SU1702285A1 - Apparatus for nondestructive control of heat treatment quality - Google Patents

Abstract

The invention relates to non-destructive testing of ferromagnetic materials and products, and is intended to control the quality of heat treatment. The goal is to improve the accuracy by eliminating the influence of the instability of the amplitude of the extremum of the differentiated measuring signal on the measurement result of the control parameter. The synchronizer 9 generates a control pulse, which starts the oscillating field generator 1 and zeroes the amplitude detector 5. The generator 1 generates a current arriving at the magnetizing winding of the electromagnetic converter 2, in the measuring winding of which a signal arrives at the input of the differentiator 3. The output signal of the latter through control key 4 is fed to the input of the detector 5. The output signal of field meter 6, proportional to the current value of the reversing field of the converter 2, is fed at the first input of the comparator 7, at the second input of which a constant voltage of a given level Ho is set (the value But for each type of controlled products is chosen empirically so that the control parameter has the maximum sensitivity). At the moment of equality of the input voltages of the comparator 7, its output signal closes the key 4, the output signal of the detector 5 does not increase and enters the indicator 8. 2 Il.

Description

The invention relates to non-destructive testing of ferromagnetic materials and products, is intended to control the quality of heat treatment, such as their hardness, after tempering, and can be used in engineering, metallurgical and other enterprises.

The purpose of the invention is to improve the accuracy by eliminating the influence of the amplitude instability of the extremum of the differentiated measuring signal on the measurement result of the control parameter.

FIG. 1 shows a block diagram of the device; in fig. 2A - 2G - timing charts of the signals of the device.

The device contains a series of a magnetizing current generator 1, an electromagnetic converter 2, a differentiator 3, a control key 4 and an amplitude detector 5 connected between the second output of the electromagnetic converter 2 and the second input of the key 4 serially connected polymer 6 and a comparator 7, an indicator 8 and a synchronizer 9, the first output of which is connected to the control inputs of the generator 1 and the amplitude detector 5, and the second to the control input of the indicator 8.

The device works as follows.

The synchronizer 9 generates a control pulse Ucx.i (F-g. 2e); which starts the generator 1 and zeroed the amplitude detector 5. The generator begins to produce a triangular-shaped current (Fig. 26) entering the magnetizing winding of the converter 2, in the measuring winding of which the signal Da appears (Fig. 2c), entering the differential 3 The output signal 11z (Fig. 2d) of the differentiator 3 through the key 4 is fed to the input of the amplitude detector 5. The output signal of polymer 6, proportional to the remagnetization field of the converter 2 (Fig. 26), is fed to the first input of the comparator 7, at the second input the cat cerned established DC voltage predetermined level H0 and the time T equal vhodnyhd voltage comparator 7 it is their changed state. The output signal U (Fig. 2d) of the comparator 7 is fed to the second input of the key 4, which closes its input at the time T | and the output signal Us (Fig. 2e) of the amplitude detector b does not increase. The output signal Us of the amplitude detector 5 is fed to the indicator 8, which at the moment Ta of the output of the output signal UCx2 (Fig. 2g) at its control input registers the value of the rate of change of the magnetic permeability (E) of the signal Us, which is a parameter of the control.

Example. This device was tested when determining the hardness of parts made of ZOHGSA steel, hardened from 860 ° C and released at temperatures of 550–580 ° C (serial mode), as well as at temperatures of 400–550 and 580–650 ° C (with violation of the serial mode). The hardness of the tested parts was 21-40 units. HRC, valid were considered parts processed by serial mode, having a hardness of 27-29 units. HRC. Using this device, the magnitude of the rate of change of magnetic permeability (E) was measured, while the field Ho was chosen such that the sensitivity of the value E to the change in hardness of the parts to be monitored during tempering was maximum.

Claims (1)

Claims An apparatus for non-destructive quality control of heat treatment, comprising a series-connected magnetising current generator, an electromagnetic transducer and a differentiator; an amplitude detector and an indicator connected to it, characterized in that, in order to increase accuracy, it is equipped with a series-connected polymer, a comparator, the second input of which is a reference, and a controllable key, the second input of which is connected to the output of the differentiator, and the output - with the input of the amplitude detector, and the synchronizer, the first output of which is connected to the generator input of the remagnetizing field and the second input of the amplitude detector, and the second output with the second input of the indicator, the second output of the electromagnetic the converter is connected to the polymer inlet.