SU1422140A1 - Method of ultrasonic shadow check of articles - Google Patents

Abstract

This invention relates to ultrasonic shadow non-destructive testing of products. The purpose of the invention is to improve the accuracy of determining the depth of defects and expand the scope of application of the method. Improving the accuracy of determining the depth of defects is achieved by measuring the distance from the emitting or receiving transducers to the surface of the test product closest to them at the time the defect is detected by both pairs of transducers. The expansion of the field of application of the method is achieved by installing radiating transducers on one side of the product so that the angles between the radiation directions of the transducers and the normal to the surface of the product are less than the critical angle. 1 il.

Description

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The invention relates to nearushi-K) control of products, namely, methods of ultrasonic shadow control, and can be used to detect defects and determine their depth.

The aim of the invention is to improve the accuracy of determining the depth of defects and the expansion of the field of application.

The drawing shows the block diagram of the device for implementing the proposed method.

The device contains a generator of 1 probe pulses connected to the radiating converters 2 and 3 mounted on product 4, the receiving ones: converters 5 and 6, each of which are connected in series with COOT amplifiers 7 and 8, threshold devices 9 and 10 and indicators 11 and 12, the first position sensor 13 connected to the first input of the differential adder 14, the output of which is connected to the indicator 15, the second position sensor 16 connected in series with the divider 17 and the multiplier 18, the angle adjuster 19, the output of which connected to the second input of the multiplier 18 ..

The essence of the method is that relative to the product under test 4, two pairs of transducers 2, 6 and 3, 5 are installed according to scheme X, so that the emitting transducers are on the same side of the product 4, and half the angle between the directions of the emitting transducers is less than critical . Ultrasonic oscillations are emitted into product 4 by radiating transducers 2 and 3 and 4 oscillations transmitted through the product are received by receiving transducers 5 and 6. To reduce the amplitude of the received ultrasonic signal, a defect between the transducers of each pair is judged. Each pair of transducers relative to the fixed product 4 and another pair of transducers before registering the presence of a defect with a corresponding pair of transducers. At the time a defect is detected, both pairs of transducers measure the distance between the emitting or receiving transducers, as well as the distance from the emitting or receiving transducers to the surface of the tested product closest to them using any position sensors (for example, potentiometric) providing the required measurement accuracy, which is determined by the required accuracy of determining the depth of defects. From the measured distances and the known angle between the directions of radiation of the transducers, the depth of the defect is determined from the location of, respectively, the emitting or receiving transducers according to the formula

H I ctgo - h,

where H is the depth of the defect; L is the distance between the radiating. or receiving transducers at the time of registration of the defect with both pairs of transducers;

K is the distance from the emitting or receiving transducers to the surface of the tested product closest to them at the time of the defect registration by both pairs of the transducer, ovatels;

 0 is the angle rug between the directions of radiation of the radiating transducers.

The method is as follows. in a way.

The probe pulse generator 1 excites radiating transducers 2 and 3, which emit ultrasonic vibrations into the controlled article 4. The oscillations that pass through the product 4 are received by receiver converters 5 and 6 and converted into electrical signals that are amplified by amplifiers 7 and 8 and fed to the inputs of threshold devices 9 and 10. In threshold devices 9 and 10, signals U (t ), entered at their input, with a threshold signal and,. When the conditions U (t) are fulfilled and the output of the threshold devices 9 and 10, a logical signal O is generated, and when U (t) impulses, the signal of the logical 1 is generated at the output of the threshold devices. Indicators 11 and 12 provide an indication of the defective areas of the controlled product 4 detected appropriate measurement channel. The first sensor 13 Polsezhe3142

It ensures the formation of a signal at its output, the amplitude of which is proportional to the distance h from the receiving transducers 5. and 6 to the surface of the tested product 4 nearest to them. The second position sensor 16 ensures the formation at its output of a signal whose amplitude is proportional to the distance L between the receiving ones converters 5 and 6, which, through the divider 17, which provides the determination of

L

r, is fed to the first input of the multiplier 18. To the second input of the multiplier 18, a signal is received from the output of the angle setting device 19, proportional to the value of ctgo. The multiplier 18 provides the definition

values of g ctgc. Multiply c-out signal

body 18, proportional to the specified value, is fed to the first input of the differential adder. 14, to the second input of which a signal is output from the first position sensor 13. Differential adder 14 provides the determination of the depth of Q

legany defect H (-h.Signal

proportional to the depth of the defect, from the output of the differential adder 14 is fed to the indicator 15.

Claims (1)

Invention Formula The method of ultrasonic shadow control of products, which consists in installing two pairs of transducers relative to the product according to the .X scheme, radiates oscillations into the product, receives oscillations passing through the product, determines their amplitudes 140. According to the amplitude change, the defect is detected, each pair of transducers is moved relative to the stationary product and another pair of transducers until the presence of the defect is detected, the distance between the transmitting or receiving transducers in 10, the time of registration of the defect and taking into account the measured distance, determine the depth of the defect, characterized in that, in order to increase the accuracy of determining the depth of the defect and expand it applications that emit transducers are installed one by one; the side of the product so that the angle between the directions of radiation of the direct formation of the 20 tel is less than the critical angle, at the time of registration of the defect, both pairs of transducers measure the distance from the emitting or receiving transducers to the one closest to them 25 of the surface of the tested product, and the depth of the defect on the side of the location of the radiating or receiving transducers, respectively, is determined by the formula 30 I, - H I ctgc / - h, where H is the depth of the defect; L is the distance between the radiation. 35 or receiving transducers at the time of registration of the defect with both pairs of transducers; h is the distance from the radiating or 40. receiving transducers to the surface nearest to them; o (- half the angle between the radiation directions of the transducers.