Distortion amount measurement method, distortion amount measuring device, and manufacturing method of steel plate

Abstract

To provide a distortion measurement method capable of precisely measuring the distortion amount even at the plate ends of a steel plate, and a distortion amount measuring device.SOLUTION: The distortion measurement method includes the following steps: a surface shape data acquisition step in which 3D surface shape data of a steel plate measured by a shape measuring device is acquired; a surface shape profile acquisition step in which, defining the predetermined position in the longitudinal or transverse direction of the steel plate as x, a curve (y=f(x)) with a surface shape profile whose height is y at a predetermined position x is acquired from the 3D surface shape data; and a distortion amount measurement step in which the distortion amount of the multiple at the predetermined position x is calculated by using the formula (1), and the maximum distortion amount among the multiple distortion amounts obtained is determined as the distortion amount δ(x) at the predetermined position x. LP is the longitudinal length of the steel plate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for measuring the amount of strain of a steel plate, a strain amount measuring device, and a method for manufacturing a steel plate using the strain amount measuring method.

Background Art

[0002] In the manufacture of steel plates, generally, a device in which a plurality of rolls called a leveler are arranged vertically, and the steel plate is conveyed between these rolls to correct shape defects such as warpage and ear waves generated during manufacture. However, since the bending moment required to correct the shape is proportional to the cube of the plate thickness, in the case of thick steel plates with a thickness of 40 mm or more, the leveler cannot correct the shape completely. For this reason, when a shape defect occurs in a thick steel plate, the steel plate is removed from the production line and the shape defect is corrected offline using a press machine.

[0003] In the shape correction operation of a thick steel plate by a press machine, the amount of strain at each position on the surface of the thick steel plate is measured, and based on the amount of strain, the pressing position and pressing force of the pressing ram of the press machine are determined. Conventionally, the measurement of the amount of strain has been performed by an operator applying a stretcher (a wedge) of a predetermined length on the steel plate surface and observing the size of the gap between the stretcher and the steel plate surface. However, in this method, since the operator manually checks the amount of strain at a large number of positions on the steel plate surface, there is a problem that the burden on the operator is large and the improvement of productivity is hindered.

[0004] In response to such problems, Patent Document 1 discloses a method for evaluating the strain of a steel plate that acquires three-dimensional surface shape data of the steel plate using a steel plate shape measuring device such as a 3D scanner and calculates the amount of strain at each position on the steel plate surface using the three-dimensional surface shape data. According to Patent Document 1, a stretcher is virtually applied to the obtained surface shape, and the gap between the stretcher and the surface shape is calculated. Further, by changing the length of the stretcher and calculating a plurality of gaps, and taking the largest of these gap sizes as the amount of strain of the steel plate, it is said that the amount of strain of the steel plate can be calculated with high accuracy.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Figure 1 is a graph showing a method of calculating the strain amount δ(x1, L) at position x1 by the method disclosed in Patent Document 1. In Patent Document 1, as shown in Figure 1, when the surface shape profile is a curve y = f(x) and the unit length is L, the strain amount δ(x1, L) at position x1 is calculated by the following formula (2).

[0007]

Equation

[0008] In calculating the strain amount δ using the above formula (2), to calculate the strain amount δ at the plate end, the unit length L must be shortened, but Patent Document 1 does not disclose the measurement of the strain amount δ near the plate end. The strain amount δ near the plate end will be measured by shortening the unit length L as described above. Considering that the strain amount δ must be 0 when x1 is 0 or L P in the case, as shown in the following formula (3), when x1 is less than L / 2, it is conceivable to make the unit length L as small as 2×x1.

[0009]

Equation

[0010] When using the above formula (3), when x1 is 0, the strain amount δ becomes 0. When x1 is L PEven when it is above -L / 2, the strain amount δ can be defined in the same way. However, if the unit length L is decreased, generally the strain amount δ becomes smaller. For this reason, there is a risk that the strain amount δ calculated using the above formula (3) will be evaluated as smaller as it approaches the plate end. According to the study by the inventors, it has been found that there is a problem that the strain amount calculated in this way often has a large deviation from the actual strain amount.

