JP6597679B2 - Method for evaluating strain of steel sheet - Google Patents

Description

  The present invention relates to a method for evaluating distortion of a steel sheet, and particularly relates to a method for evaluating distortion generated in a steel sheet in a rolling process or a heating / cooling process, and is suitable for using the evaluation result for shape correction with a press straightener. It is a thing.

  In the manufacture of steel plates, generally, a plurality of rolls called levelers are arranged one above the other, and the steel plates are transported between these rolls to correct shape defects such as warpage and ear waves that occur during manufacturing. However, since the bending moment necessary to correct the shape is proportional to the cube of the plate thickness, in the case of a steel plate having a thickness of 40 mm or more, the leveler cannot correct the shape. Therefore, when a shape defect occurs in a thick steel plate, the steel plate is removed from the line, and shape correction is performed using a press machine in a so-called offline.

  In the work to correct the shape of a thick steel plate using a press, the amount of strain at each position on the surface of the steel plate is measured, and the reduction position and force of the press ram are determined based on the amount of strain at each position. To do. Conventionally, the amount of strain has been measured by an operator applying a stretcher of a predetermined length on the steel plate surface and observing the size of the gap between the stretcher and the steel plate surface. As a distortion amount evaluation method, a stretcher is handled as a QA instrument, and correction conditions in a press machine should be determined based on the distortion amount obtained by this method. However, this method has a problem in that the operator manually examines the amount of distortion at a large number of positions on the surface of the steel sheet, which imposes a heavy burden on the operator and hinders productivity improvement.

  Therefore, in Patent Document 1, a three-dimensional surface shape data of a steel plate is acquired using a steel plate shape measuring device such as a 3D scanner, and a strain amount at each position on the surface of the steel plate is calculated from the three-dimensional surface shape data. A method for evaluating the distortion of a steel sheet is described. Specifically, the curvature at each position of the steel sheet is calculated by second-order differentiation of the three-dimensional surface shape data, and this value is used as the distortion amount.

JP 2010-155272 A

  However, according to the study by the present inventors, the strain obtained by the method described in Patent Document 1, that is, the value obtained by second-order differentiation of the three-dimensional surface shape data is the size of the gap between the stretcher and the steel plate surface. As a result, it was found that there was a deviation from the distortion amount evaluated. That is, it has been found that the method described in Patent Document 1 is not suitable as a distortion evaluation method used when performing shape correction with a press. Therefore, there is a need for an evaluation method for the amount of distortion that matches the strain obtained by the stretcher as much as possible without the operator actually measuring the amount of strain using the stretcher, that is, while avoiding the burden on the worker and productivity problems. It is done.

  Therefore, in view of the above problems, the present invention appropriately evaluates the amount of distortion and position of the steel sheet without damaging the operator's burden and productivity, and enables the operator to accurately correct the shape of the steel sheet. It aims at providing the distortion evaluation method of the steel plate which enables this.

The gist configuration of the present invention for solving the above-described problems is as follows.
[1] A step of acquiring three-dimensional surface shape data of a steel plate with a steel plate shape measuring device;
From the three-dimensional surface shape data, the position in the longitudinal direction of the steel plate at the predetermined plate width position of the steel plate is x, the height of the steel plate at the position x is y, and the curve y = f (x )
Using the curve y = f (x) to determine the strain amount δ (x) at the position x by the following method;
A method for evaluating strain of a steel sheet, comprising:
L is a unit length, and δ (x, L) is obtained based on the following formula (1):
Further, δ (x, kL) is obtained for a plurality of k values based on the equation (2), where k is a value greater than 0 and less than 1.
The maximum value among the obtained δ (x, L) and the plurality of δ (x, kL) is set as a distortion amount δ (x) at the position x.

  [2] The steel sheet strain evaluation method according to [1], wherein the plurality of k values are set at intervals of 0.05 to 0.2.

  [3] The steel sheet strain evaluation method according to [1] or [2], wherein the minimum value of kL is 0.2 m or less.

