JPS5826163B2 - Zanriyujikishiyoukiyosouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in devices for eliminating residual magnetism in steel materials.

Steel materials such as steel pipes, steel bars, and steel plates may become magnetized and have residual magnetism due to magnetic flaw detection or lifting with lifting magnets during the manufacturing process.

When such steel materials are electrostatically painted or welded, residual magnetism may cause uneven coating, strong magnetic fields may occur, making welding impossible, and adhering iron powder may cause scratches on the surface of the steel material, significantly reducing its commercial value. Sometimes I let them do it.

In order to eliminate residual magnetism that causes problems, steel pipes,
For steel bars, etc., a demagnetizing coil is installed at the end of the process, and an alternating current is passed through the coil.

However, these conventional residual magnetism erasing devices (hereinafter referred to as degaussing devices) require electrical wiring, power transformers, etc., and constantly consume power, making them uneconomical.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a demagnetizing device that eliminates the residual magnetism on the surface of a steel material easily and economically by improving the above-mentioned drawbacks.

The device of the present invention is characterized in that it is configured to generate an alternating attenuation magnetic field with a permanent magnet, and can produce the same demagnetizing effect as the conventional one using an alternating current.Moreover, it does not require a power source, and is simple and economical. It has excellent advantages such as being very accurate.

An example in which the present invention is applied to a demagnetizing device for steel pipes, steel bars, etc. will be described below.

Figure 1 is a longitudinal sectional front view showing the mechanism of this degaussing device, 1a
, 1b, 1c... are ring-shaped permanent magnets that are magnetized in the axial direction and have magnetic poles on both sides, 2a, 2b,
2b', 2c, 20'... are flat ring-shaped magnetic pole pieces made of a soft magnetic material that are in contact with the magnetic pole surface of the ring-shaped permanent magnet and whose inner diameter is smaller than the inner diameter of the ring-shaped permanent magnet; The magnetic pole pieces 2a and 2b form one magnetic circuit A, and a positive (+)ta field A is generated on the central axis XX.

Next, the permanent magnet 1b and the magnetic pole pieces 2b' and 2c constitute one magnetic circuit B, and are connected so that the polarity of the adjacent magnetic circuit A is equal to each other, and the negative ( =
A magnetic field B is generated.

The next magnetic circuit C generates a positive (ten-ugly field C), and is similarly connected in a row so that adjacent polarities are alternately made equal.

Then, the magnetic field strength acting on the central axis XX is A-B-C
The device is configured to gradually attenuate as N.

The configuration will be explained in detail later.

FIG. 2 shows an example of the magnetic field distribution on the central axis XX of the degaussing device of the present invention.
When a steel pipe with, for example, residual magnetism γ is passed through in the -+N direction, the same effect occurs as in the case of demagnetizing the steel pipe by placing it in an alternating magnetic field and reducing the current strength, or by gradually moving the steel pipe away from the magnetic field. As shown in , from γ to a − b
It is reliably demagnetized through the history of c - d - e - f - g - h.

In the present invention, the magnetic pole piece made of soft magnetic material as shown in the above embodiment is not necessarily necessary, and the same effect can be obtained by simply placing tubular permanent magnets adjacent to each other with the same magnetic pole faces facing each other. Therefore, in consideration of the assembly of this device, etc., it is also effective to interpose a spacer made of a non-magnetic material between the tubular permanent magnets.

Furthermore, the tubular permanent magnet used in the present invention is not necessarily limited to a ring shape, but may be any magnet having an inner peripheral surface that does not obstruct the passage of the object to be processed, such as a steel pipe or steel bar. Accordingly, it is preferable to appropriately select a single tubular permanent magnet or a tubular permanent magnet formed of a plurality of permanent magnets.

When a tubular shape is constructed from a plurality of permanent magnets, it is recommended to use magnetic pole pieces as shown in the above embodiment.

As a means for configuring the magnetic field strength to gradually attenuate in the X-axis direction as shown in FIG. 2 in the tubular space formed by the inner peripheral surfaces of a plurality of tubular permanent magnets, the tubular permanent magnets used include: This can be easily achieved by considering magnetic properties, magnetization strength, thickness, etc., and by appropriately using magnetic pole pieces.

Furthermore, the period of attenuation, etc. can be easily adjusted by adjusting the distance between the tubular permanent magnets.

Figure 4 is 19f x 16. Figure 1 shows the results of a demagnetization test conducted on a steel pipe of f x 10001 (1.5 tons) using the erasing device of the present invention shown in Fig. 1 and the conventional AC coil type demagnetizing device. , 2 is the residual magnetism distribution curve on the surface of the steel pipe after demagnetization with the conventional AC coil device, and 3 after demagnetization with the device of the present invention.

As shown by curve 1 in the figure, residual magnetism generally remains strongly at the ends of the steel material.

As shown in curves 2 and 3, the demagnetizing effect is comparable to that of the AC coil type, and the demagnetizing device of the present invention has the function of eliminating the residual magnetism of steel materials to a level that does not cause a problem, that is, 10 G or less. It is clear that it has.

Furthermore, since the residual magnetism erasing device of the present invention uses a permanent magnet as described above, it consumes no power, does not require wiring, can be easily installed in any location, is easy to operate, and is inexpensive. It has excellent advantages such as not having

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view showing the mechanism of the present invention, FIG. 2 is a curve diagram showing the magnetic field distribution on the central axis of the device of the present invention, and FIG. 3 is a diagram showing the magnetic field distribution of FIG. 2. The history of demagnetizing the residual magnetism γ by passing the steel material in the direction of the arrow on the central axis is shown, and Figure 4 shows the results of demagnetization tests conducted using the conventional AC coil type demagnetizer and the demagnetizer of the present invention. This is a residual magnetism distribution curve on the surface of steel. 1a, 1b, 1c"..."1n: Permanent magnet, 2a. 2b, 2b', 2c, 20'...2n: Magnetic pole piece, X-X: Central axis, A, B, C...N: Magnetic circuit, P: Pipe (steel material), Fig. 4, 1: Residual magnetic distribution curve on pipe surface while in magnetized state, 2: After demagnetization using the same AC coil type demagnetizer as above, 3: After demagnetizing using same as the above inventive eraser.

Claims (1)

[Claims] 1 A plurality of tubular permanent magnets magnetized in the axial direction are placed adjacent to each other with the same magnetic pole faces facing each other, and are placed in a tubular space formed by the inner peripheral surfaces of the plurality of tubular permanent magnets, and are placed in the axial direction. A residual magnetism erasing device configured so that the magnetic field strength is gradually attenuated.