[0011] The present invention has been made in view of such problems, and an object thereof is to provide a strain amount measuring method and a strain amount measuring device capable of measuring the strain amount with high accuracy even at the plate end of a steel plate. Another object of the present invention is to provide a method for manufacturing a steel plate capable of manufacturing a steel plate in which the strain amount is corrected.

Means for Solving the Problems

[0012] The means for solving the above problems are as follows. [1] A data acquisition step of acquiring three - dimensional surface shape data of a steel plate measured by a shape measuring device, a profile acquisition step of acquiring a curve (y = f(x)) which is a surface shape profile in which a predetermined position in the longitudinal direction or width direction of the steel plate is set as x and the height at the predetermined position x is set as y from the three - dimensional surface shape data, and a strain amount calculation step of changing k in the range of more than 0 and 1 or less and obtaining a plurality of strain amounts at the predetermined position x using the following formula (1), and setting the maximum strain amount among the plurality of strain amounts as the strain amount δ(x) at the predetermined position x.

Number

Equation

Advantages of the Invention

[0013] By using the strain amount measurement method and the strain amount measurement device according to the present invention, the strain amount δ of the steel plate can be measured with high accuracy even at the plate end. Thus, if the strain amount δ can be measured with high accuracy, the strain amount δ can be detected and the steel plate can be corrected, so that a steel plate with the strain amount stably corrected can be manufactured.

Brief Description of the Drawings

[0014]

Fig. 1

Fig. 2

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Fig. 9

Fig. 10

Mode for Carrying Out the Invention

[0015] Hereinafter, the present invention will be specifically described through embodiments of the present invention. However, the following embodiments show a preferred example of the present invention, and the present invention is not limited by these embodiments at all.

[0016] First, with reference to FIG. 2, a steel plate shape correction system 100 including a strain amount measuring device 24 according to the present embodiment will be described. FIG. 2 is a schematic diagram of a steel plate shape correction system 100 including a strain amount measuring device 24 according to the present embodiment.

[0017] The steel plate shape correction system 100 is used to correct the shape of the steel plate S offline. The steel plate shape correction system 100 includes a press 10, a shape measuring device 22, and a strain measuring device 24. The press 10 includes a pressing ram 12, an inlet bed 14, an outlet bed 16, and tracking devices 18, 20. The inlet bed 14 and the outlet bed 16 have a number of rollers for transporting the steel plate S, and the transport state of the steel plate S is controlled by controlling the rotation state of the rollers. The tracking devices 18, 20 are provided on the inlet bed 14. The tracking devices 18, 20 detect the position of the steel plate S from, for example, the rotation state of the rollers. Also, the tracking devices 18, 20 may detect the position of the steel plate S by measuring the position of the steel plate S with a laser distance meter.

[0018] The press 10 presses the steel plate S from above with the pressing ram 12, and mainly applies a bending moment to the steel plate S to correct the shape of the steel plate S. The shape of the steel plate S is measured by the shape measuring device 22 described later. Examples of the conditions for correcting the shape of the steel plate S include the pressing position of the pressing ram 12, the pressing force by the pressing ram 12, the position and interval of a backing plate called a shim, and the position of the steel plate S. The correction of the steel plate shape by the press 10 is performed, for example, by laying two shims under the steel plate S and pressing the portion of the steel plate S between the shims with the pressing ram 12. The bending moment by the pressing ram 12 occurs only in the portion of the steel plate S between the shims. Considering the amount of deformation of the steel plate S due to this bending moment and the springback amount, which is the amount of return when the pressure is released, the conditions for correcting the shape of the steel plate are determined.

