SU769647A1 - Method of process inspection of sintered ferrite blanks for magnetic properties - Google Patents

Description

nom () and parallel (i,) direction of the magnetic texture, then the reference magnets grind, magnetize and measure the specific residual magnetized Sn

ness () and coercive force but

magnetization (Hcj), then establish the relationship between the residual specific

AT

L

magnetization

and attitude

as well as the relationship between the coercive force on licj magnetization and the ratio

for reference magnets, after which

Xj. measure the susceptibility of the workpieces along and across the texture, establish the relationship and evaluate and Hcj for these XY ± ry lengths. Since the effective initial magnetic susceptibility depends not only on the properties of the material, but also on the geometry of the product, in order to find the common characteristics of BR and licj, it is necessary to know the demagnetization and the factors along both directions of measurement. Assessment of such factors is very difficult, especially for magnets of complex geometric shape, nanomery segmented magnets. Therefore, it is better to find the residual magnetization of the Hz and the coercive force but the HCJ magnetization not by calculation, but by the infirmity of the calibration curves constructed for a specific magnet size and a particular device, by means of which the effective magnetic magnetic susceptibility is measured. FIG. 1 shows a graph of the relationship between the magnitude of the residual magnetization of the coercive layer by magnetized HCJ and the ratio characterizing FOR magnets, the texture of magnet sizes K 65X45x17.5 in size from bar ferrite grade 9BA205 (texture is radial); FIG. 2 is a graph of the relationship between the effective susceptibility of the magnets and the discharge temperature {the magnets are the same as in FIG. one). The procedure for the implementation of the method is as follows: - a series of reference magnets of a specific size with different levels of magnetic properties (due to the different dark sintering temperature) is produced; -conducting measurements of effective initial magnetic susceptibility along texture etching and across non-magnetised products; - samples of reference magnets are cut out, polished and magnetised, convenient for measuring the usual characteristics of permanent magnets;

conventional methods are used to measure traditional parameters: the residual magnetization BR, the coercive force from the magnetization Hcjj of density p;

to

- and HCJstro ts graphics

7.1.

on their subsequent batches of magnet blanks, only the effective susceptibility is measured in two directions to determine the ratio / -II xj by the found values of the controlled magnet blanks, judging the quality of their material, i.e. full lisch at the stage of selection standards. In process control, it is not necessary to determine the traditional characteristics of BR and HCJ, but it is therefore sufficient to establish the norms directly on the control measured in this case becomes very operational and useful for organizing automatic sorting of magnets without their mechanical processing and magnetization, as well as for continuous monitoring the operation of the furnace roasting magnets. Example 1. The K65X45X17.5 size magnet billets with a radial texture of 9BA 205 barite ferrite are monitored with an induction sensor containing two inductors, one for measuring susceptibility along the magnet axis and the other along the diameter. The calibration curves for these magnets and the control device are shown in FIG. 1, the temperature dependence of the monitored parameter is shown in FIG. 2, norms for traditional magnetic parameters Gs, E, norms for the proposed parameters 3,, 7; 280 services. units The proposed control method makes it possible to detect petextured magnet blanks, magnet blanks with parameters that do not meet the standards, and to evaluate the basic characteristics of the magnets of BR and HCJ with an accuracy not worse than traditional methods; Example 2. The control of blanks of ring magnets of frame size K61X24X12 with an axial texture of bar ferrite grade 25BA170 was carried out in an inductive sensor with one inductance coil,

Preliminary standards were established that correspond to the validity of K61X magnets.

H24X12, marks 25BA170: 2.15 - 2.70.

Y

If, 15, then there is a marriage

f.L

(HV) max which is

which

case; 25, kJ / m if more than 2.70, then

There is a Hcg defect, which in this case becomes less than 1G5 kA / m.

in tab. I shows measurement data for a series of magnet blanks that were controlled by the proposed method and by a known method. It can be seen that the truly rejected pieces of magnets have parameters below the norm,

and those found fit - really correspond to the nopam.

Table 1

Example 3. Sintered blanks of segmented magnets for an electric motor with a radial texture of frame size Ж-1 made from bar ferrite brand 24BA210 were monitored. Were previously installed f-n

our standards by an amount that should be greater than 1.55 (otherwise there will be a marriage

BR AND (HV) max. BUT no more than 1.75, and the rest will be a marriage, but also Yasv) and a bit temperate / dependency.

In tab. 2 shows the control data of such magnets known and proposed method. From this data, it is possible to control non-texturized samples, samples with defects by some parameter,

7

as well as to identify suitable samples with an efficiency not less than using the inferior methods, to gain in measuring the magnitudes of Zh-1 from 24B210 bar ferrite by the proposed method.

Norms for the known method BI 0.37G, H (, „205 kA m. Norms for the proposed method 1.55 s - 1.75,

The proposed control allows you to make 100% control of the magnets without large losses, so that you can examine the magnets and screen the magnet into groups but the main parameters without magnetizing, which you do not need to spend a lot of time to control them with normal methods.

For process control, there is no need to make special witness samples with the convenience of well-known form measurement methods, it does not need to cut out products with a complex texture or geometry, and does not require polishing of the samples before measurements. When measuring si | |, magnetization occurs, as a result of which subsequent demagnetization is no longer necessary, and most importantly, it becomes possible

and operational efficiency

Duration of control

table 2

It is possible to organize a contactless automatic control of the flow, i.e., create a process for firing magnets with feedback between the properties of the magnets and the operating mode of the flow, since the measured values are related to the firing temperature.

Claims (2)

1. USSR author's certificate Luo 465606, cl. G 01 g 33/16, 1968. 2. Authors certificate of the USSR 465606, cl. G 01g 33/12, 1973. five/ 400 . a / sl.ed.) (° C) 1200