SU877417A1 - Method of ferromegnetic material megnetographic control - Google Patents

Description

(54) METHOD OF MAGNETOGRAPHIC CONTROL OF FERROMAGNETIC MATERIALS

one

This invention relates to magnetic flaw detection and can be used to control the quality of products made from ferromagnetic materials.

The closest to the present invention is a method of magnetographic control of ferromagnetic materials, namely, that a ferromagnetic tape is placed on the surface of the material being monitored, the material is magnetized by a constant magnetic field and the quality is judged by the obtained magnetogram 1.1.

The disadvantage of this method is the impossibility of using when monitoring the presence of a complete delamination of a metal, since a complete delamination does not create magnetic disturbances that can change the recording contrast with a magnetic tape.

The purpose of the invention is to provide control of the bundles of ferromagnetic materials.

The goal is achieved by creating a scattering field on the opposite side of the monitored material, and the signal read from the tape is compared to the signal taken from the reference sample in the same way.

Figure 1 shows the product magnetized by a known method of control in the presence of delaminations; figure 2 is the same, the proposed method in figure 3 is the same, when controlling the reference sample of the proposed method.

With the known control method (Fig. 1), the magneto-strong lines 1 are closed between the poles 2 of the magnet and not

10 emerge onto the surface of the controlled article 3 in the form of scattered fields. With the proposed control method (Fig. 2), the scattering field 4. is caused by an artificial defect made in the additional plate 5. Moreover, in the absence of delaminations, this field is scattered 6 (Fig. 3) more than in the presence of delamination. Comparing the magnetograms obtained in about 20 of their cases, by the reduction of the signal, the presence and magnitude of the bundles are judged.

EXAMPLE A “first method” controls samples of steel 09G2S 5 mm thick for the presence of delaminations.

25 Samples are taken from 2, 3, 4, 5 plates of various thickness, containing one, two, three or four plane of the connector, imitating a complete separation. On the back of the sample, lay the auxiliary plate.

6 mm thick from the same material, containing an artificial groove defect 80% of the plate thickness. With four connector planes of 0.15 mm each, the signal due to the defect decreases by about. 50%, in the presence of a single plane of the connector, by 10-15%, depending on its location, as compared with the reference sample without stratification.

In a known way, the presence of bundles is not detected.

The application of the proposed method allows the control of ferromagnetic materials for the presence of delamination.

invention formula

The method of magnetographic control of ferromagnetic materials, which consists in the fact that a ferromagnetic tape is placed on the surface of the monitored material, the material is magnetized by a constant magnetic field and the quality is judged by the resulting magnetogram obtained by on the opposite side of the monitored material, the stray field is created, and the signal read from the tape is compared to the signal taken from the reference sample in the same way.

Sources of information taken into account in the examination

1. USSR author's certificate No. 102537, cl. G01 N 27/82, 1952.

Claims (1)

Claim The method of magnetographic control of ferromagnetic materials, which consists in laying * a ferromagnetic tape on the surface of the material being monitored, magnetizing the material with a constant, magnetic field and judging the quality by the magnetogram obtained, characterized in that, in order to control delamination, the opposite is true: the sides of the controlled material create a scattering field, and the signal read from the tape is compared with * ^{and the} signal taken from the reference sample in the same way.