SU1285363A1 - Method of flaw detection in moving articles - Google Patents

Abstract

The invention relates to non-destructive testing methods and can be used in test facilities for the continuous monitoring of extended products. The purpose of the invention is to improve the control accuracy by eliminating the dependence of the results of processing the output signal of a static flaw detector on the speed of movement of the product under test. To do this, measure the amplitude of the output signal of the static flaw detector through equal lengths of the product, memorize the amplitudes of the output signal of the static flaw detector, determine the difference of the amplitudes of the current and memorized output signals of the static flaw detector and determine the presence of defects in the item being monitored. 2 Il.

Description

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The invention relates to non-destructive testing methods and can be used primarily in the metallurgical industry in test facilities for the continuous monitoring of extended products.

The purpose of the invention is to improve the control accuracy by eliminating the dependence of the results of processing the output signal of a static flaw detector on the speed of movement of the product under test.

FIG. 1 shows a flaw detector that implements a flaw detection method; in fig. 2 - signal diagrams explaining the flaw detection method.

The flaw detector contains a pulse sensor 1 of movement of the monitored object 2 relative to the probe 3 of the static flaw detector 4, a recording device 5 connected to the output of the static flaw detector 4 via a capacitor 6, which acts as an analog storage device. In parallel with the registering device 5, a switch 7 is switched on, controlled by pulses from a pulse displacement sensor 4.

The method of flaw detection of moving electrically conducting products is carried out as follows.

When the monitored object 1 moves relative to the probe 3 of the static flaw detector 4, the V4 pulses from the output of the pulse displacement sensor 1 periodically switch on key 7. At the same time, the capacitor 6 is charged to the amplitude value of the ultrasonic voltage at the output of the static flaw detector 4 (Fig. 1).

At the time of the pause between pulses U4, the key 7 is opened and the recording device 5 receives a signal Us, equal to the difference between the current values of the signal Us at

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the output of the static flaw detector 4 and the charging voltage of the capacitor 6 (Fig. 2). With a smooth change of interfering factors (electromagnetic parameters and thickness of the object, the distance between the probe and the surface of the object, etc.), sawtooth pulses Us arrive at the recording device 5, the amplitude of which is less than the amplitude of the pulse entering the recording device 5 when the defect appears under probe 3 of the static flaw detector 4. When the speed of the object 2 changes, the pulse frequency U4 changes, the switching frequency of the switch 7 and, consequently, the repetition frequency of the subtraction operation is undoubtedly and the current values of the output signals of the static flaw detector 4. However, the amplitude of the sawtooth pulses Us is still the pulse from the defect. Thereby, the control results are independent of changes in the speed of movement of the controlled object 2 and other interfering factors.

Claims (1)

Invention Formula The method of flaw detection of moving products, which measures the output signal of a static flaw detector, analyzes it with regard to the speed of movement of the test item, characterized in that, in order to improve the control accuracy, the output signal of the static flaw detector is measured through equal lengths of the item being tested, remember the measured values of the output signal of the static flaw detector, determine the difference between the current and memorized values of the output signal and determine the difference Ichiye defects in the testing item. Ich I I I I I I I I I I I I I I I I I I I need U five. -. L L vTvJ Phases. 2 L