusion (I), the detected height (H B} ) and the width (L _dB ) of the inflated part (B) are measured. The depth (D _I ) and the size (L _I ) of the inclusion (I) are derived or predicted by using.

Then, in the detection of the width (L _B) of the inclusions (I) depth (D _I) and the size of the height of the bulge portion (B) which is used to derive the (L _I) (H _B) and inflation portion (B) of and a height (H _B) and the bulge does not directly measure the width (L _B) portion of the bulge portion (B), are detected in an indirect way.

Hereinafter, a method of detecting the height and width of the inflated portion by a method according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 7 and 8 .

Figure 7 (a) is a diagram conceptually showing the inflated part detector according to an embodiment of the present invention. FIG. 7(b) is a graph illustrating optical data obtained by using the swelling part detector of FIG. 7(a). FIG. 8 is a conceptual shape of an inflated part having a height and a width detected using optical data obtained by using the inflated part detector according to an embodiment of the present invention.

Referring to (a) of FIG. 7 , the bulge detector 200 transmits or irradiates the light source 220 that generates or provides light, and the light transmitted from the light source 220 to the specimen 20, and transmits or irradiates the specimen. The optical system 210 that receives or receives the light reflected from the 20 and the detector that detects the _{height (H dB} ) and the width (L _dB ) of the inflated part (B) using the optical data transmitted from the optical system 210 (230) may be included.

The optical system 210 may be a means for irradiating, for example, white light provided from the light source 220 to the specimen 20 and receiving light reflected from the specimen 20 . The optical system 210 may be, for example, a means including a confocal sensor. In addition, the optical system 210 may be provided to be horizontally movable so that light can be irradiated to the entire area of the surface 21 of the specimen 20 . That is, the optical system 210 is horizontal in the first extension direction (X-axis direction) of the surface 21 of the specimen 20 and the second extension direction (Y-axis direction) intersecting the first extension direction (X-axis direction). provided to be movable.

At this time, when the optical system 210 moves in the first extension direction (X-axis direction) direction of the specimen 20, while the position in the second extension direction (Y-axis direction) is fixed, the optical system 210 moves horizontally in the first extension direction can That is, the optical system 210 moves from one end to the other end among both ends of the specimen 20 in the first extension direction. Accordingly, the optical system 210 may move by the length of the specimen 20 in the first extending direction.

In addition, when the optical system 210 moves from one end of the first extension direction to the other end, the position in the second extension direction is changed. For example, when the optical system 210 moving in the first extension direction reaches the other end, the optical system 210 moves a predetermined distance in the second extension direction at the other end in the first extension direction. Then, the optical system 210 again moves from the other end in the first extension direction toward one end. Thereafter, similarly, when the optical system 210 reaches one end of the first extension direction, the optical system 210 moves a predetermined distance from the one end of the first extension direction in the second extension direction, and then, one side of the first extension direction. It moves from one end to the other end. In this case, when the optical system 210 moves in the second extension direction or changes its position, it may be moved by a preset distance. And, it can be moved from one end of the second extending direction to the other end.

The path through which the optical system 210 is horizontally moved may be described in the form of a 'ㄹ' shape or a zigzag shape of Hangul consonants.

The path or method in which the optical system 210 horizontally moves is not limited to the above-described example, and the surface of the specimen may horizontally move in various ways to scan the entire area.

Of Figure 7 (a) in H _B is a swelling portion (B) the actual height, L _B, using the swelling portion detector 200 in accordance with that, the embodiment to mean the actual width of the bulge portion (B) bulging portion of the In order to describe a method of detecting the height and the width of the inflated portion, it is conceptually illustrated.

Nine minutes with the embodiment, the height (H _B) and width (L _B) of the bulging portion for detecting the inflation portion in height and the bulging portion width by the use of a detector 200, and the actual measured inflation portion (B), as described above For this, the height of the inflated portion B detected through the inflated portion detector 200 is referred to as H _dB and the width of the inflated portion B is referred to _{as L dB.}

_{In irradiating light to the surface 21 of the specimen 20 to detect the height (H dB} ) and width (L _dB ) of the inflated portion (B), the first surface (21a) and the second surface (21b) ) can be detected by irradiating each. _{For example, after detecting the height (H dB} ) and the width (L _dB ) of the inflated portion (B) formed on the first surface (21a) by irradiating light to the entire surface of the first surface (21a) (L dB), the specimen 20 ) upside down and irradiating light to the second surface 21b to detect _{the height (H dB} ) and the width (L _dB ) of the inflated portion (B) formed on the second surface 21b. Of course, the order of irradiating light to the first surface 21a and the second surface 21b is not limited to the above-described example.

A plurality of puffed portions B are formed on the surface 21 of the specimen 20, and the plurality of puffed portions B may have different shapes as shown in FIG. 7(a), and the height ( At least one of H _B ) and width L _{B may be different.} That is, a specimen 20, a plurality of inflation in accordance with the depth and size of portion (B) of the plurality of inclusions (I) in the interior of the height (H _B) and width (L _B) may be different. And, since the inflated portion B is formed to protrude from the surface 21 of the specimen 20 as shown in FIG. Compared to the height, the surface height of the inflated portion B is high. In addition, the height of the surface of the inflated portion B is not constant in the extension direction of the specimen 20 , and may have a shape in which the height of the surface changes in the extension direction of the specimen 20 . For example, if the central portion in the width direction of the inflated portion B is described as a reference, the height of the surface increases in the central direction from one side, and then the height of the surface decreases in the other direction from the central part.

The optical system 210 irradiates light to the surface of the specimen 20 , and the light reflected from the specimen 20 is received by the optical system 210 again. Then, the optical data received by the optical system 210 is transmitted to the detection unit 230 . In this case, the intensity of the light received by the optical system 210 is stronger as the light reflected from the surface closer to the optical system 210 is. That is, in the specimen 20 in which the inflated portion B is formed, the intensity of the light reflected from the inflated portion B surface and received by the optical system 210 is the same as in the specimen 20 in which the inflated portion B is not formed. 21 ) and is stronger than the intensity of light received by the optical system 210 .

In addition, as described above, the height of the inflated portion B in the extension direction of the specimen 20 may not be constant. In this case, the intensity of the reflected light at a position having a relatively high height among the surfaces of the inflated portion B is strong. Accordingly, the intensity change tendency of the light reflected from the inflated part B and received by the optical system 210 may be the same as the height change tendency of the surface of the inflatable part B. For example, as described above, when the height of the surface of the inflated part B increases from one side to the center direction, and then the surface height decreases again from the center to the other side, it is reflected from the surface of the inflated part B. The intensity of the emitted light has a tendency to increase and then decrease.

In addition, since each of the plurality of inflated portions B may have a different height, the intensity of light reflected from each of the plurality of inflated portions B may be different.

The detector 230 receives the optical data from the optical system 210 and derives optical data having an intensity of light along the extension direction of the surface 21 of the specimen 20 . That is, at least one of the first and second extending directions of the surface 21 of the specimen 20, for example, the intensity data of light obtained along the first extending direction is derived.

And, as described above, the optical system 210 horizontally moves in the first and second extension directions of the surface of the specimen 20 , and data such as a movement distance or position of the optical system 210 is transmitted to the detection unit 230 . . In addition, the detection unit 230 stores the area of the surface 21 of the specimen 20 and lengths in the first and second extension directions. Accordingly, in deriving optical data having the intensity of light along the extension direction of the surface 21 of the specimen 20 by the detector 230 , the position and the second position of the surface 21 of the specimen 20 in the first extension direction It is possible to derive the intensity of light according to the position in the extension direction. In other words, the intensity can be derived for each (X, Y) position on the X-Y coordinate plane.

