SU1320742A1 - Method of ultrasonic shadow examination of articles and device for effecting same - Google Patents

Abstract

The invention relates to the field of acoustic methods of non-destructive testing. The aim of the invention is to improve the accuracy and reliability of the control by unambiguously determining the depth of the defect and its use in setting up the product under control. The combined emitters 3 and 4 emit ultrasonic (US) vibrations, and the receivers 7 receive the vibrations that pass through the product 16. They install artificial defects 17 on the opposite surfaces of the product 15 and during the movement of the product between the radiators 3 and 4 and the receivers 7, defects 17 are recorded by decreasing the amplitude of received ultrasonic vibrations. The difference d1 of the time of detection of the defect 16 and the duration of the detection time of the receiving channels 5 and 6 are measured and, using the input unit 14, the coefficients determined by the angle o (between the acoustic axes of the radiators 3 and 4) are set. the product 15 and the speed V of the movement of the product 15. Then the product 15 is sounded to search for defects 17 and determine the depth he and the depth of the defect 17 by ut and 1e taking into account the established coefficients using a microprocessor - information processing unit 11. 3 pp . 1-yl. FO JV oo to about. GchE. "

Description

The invention relates to acoustic methods of non-destructive testing and can be used with ultrasonic (US) shadow flaw detection, for example, multilayer products.

The aim of the invention is to increase the accuracy and reliability of the control by unambiguously determining the depth of the defect and using it when setting up the product itself.

The drawing shows the block diagram of the device for ultrasonic shadow control products.

The method of ultrasound shadow control products is as follows.

Artificial defects of known length are placed on opposite surfaces of the product and a pair of emitters are installed on one side of the product, and a pair of receivers are installed on the other. The emitters align and orient the bisector of the angle, with their acoustic axes normal to the surface of the product being tested. The receivers are installed in such a way that they are acoustically coaxially emitters. Ultrasonic vibrations are emitted into the product and the oscillations that have passed through are received. The amplitudes of the received oscillations are determined during the movement of the product in the plane of the acoustic axes of the emitters and receivers to the normal bisector of angle θ and the time of detection of artificial defects by each of the receivers is recorded by reducing the amplitude of the received signal. With the help of measurements made on artificial defects, parameters are found that determine the angle ot and the distance between the surface of the product and the combined emitters.

The sounding of the product without artificial defects is carried out in a similar way; in the event of defects, the time of defect detection by each receiver is recorded to reduce the amplitude of the received signal. The depth of the defect and the extent of the defect are determined by the difference in the time of defect detection by each of the receivers, taking into account the parameters found by artificial defects.

Device for ultrasonic shadow control products contains serially connected synchronizer 1, generator 2 probe pulses and a pair of emitters 3 and 4. The device also contains two receiving channels 5 and 6. Each channel 5 or 6 includes serially connected receiver 7, amplifier 8 and block 9 of the driver time code. In addition, the device comprises a counting pulse generator 10, an information processing unit 11 made in the form of a microprocessor, an indicator 12, a memory unit 13, and an input unit 14.

The output of the generator 10 counting pulses connected to the second inputs of the blocks 9 of the time code generator. The output of the synchronizer 1 is also connected to the third inputs of the blocks 9 of the time code generator. The first input of the information processing unit 11 is connected with the output of the generator 10 counting pulses, the second input of the block 11 - with the output of the block 9 of the time code generator of the receiving channel 5, the third input of the block 1 1 - with the output of the block 9 of the time code generator of the receiving channel 6, fourth

0 input of block 11 — with the output of memory block 13; and the fifth input of block 11 — with the output of input block 14. The first output of the information processing unit 11 is connected to the input of the indicator 12, the second output of the unit 11 is connected to the DOM of the memory unit Jo. The second input of the memory unit 13 is connected to the output of the input unit 14. The method of ultrasonic shadow control products is implemented during operation of the device. Artificial defects 16 are placed on the opposite surfaces of the product 15, for example, a figure of the desired shape and area of aluminum foil with adhesive tape.

Install a pair of combined emitters 3 and 4 on one side of the product, and a pair of receivers 7 receiving channels 5 and 6 - on the other. Artificial defect 16, fixed on the surface 3 or 4 closest to the radiator, simulates a defect that is at a “zero depth, and artificial

0, the defect 16 fixed at the far from the radiator surface is located at the maximum possible depth equal to the thickness of the product 15. The emitters 3 and 4 and the receivers 7 are located at a distance of, for example, 20-50 mm from the product 15, i.e. This is an extension that during the rotation of a large-sized cylindrical product 15 of its smaller eccentricity, which eliminates mechanical damage to emitters 3 and 4 and receivers 7. Acoustic installation

The Q coaxiality of the receiver 7 at a multi-channel 5 emitter 3 and receiver 7 at a multi-channel 6 emitter 4 is performed according to the maximum amplitude of the received signal. Orient the bisector of the angle os between the acoustic axes of the emitters 3 and 4, usually

