JPS6011492Y2 - Automatic magnetic flaw detection equipment inspection equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a simulated defect signal generation device for adjustment, maintenance, inspection, etc. of automatic magnetic flaw detection equipment.

Automatic magnetic flaw detection equipment magnetizes the material to be inspected, uses a magnetic sensor to detect and measure the leakage magnetic flux coming out of the defective part of the material to be inspected, and quantitatively determines the size and depth of the defect, etc., or manufactures this determination result. This is used to improve and stabilize product quality by providing feedback with the equipment number.

In order to maintain the reliability of quantitative determination of defects, which is the basic operation of such automatic magnetic flaw detection equipment, inspection, maintenance, and adjustment are required from time to time.

Conventionally, the above-mentioned inspection and adjustment of automatic magnetic flaw detection equipment has been carried out as follows.

That is, an oscillator is connected to the output terminal of the magnetic sensor, and the output signal of the oscillator is applied to a signal processing circuit such as an amplifier after the magnetic sensor in place of the defect signal from the magnetic sensor, and the output of the oscillator is compared to the output signal of the defect. Adjustments were made to the discrimination circuit, display circuit, etc.

In this case, the magnetic sensor section is omitted from the inspection and adjustment operations, and the sensitivity is set by performing flaw detection using a standard sample for maintenance, inspection, and adjustment of the magnetic sensor section itself.

The standard sample is a normal material to be inspected with a certain amount of artificial flaws, and it is applied to the flaw detection equipment to adjust the sensitivity of the magnetic sensor section in the same way as when inspecting actual materials, so inspection of the magnetic sensor section is easy. It is difficult to perform this at any time, and the standard sample is treated in the same way as the material to be inspected during normal material inspection.
Repeated use causes wear and deformation of the artificial scratches, making it impossible to maintain the standard scratch state for a long period of time.

In other words, the sensitivity setting of the magnetic sensor section may gradually shift during repeated inspections.

Therefore, by not using a standard sample, the present invention does not separate the magnetic sensor and subsequent signal processing circuit, making it extremely easy to comprehensively inspect the flaw detection equipment in the state in which they are connected (during flaw detection operation). I am trying to make it possible.

The present invention provides a device that inspects a magnetic flaw detection device by preparing a magnetic head that simulates flaws on a material to be inspected and by placing this magnetic head in opposition to the magnetic sensor section of the magnetic flaw detection device. .

First, a general explanation will be given of the magnetic flaw detection device that is the subject of this invention.

Figure 1 shows the main parts of the magnetic flaw detection device.

Reference numeral 1 denotes a magnetic sensor, such as a Hall element or a magnet diode, which is incorporated into the holder 2 .

3 is a signal processing device following the magnetic sensor 1.

4 is a material to be inspected, and a round bar is shown.

The material to be inspected 4 is rotated in the direction of the arrow and transferred in a direction perpendicular to the plane of the drawing, and in this way the magnetic sensor 1
scans the surface of the material 4 to be inspected in a spiral manner.

Reference numeral 5 denotes an iron core of a magnetization device through which a material to be inspected passes between its magnetic poles.An excitation coil 6 is wound around this iron core, and the excitation coil 6 is connected to an excitation power source 7.

When magnetic flux is flowing through the magnetic circuit consisting of the iron core 5 and the material to be inspected 4 as shown by the arrow φ, if there is a flaw in the material to be inspected 4 as shown by 8, the leakage magnetic flux will flow through the magnetic sensor 1 as shown in the figure.
pass through.

When the inspected material 4 rotates under the assumption that DC excitation is being performed, a flaw detection signal having a waveform as shown by S in FIG. 1 is obtained from the two differentially connected magnetic sensors 1.

When the excitation is AC excitation, the flaw detection signal has a waveform as shown in FIG. 1 S'.

This concludes the explanation of the magnetic flaw detection device, and the present invention will be explained below with reference to Examples.

FIG. 2 shows an embodiment of the inspection magnetic head used in the present invention.

The main part of the magnetic head is a magnetic core 10 having a magnetic gap 9.
A coil 11 is wound around the coil 11, and the coil 11 is connected to a simulated defect detection generator 12.

The width W of the magnetic gap 9 is determined according to the width of flaws that may exist in the material to be inspected.

The magnetic flux passing through the magnetic core 10 leaks outward at the gap 9 like a fixed line.