In addition, in irradiating light to the surface 21 of the specimen 20 , the first surface 21a and the second surface 21b of the specimen 20 are irradiated, respectively. Accordingly, by receiving light data reflected from each of the first surface 21a and the second surface 21b of the specimen 20, the optical data having the intensity of light along the extension direction of the surface 21 of the specimen 20 is obtained. derive At this time, by combining or combining the optical data on the first surface 21a and the optical data on the second surface 21b, the intensity of the light on the first surface 21a and the second surface 21b is the same XY coordinates. can be derived on a flat surface.

In addition, the detector 230 may graph the intensity value along the extension direction of the surface 21 of the specimen 20 . For example, as shown in (b) of FIG. 7 , it is possible to graph the strength value along the first extension direction (X-axis direction) of the surface 21 of the specimen 20 .

Referring to (b) of FIG. 7 , there is a section in which the intensity of light increases and then decreases in the first extending direction of the specimen 20, and this section appears in a plurality of sections. That is, there is a section in which the intensity of the light is not constant in the first extending direction of the specimen 20 and the intensity tends to change in the first extending direction, and a plurality of these sections appear. This change in intensity of light is due to a change in the height of the surface of the inflated part B, and a section in which the intensity of light changes may be detected as the position of the inflated part (B).

More specifically, the detector 230 according to the intensity of light according to the extension direction of the sample 20 surface 21, group inflation to set the criterial strength position or region having a light intensity exceeding (i _s), part (B ) can be detected or identified by the location of At this time, the reference intensity (i _s) may be set by using the intensity of light reflected from the non-forming the bulge portion (B) samples (20) surface (21).

And, looking at (b) of FIG. 7, it can be seen that the intensity of light at the position where the inflated portion B is formed has a tendency to change in the first extension direction of the specimen, which has a convex shape as shown in (b) of FIG. It can be seen that the peak (P) of Accordingly, the detection unit 230 may detect or identify the position of the peak P as the position of the inflated unit B.

Hereinafter, for convenience of description, (b) of the line (base line (U)) extending along a first direction of extension of the specimen based on the intensity (i _s) and a convex-shaped peak (P) on the graph of Figure 7 The area partitioned by ' is called a 'convex portion (C)'.

In addition, below, in order to describe the intensity of light reflected from the specimen 20 in more detail, three bulging portions B ₁ , B ₂ , and B ₃ formed in the specimen 20 will be described as an example. Here, each of the first to third inflated portions B ₁ , B ₂ , and B ₃ may be formed by the first to third inclusions I ₁ , I ₂ , I _{3 .}

In (b) of FIG. 7 , the first peak (P ₁ ) represents the intensity of light reflected from the first inflated part (B ₁ ), and the second peak (P ₂ ) is reflected from the second inflated part (B _{2 )} It represents the intensity of the light, and the third peak (P ₃ ) represents the intensity of the light reflected from the third inflated part (B _{3 ).}

At this time, the bulge portion (B _1, B _2, B _3), the surface is close to the optical system 210 relative to the specimen (20) surface (21) not provided with the bulging portion (B _1, B _2, B ₃₎ of the Therefore, the intensity of the light reflected from the surface of the inflatable parts (B ₁ , B ₂ , B ₃ ) and incident to the optical system 210 is not formed on the surface of the specimen 20 in which the _{inflatable parts ( B 1} , B ₂ , B _{3 ) are not formed.} (21) is large compared to the intensity of the reflected light.

A plurality of swelling portions _{(B 1, B 2, B} 3) In addition, may be different in height (H _B) as in (a) of Fig. If arranged in ascending order of height, the height of the first inflated portion (B ₁ ), the height of the third inflated portion (B ₃ ), and the height of the second inflated portion (B ₂ ) are in this order. Thus a plurality of swelling portions _{(B 1, B 2, B} 3) respectively, the height (H _B) is changed, a plurality of bulging portion, such as in Figure _{7 (b) (B 1,} B 2, B 3) for each As for the intensity of light, the maximum intensity i _max may be different. That is, when comparing the _{peaks (P 1} , P ₂ , P ₃ ) for the intensity of light reflected from each of _{the plurality of bulging parts (B 1} , B ₂ , B ₃ ) with reference to FIG. 7 (b), the first The maximum intensity at the peak (P _{1 ) (i max-1} ) is the maximum intensity at the second and third peaks (P ₂ , P ₃ ) (i _max-2 , i _max-3 ). More specifically, if the maximum intensity (i _max ) is arranged in increasing order, the first peak (P ₁ ), the third peak (P ₃ ), and the second peak (P ₂ ) may be in the order.

In addition, the inflated portion (B ₁ , B ₂ , B ₃ ) may have a shape in which the height of the surface thereof is not constant in the extension direction of the specimen 20 as shown in FIG. The intensity of the emitted light may vary depending on the location of the surface. For example, in the surface height of the inflated portion (B), when the height of the central portion in the width direction is the highest, and the surface height decreases toward the edge of one side and the other side with respect to the central portion, the first to Like the third peaks P ₁ to P ₃ , the intensity of the central portion may be greatest, and the intensity of light at one end and the other end may be the lowest.

Further, the plurality of swelling portions _{(B 1, B 2, B} 3) is its width (L _B) the portion plurality of projections, because it may differ from each other _{(C; C 1, C 2} C 3) Each of the width ( W; W ₁ , W ₂ , W ₃ ) may be different from each other. Here, the width W of the convex portion C may mean the length of the convex portion C in the extending direction of the specimen on the graph, for example, in the first extending direction.

The first to third bulging portion; if the width (L _B) are arranged in a long net according to (B B _1, B _2, B _3), a first bulge part, and the third bulge portion, it is possible second swelling portion sunil . In this case, as shown in FIG.'S 7 (b), the first width of the convex portion (C ₁₎ (W _1), the third width of the convex portion (C ₃₎ (W _3), the second projections (C ₂ ) may be longer in the order of the width (W _{2 ).}

Thus, since the bulging portion (B) the height (H _B) and width (L _B) on the peak (P) or the shape of the convex portion (C), the height, maximum intensity (i _max) and a width depending of the specimen It can be seen that _{the height (H dB} ) and the width (L _dB ) of the inflated portion (B) can be detected using the reflected light data from (20).

And, each of the plurality of peaks P is due to the plurality of swollen portions B formed on the surface of the specimen 20 as described above. Accordingly, the detection unit 230 may analyze the positions of the plurality of peaks (P) to derive the positions of the inflated units (B). That is, the detection unit 230 detects the respective positions of the plurality of peaks P on the coordinate plane of the specimen 20 , that is, the XY coordinate plane, and derives this position as the position value of the inflating unit B. More specifically, the detection unit 230 detects the (X, Y) coordinate position of each of the plurality of peaks P, and derives it as the position of the inflated portion B on the surface of the specimen 20 . _{At this time, a position having the maximum intensity i max in} each of the plurality of peaks P may be detected as the position of the inflated portion B .

_{The detection unit 230 detects a height (H dB} ) and a width (L _dB ) of the inflated portion (B) by using the intensity of the light received by the optical system 210 .

First, a method of detecting _{the height (H dB} ) of the inflated portion B will be described.

