JPH03183940A - Infrared flaw detecting device - Google Patents

Abstract

PURPOSE:To improve the reliability of flaw detection for a material to be inspected by using a multiple heating coil which is increased in the number of turns in its radius direction and generating large electric power in a narrow area on the surface of the material to be inspected by electromagnetic induction. CONSTITUTION:The coil 2 heats the material 1 to be inspected which passes in it with an induced current. The coil 2 is supplied with a high frequency current from a high frequency power unit 3. The coil 2 is increased in the number of turns in its radius direction on the same plane to have multiple constitution. An infrared-ray detector 4 detects the temperature of the heated material 1 to be inspected (i.e. infrared rays radiated by the heated part). A flaw detecting device 5 detects a flaw on the surface of the object material 1 from surface temperature information on the object material 1 obtained by the detector 4. The power unit 3 and detecting device 5 are controlled by a controller 6. The flaw information obtained by the detecting device 5 is displayed on a result display device 7. Thus, the temperature rise by inductive heating can be made large and the reliability of the flaw detection is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an infrared flaw detection device using the principle of induction heating.

[Conventional technology]

FIG. 5 shows an example of the shape of a coil of a conventional flaw detection device using induction heating. The conventional coil (2) is a heating coil made of one or several turns in the longitudinal direction of the test material, and the test material (1) passes through it. This carp/
The material to be inspected is heated by passing a high frequency current through L, and defects are detected by utilizing the difference in the amount of heat generated between the defective area and the normal area.

[Problem to be solved by the invention]

Generally, the electric power generated in a heated object by electromagnetic induction is proportional to the square of the number of turns of the coil per unit thickness and the current flowing through the coil/l, as shown by the following equation.

P = K −n ”・T 2−−−− (1
1 In the above equation, P is the electric power generated in the heated object, is a constant determined by the magnetic permeability and specific resistance of the heated object, and the frequency of the current flowing through the coil, n is the number of coil turns per unit length,
This is the current flowing through T (yo coin 1).

As shown in equation (1), once the object to be heated is determined, the power received by the object is determined by the number of turns of the coil and the current value, and -
A coin that is heavy and has a small number of rolls! (This required the frequency power supply to have a large capacity to allow a considerable amount of current to flow.)

Also, if you increase the number of turns while keeping the coil single-layered in order to increase the power input to the heated object with a small amount of current, the length of the coil will become longer and the heating time will become longer, which will increase the amount of heat diffusion during heating. . As a result, the temperature difference between the defective part and the normal part caused by the induced current becomes small, and this temperature difference causes a deterioration in the detection performance of infrared detection devices that detect defects.

Furthermore, if you try to accommodate one type of coil end size or steel type, there will be differences in the distance between the coil and the test material and the amount of temperature rise when the same power is applied. Even if there is a flaw, there will be a difference in the signal that is detected.

This invention was made to solve such problems, and aims to generate large electric power in a narrow area by increasing the number of turns of the coil (carp) L in the radial direction within the same plane. It is.

In addition, in another invention of this invention, the heating time and heating intensity settings are changed by changing the diameter of the same coil in the longitudinal direction. The purpose is to improve the flaw detection function.

Furthermore, another invention of the present invention Z aims to optimally heat the object according to the characteristics of the object by automatically exchanging coins L having various shapes.

[Means to solve the problem]

The infrared flaw detection device according to the present invention uses a heating coin 1 having an increased number of turns in the radial direction.

A large amount of electric power is generated in a narrow area on the surface of the material being tested by electromagnetic induction.

5J An infrared flaw detection device according to another aspect of the present invention uses a heating coil whose diameter changes in the direction of movement of the test material, and sets patterns of heating time and intensity.

[For production]

The infrared flaw detection device according to the present invention uses a heating coil with the number of turns increased in the radial direction as described above, so it can improve its flaw detection ability by generating a large amount of power in a narrow area on the surface of the material to be inspected by electromagnetic induction. can be improved.

In addition, the infrared flaw detection device according to another aspect of the present invention uses a heating coil whose diameter changes in the direction of movement of the material to be inspected, so it heats up a little in advance and then gradually heats it up, generating a power of 1.-TanoL. It is possible to make settings such as increasing the size of the image, thereby improving the flaw detection ability.

〔Example〕

An embodiment of this invention will be described below.

FIG. 1 shows a configuration diagram of an embodiment of the present invention. The configuration of the equipment is the same as the conventional one, as shown in FIG.

