SU744395A1 - Attached ferromagnetic coercitimeter - Google Patents

Description

one

The invention relates to magnetic measurements and can be used to measure the coercive force of local areas of an article.

A known added coercimeter consisting of a ferrosonde and an attached electromagnet. This device allows to measure the coercive force on the local areas of the ferromagnetic product, as well as conduct layer-by-layer quality control of heat treatment. The measurement process includes pre-magnetization and gradual demagnetization. The demagnetization current is taken as a measure of the coercive force, and with which the useful signal in the measuring winding of the fluxgate is zero.

Another device is known that contains a flux probe on a U-shaped core used as an indicator element, magnetizing and demagnetizing windings located on the core of the fluxgate 2 uremychka. The U-shaped flux core of the fluxgate and the product form a closed magnetic circuit. The excitation windings are located on the cores of the fluxgate core, by means of which the rods are periodically adjusted to saturation with twice the frequency of the excitation source. On jumpers placed

2

the measuring winding is magnetizing, from which the useful signal is extracted using an indicator circuit. The disadvantage of the device is that

5, in the measuring winding of the fluxgate, there is an interfering signal that is not related to the presence of a measurable magnetic zero, in our case the coercive force of the product being tested. The interference signal increases the sensitivity threshold, reducing the accuracy of measuring small values of the coercive force and small magnitudes of the differences of the coercive force.

In order to improve measurement accuracy

15 in a coercimeter attached ferromagnet, containing a P-shaped core with magnetizing and demagnetizing windings located on its rods and an indicator element, an indicator element violiol in the form of a ferromagnetic storage counter with a variable accumulation factor located on the middle rod of the U-shaped core. On the fit. 1 shows an added ferromagnetic coherzmeter front view; in fig. 2 is a diagram of a ferro-magnetization accumulative counter with a magnetic conductor.

The added ferromagnetic coercimeter consists of a cumulative counter 1,

30 made of a toroidal core 2 with windings 3-6 respectively writing, resetting, base and reading, a rod 7, passing along the axis of the toroidal core 2, an U-shaped core 8 with windings 9 and 10 magnetizing and demagnetizing. The rod 7, which acts as a magnetic flux for the magnetic flux, the U-shaped core 8 and the product 11 form a closed magnetic circuit. The principle of measuring the coercive force of a test article with the help of this device is as follows. It is known that the accumulation factor of ferromagnetic storage counters changes when moving along the axis of the toroidal core of a constant trimming magnet. The same effect can be obtained not by moving a permanent magnet along the axis of the toroidal core, but by changing the magnetic flux encompassing the core 2 of the cumulative counter 1, passing a current through the windings 10 to demagnetize an attached electromagnet. When the product And is not magnetized and the demagnetization current is equal to the bullet, the ferromagnetic storage counter 1 has some initially set accumulation factor K. At that, a signal whose frequency is equal to f is read from the read winding 6 where / is the write signal frequency. The product 11 is magnetized by a short current pulse flowing through the magnetize windings 9. At this time, the power sources and recording signal from the cumulative counter are turned off. After magnetizing the residual induction of the product 11 creates a flow in a closed magnetic circuit of the coercimeter, the accumulation factor of the ferromagnetic counter takes the value K, which differs from / Ci by some value. At that, the signal frequency at the output of counter 1 becomes equal to f - f / S - „ / I A2 depending on the direction of the magnetic flux in the magnetic value of the coercimeter (which depends on the direction of magnetization of the product and does not affect the operating principle of the device) the number l, characterizing the change in the accumulation coefficient, has NAC + or -. Thus, the frequency of the signal from the output of the ferromagnetic storage counter 1 becomes either more Ki, Ki more times or less. Yes- "Ki-n than the original frequency / s. With an increase in the demagnetization current in the magnetic circuit of the coercimeter, a magnetic flux of the opposite direction is created. At the same time, the accumulation factor of the ferromagnetic storage counter 1 varies, approaching the value of KI. The frequency at the output of counter 1 also changes accordingly. The value of the demagnetizing current, at which the frequency of the output signal takes the initial value, is taken as a measure of the coercive force. Formula and 3 about the breach and the Attached ferromagnetic coercimeter, containing a U-shaped core with its magnetizing and demagnetizing windings located and its elements and indicator element, characterized in that, in order to increase the measurement accuracy, the indicator element made in the form of a ferromagitic accumulative counter with a variable accumulation factor located on the middle rod of the U-shaped core. Sources of information taken into account in the examination 1. Journal "Defectoscopy, 1972, X °. 6, s. 21. 2. USSR author's certificate number 407252, cl. G 01R 33/02, 07.07.71.

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Claims (1)

An attached ferromagnetic coercimeter with a U-shaped core with magnetizing and demagnetizing windings located on its rods and an indicator element, characterized in that, in order to increase measurement accuracy, the indicator element is made in the form of a ferromagnetic storage meter with a variable accumulation coefficient located on the middle rod U-shaped core.