The detection unit 230 converts the intensity of the light received by the optical system 210 to the height of the inflated portion B, and derives, that is, detects _{the height (H dB) of the inflated portion B.} As described above, as the height of the surface of the inflated portion B increases, the intensity of light received by the optical system 210 increases. Further, in any one of the bulging parts B, the intensity of light reflected from the highest position among the surfaces of the bulging parts B is the highest. Therefore, in each of the plurality of peaks P or the plurality of convex portions C, the intensity of light is converted to the height of the convex portion B, and the maximum intensity i _max is converted to the height of the convex portion B. do. Accordingly, the height (H _dB ) of the inflated portion B is detected or derived.

In converting the intensity of light (i _max ) into the height (H _dB ) of the inflated part (B), a model having the height data of the inflated part (B) according to the intensity of light (hereinafter, the height derivation model) is prepared in advance, It can be derived using the height derivation model. Hereinafter, for convenience of explanation, the intensity of the light of the height derivation model is referred to as the model intensity (i _M ), and the height of the inflated part is named as the _{model height (H M ).}

As the height derivation model, a _{data table having a model height (H M} ) (height of the inflated portion) _{according to the model intensity (i M} ) (intensity of light) may be used. Of course, the present invention is not limited thereto, _{and a regression equation for the model height H M} (height of the inflated portion) according to the model intensity _{i M (light intensity) may be used as the height derivation model.}

It is preferable to prepare the height derivation model in advance before starting the work to evaluate the metal material. In addition, the height derivation model can be obtained through experiments. That is, after forming the inflated portion (B) on the specimen 20, the actual height (HB) of the inflated portion ( _B ) is measured. In addition, by irradiating light to the surface 21 of the specimen 20 on which the inflated portion B is formed, light intensity data is obtained. Then, the actually measured height (H B ) of the inflated portion ( _B ) and the maximum intensity of light (i _max ) are combined or matched. When this experiment is performed for a plurality of bulges, a height derived model having data on the height (ie, model height H _{M ) of the bulge according to the intensity of light (ie, model intensity i M ) is obtained.}

A plurality of peaks (C), each of the maximum intensity (i _max) for use bulging portion (B) height The height derived by conversion to (H _dB) (H _dB) and width swelling portion is derived as described below the method of (L _dB ), if the inflated portion (B) having a shape, for example, may be the same as (a), (c), (ㅁ) of FIG. 8 .

_{Here, the height (H dB} ) of the inflated part (B) in (a) of FIG. 8 is detected by the maximum intensity (i _{max-1 ) of the first peak (P 1} ) in (b) of FIG. 7 , _{The height (H dB} ) of the inflated part (B) in (c) of FIG. 8 is detected by the maximum intensity (i _{max-2 ) of the second peak (P 2} ) in FIG. 7 (b), FIG. _{The height (H dB} ) of the inflated portion (B) in (ㅁ) is detected by the maximum intensity (i _{max-3 ) of the third peak (P 3} ) in (b) of FIG. 7 . That is, the maximum intensity of each of _{the plurality of peaks (P 1} , P ₂ , P ₃ ) of FIG. 7 (b) _{(i max-1} , If i _max-2 ,i _max-3 ) is applied to the corresponding model strength or the closest model strength among the model strengths (T _{M ) of the height derivation model, the model depth (D M} ) is derived. Then, the derived model depth (D _M ) is derived, that is, detected as the height of the inflated part. In this way, looking at the detected height of the inflated part, it can be seen that _{the height (H dB} ) of the inflated part B is detected differently, as shown in (a), (c), (ㅁ) of FIG. 8 . .

_{The detector 230 detects the width (L dB} ) of the inflated part B using the intensity of the light received by the optical system 210 . More specifically, on a graph showing the intensity of light along the extension direction of the surface of the specimen 20, for example, in the first extension direction, as shown in FIG. Detects _{the width (L dB} ) of the inflated part (B). Here, the convex portion (C) Area (A) is, in the specimen on the graph the area of the divided area by the reference line (U) and the peak (P) extend a reference intensity (i _s) along one direction of extension of the it means.

_{Hereinafter, a method of detecting the width (L dB} ) of the inflated portion (B) using the area (A) of the convex portion (C) will be described in more detail.

First, the area A of the convex portion C is calculated. And, to shape the inflated part (B) by using the area (A) of the convex part (C), the shape of the cross-section of the inflated part (B) is assumed to be a circle (Circe). In addition, when the inflated part B is shaped into a circle using the area A of the convex part C, the diameter 2r of the circle having the calculated area A of the convex part C is inflated. It is derived as _{the width (L dB} ) of negative (B).

The area A of the convex portion can be calculated using integration. And, since the area of the circle is πr ² (r: the radius of the circle) as is well known, the radius of the circle having the area A of the convex portion C calculated is expressed as Equation 1 below. And, in Equation 1, r is the radius, so when the radius r is multiplied by 2, the diameter 2r of the circle is calculated.

[Formula 1]

When the diameter (2r) of the circle is calculated, the calculated diameter (2r) of the circle is set or derived as _{the width (L dB) of the inflated part (B).}

When calculating the width (L _dB) of the swelling portion (B) by using a plurality of projections (C), each of the area (A), and shaping the bulging portion (B) having a calculated width (L _dB), e.g. 8 (b), (d), and (f). _{Here, the width (L dB} ) of the inflated portion (B) of FIG. 8 (b) is detected by the area (A _{1 ) of the first convex portion (C 1} ) in FIG. 7 (b), FIG. _{The width (L dB} ) of the inflated portion (B) of (d) is detected by the area (A _{2 ) of the second convex portion (C 2} ) in FIG. 7 (b), and in FIG. 8 (f) _{The width (L dB} ) of the inflated portion (B) of FIG. 7 (c) is detected by the area (A _{3 ) of the third convex portion (C 3 ).} 8 (a) to (c), according to the area (A ₁ , A ₂ , A ₃ ) of _{each of the plurality of convex portions (C 1} , C ₂ , C _{3 ) of FIG. 7 (b)} , it can be seen that _{the width (L dB} ) of the inflated portion B is detected differently.

As such, in the embodiment, rather than directly measuring the actual height and width of the inflated portion (B), the maximum intensity (i _max ) of the peak (P) and the area (A) of the convex portion (C) are used through calculations , to indirectly detect _{the height (H dB} ) and width (L _dB ) of the inflated portion (B).

_{The height (H dB} ) and width (L _dB ) of the inflated portion (B) may be detected for each position on the surface of the specimen 20. That is, the height (H) of the inflated portion B for each position in the first extension direction (X-axis direction) and the second extension direction (Y-axis direction) of the surface 21 of the specimen 20 , that is, by coordinate position on the XY coordinates. _dB ) and width (L _dB ). _{The height (H dB} ) and the width (L _dB ) of the inflated portion (B) for each position of the surface 21 of the specimen 20 are summarized and shown, for example, as shown in Table 2 below.

In Table 2, the first inflated part, the second inflated part, the third inflated part, ... , n-th inflated portion is named by assigning a number to distinguish the plurality of inflated portions (B) formed on the specimen (20). For example, when 6522 inflated portions are formed on the surface 21 of the specimen 20, the nth inflated portion may be a 6522th inflated portion.

