JP2021148453A - Discrimination device and discrimination method for steel material fracture surface - Google Patents

Abstract

To provide a discrimination device and discrimination method for a steel material fracture surface, capable of automatically discriminating a brittle fracture part and a ductile fracture part on a fracture surface of a steel material, and capable of being applied to a large test piece in addition to a small test.SOLUTION: A discrimination device 1 for a steel material fracture surface comprises: a 3D measuring device 2 that measures the shape of a fracture surface 11 of a steel material 10; and discrimination means 4 that acquires 3D point group data of the fracture surface shape measured by the 3D measuring device 2, extracts the shape data of a 2D cross section cut in a plane (XY plane) perpendicular to a crack propagation direction (Z direction) of the steel material 10 from the 3D point group data, and discriminates whether the range of a line segment is a brittle fracture part 11a or a ductile fracture part 11b based on an absolute value of inclination of a line segment (line segment 12, ..., line segment n-1n) between adjacent points (point 1 and point 2, ..., point n-1 and point n) in the extracted shape data of the 2D cross section and the absolute value of the difference in inclination of adjacent line segments (line segment 12 and line segment 23, line segment 23 and line segment 34, ..., line segment n-2n-1 and line segment n-1n).SELECTED DRAWING: Figure 1

Description

The present invention relates to a steel fracture surface discriminating device and a discriminating method for automatically discriminating between a brittle fracture portion and a ductile fracture portion of a fracture surface obtained by a fracture test of a steel material or the like.

When evaluating the mechanical performance of a steel material, it is generally necessary to break the steel material to obtain properties such as strength and toughness. For example, since brittle cracks are likely to occur in thick steel plates of structures used in low temperature environments such as ships, high brittle crack propagation stopping performance is required for steel materials in order to minimize damage.
There is an ESSO test as a method for evaluating the brittle crack propagation stopping performance. In this ESSO test, the brittle crack is propagated from the low temperature side to the high temperature side in a state where the test piece is provided with a temperature gradient, and the brittle crack arrest toughness value is obtained from the relationship between the brittle crack length and the temperature at the stopped position. In the ESSO test, the length of the test piece in the brittle crack propagation direction requires 500 mm.

In order to confirm the length of the brittle crack stopped at this time, a load is generally applied to the test piece after the test, and the part where the brittle crack has not propagated is ductilely fractured to break the test piece. Here, the fracture surface of the fractured test piece is in a state in which a brittle fracture portion that is brittle fracture during the test and a ductile fracture portion that is ductile fracture due to a load after the test are mixed.
The region where brittle cracks did not propagate during the test has effects such as energy absorption due to plastic deformation and suppression of crack opening, and contributes to improvement of brittle crack propagation stopping performance. Therefore, it is necessary to automatically discriminate between the brittle fracture part and the ductile fracture part on the fracture surface of the steel material and quantitatively evaluate the size of the ductile fracture part or the brittle fracture part in order to evaluate the characteristics of the steel material with high accuracy. Needed.

Here, conventionally, for example, in the fracture surface observation method shown in Patent Document 1, when observing the fracture surface of the test material in which cracks have occurred, the unbroken portion is forcibly destroyed and the fracture surface observation is performed. Before the forced fracture, the existing crack fracture surface is colored by heating in advance, and then the test material is forcibly fractured to observe the fracture surface.
As a result, since the forced rupture fracture surface is not colored, it becomes easy to distinguish between the existing colored crack fracture surface and the forced rupture fracture surface.
Further, in the conventional automatic fracture surface observation device shown in Patent Document 2, a microscope for observing the fracture surface of the test piece and an imager connected to the microscope to capture an image of the fracture surface of the test piece and output an analog image. The brittle fracture surface and the ductile fracture surface are discriminated by image processing using and.
As a result, fracture surface analysis can be performed at high speed and automatically.

Japanese Unexamined Patent Publication No. 4-50749 Special Fair 5-60058 No.

However, the conventional fracture surface observation method shown in Patent Document 1 and the automatic fracture surface observation device shown in Patent Document 2 have the following problems.
That is, in the case of the fracture surface observation method shown in Patent Document 1, although it is easy to distinguish between the existing colored crack fracture surface and the forced fracture surface, the brittle fracture portion and the ductile fracture portion in the fracture surface of the steel material Cannot be automatically determined.
On the other hand, in the case of the automatic fracture surface observation device shown in Patent Document 2, the brittle fracture surface and the ductile fracture surface can be discriminated at high speed and automatically, but since a microscope is required for the fracture surface analysis, the ESSO test is performed. It is not suitable for observing the fracture surface of a large test piece such as that used.
Therefore, the present invention has been made to solve these conventional problems, and an object of the present invention is to automatically discriminate between a brittle fractured portion and a ductile fractured portion on a fracture surface of a steel material, and perform a small test (drop weight test). , Charpy impact test, etc.), as well as a steel fracture surface discrimination device and a discrimination method applicable to a large test piece.

In order to achieve the above object, the steel fracture surface discriminating device according to one aspect of the present invention includes a three-dimensional measuring device for measuring the shape of the fracture surface of the steel material and a fracture surface shape measured by the three-dimensional measuring device. The three-dimensional point group data of the above is acquired, and the shape data of the two-dimensional cross section cut in a plane perpendicular to the crack propagation direction of the steel material is extracted from the three-dimensional point group data, and the extracted two-dimensional point group data is extracted. Discrimination to determine whether the range of the line segment is a brittle fracture portion or a ductile fracture portion based on the absolute value of the inclination of the line segment between adjacent points and the absolute value of the difference in the inclination of the adjacent line segments in the shape data of the cross section. The gist is that it has means.
Further, the method for discriminating the fracture surface of the steel material according to another aspect of the present invention is a three-dimensional measurement step for measuring the shape of the fracture surface of the steel material and a three-dimensional point group of the fracture surface shape measured in the three-dimensional measurement step. Data is acquired, shape data of a two-dimensional cross section cut in a plane perpendicular to the crack propagation direction of the steel material is extracted from the three-dimensional point group data, and adjacent in the extracted shape data of the two-dimensional cross section. Including a determination step of determining whether the range of the line segment is a brittle fracture portion or a ductile fracture portion based on the absolute value of the inclination of the line segment between the points to be formed and the absolute value of the difference in the inclination of the adjacent line segments. It is a summary.

According to the steel fracture surface discriminating device and the discriminating method according to the present invention, the brittle fractured portion and the ductile fractured portion are automatically discriminated on the fracture surface of the steel material, and in addition to the small test (drop weight test, Charpy impact test, etc.). It is possible to provide a steel fracture surface discriminating device and a discriminating method that can be applied to a large test piece.