[0019] The shape measuring device 22 is installed, for example, on the side of the inlet bed 14. The shape measuring device 22 includes a laser distance meter that detects the distance to a detection point by laser light, and a computer that measures the shape of the steel plate S from the distance data detected by the laser distance meter. In the laser distance meter, the surface shape of the steel plate S is obtained by measuring the distance to each detection point of the steel plate S. The laser distance meter is preferably a 3D scanner having a laser light irradiation device and a laser light receiving device.

[0020] The shape measuring device 22 measures the surface shape of the steel plate S conveyed by the input side bed 14 to obtain three-dimensional surface shape data of the steel plate S. As a specific method for measuring the three-dimensional surface shape data, the method described in Patent Document 2 can be used. That is, a laser beam is scanned in the longitudinal direction and the width direction of the steel plate S, and for example, in an XYZ space where the longitudinal direction is the X axis, the height direction is the Y axis, and the plate width direction is the Z axis, the positions on the steel plate surface are extracted as point cloud data, a regression surface is obtained from the point cloud data, and this is used as the three-dimensional surface shape data.

[0021] The strain amount measuring device 24 is also installed, for example, on the side of the input side bed 14. The strain amount measuring device 24 acquires the three-dimensional surface shape data of the steel plate S measured by the shape measuring device 22, and obtains a curve (y = f(x)) which is the surface shape profile from the three-dimensional surface shape data. The surface shape profile is a curve (y = f(x)) where a predetermined position in the longitudinal direction or the width direction of the steel plate S is x and the height at the predetermined position x is y. The strain amount measuring device 24 measures the strain amount δ of the steel plate S using the acquired surface shape profile.

[0022] Next, the strain amount measuring device 24 will be described. FIG. 3 is a schematic diagram showing a configuration example of the strain amount measuring device 24. The strain amount measuring device 24 is, for example, a general-purpose computer such as a workstation or a personal computer. The strain amount measuring device 24 includes a control unit 26, an input unit 28, an output unit 30, and a storage unit 32.

[0023] The control unit 26 is, for example, a CPU or the like, and by executing various programs stored in the storage unit 32, the control unit 26 functions as a data acquisition unit 34, a profile acquisition unit 36, and a strain amount calculation unit 38. The input unit 28 is, for example, a keyboard, a touch panel provided integrally with a display, or the like. The output unit 30 is, for example, an LCD or a CRT display. The storage unit 32 is, for example, a rewritable flash memory, a hard disk built-in or connected by a data communication terminal, an information recording medium such as a memory card, and a reading / writing device thereof. The storage unit 32 stores in advance a program, a mathematical formula, and data used to acquire a surface shape profile from the three-dimensional surface shape data, and a program, a mathematical formula, and data used to calculate the strain amount δ of the steel plate S from the surface shape profile. The mathematical formula and data may be input by an operator through the input unit 28.

[0024] Next, the processes executed by the data acquisition unit 34, the profile acquisition unit 36, and the strain amount calculation unit 38 will be described. The data acquisition unit 34 executes a data acquisition step to acquire three-dimensional surface shape data of the steel plate S from the shape measurement device 22. The data acquisition unit 34 outputs the acquired three-dimensional surface shape data to the profile acquisition unit 36.

[0025] When the profile acquisition unit 36 acquires three-dimensional surface shape data (curved surface), it executes a profile acquisition step to acquire a surface shape profile (y = f(x)) where the height at a predetermined position x in the longitudinal direction or the width direction of the steel plate S is y. When the profile acquisition unit 36 acquires three-dimensional surface shape data, it obtains an XY cross-section at the center of the plate width with respect to the three-dimensional surface shape data in the XYZ space. This XY cross-section becomes a surface shape profile where the height at a predetermined position x in the longitudinal direction is y. Similarly, the profile acquisition unit 36 obtains a YZ cross-section in the longitudinal direction of the steel plate S with respect to the three-dimensional surface shape data in the XYZ space. This YZ cross-section becomes a surface shape profile where the height at a predetermined position z in the width direction is y. The profile acquisition unit 36 outputs the surface shape profile in the longitudinal direction to the strain amount calculation unit 38. In the following description, a method for calculating the strain amount δ at a predetermined position x using a surface shape profile where the height at a predetermined position x in the longitudinal direction of the steel plate S is y will be described, but the strain amount δ at a predetermined position in the width direction of the steel plate S can also be calculated in the same manner.