Referring to Table 2, it can be seen that the positions of the first to 6522th inflated parts, and the height and width of each of the first to 6522th inflated parts were individually detected.

division 1st extension direction (X-axis direction) position (mm) 2nd extension direction (Y-axis direction) position (mm) _{Height (H dB} ) (㎛) of the detected bulge (B) _{Width (L dB} ) (㎛) of the detected bulge (B)

_{Width (L dB} ) (㎛) of the detected bulge (B) 1st inflated part 4.2 89.8 15 191 2nd inflated part 46.9 89.8 14 204 3rd inflated part 46.5 89.8 22 170 .
.
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.
. .
.
. .
.
. .
.
. 6522 Inflation part
(n = total number of inflated parts = 6522) 83.0 0.1 21 194

9 is a flowchart illustrating a method of deriving a depth and size of an inclusion by a method according to an embodiment of the present invention. 10 exemplarily illustrates a depth derivation model for deriving a depth of an inclusion by a method according to an embodiment of the present invention. 11 exemplarily shows a size derivation model for deriving the size of inclusions by a method according to an embodiment of the present invention.

When the height (H _dB ) and the width (L _dB ) of the inflated part B are detected, the inclusion predictor 300 derives the depth and the size of the inclusion I by using them. That is, the depth of the inclusion I is derived using the inclusion depth deriving unit 310 of the inclusion predictor 300 , and the size of the inclusion is derived using the inclusion size deriving unit 320 .

The inflated portion (B) is formed by the inclusion (I) in the specimen (20). And, the inclusion (I) is located inside the surface of the specimen 20 on which the inflated portion (B) is formed. In other words, the inclusion (I) is positioned at a position facing the inflated portion (B) inside the specimen (20). Accordingly, when the height (H _dB ) and the width (L _dB ) of the inflated portion (B) are detected, the depth and size of the inclusion (I) facing the inflated portion (B) detected from the inside of the specimen 20 can be derived.

As described above, in the embodiment, the depth and size of the inclusion I are derived using the inclusion depth deriving unit 310 and the inclusion size deriving unit 320, and the actually measured depth D of the inclusion I _In order to distinguish between I ) and the size (L _I ), the depth of the inclusion (I) derived using the inclusion depth deriving unit 310 and the inclusion size deriving unit 320 is D _dI , and the size of the inclusion is L _dI referred to and explained.

9, the process (S30) of deriving the depth (D _dI ) and the size (L _dI ) of the inclusion (I) is a width (L _{dB ) of the detected height (H dB) of the inflated portion (B)} ) The process of calculating the ratio (T _d ) (hereinafter, the ratio (T _d ) of the inflated part) (S31), the height (H _dB ) and the width (L _dB ) of the detected inflated part (B) The process of calculating the volume (V _dB ) of B) (S32), the process of deriving _{the depth (D dI} ) of the inclusion (I) using the _{calculated ratio (T d} ) of the inflated part (B) (S33), It includes a process (S34) of deriving _{the size (L dI} ) of the inclusion (I) using the _{calculated volume (V dB} ) of the inflated portion (B).

First, a method of deriving _{the depth D dI} of the inclusion I by the inclusion depth deriving unit 310 will be described.

When the height (H _dB ) and width (L _dB ) of the inflated part (B) are detected, the ratio of the width (L _{dB ) to the height (H dB} ) of the inflated part (B) (T _d ), that is, the inflated part (B) ) to calculate the ratio (T _d ) (S31). That is, as shown in Equation 2 below _{, the ratio (T d} ) of the _{inflated part (B) is calculated by dividing the width (L dB} ) of the inflated part (B) by the height (H _dB ) of the inflated part (B).

[Formula 2]

_{In deriving the depth D dI} of the inclusion I using the _{calculated ratio T d} of the inflated portion B, a depth derivation model may be used. That is, if the ratio (T _d ) of the inflated part (B) is applied or used to a pre-prepared depth derivation model, the depth (D _dI ) of the inclusion (I) is derived.

The depth derivation model may be a model having depth data of the inclusion (I) according to the ratio of the inflated part (B). Hereinafter, for convenience of explanation, the ratio of the inflated part of the depth derivation model is called the model ratio (T _M ), and the depth of the inclusions is called the _{model depth (D M ).} Reflecting this and describing again, the depth derivation model may be a model having model depth (D _M ) data _{according to the model ratio (T M ).}

A regression equation may be used as the depth derivation model, and the regression equation of the depth derivation model may be as shown in Equation 3 below. _{And, if the graph is graphed with the model depth (D M} ) according to the model ratio (TM) of the depth derivation model, it may be as shown in FIG. 10 . A method for preparing a depth derivation model will be described later.

[Equation 3]

_{When the ratio (T d} ) of the inflated part (B) is calculated, it is calculated by applying it to _{T M of the regression equation as in Equation 3.} Then, the model depth D _M is calculated, and the calculated model depth D _M is derived as _{the depth D dI} of the inclusion I.

_{When the ratio (T d} ) of the inflated portion (B) _{and the depth (D dI} ) of the inclusions (I) are summarized by positions in the extension direction of the surface 21 of the specimen 20, for example, it may be as shown in Table 3 below.

division detected
_{Height (H dB} ) (㎛) of the inflated part (B)

_{Height (L DH} ) (㎛) of the inflated part (B) _{Width (L dB} ) (㎛) of the detected bulge (B) of the inflated part (B)
ratio (T _d ) _{Depth (D dI} ) (μm) of the derived inclusion (I) 1st inflated part 15 191 12.7 142 2nd inflated part 14 204 14.6 161 3rd inflated part 22 170 7.7 84 .
.
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.
. .
.
. .
.
. .
.
. nth inflated part 21 194 9.5 106

The depth derivation model is not limited to the regression equation as described above, and the depth of the inclusions I according to the ratio of the inflated part B (ie, the model ratio TM) (ie, the model depth (D _M )) data You can use a data table with .

When using the data table as the depth derivation model, in the data table of the depth derivation model, the calculated ratio of the bloated part (T _d ) and the model ratio (TM) are compared, and the calculated ratio of the bloated part (T _d ) Or search for the nearest model ratio (TM). _{Then, the model depth (D M} ) according to the searched model ratio (TM) is searched, and the searched model depth (D _M ) is derived as the depth (D _{dI ) of the inclusions.}

Next, a method of deriving _{the size L dI} of the inclusion I by the inclusion size deriving unit 320 will be described.

When the width (L _dB ) and the height (H _dB ) of the inflated part (B) are derived, the volume (V _dB ) of the inflated part (B) is calculated using these. In this case, _{the volume (V dB} ) of the inflatable part B can be calculated and derived _{using Equation 4 below, which applies the width (L dB} ) and the height (H _dB ) of the inflatable part (B).

[Equation 4]

In Equation 4, R _d is calculated using the detected width (L _dB ) of the inflated portion (B) and the detected height (H _dB ) of the inflated portion (B), and can be calculated using Equation 5 below .

[Equation 5]

_{When the volume (V dB} ) of the inflated part (B) is calculated, the size (L _dI ) of the inclusion (I) is derived using this. _{In deriving the size (L dI} ) of the inclusion (I) using the _{calculated volume (V dB} ) of the inflated portion (B), a size derivation model may be used. That is, if the volume (V _dB ) of the inflated portion (B) is applied to or used in a pre-prepared size derivation model, the depth (D _dI ) of the inclusion is derived.

The size derivation model may be a model having size data of the inclusion (I) according to the volume of the inflated part (B). Hereinafter, for convenience of description, the volume of the inflated part (B) of the size derivation model is called the model volume (V _M ), and the size of the inclusions is called the _{model size (L M ).} Reflecting this again, the size derivation model may be a model having model size (D _M ) data _{according to the model volume (V M ).}

A regression equation may be used as the size derivation model, and the regression equation of the size derivation model may be as shown in Equation 6 below. And, if the size derivation model is graphed by the model size (L _{M ) according to the model volume (V M} ), it may be as shown in FIG. 11 . A method of preparing a size derivation model will be described later.

