JP3584819B2 - Dissimilar material determination method and apparatus - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for judging a different material from a test material made of a metal material sequentially conveyed on a conveying line, for example.
[0002]
[Prior art]
For example, in a factory where steel pipes, round bars and other bar materials are manufactured, there are cases where bar materials of different materials having the same or similar shape are mixed and conveyed on the same conveyance line. For this reason, in such a transport line, a different material determination inspection is performed on the bar steel that is sequentially transported.
[0003]
Conventionally, as this kind of different material determination method, for example, a method of determining by a spark test, a method of determining by analyzing emission spectrum, a method of determining by measuring physical property values such as impedance, coercive force, magnetic permeability, and the like are known. Have been.
[0004]
[Problems to be solved by the invention]
However, in the determination method based on the spark test, since it is a sensory test by a human, there is a problem that erroneous determination is likely to occur, and there is a problem that the test takes time. In addition, in the determination method based on emission spectroscopy, there is a problem that the cost is increased due to the use of the emission spectroscopy analyzer, and there is a problem that the analysis takes time. Since the surface needs to be finished smoothly, there is a problem that it takes time and effort.
[0005]
On the other hand, the determination method based on the physical property value has an advantage that the determination can be made relatively easily and in a short time. However, in the conventional determination method based on this physical property value, as disclosed in, for example, JP-A-57-69246 and JP-A-57-128842, the material, shape, Since the reference material according to the dimensions etc. is used, it is necessary to prepare various types of reference materials and replace them according to the test material, and store and manage the various types of reference materials without generating rust etc. Since it is necessary, there is a problem that operability and maintainability are poor.
[0006]
Further, in the conventional determination method based on the physical property values, a physical property value such as impedance measured using a reference material is fixedly set as a reference value, and the physical property value obtained by measuring the reference value and the test material is used. Are compared to determine whether or not a different material, for example, the detection coil or amplifier of the physical property value measurement system of the test material changes over time, or the ambient temperature changes in summer-winter, etc. An erroneous determination may occur if there is variation in the size or composition of the test material between lots. Further, in order to prevent this erroneous determination, it is necessary to frequently calibrate the gain and the like of the amplifier, and there is a problem that it takes time and effort.
[0007]
The present invention has been made in view of such conventional problems, and a first object of the present invention is to provide excellent operability and maintainability, as well as changes over time, changes in ambient temperature, and the use of test materials between lots. An object of the present invention is to provide a different material determination method that can always easily and reliably determine a different material without being affected by component variations.
[0008]
Further, a second object of the present invention is to provide a dissimilar material judging apparatus which can execute the above dissimilar material judging method simply and inexpensively and can process at a high line speed.
[0009]
[Means for Solving the Problems]
The invention according to claim 1, which achieves the first object, is a dissimilar material determination method that measures impedance of a test material and determines dissimilar material based on the measured impedance.
Prior to the determination of a different material of a test material lot having the same component and the same rolling chance, the impedance of at least one test material at the beginning of the lot is measured, and the magnitude of the average value centered on the average value of the measured impedance is measured. Then, a different value is set based on a comparison between the measured impedance of the other test materials and the normal value range.
[0010]
According to the first aspect of the invention, since no reference material is used, operability and maintainability can be improved. In addition, the impedance of at least one test material at the beginning is measured for each lot, and a normal value range of the impedance is set around the average value of the measured impedance and proportional to the magnitude of the average value. When the average value is large, a large normal value range is set. When the average value is small, a small normal value range is set. If there is a change, a variation in the size or composition of the test material between lots, or the like, the normal value range is set accordingly. Therefore, since almost no calibration or the like is required, the trouble can be greatly reduced, and the dissimilar material can always be easily and reliably determined.
[0011]
Furthermore, the invention of a dissimilar material determination device according to claim 2 that achieves the second object has a primary coil and a secondary coil, and a detection coil into which a test material is inserted;
An oscillator that supplies an exciting current to the primary coil so as to generate an eddy current in the test material;
Synchronous detection means for synchronously detecting the induced current induced in the secondary coil based on the exciting current and measuring the impedance of the test material,
Normal value range setting means for setting a normal value range proportional to the average value of the average value of the impedance measured by the synchronous detection means,
Determining means for determining a different material based on a comparison between the normal value range and the impedance measured by the synchronous detection means,
The normal value range setting means sets a normal value range based on the impedance measured by the synchronous detection means of at least one test material at the beginning of the test material lot having the same component and the same rolling chance, and sets another test material. And a control means for controlling the determination means to determine a different material based on a comparison between the impedance measured by the synchronous detection means and the normal value range of the test material. is there.