[0026] When the strain amount calculation unit 38 acquires a surface shape profile (y = f(x)), it executes a strain amount calculation step to measure the strain amount δ of the steel plate S. The strain amount calculation unit 38 changes k in the range greater than 0 and less than or equal to 1, and calculates a plurality of strain amounts δ(x, kL) at a predetermined position x using the surface shape profile (y = f(x)) and the following formula (1) with a predetermined unit length L. The unit length L is, for example, 1 m or more and 4 m or less.

[0027]

Equation

[0028] The amount-of-distortion calculation unit 38 sets the maximum amount of distortion among the calculated plurality of amounts of distortion δ as the amount of distortion at the predetermined position x. For example, when k is changed to 10 levels of 0.1, 0.2, 0.3, ···, 0.9, 1.0, the amount-of-distortion calculation unit 38 calculates 10 amounts of distortion σ(x,kL) at the predetermined position x. The amount-of-distortion calculation unit 38 sets the largest amount of distortion δ among the 10 amounts of distortion δ(x,kL) as the amount of distortion δ(x) at the predetermined position x. The amount-of-distortion calculation unit 38 calculates the amount of distortion δ(x) at all predetermined positions x in the longitudinal direction of the steel plate S. In this way, the amount-of-distortion calculation unit 38 measures the amount of distortion δ in the longitudinal direction of the steel plate S.

[0029] As shown in the above formula (1), when the predetermined position x satisfies 0 ≦ x < kL / 2 and L P -kL / 2 ≦ x < L P the amount-of-distortion calculation unit 38 separates the plate end portion of the steel plate S where the condition is satisfied and the plate center portion of the steel plate S where the predetermined position x satisfies kL / 2 ≦ x < L P -kL / 2, and calculates the amount of distortion δ. Thereby, the amount-of-distortion calculation unit 38 can measure the amount of distortion δ at the plate end portion of the steel plate S with higher accuracy than before.

[0030] The amount-of-distortion calculation unit 38 may cause the output unit 30 to display the measured amount of distortion δ of the steel plate S. In this case, for example, the amount-of-distortion calculation unit 38 may cause the output unit 30 to display the amount of distortion δ of the steel plate S in a graph with the horizontal axis being the predetermined position x and the vertical axis being the amount of distortion δ.

[0031] As described above, in the amount-of-distortion measuring device 24 according to the present embodiment, when the predetermined position x satisfies 0 ≦ x < kL / 2 and L P -kL / 2 ≦ x < L P the plate end portion of the steel plate S, and when the predetermined position x satisfies kL / 2 ≦ x < L PBy separating the central part of the steel plate S that becomes -kL / 2 and calculating the strain amount δ, the strain amount δ at the plate end of the steel plate S can be measured with higher accuracy than before. If the strain amount δ at the plate end can be measured with high accuracy in this way, the strain amount δ can be corrected by press correction under the press conditions corresponding to the strain amount δ, and a steel plate with less strain can be manufactured. Furthermore, even when a strain with a strain amount outside the standard occurs at the plate end, the strain amount δ can be detected. By performing press correction under the press conditions such that the strain amount δ is within the range of the standard value, it is possible to suppress the reduction in yield due to the production of a steel plate having a strain amount outside the standard. Note that the standard value of the strain amount is an example of a predetermined range of the strain amount.