[Equation 6]

_{When the volume (V d} ) of the inflated part (B) is calculated, it is calculated by applying it to _{V M of the regression equation as in Equation 6.} Then, the model size L _M is calculated, and the calculated model size L _M is derived as _{the size L dI} of the inclusion I.

_{If the derived volume (V d} ) of the inflated portion (B) _{and the size (L dI} ) of the inclusions (I) are summarized by positions in the extension direction of the surface 21 of the specimen 20, for example, it may be as shown in Table 4 below.

division of the detected bulging part (B)
Height (H _dB ) (㎛) of the detected bulging part (B)
Width (L _dB ) (㎛) of the inflated part (B)
Volume (V _d ) (μm ³ ) _{Size (L dI} ) (μm) of the derived inclusion (I) 1st inflated part 15 191 218918 28 2nd inflated part 14 204 230285 28 3rd inflated part 22 170 258955 30 .
.
. .
.
. .
.
. .
.
. .
.
. nth inflated part 21 194 308143 31

In the above, it has been described that the regression equation is used as the size derivation model, but it is not limited thereto, and _{the size of the inclusions according to the volume (ie, the model volume (V M} )) of the inflated part (B) (ie, the model size (L _{M ))} )) You can use a data table with data.

When using a data table as a size derivation model, in the data table of the size derivation model, the calculated volume (V _d ) and the model volume (V _M ) are compared, and the calculated volume (V _d ) of the inflated part corresponds to Find the or nearest model volume (V _M ). Then, the model size (L _M ) according to the searched model volume (T _M ) is searched, and the searched model size (L _M ) is derived as the size (L _{dI ) of the inclusions.}

Hereinafter, a method of obtaining a depth derivation model and a size derivation model will be described with reference to FIG. 12 .

12A is a photograph taken using a scanning electron microscope from the upper side of the surface of the specimen 20 on which the inflated portion B is formed. (b) of FIG. 12 is a cut (E'-E'') in the extension direction of the specimen 20, for example, in the first extension direction of the region 'E' in which the inflated portion B is formed in FIG. 12(a). This is a photograph of the cross section.

According to the depth it provided the derived model, the actual inflation portion (B) a depth (D _B) and the width (L _B) to the actual or direct measure calculates the ratio of the swelling portion (B), and inclusion (I) of The depth D _I may be provided by matching the calculated ratio of the inflated portion. At this time, the real and the depth of the measured inflation portion (B) (D _B) and the width (L _B) a swelling portion (B) ratio is model the ratio of calculated using a (T _M), the actual measured inclusions (I ) becomes the actual depth (D _I ) of the model depth (D _M ).

Further, to provide a size derived model, the depth (D _B) and the width (L _B) to the actual or directly measured value calculated on the volume of the inflation section (B), and inclusion (I) of the swelling portion (B) It can be prepared by matching the actual size (L _I ) of the calculated volume of the inflated part. At this time, the volume of the depth (D _B) and the width (L _B) a swelling portion (B) calculated by using the actual measured inflation portion (B), and the model volume (V _M), the actual measured inclusions (I ) becomes the actual size (L _I ) of the model size (L _M ).

Hereinafter, a method for preparing a depth derivation model and a size derivation model will be described with more specific examples.

First, hydrogen permeates into the specimen 20 through an electrochemical reaction to form an inflated portion B on the surface 21 of the specimen 20 . For this purpose, the inflated part generator 100 shown in FIG. 3 may be used.

When the sample bulging portion (B) to (20) the surface 21 is formed, it is measured for each of (H _B) a plurality of high swelling portion (B) and width (L _B). For this purpose, it can be measured using a scanning electron microscope. More specifically, in the surface area of the specimen in which any one of the puffing parts B is formed, for example, in the 'E' region of FIG. Acquire a cut cross-sectional image in the -E'' direction. Then, on the acquired image, the height (H _B ) of the inflated portion (B) and the width (LB ) of the inflated portion ( _B ) are measured.

Since the inclusions are located within the voids or between the bulges and the voids, they can be identified from photographs obtained through scanning electron microscopy. Referring to (b) of FIG. 12 , the inclusion (I) positioned between the inflated part and the void can be identified. _{Accordingly, the size (L I} ) of the inclusion (I) on the acquired image is measured.

_{In addition, the depth (D I} ) of the inclusion (I) on the image is measured. Here, the depth (D _I), the first interface (GF ₁₎ and the second interface (GF _2), the specimen (20) of the bulge portion (B) is formed of the air gap (G) as described above of the inclusion (I) It means a separation distance between the interface facing the opposite surface of the surface 21 and the surface 21 of the specimen 20 on which the inflated portion B is formed.

In the case of FIG. 12 , as described in FIG. 5 , ^{the penetration direction of H +} ions and the direction in which the inflated portion B is formed are the same, so that the inclusion I is moved from the initial position. And, the inflated portion (B) is in a state formed on the second surface (21b). _{Accordingly, the first interface GF 1} of the void G facing the first surface 21a of the specimen 20 in which the inflated portion B is not formed and the inflamed portion B are formed in the specimen 20 second measuring the distance between the surface (21b) of, and to the distance measured to a depth (D _I) of the inclusions (I).

And, the inflated portion (B) is formed by the inclusion (I) positioned to face the inflated portion (B) in the inside of the specimen 20 or to overlap its horizontal position. Therefore, the depth (D _I of the height (H _B) and a width measured (L _B) and facing the said bulging portion (B) samples (20) the inclusion (I) located in the interior of the bulging portion (B) ) and width (L _I ) are measured, they are combined into a pair or matched to form data. That is, the height (H _B) and width (L _B) data and the depth (D _I) and width (L _I) of the inclusions (I) that caused the one bulge portion (B) of one bulging portion (B) It is processed as one group of data.

In this way, the surface of the specimen (20) (21) That is, the height of the bulge portion (B) formed in each first face (21a) and a second side (21b), (H _B) and width (L _B) is measured, and the depth (D _I ) and width (L _I ) of the plurality of inclusions (I) are measured. And, the height (H _B ) and width (L _{I ) data for each inflated part (B) and the depth (D I} ) and width (L _I ) of the inclusion (I) that generated each of the inflated parts (B) It is processed as one group of data.

Next, the height of the measured inflation portion (B) (H _B) and width (L _B) and, where width (L _B) ratio of the height (H _B) of the swelling portion (B), using the swelling portion (B ) and the volume of the inflated part (B) are calculated.

Rate of swelling portions (B) is divided by the height (H _B) of the measured width (L _B) of the measured inflation portion (B) bulging portion (B). And, since the bulging portion in the depth ratio derived model is designated as Model ratio (T _M), it represents an equation for calculating the rate the model (T _M), following the same as Equation 7.

[Equation 7]

This model ratio TM is calculated for each of the plurality of bulges B. Then, when ingested tie depth that is, model depth (D _M) of data of the inclusion (I) that caused the respective bulging portions (B) in accordance with a plurality of swelling portions (B) each of the model ratio (TM), the depth deriving model this is obtained That is, a depth derivation model having _{model depth (D M} ) data according to the model ratio (TM) is obtained. In addition, if the model depth (D _M ) change tendency according to the model ratio (TM) is formulated, a regression equation is derived, for example, a regression equation such as Equation 3 can be obtained. _{And, it can be represented by graphing the model depth (D M} ) change tendency or the regression equation according to the model ratio (TM), for example, as shown in FIG. 10 .