Therefore, this gap 9 is placed opposite to the intermediate position between the two magnetic sensors 1 of the magnetic flaw detection device, and if the iron core 5 of the magnetic flaw detection device is DC-excited, a current having a waveform as shown in FIG. 3B is passed through the coil 11. If the iron core 5 is AC-excited, when an AC current amplitude-modulated with a waveform as shown in FIG. 3A is passed through the coil 11, an output signal with the same waveform as S or S' in FIG. 1 is output from the magnetic sensor 1, and the signal processing device 3 is applied.

The magnitude of the excitation current of the coil 11 is determined by the simulated defect signal generator 1.
By adjusting the amplitude of the output current in step 2, the amplitude can be arbitrarily changed, and thereby the depth of the simulated defect can be set variously, and by changing the signal length l, the width of the simulated defect can be changed. be able to.

FIG. 4 shows the magnetic head shown in FIG. 2 housed in the holder 13. As shown in FIG.

The magnetic holder 13 has a recess 14 on its upper surface, into which the magnetic sensor holder 2 of the magnetic flaw detector is inserted and fitted.

To inspect the magnetic flaw detection apparatus, remove the material to be inspected as shown in FIG. 1, fit the holder 13 of the inspection magnetic head into the holder 2, and apply a current having the waveform shown in FIG. 3A or B to the coil 11.

Figure 5 shows another embodiment of the magnetic head for inspection, in which semicircular permanent magnets ml and m2 are placed facing each other with a gap W, and are attached to the output shaft of a rotating device so that they can rotate as shown by the arrow. It serves as both a magnetic head and a simulated defect signal generator.

The magnetic flux leaks to the outside in the gap W between the magnetic poles (it also leaks inward, but the simulated defect detection signal is output to the outside),
This corresponds to the magnetic flux leaking from scratches on the inspected material.

By placing this object at the position of the inspected material in FIG. 1 and rotating it at the same speed as the inspected material, the magnetic sensor 1 can output a simulated defect detection signal.

This case corresponds to the case of DC excitation, and cannot be applied to the case of AC excitation when using this magnetic head.

The present invention has the above-mentioned configuration, and since it only uses a magnetic head that is extremely small compared to the material to be inspected, the inspection operation is much simpler than using a standard sample of the same size as the material to be inspected. When viewed from the magnetic sensor of the magnetic flaw detection device, the magnetic head is exactly the same as a flaw in the material being inspected, so comprehensive inspection of the entire magnetic flaw detection device can be done at once, and it can be inspected just like a standard sample. Since there is no possibility of deformation due to wear, there is no fear that the adjustment will gradually deviate, and there is no problem even if the dimensions or steel type of the material to be inspected are changed.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram of a magnetic flaw detection device, Fig. 2 is a front view of a magnetic head of an embodiment of the device of the present invention, Fig. 3 is a diagram showing the waveform of the excitation current flowing through the coil of the magnetic head, and Fig. 4 The figure is a longitudinal sectional front view of a holder incorporating the magnetic rad, and FIG. 5 is a front view of another embodiment of the device of the present invention. DESCRIPTION OF SYMBOLS 1... Magnetic sensor, 3... Signal processing device, 4... Material to be inspected, 5...... Strut excitation core to be inspected, 10... ... Magnetic head magnetic core, 11 ... Coil, 12 ... Signal generator for generating simulated signals.

Claims (3)

[Scope of utility model registration request] (1) It consists of a magnetic head having a gap through which magnetic flux leaks, and a simulated defect signal generating means that produces the same effect as when a defect in the inspected material is detected by a magnetic sensor of a magnetic flaw detection device via this magnetic head, An automatic magnetic flaw detector inspection device, wherein the magnetic head is opposed to the magnetic sensor. (2) Automatic magnetic flaw detection according to claim 1, wherein the means for generating the simulated defect signal is a device that causes a current having the same waveform as the defect detection signal to flow through a coil wound around a magnetic core constituting a magnetic head. Equipment inspection equipment. (3) A utility model registration request in which the magnetic head has a structure in which a plurality of permanent magnets in the shape of a divided circumference are arranged circumferentially with gaps, and the means for generating the simulated defect signal is means for rotating the magnetic head. Automatic magnetic flaw detection device inspection device according to scope 1.