Example

[0032] Next, an example in which the strain amount δ of a steel plate is measured by the strain amount measuring device 24 according to the present embodiment will be described. FIG. 4 is a graph (comparative example) showing the result of measuring the strain amount δ of a steel plate using the above formula (3). FIG. 5 is a graph (invention example) showing the result of measuring the strain amount δ of the same steel plate by the strain amount measuring device 24 according to the present embodiment. In both FIGS. 4 and 5, (a) shows the strain amount δ in the longitudinal direction when the unit length L is 1 m, and (b) shows the strain amount δ in the longitudinal direction when the unit length L is 2 m. Further, (c) shows the strain amount δ in the width direction when the unit length L is 1 m, and (d) shows the strain amount δ in the width direction when the unit length L is 2 m.

[0033] In FIGS. 4 and 5, the portions shown in black indicate that the strain amount δ is large (±2 mm to ±3 mm), and the portions shown in white indicate that the strain amount δ is small (0 to ±1 mm). Regarding the strain amount δ in the longitudinal direction, although no difference in magnitude was observed between the invention example and the comparative example, regarding the strain amount δ in the width direction, a clear difference was observed between the invention example and the comparative example in the portions near the plate end (z = 0.2, z = 2.2).

[0034] FIG. 6 is a graph showing the strain amount δ at the plate width direction position of 1.25 m (z = 1.25 m) in FIGS. 4(a) and 5(a). In the strain amount δ in the longitudinal direction with the unit length L being 1 m, no difference in magnitude was confirmed in the strain amount δ measured between FIG. 4(a) which is a comparative example and FIG. 5(a) which is an invention example.

[0035] Figure 7 is a graph showing the amount of strain δ at the position 1.25 m (z = 1.25 m) in the plate width direction in FIGS. 4(b) and 5(b). For the amount of strain δ in the longitudinal direction with the unit length L being 2 m, a difference in the amount of strain δ was confirmed between the comparative example and the inventive example at the plate end portion far from 0. The ○ marks in FIG. 7 are the results of manually measuring the amount of strain δ using a 2 m stretcher. As shown in FIG. 7, the amount of strain δ in the inventive example and the amount of strain δ by manual measurement were almost the same. From this result, it was confirmed that by using the strain measurement device 24 according to the present embodiment, the amount of strain δ at the plate end portion in the longitudinal direction of the steel plate can be measured with high accuracy.

[0036] Figure 8 is a graph showing the amount of strain δ at the longitudinal position 4.0 m (x = 4.0 m) in FIGS. 4(c) and 5(c). For the amount of strain δ in the width direction with the unit length L being 1 m, a difference in the amount of strain δ was confirmed between the comparative example and the inventive example in the region excluding the vicinity of the center in the width direction. The ○ marks in FIG. 8 are the results of manually measuring the amount of strain δ using a 1 m stretcher. As shown in FIG. 8, the amount of strain δ in the inventive example and the amount of strain δ by manual measurement were almost the same. From this result, it was confirmed that by using the strain measurement device 24 according to the present embodiment, the amount of strain δ of the steel plate can be measured with high accuracy.

[0037] Figure 9 is a graph showing the amount of strain δ at the longitudinal position 4.0 m (x = 4.0 m) in FIGS. 4(d) and 5(d). For the amount of strain δ in the width direction with the unit length L being 2 m, a difference in the amount of strain δ was confirmed between the comparative example and the inventive example in the region excluding the vicinity of the center in the width direction (L / 2 ≤ z < L P -L / 2). The ○ marks in FIG. 9 are the results of manually measuring the amount of strain δ using a 2 m stretcher. As shown in FIG. 9, the amount of strain δ in the inventive example and the amount of strain δ by manual measurement were almost the same. From this result, it was confirmed that by using the strain measurement device 24 according to the present embodiment, the amount of strain δ of the steel plate can be measured with high accuracy.