It is a schematic diagram which shows the fractured steel material which has the fracture surface to which the method of discriminating the steel material fracture surface which concerns on one Embodiment of this invention is applied. It is a schematic block diagram of the steel material fracture surface discriminating device which concerns on one Embodiment of this invention. It is a flowchart which shows the procedure of the method of discriminating the steel material fracture surface using the steel material fracture surface discriminating device shown in FIG. It is a flowchart which shows the procedure of step S2 (discrimination step) in the flowchart shown in FIG. It is a schematic diagram showing a pattern of a fracture surface that can be considered when it is assumed that the brittle fracture portion on the steel fracture surface has a small inclination and the ductile fracture portion has a large inclination. (A) is a line between points 1 and 2. Minute 12 shows a fracture surface pattern in which the line segment 23 between the points 2 and 3 is the brittle fracture portion, and in (B), the line segment 12 between the points 1 and 2 shows the ductile fracture. The fracture surface pattern in which the line 23 between the points 2 and 3 is the ductile fracture surface is shown, and in (C), the line 12 between the points 1 and 2 is the ductile fracture and the points 2. The line segment 23 between the point 3 shows the fracture surface pattern which is the brittle fracture portion, and in (D), the line segment 12 between the point 1 and the point 2 is the ductile fracture portion, and between the point 2 and the point 3. Line 23 shows a fracture surface pattern that is a ductile fracture portion. It is a graph which shows an example of the shape data of the 2D cross section cut in the plane perpendicular to the crack propagation direction of a steel material in the mixed part where the brittle fracture part and the ductile fracture part are mixed in the steel material fracture surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below exemplify devices and methods for embodying the technical idea of the present invention, and the technical idea of the present invention describes the material, shape, structure, arrangement, etc. of the components. It is not specified in the following embodiments. The drawings are schematic. Therefore, it should be noted that the relationship, ratio, etc. between the thickness and the plane dimension are different from the actual ones, and there are parts where the relationship and ratio of the dimensions are different between the drawings.

FIG. 1 shows an example of a fractured steel material having a fracture surface to which the method for determining a fracture surface of a steel material according to an embodiment of the present invention is applied. In the fractured steel material 10 shown in FIG. 1, for example, in the ESSO test, a temperature gradient is provided on the test piece to propagate brittle cracks from the low temperature side to the high temperature side, and then a load is applied to the test piece to propagate the brittle cracks. The unbroken part that did not propagate was forcibly ductilely broken and broken. Here, the broken steel material 10 has a predetermined thickness in the width direction indicated by the arrow X, 500 mm in the longitudinal direction indicated by the arrow Z, and a predetermined thickness in the height direction indicated by the arrow Y. The upper surface of the fractured steel material 10 constitutes the fracture surface 11, and the crack propagation direction is the longitudinal direction indicated by the arrow Z described above from one end surface 10a to the other end surface 10b of the steel material 10. The fracture surface 11 of the steel material 10 includes a brittle fracture portion 11a formed from one end surface 10a of the steel material 10 which is the start end of the crack to the vicinity of the end of the crack, and the end of the crack from the other end surface 10b of the steel material 10. A mixed portion 11c in which the ductile fracture portion 11b formed up to the vicinity and the brittle fracture portion 11a and the ductile fracture portion 11b formed in the longitudinal direction indicated by the arrow Z in the vicinity of the end of the crack are mixed. And include.

The discriminating device 1 (see FIG. 2) according to the present embodiment is used to discriminate between the brittle fractured portion 11a and the ductile fractured portion 11b in the fracture surface 11 of the steel material 10, particularly the mixed portion 11c of the fracture surface 11. ..
In the fracture surface 11 in which the unbroken portion was forcibly fractured after the brittle crack propagation, the two-dimensional cross section perpendicular to the macroscopic crack propagation direction (Z direction in FIG. 1) shows that the brittle fracture portion 11a It is characterized in that the inclination of the fracture surface is significantly different at the boundary with the ductile fracture portion 11b. In the discrimination device 1 according to the present embodiment, this feature is utilized to discriminate between the brittle fracture portion 11a and the ductile fracture portion 11b.

The discrimination device 1 shown in FIG. 2 includes a three-dimensional measuring device 2, a data processing device 3, and an output device 8.
The three-dimensional measuring device 2 is installed above the broken steel material 10 and measures the shape of the fracture surface 11 of the steel material 10. As the three-dimensional measuring device 2, for example, a laser measuring device (3D scanner) using a laser is used. The three-dimensional measuring device 2 measures the distance by, for example, a laser, and the distance measurement may be a triangular distance measuring method or a phase difference distance measuring method.

Further, the data processing device 3 processes the three-dimensional point cloud data of the fracture surface shape measured by the three-dimensional measuring device 2, determines whether it is the brittle fracture portion 11a or the ductile fracture portion 11b, and finally the ductility. The surface area of the broken portion 11b is calculated.
The data processing device 3 is an operation for realizing each function of the discriminating means 4, the projected length calculating means 5, the actual length calculating means 6, and the surface area calculating means 7 described later by executing a program on the computer software. It is a computer system having a processing function. The computer system is configured to include a ROM, RAM, CPU, etc., and a data processing device 3 that realizes each of the above-mentioned functions on software by executing various dedicated programs stored in the ROM or the like in advance. Acquires three-dimensional point group data of the fracture surface shape measured by the three-dimensional measuring device 2, and from the three-dimensional point group data, a plane (XY) perpendicular to the crack propagation direction (Z direction) of the steel material 10. The shape data (see FIG. 6) of the two-dimensional cross section cut by the plane) is extracted, and adjacent points (point 1 and point 2, ..., Point n-1 and point) in the extracted shape data of the two-dimensional cross section are extracted. The absolute value of the inclination of the line segment (line segment 12, ..., Line segment n-1n) between n) and the adjacent line segment (line segment 12 and line segment 23, line segment 23 and line segment 34, ... A discriminating means 4 for determining whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b based on the absolute value of the difference in inclination between the line segment n-2n-1 and the line segment n-1n) is provided. ing.

In the discriminating means 4, when extracting the shape data of the two-dimensional cross section cut in the plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10 from the three-dimensional point group data, it is shown in FIG. As described above, the shape data of a plurality (m pieces) of two-dimensional cross sections cut over a predetermined range at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 is extracted, and the extracted plurality (m pieces). Line segment (line segment 12, ..., line segment n-1n) between adjacent points (point 1 and point 2, ..., Point n-1 and point n) in each of the shape data of the two-dimensional cross section of ) And the difference in the inclination of adjacent line segments (line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Line segment n-2n-1 and line segment n-1n). Based on the absolute value of, whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b is determined for each shape data of the two-dimensional cross section.
Here, a specific method for determining whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b for each shape data of the two-dimensional cross section will be described with reference to FIG. FIG. 5 shows a pattern of the fracture surface that can be considered when it is assumed that the brittle fracture portion 11a on the fracture surface 11 has a small inclination and the ductile fracture portion 11b has a large inclination.

