RU2003999C1 - Method of determination of inhomogeneity of plastic deformation in thin sheet - Google Patents

Abstract

The invention relates to non-destructive quality control of materials and is intended to control the stampability of a sample. Summary of the invention: the amplitude of the third harmonic of the output EMF of the overhead transducer is measured at seven points in a section 100 x 100 mm across the rolling, then the maximum and minimum values of the amplitude a third harmonic, the arithmetic average of the measured amplitudes of the third harmonic is found. The inhomogeneity of plastic deformation is determined from the expression (a - ")" / a} 100%. 1 ill. Zmaks Zmin Zsr

Description

The invention relates to measuring technique, in particular to non-destructive testing of the quality of materials, and can be used to control the stampability of a sheet.

An object of the invention is to increase sensitivity and reliability.

The drawing shows a block diagram of a device that implements this method.

The device consists of a generator 1, a power amplifier 2, a converter 3, a third harmonic selective amplifier 4, an indicator 5. The generator 1 is designed to supply an alternating sinusoidal current to the excitation coil of the converter 3. The output of the generator 1 is connected to the input of the amplifier 2, the output of which is connected to the excitation coil transducer 3. At the ends, the excitation coils are coaxially mounted with the measuring and compensation coils, included in the opposite direction. Selective amplifier 4 serves to isolate the third harmonic from the total signal, which is detected by indicator 5.

The method is carried out as follows.

From a batch of metal, a sheet or the first coil of a roll is taken. Closer to the center, an area of approximately 100x100 mm is marked. Mount converter 3 on

marked area. The required excitation current is set by the generator 1 through the excitation coil of the converter 3. The third harmonic of the output signal of the measuring coil is selected by selective amplifier 4, which is fixed by indicator 5. Then, the amplitude of the third harmonic is measured at other points of the section across the rolling direction. The maximum and minimum values of the amplitude a of the third harmonic are determined. The arithmetic average of the measurements of the amplitude of the third harmonic at all points is found. The magnitude of the plastic strain non-uniformity is determined from

expressions

d OZmax MIN1PPO / GJJcp

(56) USSR Copyright Certificate Me 1211646, cl. G01 N27 / 72. 1986.

Claims (1)

The claims A METHOD FOR DETERMINING PLASTIC DEFORMATION HETEROGENEITY IN A THIN SHEET, namely, that a sheet portion is magnetized by the alternating magnetic field of the overlay transducer and measuring the output signal of the measuring coil, characterized in that, in order to increase the sensitivity and reliability of the control, they are measured in n (ns 7 ) points on the 100 100 mm thin sheet section across the rolling amplitude of the third harmonic of the output emf of the converter, due to the component of magnetic induction normal to the sheet surface, reveal the maximum and minimum values of the amplitude of the third harmonic, find the arithmetic average of the measured amplitudes of the third harmonic, and plastic strain heterogeneity is determined from the expression x "Ztakh - 1PPO / rt-, lUU / b, SZsR where is the maximum amplitude of the third harmonic; “3min is the minimum value of the amplitude of the third harmonic; “Zsr is the arithmetic mean of the measurements of the amplitude of the third harmonic.