Further, by using the height of the measured inflation portion _(B) (H B) and width (L _B) to calculate the volume (V _B) of the swelling portion (B). And, since the volume of the inflated part in the size derivation model is named as the model volume, _{the formula for calculating the model volume (V M} ) may be expressed as Equation 8 and Equation 9 below. _{That is, if the actually measured height (H B} ) and width (LB ) of the inflated portion _{(B ) is applied to H dB} and L _dB of Equations 4 and 5, respectively, Equations 8 and 9 may be obtained.

[Equation 8]

[Equation 9]

This model volume (V _M ) is calculated for each of the plurality of bulges (B). And, the size of the inclusions (I) that caused each inflated part according to _{the model volume (V M} ) of each of the plurality of inflatable parts (B) _{, that is, the model size (L M} ) When data is bundled into data, a size derivation model is obtained . That is, a length derivation model having model size (L _{M ) data according to the model volume (V M ) is obtained.} In addition, by formulating the model size (L _M ) change tendency according to the model volume (V _M ), a regression equation is derived, for example, a regression equation such as Equation 6 can be obtained. In addition, the model size (L _M ) change tendency or regression equation according to the model volume (V _M ) may be represented by graphing, for example, as shown in FIG. 11 .

It is preferable that such a depth derivation model and a size derivation model be prepared before starting the evaluation of the metal material. In addition, the depth derivation model and the size derivation model may be prepared according to the steel type of the metal material to be evaluated. That is, data or its shape included in the depth derivation model and the size derivation model may differ depending on the steel type.

Hereinafter, the process of deriving the depth and size of the inclusions will be described again.

When the ratio (T _d ) of the bulge and the volume (V _{d ) of the bulge are calculated, the depth (D dI} ) and the size (L _dI ) of the inclusion (I) are derived using the depth derivation model and the size derivation model, respectively. do. For example, if the ratio (T _{d ) of the inflated part (B) is applied to T M} of the depth derivation model regression equation (Equation 3) and calculated, the model depth (D _M ) is calculated, and this is the depth (D) of the inclusion (I) _dI ). In addition, when the volume (V _{d ) of the inflated part (B) is applied to V M} of the size derivation model regression equation (Equation 6) and calculated, the model size (L _M ) is calculated, and this is the size of the inclusion (I) ( L _dI ).

_{When the depth (D dI} ) and the size (L _dI ) of the inclusions (I) derived in this way are summarized for each position in the extension direction of the surface 21 of the specimen 20, for example, it may be shown in Table 5.

division of the inflated part (B)
ratio (T _d ) of the inflated part (B)
volume (V _d )
(μm ³ ) _{Depth (D dI} ) (μm) of the derived inclusion (I) _{Size (L dI} ) (μm) of the derived inclusion (I) 1st inflated part 12.7 218918 142 28 2nd inflated part 14.6 230285 161 28 3rd inflated part 7.7 258955 84 30 .
.
. .
.
. .
.
. .
.
. .
.
. nth inflated part 9.5 308143 106 31

_{13 is a graph showing the depth (D dI} ) of the inclusion and the size (L _dI ) of the inclusion derived by the method according to the embodiment of the present invention on one coordinate.

_{When the derived depth (D dI} ) and size (L _dI ) of each of the plurality of inclusions (I) are represented on a coordinate plane, for example, it may be in the form of FIG. 13 .

_{The depth (D dI} ) and the size (L _dI ) of the plurality of inclusions (I) derived by the method as described above may be used in the evaluation unit 400 to evaluate the metal material serving as the base material of the specimen 20 .

The process of evaluating the metal material (S40), as shown in FIG. 1, is a process of comparing the ratio of defect-inducing inclusions with the reference ratio (S41). It may include a process of evaluating (S42), and a process (S43) of evaluating the metal material as abnormal in which shipment is not possible when the ratio of defect-inducing inclusions exceeds the reference ratio.

Evaluating the metal material may mean determining the possibility of occurrence of defects due to the inclusion (I) during processing of the metal material according to the derived depth (D _dI ) and size (L _{dI ) distribution of the inclusions.} Here, the distribution of the depth (D _dI ) and the size (L _dI ) of the inclusions (I) refers to the depth (D _dI ) and the size (L _dI ) that cause surface defects during processing among all detected inclusions (I). The branch may mean a ratio to the number of inclusions I (ie, a ratio of defect-inducing inclusions). And, as the ratio of the defect-inducing inclusions increases, it may be determined that the possibility of surface defects occurring due to the inclusions I during processing is high.

Here, the ratio of the defect-inducing inclusions may be a ratio to the number of inclusions having a size equal to or less than the reference depth among all inclusions I and greater than or equal to the reference size (refer to FIG. 13 ). In other words, the depth (D _dI ) and size (L _dI ) derived for each of the plurality of inclusions may be a ratio to the number of inclusions equal to or less than the reference depth and at the same time equal to or greater than the reference size.

Accordingly, a reference depth and a reference size may be set in the evaluation unit 400 . In addition, the evaluation unit 400 may set a reference ratio for determining the possibility of occurrence of a defect using the calculated ratio of the defect-inducing inclusions.

The evaluation unit 400 first calculates a ratio of defect-inducing inclusions for evaluation of the metal material. That is, in all of the derived inclusions, a ratio of inclusions that are less than or equal to the reference depth and greater than or equal to the reference size is calculated. Then, the calculated ratio of defect-inducing inclusions is compared with a preset reference ratio (S41) and evaluated.

As a result of the comparison, if the defect-causing inclusion ratio is less than or equal to the reference ratio (Yes), the evaluation unit 400 determines or evaluates the metal material as normal ( S42 ). In this case, the rolled material, which is the base material of the specimen 20, is shipped to the customer.

However, when the defect-causing inclusion ratio exceeds the reference ratio (No), the evaluation unit 400 determines or evaluates the metal material as abnormal ( S43 ). When the metal material is evaluated as abnormal, the rolled material, which is the base material of the specimen 20, cannot be shipped to the customer, and the metal material is discarded. Then, by changing the operating conditions during the refining process of molten steel, measures are taken to reduce the amount of inclusions.

On the other hand, when a rolled material obtained by rolling a cast slab is shipped to a customer, the customer is processed and used. In addition, the type of processing such as bending or tapping may be different for each customer, and the degree of processing may also be different. And during such processing, defects on the surface 21 due to the inclusions I should not occur or be small.

Therefore, the reference depth, the reference size, and the reference ratio may be set differently according to the type and degree of processing performed by the customer. The reference depth, the reference size, and the reference ratio may vary depending on the required quality of the metal material required by the customer to deliver or ship the metal material serving as the base material of the specimen 20 . In addition, it may vary depending on the type and processing degree of processing the metal material at the customer.

Hereinafter, a method for evaluating a metal material according to an embodiment of the present invention will be sequentially described with reference to FIGS. 1 to 11 and 13 . In this case, the content overlapping with the previously described content will be omitted or briefly described.

First, a specimen 20 is prepared, and an inflated portion B is formed on the surface 21 of the specimen 20 ( S10 ). To this end, as shown in FIG. 3 , the specimen 20 and the conductor 30 are immersed in the aqueous solution 14 in the water tank 110 . At this time, one of the first surface 21a and the second surface 21b of the specimen 20, for example, the first surface 21a is immersed to face the conductor 30 . When the specimen 20 and the conductor 30 are immersed in the aqueous solution in the water tank 110 , the power supply line 130 is connected to each of the specimen 20 and the conductor 30 , and then power is applied. That is, a current is applied with the specimen 20 as the negative electrode (-) and the conductor as the positive electrode (+).