Here, in each of the extracted multiple (m) two-dimensional cross-sectional shape data, points 1 and 2, points 2 and 3, points 3 and points 4, ..., Points that are adjacent to each other in succession. The absolute values of the slopes of the line segment 12, the line segment 23, the line segment 34, ..., The line segment n-1n between n-1 and the point n are a _12, a ₂₃ , a _34, ..., A, respectively. _{Let n-1n,} and the absolute value of the difference in inclination between the adjacent line segment 12 and line segment 23, the line segment 23 and line segment 34, ..., The line segment n-2n-1 and the line segment n-1n, respectively, is b. ₁₃ , b ₂₄ , ..., b _n-2n, and the thresholds α and β differ depending on the steel material.
Here, the coordinates of these points 1, point 2, point 3, ..., Point n on the two-dimensional cross section are (x ₁ , y ₁ ), (x ₂ , y ₂ ), (x ₃ , y _{3), respectively.} ), ..., (x _n , y _n ), point 1 and point 2, point 2 and point 3, point 3 and point 4, ..., Point n-1 and point n that are adjacent to each other in succession. line 12, line 23 between the line segment 34, ..., the absolute value _a 12 inclination of the line segment _{n-1n, a 23, a} 34, ···, a n-1n are _{(a 12,} a ₂₃ only will be described), the following equation (1), expressed as (2).

Further, the absolute values of the difference in slope between the adjacent line segment 12 and the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n, b ₁₃ and b ₂₄ , ..., B _n-2n ( _{only b 13} will be described) can be expressed as the following equation (3).

At this time, first, for the line segment 12 between the points 1 and 2, the discriminating means 4 first has a ductile fracture portion 11b if _{a 12} > α and a brittle fracture portion 11a if _{a 12 ≦ α.} Judge. The reason for this is that in a test of propagating brittle cracks, when the unbroken portion is forcibly fractured after the propagation of cracks has stopped, the brittle fractured portion at the time of the test generally remains in a flat state. This is because the unbroken portion undergoes ductile fracture with a large deformation, so that the inclination of the ductile fracture portion 11b becomes larger than the inclination of the brittle fracture portion 11a. For the threshold value α, the optimum value for discrimination is determined in consideration of the characteristics of the target steel fracture surface.

Next, the discriminating means 4 (b) regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the brittle fracture portion 11a, b ₁₃ > β. If it is, it is determined that it is a ductile fracture portion 11b (shown in FIG. 5 (B)), _{and if b 13} ≦ β, it is determined that it is a brittle fracture portion 11a (shown in FIG. 5 (A)). For the threshold value β, the optimum value for discrimination is determined in consideration of the characteristics of the target steel fracture surface.
Further, the discriminating means 4 (c) regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion 11b, a ₂₃ > α. If b ₁₃ ≤ β, it is determined to be ductile fracture portion 11b (shown in FIG. 5 (D)), and if a ₂₃ ≤ α or b ₁₃ > β, it is determined to be brittle fracture portion 11a (FIG. 5 (C)). Shown in).

Further, the discriminating means 4 is brittle according to the determination criteria of (b) and (c) for (d) the line segment 34, ..., The line segment n-1n after the line segment 34 between the point 3 and the point 4. It is determined whether the fracture portion 11a or the ductile fracture portion 11b.
In this way, when the discriminating means 4 determines whether the brittle fracture portion 11a or the ductile fracture portion 11b, the points 1 and 2, the points 2 and 3, the points 3 and 4, ... Absolute values of the slopes of line segment 12, line segment 23, line segment 34, ..., Line segment n-1n between n-1 and point n, a _{12, a 23} , a _34, ..., _{an- Not only 1n} , but also adjacent line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Absolute value b ₁₃ of the difference in slope between line segment n-2n-1 and line segment n-1n, The _{reason why b 24} , ..., B _n-2n is used is to detect the sudden change point of the inclination as the boundary between the brittle fracture part and the ductile fracture part because the error is large when judging only by the magnitude of the inclination. be.

Further, the data processing device 3 calculates the projection length of the ductile fracture unit 11b determined for each shape data of the two-dimensional cross section by the discrimination means 4 with respect to an arbitrary two-dimensional plane (ZX plane and YZ plane). A specific method for calculating the projection length of the ductile fracture portion 11b by the projection length calculation means 5 with respect to an arbitrary two-dimensional plane (ZX plane and YZ plane) by the projection length calculation means 5 will be described with reference to FIG. do.

In the two-dimensional plane (XY plane) used for discrimination, when the number of line segments determined to be the ductile fracture portion 11b is p (p> 0), the difference in x coordinates for the two points constituting each line segment. If the absolute values of are Δx ₁ , Δx ₂ , ..., Δx _p , and the absolute values of the difference between the y coordinate are Δy ₁ , Δy ₂ , ..., Δy _p , respectively, then to the ZX plane of the ductile fracture portion 11b. projected length _{l x} of each projection length _{l y} to the YZ plane of the ductile fracture portion 11b of the next equation (4), is expressed as equation (5). In Figure 6, the projection length l _y to the YZ plane of the projected length l _x and ductile fracture portion 11b of the ZX plane of the ductile fracture portion 11b is not only partially shown.

Projected length calculating unit 5, the projected length l _y to 2-dimensional cross-sectional shape data for each of the projected length l _x and YZ plane of ductile fracture portion 11b of the ZX plane of the ductile fracture portion 11b of the aforementioned (4 ) And (5) are used for calculation.
Further, the data processing device 3 includes an actual length calculating means 6 for calculating the actual length of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section by the determining means 4.
A specific method for calculating the actual length of the ductile fracture portion 11b by the actual length calculating means 6 will be described with reference to FIG.
In the two-dimensional plane (XY plane) used for discrimination, when the line segment determined to be the ductile fracture portion 11b is p lines (p> 0), the two points (x _a , ya _{a) constituting each line segment are formed.} ), _{The actual length Δxy of (x b} , y _b ) is expressed by the following equation (6).

Then, in the two-dimensional plane (XY plane) used for discrimination, when the line segments determined to be the ductile fracture portion 11b are p lines (p> 0), the actual lengths of the line segments are the actual lengths Δxy ₁ and Δxy _2. , ..., Δxy _p , the actual length lxy of the ductile fracture portion 11b is expressed by the following equation (7).

The actual length calculating means 6 calculates the actual length lxy of the ductile fracture portion 11b for each shape data of the two-dimensional cross section by using the above equation (7).
Further, the data processing device 3 includes the actual length lxy of the ductile fracture portion 11b for each shape data of the two-dimensional cross section calculated by the actual length calculating means 6, and the cracks of the steel material 10 having a plurality of (m pieces) two-dimensional cross sections. A cross-section calculation means 7 for calculating the surface area of the fractured fracture portion 11b in the predetermined range in the crack propagation direction (Z direction) of the steel material 10 based on the cutting interval Δz in the propagation direction (Z direction) is provided.

A specific method for calculating the surface area of the ductile fracture portion 11b by the surface area calculation means 7 will be described.
As described above, the discriminating means 4 extracts the shape data of the two-dimensional cross section cut in the plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10 from the three-dimensional point group data. As shown in FIG. 1, shape data of a plurality of (m pieces) two-dimensional cross sections cut over a predetermined range at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 are extracted.
Then, the actual length calculating means 6 calculates the actual length lxy of the ductile fracture portion 11b for each shape data of the two-dimensional cross section.
Here, since the actual lengths of the ductile fracture portions 11b in the two-dimensional cross section are plural (m), the actual lengths of the ductile fracture portions 11b in each two-dimensional cross section are lxy ₁ , lxy ₂ , ..., Lxy. _{Assuming m} , the surface surface S of the ductile fracture portion 11b in the above-mentioned predetermined range can be approximated by the following equation (8).