  [4] Any one of [1] to [3], further including a step of obtaining a strain amount profile δ (x) at a plurality of positions x in the longitudinal direction of the steel sheet to obtain a strain amount profile in the longitudinal direction of the steel sheet. The distortion | strain evaluation method of the steel plate as described in a term.

  The steel sheet distortion evaluation method of the present invention can appropriately evaluate the distortion amount and position of the steel sheet without impairing the burden and productivity of the operator, so that the operator can accurately correct the shape of the steel sheet. Is possible.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic whole block diagram which shows the shape correction system of the steel plate which can implement the distortion evaluation method of the steel plate by one Embodiment of this invention. In one Embodiment of this invention, it is a conceptual diagram for demonstrating a part of calculation which calculates | requires distortion amount (delta) (x) in the position x of the longitudinal direction of a steel plate. In one Embodiment of this invention, it is a conceptual diagram for demonstrating an example of the calculation which calculates | requires distortion amount (delta) (x) in the position x of the longitudinal direction of a steel plate. It is the surface shape profile of the thick steel plate acquired using the 3D scanner. It is the distortion amount profile in the longitudinal direction of the steel plate calculated | required by the conventional method (2nd-order differentiation) from FIG. FIG. 4 is a strain profile in the longitudinal direction of the steel sheet obtained by the method of the present invention.

  First, a steel sheet shape correction system 100 capable of performing a steel sheet distortion evaluation method according to an embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a schematic overall view of a steel sheet shape correction system 100 that can be used in this embodiment. The shape correction system 100 corrects the shape of a steel sheet offline. Reference numeral 1 in the drawing denotes a press machine that corrects the shape of the steel sheet S. An entrance bed 3 is disposed on the entry side of the press machine 1, and an exit bed 4 is disposed on the exit side of the press machine 1. . Each of the beds 3 and 4 is provided with a large number of rollers for transporting the steel sheet S, and the transport state of the steel sheet S can be controlled by controlling the rotation state of the rollers. That is, these beds 3 and 4 constitute a conveying device for the steel sheet S. In particular, the entrance bed 3 is provided with tracking devices 7 and 8 for detecting the conveying state of the steel sheet S from the rotating state of the rollers, for example. The tracking devices 7 and 8 can detect the position of the steel sheet S by, for example, calculating the transport amount of the steel sheet S from the rotation amount of the roller and the diameter of the roller.

  In the case of the press machine 1 in the present embodiment, the steel plate S is pressed from above with the pressurization ram 2, and a bending moment is mainly applied to the steel plate S to correct the shape of the steel plate. The shape of the steel plate S is measured by a steel plate shape measuring device 5 described later. The conditions for correcting the shape of the steel sheet include, for example, the pressing position of the pressurizing ram 2, the pressure applied by the pressurizing ram 2, the position and interval of the laying bar called shim, the position of the steel sheet S, and the like. In the steel plate shape correction by the press machine 1 in the present embodiment, two shims are laid under the steel plate S, and the steel plate S in the portion between the shims is pressed with the pressure ram 2. The bending moment due to the pressure ram 2 is generated only in the steel plate S in the portion between the shims. The above-described various parameters are adjusted in consideration of the deformation amount of the steel sheet S due to this bending moment and the return amount when pressure is released, the so-called springback amount.

  A steel plate shape measuring device 5 and a control device 6 were installed on the side of the entrance bed 3. Among these, the shape measuring device 5 includes a laser distance meter that detects the distance to the detection point with laser light, and a computer system that measures the shape of the steel sheet S from the distance data detected by the laser distance meter. By measuring the distance to each detection point of the steel sheet S with a laser distance meter, the surface shape of the steel sheet S can be obtained. The laser distance meter includes a laser light irradiation device and a laser light receiving device.

  The steel plate shape measuring device 5 is preferably a 3D scanner. In the steel plate distortion evaluation method according to the present embodiment, first, the steel plate shape measuring device 5 acquires the three-dimensional surface shape data of the steel plate. A specific method for acquiring three-dimensional surface shape data can be the method described in Patent Document 1. That is, the laser beam is polarized and scanned in the longitudinal direction and the width direction of the steel sheet. For example, in the XYZ space where the longitudinal direction is the X axis, the height direction is the Y axis, and the sheet width direction is the Z axis, After extracting the position as a detection point group and performing a thinning process for making the density of the detection point group uniform, a regression surface is obtained from the data of the detection point group, and this is used as three-dimensional surface shape data.