When an electric current flows through each of the specimen 20 and the conductor 30, an electrochemical reaction occurs between the specimen 20, the conductor 30, and the aqueous solution 14 ^{to generate hydrogen, that is, H +} ions (refer to Scheme 1) .

The generated H ⁺ ions penetrate into the negative (-) specimen 20 . When the penetrating H ⁺ ions reach the surface of the inclusion (I) inside the specimen 20, they are not penetrated or moved anymore and are accumulated on the surface of the inclusion (I). ^{At this time, as H +} ions accumulated on the surface of the inclusion (I) are combined, hydrogen (H ₂ ) gas is formed.

And, as the hydrogen gas increases, the gap between the inclusion (I) and the specimen (20) gradually widens, and as a part of the surface of the inclusion (I) and the specimen (20) are separated, between the surface of the inclusion (I) and the specimen (20) Gap (G) is formed in the. The void G expands as the amount of hydrogen gas generated increases, and an inflated portion B is formed on the surface of the specimen 20 as shown in FIGS. 4 and 5 .

When the formation of the inflated portion B on the specimen 20 is finished, the height (H _dB ) and width (L _dB ) of the inflated portion B are detected (S20). To this end, light is irradiated to the surface of the specimen 20 using the optical system 210 of the swelling part detector 200 (refer to (a) of FIG. 7). At this time, light is irradiated while horizontally moving the optical system 210 in the first extension direction and the second extension direction, which are the extension directions of the surface 21 of the specimen 20 . Then, the light reflected from the surface 21 of the specimen 20 is again received by the optical system 210 , and intensity data of the light received by the optical system 210 is transmitted to the detector 230 .

The detector 230 derives optical data having an intensity of light along the extension direction of the surface of the specimen 20 by using the optical data transmitted from the optical system 210 . In addition, the detector 230 may graph the light intensity value along the extension direction of the surface 21 of the specimen 20 to appear. For example, as shown in (b) of FIG. 7 , it is possible to graph the light intensity value along the first extension direction (X-axis direction) of the surface 21 of the specimen 20 .

The detection unit 230 compares and analyzes the intensity of light along the extension direction of the surface 21 of the specimen 20 to derive positions of the plurality of bulging portions B formed on the surface 21 of the specimen 20 . That is, to detect the position or the region that exceeds the reference intensity (i _s) in bulge part is formed or located bulge portion position. At this time, the position of the inflated portion B on the XY coordinate plane that is the coordinate plane with respect to the extension direction of the surface 21 of the specimen 20 may be derived.

_{In addition, the detection unit 230 detects the height (H dB} ) and the width (L _dB ) of the inflated portion (B) by using the intensity of the light received by the optical system 210 (S20).

_{In detecting the height (H dB} ) of the inflated portion (B), the detection unit 230 is the extension direction of the surface 21 of the specimen 20, for example, the first extension direction (X-axis direction) as shown in FIG. A graph in which the intensity of light is graphed may be used. That is, the intensity of light at each of the plurality of peaks P on the graph _{is derived as the height (H dB} ) of the inflated portion (B), and the maximum intensity (i _max ) is the height (H _dB ) of the inflated portion (B). derive In this case, it can be derived using a height derivation model having _{model height (H M ) (height of the inflated part) data according to the model intensity (i M} ) (intensity of light).

_{In addition, the detection unit 230 detects the width (L dB} ) of the inflated portion (B) by using the intensity of the light received by the optical system (210). More specifically, on a graph showing the intensity of light along the extension direction of the surface of the specimen 20, for example, in the first extension direction (X-axis direction) as shown in FIG. A) is used to detect _{the width (L dB} ) of the inflated part (B). That is, when the area A of the convex portion C is calculated and a circle having the calculated area A of the convex portion C is realized, the diameter of the circle having the calculated area A ( 2r) (refer to Equation 1) is derived as _{the width (L dB) of the inflated part (B).}

The detection of the height (H _dB ) and width (L _dB ) of the swollen portion (B) is performed for a plurality of the swollen portions (B) formed on the surface (21) of the specimen (20). _{In other words, the height (H dB} ) and the width (L _dB ) are detected for each position of the surface 21 of the specimen 20 . _{If the height (H dB} ) and the width (L _dB ) of the inflated portion (B) for each position of the surface 21 of the specimen 20 are summarized, for example, it may be as shown in Table 2 above.

_{When the height (H dB} ) and the width (L _dB ) of the inflated part B for each position of the surface 21 of the specimen 20 are detected, the inclusion depth derivation unit 310 and the inclusion size derivation unit 320 each _{The depth (D dI} ) of the inclusion (I) and the size (L _dI ) of the inclusion are derived ( S30 ). That is, the bulging portion bulging portion (B) the width (L _dB) and heights (H _dB) that when detected, the width (L _dB) ratio (T _d) to height (H _dB) of the swelling portion (B) of ( The ratio (T _d ) of B) is calculated (S31) (refer to Equation 2).

_{When the ratio (T d} ) of the inflated part (B) _{is calculated, the depth (D dI} ) of the inclusion (I) is derived by applying it to a depth derivation model having model depth data according to the model ratio. At this time, when using the regression formula as the depth derivation model, if the calculated ratio (T _{d ) of the inflated part (B) is applied to the T M} (model ratio) of the depth derivation model regression formula _{, the model depth (D M} ) is It is calculated, and the calculated model depth (D _M ) is derived as _{the depth (D dI} ) of the inclusion (I). As another example, when a data table is used as a depth derivation model, a model ratio TM corresponding to or closest to the _{calculated ratio T d of the inflated portion B is searched. Then, the model depth D M} corresponding to the searched model ratio TM is derived as _{the depth D dI} of the inclusion I.

In addition, when the width (L _dB ) and the height (H _dB ) of the inflated portion (B) are derived, the size (L _dB ) of the inclusion (I) is derived using this. To this end, first _{, the volume (V dB ) of the inflated part (B) is calculated using the width (L dB} ) and the height (H _dB ) of the inflated part (B), and at this time, using Equations 4 and 5 described above can be calculated by

_{When the volume (V dB} ) of the inflated part (B) _{is calculated, the size (L dI} ) of the inclusion (I) is derived by applying it to the size derivation model having the model size (L _M ) data according to the model volume (V _{M )} do. At this time, when using the regression formula as the size derivation model, if the calculated volume (V _{d ) of the inflated part (B) is applied to the V M} (model volume) of the size derivation model regression equation (Equation 6), the model size ( L _M ) is calculated, and the calculated model size L _M is derived as _{the size L dI} of the inclusion I. As another example, when a data table is used as a size derivation model, the _{model volume V M} corresponding to or closest to the _{calculated volume V d} of the inflated part B is searched. Then, the model size (L _M ) corresponding to the searched model volume (V _M ) is derived as the depth (D _dI ) of the inclusion (V _{M ).}

_{When the depth (D dI} ) and the size (L _dI ) of the plurality of inclusions (I) are derived, the evaluation unit 400 evaluates the metal material using them ( S40 ). That is, the evaluation unit 400 compares the ratio of inclusions that are less than the reference depth and greater than or equal to the reference size, that is, the ratio of defect-inducing inclusions and a preset reference ratio in all of the derived inclusions (S41).