[0038] FIG. 10 is a graph showing the measurement results of the amount of longitudinal strain δ in another steel plate. In FIG. 10, the unit length L was set to 2 m, and the amount of longitudinal strain δ at the center in the width direction was measured. Also in this measurement of the amount of strain δ, a difference in the amount of strain δ was confirmed between the comparative example and the inventive example at the plate end portions closer to 0 and the plate end portions farther from 0. The ○ marks in FIG. 10 are the results of manually measuring the amount of strain δ using a 2 m stretcher. As shown in FIG. 10, the amount of strain δ in the inventive example and the amount of strain δ by manual measurement were almost the same. From this result, it was confirmed that by using the strain amount measuring device 24 according to the present embodiment, the amount of strain δ at the plate end portion in the longitudinal direction of the steel plate can be measured with high accuracy.

[0039] Further, the steel plate for which the amount of strain δ was measured in FIG. 10 is press-corrected by the press 10 as out of specification when the amount of strain δ is 2 mm or more. As shown in FIG. 10, in the measurement of the amount of strain δ according to the comparative example, since the amount of strain δ is measured to be less than 2 mm, it is determined not to perform press correction by the press 10. For this reason, a steel plate having a strain of 2 mm or more, which is actually out of specification, flows as it is to the downstream process. On the other hand, in the strain amount measuring device 24 according to the present embodiment, a strain of 2 mm or more existing at the plate end portion can be detected, and press correction can be performed under press conditions corresponding to the amount of strain δ, so that a steel plate whose strain amount is stably corrected within the specification can be manufactured.

Description of Signs

[0040] 10 Press 12 Pressing ram 14 Inlet bed 16 Outlet bed 18 Tracking device 20 Tracking device 22 Shape measuring device 24 Strain amount measuring device 26 Control unit 28 Input unit 30 Output unit 32 Storage unit 34 Data acquisition unit 36 Profile acquisition unit 38 Strain amount calculation unit Shape correction system for 100 steel plates S steel plate

Claims

1. A data acquisition step of acquiring three-dimensional surface shape data of a steel plate measured by a shape measuring device, A profile acquisition step of acquiring a curve (y = f(x)), which is a surface shape profile in which a predetermined position in the longitudinal direction or the width direction of the steel plate is x and the height at the predetermined position x is y, from the three-dimensional surface shape data, A strain amount calculation step of changing k in a range greater than 0 and less than or equal to 1, obtaining a plurality of strain amounts at the predetermined position x using the following formula (1), and setting the maximum strain amount among the plurality of strain amounts as the strain amount δ(x) at the predetermined position x, A strain amount measurement method comprising the above steps. 【Number 1】 In the above formula (1), k is a numerical value greater than 0 and less than or equal to 1, and L Ｐ is the length (m) in the longitudinal direction of the steel plate or the plate width (m) of the steel plate, and L is the unit length (m).

2. A data acquisition unit that acquires three-dimensional surface shape data of a steel plate measured by a shape measuring device, A profile acquisition unit that acquires a curve (y = f(x)), which is a surface shape profile in which a predetermined position in the longitudinal direction or the width direction of the steel plate is x and the height at the predetermined position x is y, from the three-dimensional surface shape data, A strain amount calculation unit that changes k in a range greater than 0 and less than or equal to 1, obtains a plurality of strain amounts at the predetermined position x using the following formula (1), and sets the maximum strain amount among the plurality of strain amounts as the strain amount δ(x) at the predetermined position x, A strain amount measuring device comprising the above units. 【Number 2】 In the above formula (1), k is a numerical value greater than 0 and less than or equal to 1, and L Ｐ is the length (m) in the longitudinal direction of the steel plate or the plate width (m) of the steel plate, and L is the unit length (m).

3. Measuring the strain amount of a steel plate by the strain amount measurement method according to Claim 1, A method for manufacturing a steel plate, wherein the strain of the steel plate is press-corrected by a press so that the measured strain amount is within a predetermined range.

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