JPH0255902A - Measuring method for depth of minute groove on steel sheet - Google Patents

Abstract

PURPOSE:To accurately measure the depth of a minute groove existing on a material to be measured by correcting the effect of a variation of the gap amount between a magnetosensitive element and the material to be measured or the effect of a size of the groove width. CONSTITUTION:When the material to be measured is magnetized by a magnetizer 2, a magnetism is made to leak from the discontinued part blocking the magnetic flux, e.g. from the part where the minute groove etc., are existent if any. This leaked magnetism is detected by the magnetosensitive element 3 and amplified by a signal processing circuit 6. In an arithmetically processing device 5 for the signal, a signal voltage on a reference gap amount is calculated from the signal voltage, gap amount, signal voltage characteristic value which is obtained from the relation of groove width/depth against the gap amount shown in a figure 3, and groove width value measured separately. Next, from the signal voltage V1 obtained by this process and the relation of the groove depth against the signal voltage characteristic value with a parameter of the groove width in a figure 2, the groove depth d1 is immediately obtained from the figure 2, as the signal voltage obtained by a process to calculate the groove depth is V1 and the groove width is W1. The accurate groove depth which the gap amount for the groove width is corrected, is expressed by the value obtained from these arithmetic process.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is based on the invention that the depth of micro-grooves existing on the surface of a thin steel sheet or the micro-grooves machined on the surface of the thin steel sheet determines the magnetic properties and workability of the thin steel sheet. Microgrooves in thin steel sheets to provide accurate groove depth information necessary to determine the control value or operation amount for machining grooves to maintain optimal magnetic properties and workability when affecting Concerning depth measurement method.

(Conventional technology) Stylus type roughness meters and distance meters using lasers are good techniques for measuring the depth of micro grooves (it is known that the accuracy of these techniques is guaranteed only if the object to be measured is in a stationary state). Limited to slow movement.

(Problems to be Solved by the Invention) When controlling the depth of microgrooves machined into a thin steel plate on a production line, it is necessary to constantly grasp the groove depth and feed it back to the processing reduction blade. Conventional stylus-type roughness meters and laser distance meters first have an error due to the vertical vibration of the steel plate (as the material to be measured passes) (as opposed to II quantification of 5 to 30 μ-, the amount of vertical vibration is ±100 μ-). (above)).Secondly, the detection end of the stylus roughness meter has a mechanical structure and does not have the ability to follow the threading speed.Thirdly, the laser distance meter does not have the ability to track the threading speed. There is no resolution of micro grooves, that is, the threading speed is 1
At 00 m/min, the time it takes for a 100 μ-wide microgroove to pass is 60 μsec, so a signal processing device with a processing speed of at least 30 μSee is required, but there is currently no device with such a function. Both technologies do not allow online depth measurement on the production line.

In addition, as a technique for detecting internal defects such as non-metallic inclusions and blowholes existing in the material to be measured, for example,
There is a device described in Publication No. 2-160282, and the device configuration is shown in Figure #S4. A gas injection type 70-ter 1 that faces the test material S and maintains a constant gap between the test material S and the test material S, which has a built-in magnetically sensitive probe group 9.
It is composed of 0 and ζ. This device mainly measures the presence or absence of a defect by determining that a defect exists when the signal voltage detected by the magnetically sensitive probe is above a certain level, and is useful for quantitatively measuring groove depth. is problematic.

(Means for Solving the Problems) The present invention incorporates a magnetically sensitive probe and a gap sensor integrated with a magnetizer facing a material to be measured, and a detection head having a fluid floating type tracking mechanism. The signal voltage obtained by amplifying and removing noise from the leakage magnetism detected by the magnetically sensitive cord, the gap amount between the magnetically sensitive cord and the material to be measured measured by the gap sensor, and the pre-ascertained groove width are used as parameters. The characteristic value of the groove depth vs. signal voltage, the characteristic value of the signal voltage obtained from the groove width/groove depth with respect to the gap amount grasped in advance, and the value of the groove width given separately from these four types of information. This is a method for measuring the depth of microgrooves in thin steel sheets, which calculates the depth of microgrooves existing in a material to be measured from the following.

(Operation, Example) The operation of the present invention will be explained below based on the illustrated example.

FIG. 1 is a block diagram showing an embodiment of the present invention. The RAD 1 is installed in a detection device equipped with a fluid floating type tracking mechanism on the upper surface side of the material to be measured. The detection head 1 includes a magnetizer 2 that magnetizes the material to be measured, a magnetically sensitive element 3 that is integrated with the magnetizer 2, and a gap sensor 4 that measures the gap between the magnetically sensitive probe 3 and the material to be measured. has been done. Signal calculation processing! ! Place 5
Now, let us consider the signal voltage obtained by the magnetically sensitive cord 3 and the signal processing circuit 6, the gap amount between the magnetically sensitive cord 3 and the material to be measured measured by the gap sensor 4, and the groove width stored in the data table 7. Characteristic values of groove depth versus signal voltage as parameters,
Quantitative calculation of the depth of micro grooves existing in the material to be measured using the Iho voltage characteristic value obtained from the groove width and groove depth with respect to the amount of groove, and the value of the groove width given separately from these 4Ml [information. It is something to do.

