SU1486917A1 - Method of ultrasonic monitoring of quality of elongated articles - Google Patents

Description

The invention relates to non-destructive methods of controlling the material of products. The purpose of the invention is to increase the information content of the control due to the location on the side surface of the product of the location of the boundaries of the tense sections in the long product. The method of ultrasonic quality control of extended products is implemented

The invention relates to non-destructive methods of control, material products. For example, extended single-crystal-> tall ingots with internal mechanical stresses, and can be used to locate the boundaries of stressed sections of the ingot with inadmissible mechanical stresses on the side surface of the extended product, in particular, long single crystal ingot ^ cylindrical

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in the following way. The pulses of ultrasonic vibrations are emitted into the controlled product. In the process of radiation, an ultrasonic transducer is scanned along the end surface of the monitored extended article. In the process of radiation and reception rotate the transducer around its own axis and by changing the deviation of the envelope of a series of received echo pulses from the exponent determine the presence of internal mechanical stresses in the controlled product. To find the location of the boundaries of the stressed sections on the side surface of the product, ultrasonic vibrations are introduced from the side surface of the product. When an ultrasonic transducer is moved, reflected echo pulses are taken, their amplitude is measured, and the boundaries of strained lines are determined from the condition when the measured amplitude of the echo pulse becomes less than the allowable value. 3 il.

forms having at least one flat surface on their side surface.

The purpose of the invention is to increase the information content of the control due to the location on the side surface of the product of the location of the boundaries of the tense sections in the long product.

1 shows a diagram for implementing the method of ultrasonic quality control of extended products;

figure 2 - the dependence of the amplitude od5TS „„ 1486917

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Of the echo pulses, reflected from the lateral surface of the test product opposite to the ultrasonic transducer along the length of the test product, characteristic of the product with internal mechanical stresses; on fig.Z - block diagram of one of the devices, allowing to implement the method of ultrasonic control-extended products.

An ultrasonic transducer 3 is installed on the end surface 1 (a plane-parallel face) of the controlled length 2, by means of which ultrasonic oscillations are emitted and receive a series of echo pulses reflected from the opposite end surface 20 of the length 2 that is controlled 2. On the end surface 1 side 2 is acoustically connected to the ultrasound transducer 3. The latter may also have acoustic contact with the monitored product 2 lateral side of the flat surface 4.. A device for ultrasonic quality control, in addition, contains a generator of 5 pulses, a receiver 6, whose input is connected to the output of a generator of 5 pulses and to an ultrasonic transducer 3, a two-channel oscilloscope 7, an exponential generator 8 and a synchronizer 9, first, second, and the third outputs of which are connected respectively to the input of the generator 5 pulses, the input of the generator 8 of the exponent and the input of a two-channel oscilloscope 7, the input of the first and second channels of a two-channel oscilloscope 7 are connected to the outputs respectively 6 and generator 8. exhibitors.

The method of ultrasonic quality control extended products as follows.

The ultrasonic oscillations are pulsed into an extensively monitored product 2 by means of an ultrasonic transducer 3. For this, a generator of 5 pulses produces high-frequency electrical pulses that are fed from its output to the ultrasonic transducer 3. 55

Ultrasonic pulses propagate in a controlled length of the product 2, repeatedly reflected from its