As a result of the comparison, if the defect-causing inclusion ratio is less than or equal to the reference ratio (Yes), the evaluation unit 400 determines or evaluates the metal material as normal ( S42 ). In this case, the rolled material, which is the base material of the specimen 20, is shipped to the customer.

However, when the defect-causing inclusion ratio exceeds the reference ratio (No), the evaluation unit 400 determines or evaluates the metal material as abnormal ( S43 ).

As described above, according to the method for evaluating a metal material and an apparatus for evaluating a metal material according to an embodiment of the present invention, the depth of the inclusion and the size of the inclusion may be derived. And, using the derived depth and size of the inclusions, it is predicted whether or not a defect will occur during processing of the metal material. Accordingly, there is an effect of improving the reliability of determining whether a defect is generated due to an inclusion during processing of a metal material. Accordingly, it is possible to prevent the metal material, which is to be defective during processing, from being shipped to the customer.

In addition, without directly or actually measuring the depth and size of the inclusions, the bulge (B) is artificially generated, and the inclusion (I) using the _{height (H dB} ) and width (L _{dB ) of the bulge (B)} Indirectly derive the depth (D _dI ) and size (L _{dI ) of} This method has the advantage of being quick compared to the method of directly or actually measuring the depth and size of the inclusions I.

20: Psalm B: Inflated part
G: voids

Claims (22)

The process of preparing a specimen from the metal material to be evaluated;
forming an inflated portion on the surface of the specimen;
The process of detecting the height (H _dB ) and width (L _{dB) of the inflated portion;} and
a process of deriving a _{depth (D dI} ) and a size (L _dI ) of inclusions in the specimen by using the detected height (H _dB ) and width (L _{dB ) of the inflated portion;}
Evaluation method of a metal material comprising a. The method according to claim 1,
The process of detecting the height (H _dB ) and width (L _{dB) of the inflated part is,}
An evaluation method of a metal material, comprising the steps of transmitting and receiving light with respect to the specimen, _{and calculating the height (H dB} ) and width (L _{dB ) of the inflated portion by an indirect method using optical data.} The method according to claim 1,
The process of deriving the depth (D _{dI ) of the inclusion is,}
Evaluation of a metal material by using the ratio (T _d) rate of swelling portions (T _d) of the width (L _dB) for a height (H _dB) the bulge portion includes the step of deriving a depth (D _dI) of the inclusions Way. 4. The method according to claim 3,
The process of deriving _{the depth (D dI} ) of the inclusions using the ratio (T _{d ) of the inflated part is,}
Model depth in accordance with the model ratio (T _M) (D _M) to provide a depth deriving model having the data, and the model ratio (T _M) of the ratio of the swelling portion to (T _d) the model ratio selected against ( An evaluation method of a metal material, including the process of deriving the model depth (D _M ) for the T _M ) as the depth (D _{dI ) of the inclusions.} 5. The method according to claim 4,
The depth deriving model evaluation method of a metal material having a tendency to increase the depth model (D _M) with the increase of the model, the ratio (T _M). The method according to claim 1,
The process of deriving the size (L _{dI ) of the inclusion is,}
The process of calculating the _{volume (V dB} ) of the inflated part using the height (H _dB ) and the width (L _{dB) of the inflatable part;}
The process of deriving _{the size (L dI} ) of the inclusion using the volume (V _{dB ) of the inflated portion;}
Evaluation method of a metal material comprising a. 7. The method of claim 6,
The process of deriving _{the size (L dI} ) of the inclusion using the volume (V _{dB) of the inflated part is,}
Model size (L _M) to provide a size derived model having the data, selected in case the volume (V _dB) the swelling portion to said model volume (V _M) model volume in accordance with the model volume (V _M) ( A method for evaluating a metal material, including the process of deriving a model size (L _{M ) for V M} ) as the size of inclusions (L _{dI ).} 8. The method of claim 7,
The size derivation model is an evaluation method of a metal material having a tendency to increase the model size (L _{M ) as the model volume (V M ) increases.} The process of preparing a specimen from the metal material to be evaluated;
forming an inflated portion on the surface of the specimen;
irradiating light to the specimen;
receiving light reflected from the surface of the specimen;
The process of detecting a _{height (H dB} ) and a width (L _dB ) of the inflated portion by using the intensity of the received light; and
The process of deriving _{the depth (D dI} ) and the size (L _dI ) of the inclusions in the specimen by using the height (H _dB ) and the width (L _{dB) of the inflated portion;}
Evaluation method of a metal material comprising a. 10. The method of claim 9,
The process of detecting the height (H _dB ) and width (L _{dB) of the inflated part is,}
a process of graphing the intensity of the reflected light along the extension direction of the specimen surface;
identifying, on the graph, a peak indicating a change in intensity of light reflected from the inflated portion;
using the identified peak, detecting a _{height (H dB} ) and a width (L _{dB ) of the inflated portion;}
Evaluation method of a metal material comprising a. 11. The method of claim 10,
In identifying the peak, on the graph, an intensity of light exceeding a reference intensity, which is the intensity of light reflected from the surface of the specimen on which the bulge is not formed, is identified as a peak. 11. The method of claim 10,
The process of detecting the height (H _dB ) of the inflated portion includes the process of detecting the _{height (H dB} ) of the inflated portion using the maximum intensity of the peak. 11. The method of claim 10,
The process of detecting the width (L _dB ) of the inflated portion is an evaluation method of a metal material for detecting the _{width (L dB} ) of the inflated portion using the area of the peak. 14. The method of claim 13,
The process of detecting the _{width (L dB} ) of the inflated portion using the area of the peak is,
forming a virtual circle having an area of the peak;
calculating a diameter of the virtual circle;
An evaluation method of a metal material using the diameter as the width (L _{dB) of the inflated portion.} delete 10. The method according to any one of claims 1 to 9,
Using the depth (D _dI ) and the size (L _dI ) of the inclusions, the metal material serving as the base material of the specimen, including the process of evaluating whether shipment is possible. 17. The method of claim 16,
Deriving the depth and size of each of the plurality of inclusions respectively corresponding to the plurality of inflated portions,
The process of evaluating whether the shipment is
deriving the number of defect-inducing inclusions that are less than or equal to a reference depth and greater than or equal to a reference size from among the depths and sizes of the plurality of inclusions;
calculating a ratio of defect-causing inclusions to all of the plurality of inclusions; and
When the ratio of the defect-causing inclusions is less than or equal to the reference ratio, the process of evaluating the metal material as normal capable of shipment;
Evaluation method of a metal material comprising a. a bulging part generator for generating bulging parts on the surface of the specimen by electrolysis;
a bulging part detector irradiating light to the specimen and detecting the bulging part by using the intensity of light reflected from the specimen;
an inclusion predictor predicting an inclusion in the specimen corresponding to the inflated portion and calculating information on the inclusion;
including,
The inclusion predictor,
an inclusion depth derivation unit storing a depth derivation model for deriving the depth of the inclusions using the detected inflated unit;
an inclusion size derivation unit storing a size derivation model for deriving the size of the inclusions using the detected inflated unit;
A metal evaluation device comprising a. 19. The method of claim 18,
The swelling part detector,
a light source that generates light; and
an optical system that irradiates the generated light to the surface of the specimen, receives the light reflected from the surface of the specimen, and is horizontally movable along an extension direction of the surface of the specimen;
A metal evaluation device comprising a. 20. The method of claim 19,
The light source is an evaluation device for a metal material that generates white light. 20. The method of claim 19,
The bulge detector includes a detector that generates a graph to continuously show the intensity of light by using the light data transmitted from the optical system. delete

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