  The control device 6 is constructed with a computer system such as a host computer, and calculates the amount of strain at each position on the surface of the steel plate from the three-dimensional surface shape data of the steel plate S measured by the shape measuring device 5. I do. The distortion evaluation method for a steel sheet of the present disclosure is characterized by this calculation process.

  And the control apparatus 6 is based on the calculated distortion amount in each position of the steel plate surface, for example, the pressing-down position of the pressurization ram 2, the pressurization force by the pressurization ram 2, and the position and space | interval of a laying bar called a shim The steel plate shape correction conditions such as the position of the steel sheet S are determined, and the operating states of the press machine 1 and the beds 3 and 4 are controlled under the determined conditions. The determination method of correction conditions is not specifically limited, For example, the method of patent document 1 can be used.

  Hereinafter, a method for evaluating the distortion of the steel sheet by the control device 6 will be described. First, from the three-dimensional surface shape data of the steel plate measured by the shape measuring device 5, the position in the longitudinal direction of the steel plate at a predetermined plate width position (for example, the center position of the plate width) is set to x, and the steel plate at the position x. A curve y = f (x) is obtained as the surface shape profile of the steel sheet, where y is the height. That is, the XY cross section of the regression surface (three-dimensional surface shape data) in the XYZ space at the center position of the plate width is the curve y = f (x). An example of the surface shape profile in an actual thick steel plate is shown in FIG.

Next, using the curve y = f (x), the distortion amount δ (x) at the position x is obtained by the following method.
First, δ (x, L) is obtained based on the following formula (1), where L is a unit length, and a plurality of numerical values less than 1 and greater than 0 are calculated based on formula (2). δ (x, kL) is obtained with respect to the value of k, and the maximum value among the obtained δ (x, L) and a plurality of δ (x, kL) is defined as the distortion amount δ (x) at the position x.

となる。 Formula (1) is demonstrated with reference to FIG. In FIG. 2, when the surface shape profile is a curve y = f (x), the distortion amount δ (x ₁ , L) at x = x ₁ when the unit length is L is as shown in FIG. In addition,

It becomes.

However, for example, when the curve y = f (x) is the shape shown in FIG. 3 in the surface shape profile, the equation is more than the strain amount δ (x ₁ , L) at x = x ₁ when the unit length is L. The distortion amount δ (x ₁ , 1 / 2L) at x = x ₁ when k = 1/2 calculated based on (2) is larger.

As information on the amount of distortion necessary for the correction work, it is necessary to use the maximum amount of distortion. Therefore, δ (x ₁ , 1 / 2L) is appropriate instead of δ (x ₁ , L) as information on the distortion amount δ at x = x ₁ presented to the correction worker.

  Therefore, in the strain evaluation method of the steel sheet of the present disclosure, not only δ (x, L) is obtained, but δ (x, kL) is obtained for a plurality of k values in a range of 0 <k <1, and the maximum of them is obtained. The value is a distortion amount δ (x) at the position x. Thereby, the distortion amount of the steel plate in the position x can be evaluated appropriately, and the operator can correct the shape of the steel plate with high accuracy.

  Here, the unit length L is not particularly limited, but may be 1 m or more and 4 m or less.

  The plurality of k values when calculating δ (x, kL) are preferably set at intervals of 0.05 or more and 0.2 or less, and the minimum value of kL is preferably 0.2 m or less. By setting the k interval to 0.2 or less, the amount of distortion of the steel plate at the position x can be more appropriately evaluated. If the k interval is about 0.05, the accuracy of the maximum distortion amount is saturated. Moreover, if the minimum value of kL is 0.2 m or less, the accuracy of the maximum value of the distortion amount is saturated. As a preferred embodiment, for example, δ (x, kL) is obtained in increments of 0.1 in the range of k = 0.9 to 0.2, and δ (x, L) and eight δ (x, kL) are obtained. ) Can be the distortion amount δ (x) at the position x.