plane-parallel surfaces. Reflected from the opposite ultrasound transducer 3 of the end surface of the monitored extended article 2, a series of echo pulses are received by an ultrasonic transducer 3, which converts them into electrical signals. These signals are fed to the input of the receiver 6, amplified in it to the required value, and from the output of the last are fed to the input of the first channel of the two-channel oscilloscope 7 for visual indication on the screen of the cathode ray tube. The input of the second channel of the two-channel oscilloscope 7 is supplied with an exponential signal from the oscillator 8 exponent. The synchronizer 9 provides a consistent start of the generator of 5 pulses, the generator 8 of the exponent and the scan generator of the two-channel oscilloscope 7 in such a way that on the screen of the two-channel oscilloscope 7 simultaneously with the r series of received echo pulses there is an exponential signal that is combined with the envelope of a series of received echo signals by changing the generator time constant 8 exponentials. The ultrasonic transducer 3 is scanned on the end surface 1 of the controlled extended article 2 by moving it. When scanning, the ultrasonic transducer 3 rotates around its own axis' in the process of radiation and reception, and the change in the deviation of the envelope of a series of received echo pulses from the exponent, carried out visually on the screen of a two-channel oscilloscope 7, determines the presence of internal mechanical stresses in the controlled extended product 2. Internal mechanical stresses in the controlled length of the product 2 are in the case when the exponential envelope of a series of received echo pulses during the rotation of the ultrasounds th transducer 3, on its axis, goes to an exponent decreasing cosine and back. For being on the side surface of the controlled length 2, the location of the boundaries of the stressed sections when detecting in the controlled length of the product 2 internal Mechanical stresses ultrasonic transducer 3 with end on top5 148691

of the controlled extended product 2 is transferred to its lateral flat surface 4. Ultrasonic transducer 3 is moved along the controlled extended ⁵ product 2, while emitting ultrasonic vibration pulses and receiving echo pulses reflected from the opposite lateral surface of the controlled ₁₀ extended product 2.

On the screen of a two-channel oscilloscope 7, the amplitude of one of the echo pulses and its dependence on the movement of the ultrasonic transducer 3 along the lateral flat surface 4 along the length of the controlled length of product 2 is measured. The ultrasonic wave propagates perpendicular to the mechanical stress. In this case, there is a phenomenon of double refraction. If 25 the magnitude of the mechanical stress on the path of propagation of the ultrasonic beam changes, then in addition to birefringence, a curvature of the propagation path of the ultrasonic beam occurs and the ultrasonic wave falls on the opposite side surface of the tested extended article 2 and is reflected from it at an angle. As a result, the reflected ultrasonic pulse hits the ultrasonic transducer 3 not with all of its cross section, but only partly or not at all, depending on the nature of the change in the magnitude of the mechanical stresses. The amplitude of the received reflected pulse-echo correspondingly decreases with increasing angle of incidence ₍₄₅ Nia reflection) caused by an increase in change of mechanical stress within the cross section of the ultrasonic beam path in its propagation. Measure the amplitude of one of the echo pulses when moving the ultrasonic transducer 3 on the lateral flat surface 4 along the controlled length of the product 2 and determine the boundaries of the stressed sections from the condition when the measured amplitude of the echo pulse becomes less than the allowable value A _Dsp . A value _extra 35

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but defined as follows. Measure the dependence of the amplitude of one of the reflected echo pulses along. the length of the ingot, and build the corresponding schedule. Then the entire ingot must be cut into plates and identify the plate with the maximum permissible internal mechanical stresses, for example, the polarization-optical method. According to the schedule, it is determined what value of the amplitude of the echo pulse corresponds to these plates. The value of the amplitude of the echo impulse found in this way is a valid value A _ext . When А ^ А _ао п, the mechanical internal stresses in the product exceed the maximum permissible.

Claims (1)

The method of ultrasonic quality control of extended products, which consists in installing an ultrasonic transducer on the end surface of a cylindrical controlled product, emitting ultrasonic vibration pulses, taking a series of echo pulse reflected from the opposite surface of the product, scanning the end surface of the controlled product with an ultrasonic transducer, when scanning the transducer in the process of radiation and reception rotate around its own axis, according to The variation in the deviation of the envelope of a series of received echo pulses from the exponent is determined by the presence of internal mechanical stresses, which, in order to increase the information content of the control by finding the location of the boundaries on the side surface of the product plots in the extended product, additionally install the ultrasonic transducer on the lateral flat surface of the product, move it along the component of the product, emit pulses of ultrasonic vibrations, receive reflected from opolozhnoy product surface echo pulses .izmeryayut amplitude one of the echo pulses and boundary strained portions determined from the condition when the measured amlituda echo pulse becomes less than the allowable value. 1486917