[0012]
According to the second aspect of the present invention, since the detection coil, the oscillator, and the synchronous detection means can use a flaw detection device based on impedance measurement, it can be implemented simply and inexpensively, and the impedance is measured using the detection coil. Therefore, processing at a high line speed (up to 200 m / min) becomes possible.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing one embodiment of a dissimilar material judging device for performing the dissimilar material judging method according to the present invention. In the present embodiment, the detection coil 3 is installed on the transport line 1 so that the test material 2 sequentially transported on the transport line 1 is inserted and passed. The detection coil 3 is connected to the impedance measuring unit 4, measures the impedance of each test material 2 continuously or intermittently, and supplies the measured impedance to the determining unit 5. The determination unit 5 determines a different material based on the measured impedance from the impedance measurement unit 4 under the control of the control device 6, and supplies the determination result to the control device 6. In the control device 6, on the basis of the result of the determination by the determination unit 5, for example, a marking device (not shown) is driven to apply marking to the different material, or a sorting device (not shown) is driven to send a regular steel material and a different material from the transport line 1. And sort them out.
[0014]
FIG. 2 is a block diagram showing a detailed configuration of the dissimilar material determination device shown in FIG. The detection coil 3 includes a primary coil 31 and a secondary coil 32. The impedance measuring unit 4 includes an oscillator 41, an amplifier 42, a synchronous detector 43, and a phase shifter 44 in the same manner as the measuring unit of the flaw detector, and excites the primary coil 31 of the detection coil 3 from the oscillator 41. An eddy current is generated in the test material 2 inserted into the detection coil 3 by supplying a noble current, whereby an induced current induced in the secondary coil 32 is amplified by the amplifier 42 and supplied to the synchronous detector 43. I do.
[0015]
The output from the oscillator 41, that is, a signal having the same phase (0 °) as the exciting current supplied to the primary coil 31 and a signal shifted by 90 ° by the phase shifter 44 are also supplied to the synchronous detector 43, Thereby, the output of the amplifier 42, that is, the induced current induced in the secondary coil 32 is synchronously detected to measure the impedance of the test material 2.
[0016]
The determination unit 5 includes a switch circuit 51, a normal value range setting circuit 52, and a determination circuit 53, and measures the measured impedance from the impedance measurement unit 4 under the control of the control device 6. And selectively supplies them to the normal value range setting circuit 52 and the determination circuit 53. The normal value range setting circuit 52 calculates the average value from the input measured impedance, and sets the normal value range D of the impedance centered on the average value C and proportional to the magnitude, as shown in FIG. I do.
[0017]
That is, for the real part (pure resistance component) of the measured impedance, a value proportional to the magnitude (Z) of the average value of the measured impedance is added to or subtracted from the average value R of the real part (R ± kZ, k is a proportional constant). Also, for the imaginary part (reactance component) of the measured impedance, a value proportional to the average value of the measured impedance is added to or subtracted from the average value X of the imaginary part (X ± kZ) to obtain a normal value of the impedance. Set the range D.
[0018]
The normal value range D set by the normal value range setting circuit 52 is supplied to the determination circuit 53 and compared with the measured impedance supplied through the switch circuit 51. When the measured impedance is in the normal value range D, the normal value range D Is determined to be a different steel material, and when it is out of the normal value range D, it is determined to be a different material, and the determination result is supplied to the control device 6.
[0019]
Next, the operation of the present embodiment will be described.
First, prior to the determination of a different material of the test material lot having the same rolling chance with the same component, the control device 6 switches the switch circuit 51 so that the output of the impedance measuring unit 4 is supplied to the normal value range setting circuit 52. In this state, the impedance of one or more test materials 2 at the beginning of the lot conveyed on the conveyance line 1 is measured by the impedance measuring unit 4 via the detection coil 3 and the measured impedance is switched. The normal value range D is supplied to the normal value range setting circuit 52 through the above step.
[0020]
Here, when one test material 2 at the beginning of the lot is used for setting a normal value range, the measurement impedance (generally, the test material 2) of the test material 2 obtained continuously or intermittently is obtained. Since the magnetic field lines are unsteady within 1 m from the end face, it is desirable to measure at the center side from this area.) When calculating the average value and using a plurality of test materials 2, for example, Similarly, the average value of the measured impedances of the plurality of test materials 2 is calculated, and as shown in FIG. 3, the normal value range D of the impedance is set centered on the average value and proportional to the average value. . The above setting operation of the normal value range is performed for each lot of the test material under the control of the control device 6.