In order to avoid a large deviation between this approximate value and the actual surface area, it is preferable to set the cutting interval Δz in consideration of the size of the target fracture surface 11.
The surface area calculation means 7 calculates the surface area S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) by the above equation (8).

The output device 8 outputs the calculation result by the data processing device 3, for example, to the ZX plane of the ductile fracture unit 11b for each shape data of the two-dimensional cross section by the projection length calculation means 5, which is composed of a printer or the like. According projection length l _x and projected length l _y to the YZ plane of the ductile fracture portion _11b, the actual length lxy ductile fracture portion 11b of each shape data of the two-dimensional cross-section by the actual length calculating unit 6, the surface area calculation means 7 The calculation result of the surface surface S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) is output.

As described above, according to the steel material fracture surface discriminating device 1 according to the present embodiment, the three-dimensional measuring device 2 for measuring the shape of the fracture surface 11 of the steel material 10 and the fracture surface shape measured by the three-dimensional measuring device 2 The three-dimensional point group data of the above is acquired, and the shape data of the two-dimensional cross section cut in the plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10 is extracted from the three-dimensional point group data. Based on the absolute value of the inclination of the line segment between adjacent points and the absolute value of the difference in inclination of the adjacent line segment in the extracted shape data of the two-dimensional cross section, the range of the line segment is brittle fracture portion 11a or ductility. It is provided with a discriminating means 4 for discriminating whether it is the broken portion 11b.
As a result, the brittle fracture portion 11a and the ductile fracture portion 11b can be automatically discriminated from the fracture surface 11 of the steel material 10. Further, when measuring the shape of the fracture surface 11 of the steel material 10, a three-dimensional measuring device (for example, a 3D scanner) is used, and since a microscope is not used, in addition to a small test (drop weight test, Charpy impact test, etc.) It can be a steel fracture surface discrimination device 1 that can be applied to a large test piece.

Further, according to the steel material fracture surface discriminating device 1 according to the present embodiment, the discriminating means 4 is a plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10 from the three-dimensional point group data. When extracting the shape data of the two-dimensional cross section cut in 1 above, the shape data of a plurality (m pieces) of the two-dimensional cross section cut at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 is extracted. Then, a line segment (line segment 12) between adjacent points (point 1 and point 2, ..., Point n-1 and point n) in each of the extracted plurality (m) two-dimensional cross-sectional shape data. , ..., Based on the absolute value of the inclination of the line segment n-1n) and the absolute value of the difference in the inclination of the adjacent line segments, it is two-dimensional whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b. It is determined for each cross-sectional shape data.
As a result, in the shape data of a plurality of (m) two-dimensional cross sections in the crack propagation direction (Z direction) of the steel material 10, the shape of the two-dimensional cross section determines whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b. It can be identified for each data.

Further, according to the steel material fracture surface discriminating device 1 according to the present embodiment, the discriminating means 4 is continuously adjacent to the points 1 in each of the extracted shape data of the plurality of (m) two-dimensional cross sections. Point 2, point 2 and point 3, point 3 and point 4, ..., Line segment 12 between point n-1 and point n, line segment 23, line segment 34, ..., Line segment n-1n The absolute values of the slopes are a _12, a ₂₃ , a _34, ..., _An-1n , respectively, and the adjacent line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Line segment n. When the absolute values of the difference in inclination between -2n-1 and the line segment n-1n are b ₁₃ , b ₂₄ , ..., B _n-2n , respectively, and the thresholds α and β differ depending on the steel material, the following method is used. It is determined whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b for each shape data of the two-dimensional cross section.

(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be the ductile fracture portion 11b, _{and if a 12} ≤ α, it is determined to be the brittle fracture portion 11a.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the brittle fracture portion 11a _{, if b 13} > β, the ductile fracture portion 11b If b ₁₃ ≤ β, it is determined that the brittle fracture portion 11a is formed.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion 11b, a ₂₃ > α and b ₁₃ ≤ β. If it is determined to be the ductile fracture portion 11b, and if a ₂₃ ≤ α or b ₁₃ > β, it is determined to be the brittle fracture portion 11a.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, the brittle fracture portion 11a or the ductile fracture portion 11a or the ductile fracture portion according to the judgment criteria of (b) and (c). Judge whether it is 11b.

As a result, in each of the extracted shape data of the plurality of (m) two-dimensional cross sections, the brittle fracture portion 11a is provided for each of the line segment 12, the line segment 23, the line segment 34, ..., And the line segment n-1n. It is possible to accurately determine whether it is the ductile fracture portion 11b.
In this way, when the discriminating means 4 determines whether the brittle fracture portion 11a or the ductile fracture portion 11b, the points 1 and 2, the points 2 and 3, the points 3 and 4, ... Absolute values of the slopes of line segment 12, line segment 23, line segment 34, ..., Line segment n-1n between n-1 and point n, a _{12, a 23} , a _34, ..., _{an- Not only 1n} , but also adjacent line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Absolute value b ₁₃ of the difference in slope between line segment n-2n-1 and line segment n-1n, The _{reason why b 24} , ..., B _n-2n is used is to detect the sudden change point of the inclination as the boundary between the brittle fracture part and the ductile fracture part because the error is large when judging only by the magnitude of the inclination. be.

Further, according to the determination device 1 of the steel material fracture surface according to the present embodiment, the projection length l _x and ductile fracture of the discriminating means 4 to determine ductility fracture portion 11b of the ZX plane for each shape data of the two-dimensional cross-section and a projected length calculating unit 5 that calculates a projected length l _y to the YZ plane parts 11b.
Thus, it is possible to calculate the projected length l _y to 2-dimensional cross-sectional shape data for each of the projected length l _x and YZ plane of ductile fracture portion 11b of the ZX plane of the ductile fracture portion 11b, ductile fracture portion the projected length l _y to 11b of the projection length l _x and YZ plane of ductile fracture portion 11b of the ZX plane can be quantitatively evaluated.

Further, according to the steel fracture surface discriminating device 1 according to the present embodiment, the actual length calculating means 6 for calculating the actual length lxy of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section by the discriminating means 4 is provided. I have.
Thereby, the actual length lxy of the ductile fracture portion 11b can be calculated for each shape data of the two-dimensional cross section, and the actual length lxy of the ductile fracture portion 11b can be quantitatively evaluated.

Further, according to the steel fracture surface discriminating device 1 according to the present embodiment, the actual length lxy of the ductile fracture portions 11b for each shape data of the two-dimensional cross section calculated by the actual length calculating means 6 and a plurality (m pieces). The surface surface S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) of the steel material 10 is calculated based on the cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 in the two-dimensional cross section of the above. The surface area calculation means 7 is provided.
Thereby, the surface area S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) can be calculated, and the surface area S of the ductile fracture portion 11b can be quantitatively evaluated.