5 equal to 10-40 °, normal surface controlled by the product. 3 and 4 ultrasonic vibrations are emitted into the product 15 by emitters and receive 15 vibrations transmitted through the product. The amplitudes of the received oscillations during the movement of the product 15 in the plane of the acoustic axes of the receivers 7 are determined by the normal bisector of the angle with the velocity V and the time of detection of artificial defects 16 by each of the receiving channels 5 and 6 is determined by reducing the amplitude

5 received signal. From the difference d t of the detection times of each of the receivers 7, the depth h of the depth of the defect 17 can be found from the dependence

N (d1 - K „),

where Kd; is the coefficient determined by the angle d;

Ku is the coefficient determined by the speed (linear or angular) of the movement of article 5;

KN is the coefficient determined by the distance H from the emitters 3 and 4 to the surface of the product 15.

Coefficient Krf. directly proportional to the magnitude of the angle — in degrees, however, the magnitude of this coefficient is not always equal to the angle θ (/ 2, but may differ from it by + 30%. The coefficient K is specified as digital values of the speed of the control object — product 15. The coefficient Km set in the distance H from the center of radiation of the emitters 3 and 4 to the nearest surface of the product 15.

For the duration of 1d of the time of detection of the defect 17, the length of 1 defect can be found according to

1 Kv-t ",

where d is the arithmetic average time of detection of the defect 17 of the receiver 7 of the first and second receiving channels 5 and 6.

Using measurements made on artificial defects 16, the values of the coefficients Kj ,, Kn- are found. When setting up the device, first enter the value of the coefficient KU, which is equal to the value of the velocity, for example In mm / s. Then enter the value of Kl. The input starts from the minimum values to obtain acceptable deviations (no more than ± 10%) of the calculated defect length from the true value measured at the artificial defect 17. Then the K value is entered, also starting from the minimum values, and a reduction in the depth calculation error is achieved and the extent of the defect. The values of the K, Kv and Kn coefficients are entered using an input unit 14, for example, a keypad associated with the memory unit 13 and an information processing unit 11, such as a microprocessor type KR580IK80A. Then, natural defects 17 are detected. When the product 15 is heard, synchronizer 1 starts a generator of 2 probe pulses, which excites emitters 3 and 4. The signal passing through the products 15 is received by receivers 7, amplified by amplifiers 8 and converted by block 9 into the corresponding code of time. According to the time code, using the coefficients entered by block 14 or extracted from block 13, the information processing AND block determines l t and 1e and calculate h, 1. For setting the measurement scale, a generator of 10 counting pulses is used, for example, which forms the quartz frequency I MHz . Measurement and calculation results are fixed by indicator 12.

Accuracy of control is ensured by the fact that the indicator characterizing the optimality of the set of coefficients K,;, K, and K is the accuracy of determining the i-brute near and far artifacts 1x defects. Microprocessor application; iio.i can produce a large amount of computations that ensure the processing of measurement results and the automation of the control process. The combination of emitters in space eliminates the possibility of the location of the point of intersection of their acoustic axes inside the controlled object, in which

in turn, eliminates the ambiguity of determining the depth of the defect.

Claims (2)

1. The method of ultrasonic shadow control of products, which consists in establishing a pair of radiation. on one side of the product, and a pair of receivers, acoustically coaxially emitters, on the other side of the product, emit ultrasonic vibrations into the product, receive the oscillations, determine the amplitudes of the received vibrations, record the time of defect detection by reducing the amplitude of one pair of emitter-receiver , then the product is moved towards the other emitter-receiver pair, the time it takes to detect the defect is recorded and the depth of the defect and the extent of the defect are determined by the time difference, In order to increase accuracy and reliability, when installed from, the printers align them and orient the bisector of the angle between their acoustic axes normally to the surface of the product under test, are placed in front of the counter. Hume on opposite surfaces artificial defects of known length and with their help find the parameters defining the angle cx. and the space is not 1 between the surface of the product and the combined one, and radiators, and the depth of the deposit and the extent of the defect are determined by the difference since the present time paramstro15. 2. Device for ultrasonic KoiuH o control of products. containing legs, ii / dovedno connected () P1iz; 1 ts- .. rv pulse probe generator: -; and a couple, and, radiators, two foster kan. p ;, n chiochak: sequentially connected PRMSM-nick, amplifier and unit formprovp km ss. time generator counting pulses. connected to the output with the second inputs b / i Former of the time code generator. The trogs whose inputs are connected to the synchronizer BWNO.IOM, are connected first L.: xc.ioM to the output of the calculator mpsop. but 1320742 56 the second and third entrances with an exit of a blo-maii and an exit with the fourth entrance of the block a time code generator, a memory information processing block, and processing information and associated with the output-input unit, the output of which is associated with the last last indicator, characterized by the input of the information processing unit and By the fact that, in order to increase accuracy and to reach-5 with the second input of the memory unit, and with the matching module, it is equipped with a connected input of information made in the form of micros with the second output of the information processor processing unit.