(1) is the material to be tested, (2) is a coil that heats the material to be tested (41) by an induced current, and the material to be tested [11] passes through this. A high-frequency power supply device that supplies high-frequency current, (4) an infrared detector that detects the humidity of the heated test material, and (5) an infrared detector that uses temperature information on the surface of the test material obtained by the infrared detector (4). A flaw detection device for detecting flaws, (6) a control device for controlling the high frequency power supply device (2) and the flaw detection device (5), and (7) for displaying flaw information detected by the flaw detection device (5). It is a result display.

FIG. 2 shows an example of a coil according to the present invention. Figure 2 (a
) is an external view of the coil, and (b) is a cross-sectional view of the coil and the material to be tested. As shown in FIG. 2, by increasing the number of turns of the coil outward within the same plane, the magnetic flux density to the test material increases, and a large current flows in a concentrated manner directly below the coil on the surface of the test material.

As a result, the temperature rise at the surface flaws increases.

Contrast between flaws and normal surface area By increasing the signal component of flaws in this way, the detection rate of minute flaws improves, and it is also possible to detect flaws even on materials with low magnetic permeability that are difficult to generate heat due to electromagnetic induction. It becomes easier to detect the signal.

J, Figure 3 shows an example of 1, 1, and 3 in other inventions of this invention. FIG. 3(il) shows the outline of line 1, and FIG. 3(b) shows a cross-sectional view of the carp/L and the steel material. 1 shown in Figure 3: I 771. 1 to gradually reduce the diameter of
Instead of heating it to a high degree, you can start by heating it a little and gradually increase the degree of heating.

If the degree of change in the diameter of the coil is small, it would be possible to heat the sea urchin slowly over a certain amount of time like the conventional single-layered sea urchin. By increasing the degree of change in the coil diameter, it is possible to generate a large amount of power in a narrow area, similar to the 1-il coil shown in Figure 2. This, j
: By using the coil according to this invention, it is possible to have a heating pattern intermediate between the conventional single-wound coil A and the coil N shown in FIG. 2, which has low thermal conductivity and is not affected by thermal diffusion. It is possible to heat a small amount of material to be tested sufficiently and obtain a large amount of confidence.

FIG. 4 shows an example of the configuration of an infrared flaw detection device according to still another aspect of the present invention. In Fig. 4, (1) to (7) are the same as the configuration example shown in Fig. 1, and (8) is carp/l.
This is a support part for automatic replacement.

In this configuration example, according to the command from the control unit (6), the automatic exchange support unit (8) selects and transports 1I: carp/l, which is set in advance by the automatic exchange support unit (8). Install it in the line. This allows the operator to:
Hi) It saves you the hassle of changing L. 1. Even if there are different characteristics or materials to be inspected of TLT-IJ size, it will not be possible to output signals for flaws. You can do the same thing.

F: It is possible to improve the reliability of flaw detection.

〔Effect of the invention〕

According to the above invention, it is possible to increase the temperature by induction heating, and improve the reliability of flaw detection.

” Two. 4. Other inventions of this invention. This makes it possible to realize a heating pattern that matches the material to be inspected, and improves the reliability of flaw detection.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an embodiment of a surface flaw detection device according to the present invention, FIG. 2 is an explanatory diagram showing an example of a line 1 according to the present invention, and FIG. 3 is an example of a coil according to another invention of the present invention. The explanatory diagram shown in FIG.
Fig. 5 is an explanatory diagram showing an example of conventional ml (, +1). In the figure, (1) is the test material, (2) is the heating coil, (
3) (High frequency power supply device, (4) is infrared detection type, (5)
)(ll flaw detection device, (6) is the control device 2, (7) is the result display section, and (8) is the support section for automatic replacement of :tI/L. Note that the same arrows in the two figures are the same. Or sell a considerable portion entirely.

Claims (2)

[Claims] (1) A radially wound multiple coil that applies a magnetic field to the material to be tested and heats it by electromagnetic induction, a high-frequency power supply that sends a high-frequency current through this coil, and an infrared detector that detects infrared rays from the material to be tested. and a flaw detection device that detects flaws from temperature information on the surface of the material to be inspected obtained by the infrared detector;
An infrared flaw detection device comprising: a control device that controls the flaw detection device and the high-frequency power supply; and a result display that displays flaw detection results obtained by the flaw detection device. (2) A multi-wound coil whose diameter gradually changes to heat the material by electromagnetic induction by applying a magnetic field to the material to be tested, a high-frequency power supply that flows a high-frequency current through this coil, and detects infrared rays from the material to be tested. an infrared detector for detecting defects, a flaw detection device for detecting flaws based on temperature information on the surface of a material to be inspected obtained by the infrared detector, a control device for controlling this flaw detection device and a high-frequency power supply device, and the above-mentioned flaw detection device. An infrared flaw detection device characterized by comprising a result display that displays flaw detection results obtained by.