Next, a method for discriminating the steel fracture surface according to the present embodiment using the steel fracture surface discriminating device 1 shown in FIG. 2 will be described with reference to FIGS. 3 and 4.
First, in step S1, the three-dimensional measuring device 2 measures the shape of the fracture surface 11 of the steel material 10 from above the broken steel material 10 shown in FIG. 1 (three-dimensional measurement step).
Next, in step S2, the discriminating means 4 of the data processing device 3 acquires the three-dimensional point group data of the fracture surface shape measured by the three-dimensional measuring device 2, and the steel material 10 is obtained from the three-dimensional point group data. The shape data (see FIG. 6) of the two-dimensional cross section cut in the plane (XY plane) perpendicular to the crack propagation direction (Z direction) is extracted, and the adjacent points (point 1) in the extracted shape data of the two-dimensional cross section are extracted. And the absolute value of the inclination of the line segment (line segment 12, ..., Line segment n-1n) between the point 2, ..., Point n-1 and point n) and the adjacent line segment (line segment 12 and Based on the absolute value of the difference in inclination between the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n), the range of the line segment is the brittle fracture portion 11a. It is determined whether it is the ductile fracture portion 11b (discrimination step).

The step S2 (discrimination step) will be specifically described with reference to FIG. 4. First, in step S21, the discriminating means 4 is a three-dimensional point cloud having a fracture surface shape measured by the three-dimensional measuring device 2. Acquire data (point cloud data acquisition step).
Next, in step S22, the discriminating means 4 extracts shape data of a two-dimensional cross section cut in a plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10 from the three-dimensional point group data. At this time, the shape data of a plurality of (m) two-dimensional cross sections cut over a predetermined range at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 are extracted (shape data extraction step of the two-dimensional cross section). ..

After that, in step S23, the discriminating means 4 determines adjacent points (points 1 and 2, ..., Points n-1 and n) in each of the extracted shape data of the plurality of (m) two-dimensional cross sections. ) And the absolute value of the inclination of the line segment (line segment 12, ..., Line segment n-1n) and the adjacent line segment (line segment 12 and line segment 23, line segment 23 and line segment 34, ...) , Based on the absolute value of the difference in inclination between the line segment n-2n-1 and the line segment n-1n), it is determined whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b (determination step).
In the determination step in step S23, similarly to the above, the determination means 4 continuously adjacent points 1, points 2, and points 2 in each of the extracted plurality (m) of the shape data of the two-dimensional cross sections. And point 3, point 3 and point 4, ..., Line segment 12, line segment 23, line segment 34, ..., The absolute value of the inclination of line segment n-1n between point n-1 and point n. Let a _12, a ₂₃ , a _34, ..., _An-1n , respectively, and adjacent line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Line segment n-2n-1. The absolute values of the difference in the inclinations of the line segments n-1n are b ₁₃ , b ₂₄ , ..., B _{n-2n, respectively,} and the above-mentioned thresholds α and β differ depending on the steel material.

Then, the discriminating means 4 first determines (a) that the line segment 12 between the points 1 and 2 is a ductile fracture portion if _{a 12} > α and a brittle fracture portion 11a if _{a 12 ≦ α.} .. Next, the discriminating means 4 (b) regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the brittle fracture portion 11a, b ₁₃ > β. If it is, it is determined that it is a ductile fracture portion 11b, and _{if b 13} ≦ β, it is determined that it is a brittle fracture portion 11a. Further, the discriminating means 4 (c) regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion 11b, a ₂₃ > α. If b ₁₃ ≤ β, it is determined to be the ductile fracture portion 11b, and if a ₂₃ ≤ α or b ₁₃ > β, it is determined to be the brittle fracture portion 11a. Further, the discriminating means 4 is brittle according to the determination criteria of (b) and (c) for (d) the line segment 34, ..., The line segment n-1n after the line segment 34 between the point 3 and the point 4. It is determined whether the fracture portion 11a or the ductile fracture portion 11b.
As a result, step S2 (discrimination step) is completed, and the discrimination result is sent to the projection length calculating means 5.

Next, the process proceeds to step S3, and the projection length calculation means 5 of the data processing device 3 projects the ductile fracture unit 11b determined for each shape data of the two-dimensional cross section on the ZX plane by step S2 (discrimination step). calculating the length l _x and projected length l _y to the YZ plane of the ductile fracture portion 11b (projected length calculation step).
Specifically the projected length l _y to the YZ plane of the projected length l _x and ductile fracture portion 11b of the ZX plane of the determined ductile fracture portion 11b in a two-dimensional cross-section each of shape data by the projected length calculating unit 5 The specific calculation method is the same as described above.
Next, the process proceeds to step S4, and the actual length calculating means 6 of the data processing device 3 calculates the actual length lxy of the ductile fracture unit 11b determined for each shape data of the two-dimensional cross section in step S2 (discrimination step). (Actual length calculation step).

The specific calculation method of the actual length lxy of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section by the actual length calculating means 6 is the same as described above.
Next, in step S5, the surface area calculation means 7 of the data processing device 3 includes the actual length lxy of the ductile fracture unit 11b for each shape data of the two-dimensional cross section calculated in step S4 (actual length calculation step). A ductile fracture portion 11b in a predetermined range of the crack propagation direction (Z direction) of the steel material 10 based on the cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 having a plurality of (m pieces) two-dimensional cross sections. The cross section S is calculated (cross section calculation step).

The specific method for calculating the surface area S in a predetermined range in the crack propagation direction (Z direction) by the surface area calculation means 7 is the same as described above.
Finally proceeds to a step S6, the output device 8, YZ plane of the projection length l _x and ductile fracture portion 11b of the ZX plane of the ductile fracture portion 11b of each shape data of the two-dimensional cross-section by the projected length calculating unit 5 ductile fracture in a predetermined range of the projected length l _y, the actual length calculating means actual length of the ductile fracture portion 11b of each shape data of the two-dimensional cross-section by 6 lxy, by crack propagation direction in the surface area calculation unit 7 (Z direction) to The calculation result of the surface surface S of the part 11b is output.

As described above, according to the method for determining the fracture surface of the steel material according to the present embodiment, the measurement is performed in step S1 (three-dimensional measurement step) for measuring the shape of the fracture surface 11 of the steel material 10 and step S1 (three-dimensional measurement step). A two-dimensional cross section obtained by acquiring three-dimensional point group data of the fractured surface shape and cutting from the three-dimensional point group data in a plane (XY plane) perpendicular to the crack propagation direction (Z direction) of the steel material 10. The shape data is extracted, and the range of the line segment is brittle based on the absolute value of the inclination of the line segment between adjacent points and the absolute value of the difference in the inclination of the adjacent line segment in the extracted shape data of the two-dimensional cross section. It includes a step S2 (discrimination step) of determining whether the fractured portion 11a or the ductile fractured portion 11b.
As a result, the brittle fracture portion 11a and the ductile fracture portion 11b can be automatically discriminated from the fracture surface 11 of the steel material 10. Further, when measuring the shape of the fracture surface 11 of the steel material 10, a three-dimensional measuring device (for example, a 3D scanner) is used, and since a microscope is not used, in addition to a small test (drop weight test, Charpy impact test, etc.) It can be a steel fracture surface discrimination device 1 that can be applied to a large test piece.