When the material to be measured is magnetized by the magnetizer 2, if there is a discontinuous portion such as a micro groove that obstructs the magnetic flux, magnetism leaks from that portion. This magnetic leakage is detected by the magnetically sensitive cable 3. The detected magnetic leakage is converted into an electrical signal, amplified by the signal processing circuit 6, and passed through a frequency filter for noise removal. It is determined whether the voltage is above a certain level, and if it is above a certain level, If so, the signal voltage is sent to the signal arithmetic processing device 5, and at the same time, the signal arithmetic processing device 5 outputs the signal voltage to the magnetically sensitive element 3 at the time when a signal of a certain level or higher is generated.
Read the gap amount between the material and the material to be measured.

The signal voltage input to the signal processing device 15 includes information such as the groove depth, groove width, and gap amount between the magnetically sensitive element 3 and the material to be measured. is impossible to quantify. For this reason, in the present invention, grooves are machined in advance in a sample made of the same material as the material to be measured, with various depths and groove widths, and a reference gap amount between the magnetically sensitive cord and the sample is determined, and detection is performed using the reference gap amount. A test is conducted, and from the test results, the characteristic value of the groove depth versus signal voltage with the groove width as a parameter is determined, and the information is stored in the data table 7.

In addition, with manufactured fins, there is vibration of the plate due to threading, so
The amount of gap between the magnetically sensitive element 3 and the material to be measured changes. In the present invention, a fluid floating type tracking mechanism is provided, and the magnetically sensitive element 3
The variation in the amount of gap between the magnetic element 3 and the material to be measured is minimized (although some tracing errors will occur. Therefore, in the present invention, the signal voltage obtained from the groove width and groove depth is applied to the magnetically sensitive element 3 and the material to be measured. The characteristic values of the signal voltage obtained from the groove width and groove depth with respect to the gap amount were obtained by performing tests with various gap amounts to see how it changes with changes in the gap amount, and this information is also shown in data table 7. Store it away.

FIG. 2 shows an example of the characteristic value of the groove depth versus signal voltage with the groove width as a parameter, and FIG. fjS3 shows an example of the characteristic value of the signal voltage obtained from the groove width/m depth with respect to the gap amount.

The signal processing device 5 calculates the signal voltage, the gap amount, and
The signal voltage at the reference gap amount is calculated from the characteristic value of the signal voltage obtained from the groove width and groove depth with respect to the gap amount shown in FIG. 3 and the separately measured value of the groove width. For example, on the graph of voltage characteristic values in Figure 3, if the signal detection voltage is vl, the ear dent amount is gl, and the groove width is 1, the signal voltage when the reference gap j1go is vl. The depth of the groove is calculated from the characteristic value of groove depth versus signal voltage using the signal voltage v1 obtained in step 1 and the groove width shown in FIG. 2 as a parameter.

Since the signal voltage obtained in the above processing is vl and the groove width is , the groove depth d can be immediately determined from the diagram tJ&2. The values obtained through these calculation processes represent accurate groove depths with the groove width and gap amount corrected.

(Effects of the Invention) As described above, according to the present invention, the depth of the microgroove existing in the material to be measured can be determined by the influence of the variation in the amount of gap between the magnetically sensitive element and the material to be measured and the size of the groove width. It is now possible to accurately measure the groove depth by correcting the influence, and when the depth of micro grooves machined in a thin steel sheet affects the magnetic properties or workability of the thin steel sheet, the groove depth can be adjusted with the manufacturing fin. It is possible to provide the precise groove depth necessary for control, which greatly contributes to improving product yield and quality assurance.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is a diagram showing characteristic values of groove depth versus signal voltage with groove width as a parameter, Figure 3 is groove width and groove depth versus gap amount. FIG. 4 is a diagram showing an example of a conventional detection device. DESCRIPTION OF SYMBOLS 1... Detection head, 2... Magnetizer, 3... Magnetically sensitive element 4... Gap sensor 5... Signal arithmetic processing device, 6... Signal processing circuit, 7... Data table , 8... DC electromagnet, 9-... Magnetism sensitive element group, 10.
...Gas injection type % type % dI situation

Claims (1)

[Claims] (1) A detection head with a fluid-levitation tracking mechanism is installed, which includes a magnetically sensitive element integrated with a magnetizer and a gap sensor facing the material to be measured, and detects leakage magnetism detected by the magnetically sensitive element. The signal voltage obtained by amplification and noise removal, the amount of gap between the magnetically sensitive element and the material to be measured measured by the gap sensor, and the characteristic value of groove depth versus signal voltage using the pre-ascertained groove width as a parameter, The depth of the minute groove existing in the material to be measured is determined from the characteristic value of the signal voltage obtained from the groove width and groove depth for the gap amount known in advance, and the groove width value given separately from these four types of information. A method for measuring the depth of micro grooves in thin steel sheets.