[0021]
When the setting of the normal value range D is completed, the normal value range D is supplied to the determination circuit 53, and the control device 6 switches the switch circuit 51 so that the output of the impedance measuring unit 4 is supplied to the determination circuit 53. In this state, thereafter, the impedance of the test material 2 passing through the detection coil 3 is measured by the impedance measuring unit 4 via the detection coil 3 and supplied to the determination circuit 53 via the switch circuit 51. Compared with D, it is determined whether the test material 2 is a regular steel bar or a dissimilar material.
[0022]
4 (a) and 4 (b) are plots obtained by measuring the magnitudes of the test materials of various diameters measured according to the present embodiment, and FIG. 4 (a) shows the measured impedance of JIS S45C. FIG. 4 (b) shows the magnitude of the measured impedance of SUJ2 (azurol). As is clear from FIGS. 4A and 4B, the magnitude of the impedance of the test material differs depending on the material and diameter of the test material. Can be accurately determined.
[0023]
As described above, according to the present embodiment, it is noted that the impedance of the test material 2 differs depending on the size and the material of the test material 2 without using the reference material. , The impedance of the initial test material 2 is measured, and a normal value range D which is proportional to the average value of the measured impedance is set around the average value of the measured impedance. Since the different material is determined based on the comparison between the impedance and the normal value range D, operability and maintainability can be improved.
[0024]
In addition, the normal value range D described above is assumed in FIG. 3 according to the time-dependent change of the measurement system, the change in the ambient temperature during summer-winter, etc., and the variation in the size and components of the test material between lots. Since the setting is made as shown by the line, operations such as calibration are almost unnecessary, and the dissimilar material can always be easily and reliably determined.
[0025]
In addition, since the detection coil 3 and the impedance measuring unit 4 can use a known flaw detector, it can be made simple and inexpensive, and can perform different material judgment at a high line speed (up to 200 m / min). Further, since the impedance is measured, even if the test material 2 has the same component, it is possible to reliably discriminate if the size and the manufacturing history (azurol material and heat-treated material) are different.
[0026]
【The invention's effect】
As described above, according to the dissimilar material determination method according to the present invention, the impedance is measured using the initial test material for each lot without using the reference material, and the normal value range is determined based on the measured impedance. After that, different materials are judged based on the comparison between the measured impedance and the normal value range, so that the operability and the maintainability can be improved, and the secular change, ambient temperature change, lot Dissimilar materials can always be determined easily and reliably without being affected by variations in the size or composition of the test material between samples.
[0027]
Further, according to the dissimilar material determination device of the present invention, since the impedance of the test material can be measured using a flaw detector using a detection coil, the dissimilar material can be determined simply and inexpensively and at a high line speed. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic view showing one embodiment of a dissimilar material judging device for performing a dissimilar material judging method according to the present invention.
FIG. 2 is a block diagram showing a detailed configuration of the dissimilar material determination device shown in FIG.
FIG. 3 is a diagram showing a setting example of a normal value range.
FIG. 4 is a diagram showing the magnitude of impedance of two kinds of test materials.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Conveyance line 2 Test material 3 Detection coil 4 Impedance measurement part 5 Judgment part 6 Controller 31 Primary coil 32 Secondary coil 41 Oscillator 42 Amplifier 43 Synchronous detector 44 Phase shifter 51 Switch circuit 52 Normal value range setting circuit 53 Judgment circuit

Claims (2)

A different material determination method that measures the impedance of a test material and determines a different material based on the measured impedance,
Prior to the determination of a different material of a test material lot having the same component and the same rolling chance, the impedance of at least one test material at the beginning of the lot is measured, and the magnitude of the average value centered on the average value of the measured impedance is measured. And determining a different material for another test material based on a comparison between the measured impedance and the normal value range. Having a primary side coil and a secondary side coil, a detection coil into which a test material is inserted,
An oscillator that supplies an exciting current to the primary coil so as to generate an eddy current in the test material;
Synchronous detection means for synchronously detecting the induced current induced in the secondary coil based on the exciting current and measuring the impedance of the test material,
Normal value range setting means for setting a normal value range proportional to the average value of the average value of the impedance measured by the synchronous detection means,
Determining means for determining a different material based on a comparison between the normal value range and the impedance measured by the synchronous detection means,
The normal value range setting means sets a normal value range based on the impedance measured by the synchronous detection means of at least one test material at the beginning of the test material lot having the same component and the same rolling chance, and sets another test material. Control means for controlling the judgment means to judge a different material based on a comparison between the impedance measured by the synchronous detection means and the normal value range of the test material, apparatus.

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