Further, according to the method for discriminating the fracture surface of the steel material according to the present embodiment, in step S2 (discrimination step), a plane (XY) perpendicular to the crack propagation direction (Z direction) of the steel material 10 is obtained from the three-dimensional point group data. When extracting the shape data of the two-dimensional cross section cut in the plane), the shape of a plurality (m pieces) of the two-dimensional cross section cut over a predetermined range at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10. Extract the data. Then, a line segment (line segment 12) between adjacent points (point 1 and point 2, ..., Point n-1 and point n) in each of the extracted plurality (m) two-dimensional cross-sectional shape data. , ..., Based on the absolute value of the inclination of the line segment n-1n) and the absolute value of the difference in the inclination of the adjacent line segments, it is two-dimensional whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b. It is determined for each cross-sectional shape data.

As a result, in the shape data of a plurality of (m) two-dimensional cross sections in the crack propagation direction (Z direction) of the steel material 10, the shape of the two-dimensional cross section determines whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b. It can be identified for each data.
Further, according to the method for discriminating steel fracture surfaces according to the present embodiment, in step S2 (discrimination step), points that are continuously adjacent to each other in each of the extracted shape data of a plurality of (m) two-dimensional cross sections. 1 and point 2, point 2 and point 3, point 3 and point 4, ..., Line segment 12 between point n-1 and point n, line segment 23, line segment 34, ..., Line segment n- The absolute values of the inclination of 1n are a _12, a ₂₃ , a _34, ..., _An-1n , respectively, and the adjacent line segment 12 and line segment 23, line segment 23 and line segment 34, ..., Line When the absolute values of the difference in inclination between the line segment n-2n-1 and the line segment n-1n are b ₁₃ , b ₂₄ , ..., B _n-2n , respectively, and the thresholds α and β differ depending on the steel material, the following Whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b is determined for each shape data of the two-dimensional cross section by the method of.

(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be the ductile fracture portion 11b, _{and if a 12} ≤ α, it is determined to be the brittle fracture portion 11a.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the brittle fracture portion 11a _{, if b 13} > β, the ductile fracture portion 11b If b ₁₃ ≤ β, it is determined that the brittle fracture portion 11a is formed.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion 11b, a ₂₃ > α and b ₁₃ ≤ β. If it is determined to be the ductile fracture portion 11b, and if a ₂₃ ≤ α or b ₁₃ > β, it is determined to be the brittle fracture portion 11a.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, the brittle fracture portion 11a or the ductile fracture portion 11a or the ductile fracture portion according to the judgment criteria of (b) and (c). Judge whether it is 11b.

As a result, in each of the extracted shape data of the plurality of (m) two-dimensional cross sections, the brittle fracture portion 11a is provided for each of the line segment 12, the line segment 23, the line segment 34, ..., And the line segment n-1n. It is possible to accurately determine whether it is the ductile fracture portion 11b.
The present according to the determination method of the steel material fracture according to the embodiment, the step S2 (determination step) by projected length l _x and to the determined ductile fracture portion 11b of the ZX plane for each shape data of the two-dimensional cross-section includes the step S3 (projected length calculation step) for calculating a projected length l _y to the YZ plane of the ductile fracture portion 11b.

Thus, it is possible to calculate the projected length l _y to 2-dimensional cross-sectional shape data for each of the projected length l _x and YZ plane of ductile fracture portion 11b of the ZX plane of the ductile fracture portion 11b, ductile fracture portion the projected length l _y to 11b of the projection length l _x and YZ plane of ductile fracture portion 11b of the ZX plane can be quantitatively evaluated.
Further, according to the method for discriminating the fracture surface of the steel material according to the present embodiment, step S4 (actual) for calculating the actual length lxy of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section in step S2 (discrimination step). Length calculation step) is included.

Thereby, the actual length lxy of the ductile fracture portion 11b can be calculated for each shape data of the two-dimensional cross section, and the actual length lxy of the ductile fracture portion 11b can be quantitatively evaluated.
Further, according to the method for determining the fracture surface of the steel material according to the present embodiment, the actual length lxy of the ductile fracture portion 11b for each shape data of the two-dimensional cross section calculated in step S4 (actual length calculation step) and a plurality (m). The surface surface S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) of the steel material 10 is determined based on the cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 in the two-dimensional cross section. The calculation step S5 (cross-section calculation step) is provided.

Thereby, the surface area S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) can be calculated, and the surface area S of the ductile fracture portion 11b can be quantitatively evaluated.
Although the embodiments of the present invention have been described above, the present invention is not limited to this, and various modifications and improvements can be made.
_{For example, the projection length calculation means 5 (projection length calculation step) has a projection length l x} on the ZX plane of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section by the discrimination means 4 (discrimination step). and it has to calculate the projected length l _y to the YZ plane of the ductile fracture portion 11b, discriminating means 4 (determination step) by to the determined brittle fracture portion 11a of the ZX plane for each shape data of the two-dimensional cross-section The projected length and the projected length of the brittle fracture portion 11a on the YZ plane may be calculated.

Further, the actual length calculation means 6 (actual length calculation step) calculates the actual length lxy of the ductile fracture portion 11b determined for each shape data of the two-dimensional cross section by the determination means 4 (discrimination step). The actual length of the brittle fracture portion 11a determined for each shape data of the two-dimensional cross section by the means 4 (discrimination step) may be calculated.
Further, the surface area calculation means 7 (surface area calculation step) includes a plurality (m pieces) of the actual length lxy of the ductile fracture portion 11b for each shape data of the two-dimensional cross section calculated by the actual length calculation means 6 (actual length calculation step). ), The surface surface S of the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction) is calculated based on the cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10 in the two-dimensional cross section. However, the actual length of the brittle fracture portion 11a for each shape data of the two-dimensional cross section calculated by the actual length calculating means 6 (actual length calculation step) and the cracks of a plurality (m pieces) of steel materials 10 having a two-dimensional cross section. The surface surface S of the brittle fracture portion 11a in a predetermined range in the crack propagation direction (Z direction) may be calculated based on the cutting interval Δz in the propagation direction (Z direction).

Further, in the present embodiment, the discriminating means 4 (discrimination step) has a plurality (m pieces) of two-dimensional cross-sectional shapes in a predetermined range cut at a constant cutting interval Δz in the crack propagation direction (Z direction) of the steel material 10. Data is extracted, and a line segment (point 1 and point 2, ..., Point n-1 and point n) between adjacent points (point 1 and point 2, ..., Point n-1 and point n) in each of the extracted shape data of a plurality of (m) two-dimensional cross sections ( Whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b based on the absolute value of the inclination of the line segment 12, ..., The line segment n-1n) and the absolute value of the difference in the inclination of the adjacent line segments. Is determined for each shape data of the two-dimensional cross section.

However, the discrimination means 4 (discrimination step) extracts the shape data of one two-dimensional cross section cut at one place in the crack propagation direction (Z direction) of the steel material 10, and extracts one two-dimensional. Absolute inclination of the line segment (line segment 12, ..., line segment n-1n) between adjacent points (point 1 and point 2, ..., Point n-1 and point n) in the shape data of the cross section. It may be determined whether the range of the line segment is the brittle fracture portion 11a or the ductile fracture portion 11b based on the absolute value of the difference between the value and the inclination of the adjacent line segments.
In this case, the projection length calculation means 5 (projection length calculation step) is the projection length of the brittle fracture portion 11a or the ductile fracture portion 11b determined by the discrimination means 4 (discrimination step) on the ZX plane and the brittle fracture portion. The projected length of the ductile fracture portion 11a or the ductile fracture portion 11b onto the YZ plane may be calculated for the shape data of one two-dimensional cross section.

