SU838622A1 - Method of measuring ferromagnetic material parameters - Google Patents

Description

one

The invention relates to non-destructive magnetic quality control of steel and cast iron products and can be used for non-destructive quality control of medium and high tempering of medium and high carbon steels.

There is a method of non-destructive quality control of products by relaxation coercivity, which consists in preliminary magnetization and subsequent demagnetization on the limiting hysteresis loop using an electromagnet and recording the magnitude of the demagnetizing current corresponding to the return field (relaxation coercive force) 1.

However, the measurement of the absolute magnitude of the relaxation coercive force on products under production conditions is difficult due to the difficulty of fixing the magnetic field, the disabling of which will cause the product to be statically demagnetized.

The aim of the invention is to expand the range of measurable products.

The goal is achieved by the fact that in the method consisting in preliminary magnetization and subsequent magnetization reversal

Attachable electromagnet with ferro sensor, the reversal current is increased to achieve the specified output currents in the measuring circuit of the ferro sensor, after which the reversal magnetization current is turned off.

FIG. 1 shows a device that implements the proposed method; in fig. 2 - the back of the hysteresis loop of the test product.

FIG. 2 F, IS AB denotes the curves for the A C, F, (working curve) and VO (curve corresponding to the repaction coercive force, where t is the average length of the test section of the product; Uj is the fall of the magnetic potential at Hj ,.

After the cycle of magnetization reversal, the magnetic state of the product is determined by the point Fu, (the arrow indicates the change in the magnetic state of the product when the current in the electromagnet coils is changed according to the proposed method).

The current in the indicator winding of the sensor Ij is equal to

t AV (1) ..

Claims (1)

 (+ n a + i4) where A is constant, depending on the excitation parameters of the ferro sensor; W is the number of turns of the indicator hanks; g - electrical resistance indicator tsegsh; k f |, are the constants determined by the magnetic resistances of the edel and the sensor magnetic circuit. Since in the region of the relaxation-coercive force, the return curves and divides are almost parallel, the triangles Ф, and О and BOUfj (Fig; 2) can be considered similar. Where Phg K-i Uj KU., Tf1 and where K is a coefficient. Bearing in mind that H,.}, We obtain Wll z IiKJL r-tg Ia d (II - 1-,) a +. Thus, the output current of the device is proportional to the relaxation coercive force, which is monotonously related to the tempering temperature - and high carbon steels A device that implements the proposed method (Fig. 1) contains a source of magnetization current 1 (it is also a source of magnetization reversal current), a source of excitation current of a ferro sensor, a test sample 3, magnetizing (they peremagnetizing) electromagnet 4 electromagnet, ferro-core electrode 4 (ferro sensor) 5, phase sensations Tel'nykh detectors used Microammeters and 7 and 8 and 9. The measurements are made out in the following gfocledovatelnocti. After installing the test sample 3 on the pole of the electromagnet in the windings 4 from source 1, turn on the magnetizing current. After turning off the magnetizing current E. The source of the excitation current of the ferro sensor is turned off and from the source 1 to the windings 4 reverse current is applied; the microammeter 9 arrow will not pass through zero and will not reach the set value. After that, the current is reduced to zero. Further, the windings 4 are switched to a microammeter 9 through a phase-to-susceptible detector 6. The readings of the microammeter 9 are considered to be indications of the device. The proposed method allows for 100% non-destructive testing of products from medium to high carbon steels after tempering, to improve the quality and reliability of the structures, machines and mechanisms in which these products are used. The invention The method of measuring the magnetic parameters of ferromagnetic materials, which consists in pre-magnetization and subsequent reversal of magnetization using an attached electromagnet with a ferro sensor, p. If, in order to expand the range of the measured items, the remagnetization current is increased to achieve the specified identical output currents in the measuring circuit of the ferrometer, after which the remagnetizing current is turned off. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 429329, cl. G 01 N 27/80, 1974. five  " ) t ...- S five ig.2