SU896534A1 - Device for inspection of surface layers of ferromagnetic objects - Google Patents

Description

(54) DEVICE FOR MONITORING SURFACE LAYERS OF FERROMAGNETIC OBJECTS

one

The invention relates to non-destructive testing and can be used to control the depth and percentage of chill (cementite) in ferromagnetic objects.

A device for quality control of ferromagnetic objects by the method of higher harmonics is known, comprising a generator, two eddy current transducers, a first and third harmonic filter, a phase meter, an adder and an indicator 1.

However, the known device is characterized by insufficient reliability of the control, which is associated with the ambiguity of the control results with variations in the content of cementite in the monitored object.

The closest to the invention in its technical essence is a device for monitoring surface layers of ferromagnetic objects, comprising a blocking generator, a transformer eddy current transducer connected in series, a blocking oscillator connected in feedback, a selective amplifier and an amplitude detector, and an indicator C27.

However, this device does not provide the necessary reliability of control, which is associated with an ambiguous relationship between the results of the control and the content of chill in the controlled object.

The aim of the invention is to increase the reliability of the control.

The goal is achieved by the fact that the device is equipped with a program block, connected in series by a switch, connected by a first input to an output of an amplitude detector and a second input to a first output of a program block, a memory block and a crucial block connected

10 with their second and third inputs to the second outputs of the switch and program block, respectively, and their output - to the indicator, connected to the input of the program block and the heating element connected by the second input with a heating control unit; the third output of the program block.

The drawing shows a structural diagram 20 of the device for controlling the surface of layers of ferromagnetic objects.

The device consists of a transformer eddy current transducer 1, included in the feedback of a blocking generator 2 and connected in series with a selective amplifier 3, an amplitude detector 4, a switch 5, a memory block b, a decisive block 7 and an indicator 8 connected in series with a temperature measuring transducer 9 heating control unit 10 and heating element 11, program block 12 connected by its input to the output of heating control unit 10, its first output to the second input of the switch ora 5, second input - to the third input replai unit 7 is connected to its second input to the second output switch 5, and its third output to the second input 11 of the heating element.

The device works as follows.

The eddy current transducer 1, connected to the feedback circuit of generator 2, interacts with a controlled ferromagnetic object and produces a voltage applied to the input of selective amplifier 3, tuned to one of the highest harmonics of the generator. From the output of amplifier 3, the signal passes through an amplitude detector 4 and is fed through switch 5 to the input of memory block 6, from where it arrives at the first input of decision block 7. After this, program 12 sets the heating mode. With the help of heating element II, which is recommended to use an induction element, the controlled object is heated to a predetermined temperature: 220 ° C. When a predetermined temperature is reached, measured by the temperature measuring transducer 9, for example, a thermocouple, the heating control unit 10 shuts down the heating element 11, and the program block 12 provides a repeated measurement with fixation of the results in the decision block 7 coming through the second output of the switch 5 to its second entrance. When both signals arrive at the decision block 7, the program unit 12 issues a command to calculate the difference between the received signals. Information about the first, second measurement results and their difference is fed to indicator 8, according to which it is judged on the percentage of chill, its depth and hardness.

The proposed device makes it possible to unambiguously judge the presence of chill in a controlled ferromagnetic object and estimate its percentage and depth, which increases the reliability of control of the surface layers of ferromagnetic objects.

Claims (2)

Invention Formula Device for controlling surface layers of ferromagnetic objects, containing a blocking generator, a serially connected transformer eddy current transducer, included in the feedback of the blocking generator, a selective amplifier and an amplitude detector, and an indicator, characterized in that it is equipped with a program block to increase the reliability of the control connected by a switch connected by the first input to the output of the amplitude detector and the second input to the first output of the program block, the memory block and the resolver block connected by their second and third inputs to the second outputs of the switch and the program block, respectively, 0 and its output to the indicator, connected in series by a temperature measuring transducer, a heating control unit connected by its output to an input of a program block and a heating element connected by a second input to a third output of a program block. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 411367, cl. G 01 N 27/84, 1975. 2. USSR author's certificate No. 492796, G 01 N 27/80, 1975 (prototype).