Further, in this case, the actual length calculation means 6 (actual length calculation step) has the actual length of the brittle fracture portion 11a or the ductile fracture portion 11b determined by the discrimination means 4 (discrimination step) in the shape of one two-dimensional cross section. It may be calculated for the data.
Further, in this case, the surface area calculation means 7 (surface area calculation step) does not calculate the surface area S of the brittle fracture portion 11a or the ductile fracture portion 11b in a predetermined range in the crack propagation direction (Z direction).

Further, the projection length calculation means 5 (projection length calculation step) is the projection length of the brittle fracture portion 11a or the ductile fracture portion 11b determined by the discrimination means 4 (discrimination step) on the ZX plane and the brittle fracture portion 11a. Alternatively, the projection length of the ductile fracture portion 11b onto the YZ plane is calculated, but the projection length calculation means 5 (projection length calculation step) is not limited to the ZX plane and the YZ plane, but the discrimination means 4 (discrimination step). ), The projected length of the brittle fracture portion 11a or the ductile fracture portion 11b with respect to an arbitrary two-dimensional plane may be calculated.

Next, examples of the present invention will be described. As shown in FIG. 1, the fracture surface 11 used in this embodiment is the fracture surface 11 of the steel material 10 in which the unbroken portion is ductilely fractured by a load after the brittle cracks are propagated. The fracture surface 11 of the steel material 10 is 70 mm (X direction) × 500 mm (Z direction), and the crack propagates macroscopically in the direction of 500 mm (Z direction). In the mixed portion 11c in which the brittle fracture portion 11a and the ductile fracture portion 11b are mixed in the fracture surface 11, the discrimination method of the present invention is applied within a range of 30 mm over the crack propagation direction (Z direction).

In FIG. 6, in the mixed portion 11c (range of 30 mm) in which the brittle fracture portion 11a and the ductile fracture portion 11b are mixed in the fracture surface 11 of the steel material, the fracture surface 11 is cut in a plane perpendicular to the crack propagation direction (Z direction). An example of the shape data of the dimensional cross section is shown.
In the specific two-dimensional cross section shown in FIG. 6, the visual determination of the brittle fracture portion 11a or the ductile fracture portion 11b coincides with the determination of the brittle fracture portion 11a or the ductile fracture portion 11b by the discrimination method of the present invention. The rate was 85.8%, and it was found that the discrimination method of the present invention was a good result.

In Table 1, the specific projected length l _x to the ZX plane of the ductile fracture portion 11b in the two-dimensional _{cross-section,} projected length l _y to the YZ plane of the ductile fracture portion 11b shown in FIG. _6, ductile fracture portion The actual length lxy of 11b and the surface surface S of the ductile fracture portion 11b in the target range (30 mm) are shown.

1 Steel fracture surface discrimination device 2 3D measuring device 3 Data processing device 4 Discrimination means 5 Projection length calculation means 6 Actual length calculation means 7 Surface area calculation means 8 Output device 10 Steel material 10a One end surface 10b End end surface 11 Fracture surface 11a Brittleness Breaking part 11b Ductile breaking part 11c Mixed part

Claims (18)