By calculating not only the strain amount δ at x = x ₁ but also the strain amounts δ (x) at a plurality of positions x in the longitudinal direction of the steel sheet by such a method, a strain amount profile in the longitudinal direction of the steel sheet can be obtained. it can. An example of the strain profile in an actual thick steel plate is shown in FIG. Based on this distortion amount profile, the straightening operator determines the conditions for correcting the steel plate shape, and the control device 6 controls the operating state of the press machine 1 and the beds 3 and 4 under the determined conditions.

  For the rolled steel plate (plate thickness: 200 mm, plate length: 6000 mm, plate width: 1337 mm), the steel plate surface was measured with a 3D scanner, and three-dimensional surface shape data was obtained. From the acquired three-dimensional surface shape data, the position in the longitudinal direction of the steel plate at the center position of the plate width of the steel plate is x, the height of the steel plate at the position x is y, and the curve y = f ( x) was obtained. This surface shape profile is shown in FIG.

(Comparative example)
FIG. 5 shows a strain profile in the longitudinal direction of the steel sheet obtained by second-order differentiation of the surface shape profile of FIG.

(Invention example)
FIG. 6 shows a strain profile in the longitudinal direction of the steel sheet obtained by the method of the present invention from the surface shape profile of FIG. The amount of distortion at each position in the longitudinal direction is set to L = 2 m, and δ (x, L) is obtained using Equation (1), and δ is obtained in increments of 0.1 in the range of k = 0.9 to 0.5. (X, kL) was obtained, and the maximum value of δ (x, L) and the five δ (x, kL) was defined as the distortion amount δ (x) at the position x.

(Evaluation)
At the position of x = 1000 mm of the thick steel plate, a stretcher having a length of 2 m was applied to the steel plate surface, and the size of the gap between the stretcher and the steel plate surface was measured. The measured values are shown in FIG. 5 and FIG. As is apparent from FIG. 6, the strain amount obtained by the method of the present invention coincided with the measured value obtained by the stretcher with high accuracy. On the other hand, as is clear from FIG. 5, the distortion obtained in the comparative example showed a deviation from the actually measured value obtained by the stretcher. Thus, it can be seen that the method of the present invention is a strain evaluation method that matches the strain amount obtained by the stretcher with high accuracy.

  The steel sheet distortion evaluation method of the present invention can appropriately evaluate the distortion amount and position of the steel sheet without impairing the burden and productivity of the operator, so that the operator can accurately correct the shape of the steel sheet. Is possible.

DESCRIPTION OF SYMBOLS 100 Shape correction system 1 Press machine 2 Pressurization ram 3 Incoming bed 4 Outgoing bed 5 Steel plate shape measuring device (3D scanner)
6 Control device 7, 8 Tracking device

Claims (4)

A step of acquiring three-dimensional surface shape data of a steel plate with a steel plate shape measuring device;
From the three-dimensional surface shape data, the position in the longitudinal direction of the steel plate at the predetermined plate width position of the steel plate is x, the height of the steel plate at the position x is y, and the curve y = f (x )
Using the curve y = f (x) to determine the strain amount δ (x) at the position x by the following method;
A method for evaluating strain of a steel sheet, comprising:
L is a unit length, and δ (x, L) is obtained based on the following formula (1):
Further, δ (x, kL) is obtained for a plurality of k values based on the formula (2), where k is a value greater than 0 and less than 1.
The maximum value among the obtained δ (x, L) and the plurality of δ (x, kL) is set as a distortion amount δ (x) at the position x.

  The method for evaluating strain of a steel sheet according to claim 1, wherein the plurality of k values are set at intervals of 0.05 to 0.2.   The distortion evaluation method for a steel sheet according to claim 1 or 2, wherein the minimum value of kL is 0.2 m or less.   The steel plate according to any one of claims 1 to 3, further comprising a step of obtaining a strain amount profile δ (x) at a plurality of positions x in the longitudinal direction of the steel plate to obtain a strain amount profile in the longitudinal direction of the steel plate. Distortion evaluation method.

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