A three-dimensional measuring device for measuring the shape of the fracture surface of the steel material and three-dimensional point group data of the fracture surface shape measured by the three-dimensional measuring device are acquired, and the steel material is used from the three-dimensional point group data. The shape data of the two-dimensional cross section cut in the plane perpendicular to the crack propagation direction is extracted, and the absolute value of the inclination of the line segment between the adjacent points and the adjacent line segment in the extracted shape data of the two-dimensional cross section. A steel fracture surface discriminating device comprising a discriminating means for discriminating whether the range of a line segment is a brittle fracture portion or a ductile fracture portion based on an absolute value of a difference in inclination. In the extracted shape data of the two-dimensional cross section, the discriminating means continuously adjacent points 1 and 2, points 2 and 3, points 3 and 4, ..., Points n-1 and points. The absolute values of the inclinations of the line segment 12, the line segment 23, the line segment 34, ..., The line segment n-1n between n are set to a _12, a ₂₃ , a _34, ..., _An-1n , respectively. The absolute values of the difference in inclination between the adjacent line segment 12 and the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n are b ₁₃ , b ₂₄ , respectively. ..., b _n-2n, and when the line segments α and β differ depending on the steel material,
(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be a ductile fracture portion, _{and if a 12} ≤ α, it is determined to be a brittle fracture portion.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be a brittle fracture portion _{, if b 13} > β, it is determined to be a ductile fracture portion. Then _{, if b 13} ≤ β, it is judged to be a brittle fracture part, and it is judged.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion, if a ₂₃ > α and b ₁₃ ≦ β. It is judged to be a ductile fracture part, and if a ₂₃ ≤ α or b ₁₃ > β, it is judged to be a brittle fracture part.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, whether they are brittle fracture parts or ductile fracture parts according to the judgment criteria of (b) and (c). The steel fracture surface discriminating device according to claim 1, further comprising determining. The steel fracture surface according to claim 2, further comprising a projection length calculating means for calculating the projection length of the brittle fracture portion or the ductile fracture portion determined by the discrimination means with respect to an arbitrary two-dimensional plane. Discriminating device. The device for discriminating a fracture surface of a steel material according to claim 2 or 3, further comprising an actual length calculating means for calculating the actual length of the brittle fractured portion or the ductile fractured portion determined by the discriminating means. When the discriminating means extracts shape data of a two-dimensional cross section cut in a plane perpendicular to the crack propagation direction of the steel material from the three-dimensional point group data, the cutting means is constant in the crack propagation direction of the steel material. The shape data of a plurality of two-dimensional cross sections cut over a predetermined range at intervals are extracted, and the absolute value of the inclination of the line segment between the adjacent points and the adjacent lines in each of the extracted shape data of the plurality of two-dimensional cross sections. The steel fracture surface according to claim 1, wherein the range of the line segment is determined for each shape data of the two-dimensional cross section based on the absolute value of the difference in the inclination of the minutes. Discriminating device. In each of the extracted shape data of the plurality of two-dimensional cross sections, the discriminating means continuously adjacent points 1 and 2, points 2 and 3, points 3 and 4, ..., Point n. The absolute values of the slopes of the line segment 12, the line segment 23, the line segment 34, ..., The line segment n-1n between -1 and the point n are a _12, a ₂₃ , a _34, ..., An, _{respectively. Set to -1n,} and the absolute value of the difference in inclination between the adjacent line segment 12 and the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n is b _{13 respectively.} , B ₂₄ , ..., b _n-2n, and when the line segments α and β differ depending on the steel material,
(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be a ductile fracture portion, _{and if a 12} ≤ α, it is determined to be a brittle fracture portion.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be a brittle fracture portion _{, if b 13} > β, it is determined to be a ductile fracture portion. Then _{, if b 13} ≤ β, it is judged to be a brittle fracture part, and it is judged.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion, if a ₂₃ > α and b ₁₃ ≦ β. It is judged to be a ductile fracture part, and if a ₂₃ ≤ α or b ₁₃ > β, it is judged to be a brittle fracture part.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, whether they are brittle fracture parts or ductile fracture parts according to the judgment criteria of (b) and (c). The steel fracture surface discriminating device according to claim 5, further comprising determining. A claim comprising a projection length calculating means for calculating the projection length of a brittle fracture portion or a ductile fracture portion determined for each shape data of a two-dimensional cross section with respect to an arbitrary two-dimensional plane by the discrimination means. Item 6. The device for discriminating the fracture surface of a steel material according to Item 6. The steel material according to claim 6 or 7, further comprising an actual length calculating means for calculating the actual length of the brittle fractured portion or the ductile fractured portion determined for each shape data of the two-dimensional cross section by the discriminating means. Fracture surface discrimination device. Based on the actual length of the brittle fracture part or ductile fracture part for each shape data of the two-dimensional cross section calculated by the actual length calculation means, and the cutting interval in the crack propagation direction of the steel material of the plurality of two-dimensional cross sections. The device for determining a fracture surface of a steel material according to claim 8, further comprising a cross-section calculating means for calculating the cross section of the brittle fracture portion or the ductile fracture portion in the predetermined range in the crack propagation direction of the steel material. A three-dimensional measurement step that measures the shape of the fracture surface of a steel material,
The three-dimensional point group data of the fracture surface shape measured in the three-dimensional measurement step is acquired, and the two-dimensional cross section cut from the three-dimensional point group data in a plane perpendicular to the crack propagation direction of the steel material. The shape data is extracted, and the range of the line segment is determined based on the absolute value of the inclination of the line segment between the adjacent points and the absolute value of the difference in the inclination of the adjacent line segments in the extracted shape data of the two-dimensional cross section. A method for discriminating a fracture surface of a steel material, which comprises a discriminating step for discriminating between a brittle fractured portion and a ductile fractured portion. In the determination step, in the extracted shape data of the two-dimensional cross section, points 1 and 2, points 2 and 3, points 3 and 4, ..., Points n-1 and points that are adjacent to each other in succession. The absolute values of the inclinations of the line segment 12, the line segment 23, the line segment 34, ..., The line segment n-1n between n are set to a _12, a ₂₃ , a _34, ..., _An-1n , respectively. The absolute values of the difference in inclination between the adjacent line segment 12 and the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n are b ₁₃ , b ₂₄ , respectively. ..., b _n-2n, and when the line segments α and β differ depending on the steel material,
(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be a ductile fracture portion, _{and if a 12} ≤ α, it is determined to be a brittle fracture portion.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be a brittle fracture portion _{, if b 13} > β, it is determined to be a ductile fracture portion. Then _{, if b 13} ≤ β, it is judged to be a brittle fracture part, and it is judged.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion, if a ₂₃ > α and b ₁₃ ≦ β. It is judged to be a ductile fracture part, and if a ₂₃ ≤ α or b ₁₃ > β, it is judged to be a brittle fracture part.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, whether they are brittle fracture parts or ductile fracture parts according to the judgment criteria of (b) and (c). The method for discriminating a fracture surface of a steel material according to claim 10, wherein the method for determining the fracture surface of a steel material. The determination of a steel fracture surface according to claim 11, further comprising a projection length calculation step for calculating the projection length of the brittle fracture portion or the ductile fracture portion determined by the determination step with respect to an arbitrary two-dimensional plane. Method. The method for discriminating a steel fracture surface according to claim 11 or 12, wherein the actual length calculation step for calculating the actual length of the brittle fracture portion or the ductile fracture portion determined by the discrimination step is included. In the discrimination step, when extracting the shape data of the two-dimensional cross section cut in the plane perpendicular to the crack propagation direction of the steel material from the three-dimensional point group data, the cutting is constant in the crack propagation direction of the steel material. The shape data of a plurality of two-dimensional cross sections cut over a predetermined range at intervals are extracted, and the absolute value of the inclination of the line segment between the adjacent points and the adjacent lines in each of the extracted shape data of the plurality of two-dimensional cross sections. The steel fracture surface according to claim 10, wherein the range of the line segment is determined for each shape data of the two-dimensional cross section based on the absolute value of the difference in the inclination of the minutes. How to determine. In the determination step, in each of the extracted shape data of the plurality of two-dimensional cross sections, points 1 and 2, point 2 and point 3, point 3 and point 4, ..., Point n that are adjacent to each other in succession. The absolute values of the slopes of the line segment 12, the line segment 23, the line segment 34, ..., The line segment n-1n between -1 and the point n are a _12, a ₂₃ , a _34, ..., An, _{respectively. Set to -1n,} and the absolute value of the difference in inclination between the adjacent line segment 12 and the line segment 23, the line segment 23 and the line segment 34, ..., The line segment n-2n-1 and the line segment n-1n is b _{13 respectively.} , B ₂₄ , ..., b _n-2n, and when the line segments α and β differ depending on the steel material,
(A) Regarding the line segment 12 between the points 1 and 2 _{, if a 12} > α, it is determined to be a ductile fracture portion, _{and if a 12} ≤ α, it is determined to be a brittle fracture portion.
(B) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be a brittle fracture portion _{, if b 13} > β, it is determined to be a ductile fracture portion. Then _{, if b 13} ≤ β, it is judged to be a brittle fracture part, and it is judged.
(C) Regarding the line segment 23 between the points 2 and 3, when the line segment 12 between the points 1 and 2 is determined to be the ductile fracture portion, if a ₂₃ > α and b ₁₃ ≦ β. It is judged to be a ductile fracture part, and if a ₂₃ ≤ α or b ₁₃ > β, it is judged to be a brittle fracture part.
(D) Regarding the line segments 34, ..., Line segments n-1n after the line segment 34 between the points 3 and 4, whether they are brittle fracture parts or ductile fracture parts according to the judgment criteria of (b) and (c). The method for determining a fracture surface of a steel material according to claim 14, wherein the method for determining a fracture surface of a steel material is characterized. 15. Claim 15 including a projection length calculation step for calculating the projection length of a brittle fracture portion or a ductile fracture portion determined for each shape data of a two-dimensional cross section with respect to an arbitrary two-dimensional plane by the determination step. The method for discriminating the fracture surface of steel material described in 1. The steel fracture surface according to claim 15 or 16, wherein the actual length calculation step for calculating the actual length of the brittle fracture portion or the ductile fracture portion determined for each shape data of the two-dimensional cross section by the determination step is included. How to determine. Based on the actual length of the brittle fractured portion or ductile fractured portion for each shape data of the two-dimensional cross section calculated by the actual length calculation step, and the cutting interval of the plurality of two-dimensional cross sections in the crack propagation direction of the steel material. The method for determining a fracture surface of a steel material according to claim 17, further comprising a step of calculating the cross section of the brittle fractured portion or the ductile fractured portion in the predetermined range in the crack propagation direction of the steel material.

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