SU1206690A1 - Method of ultrasonic quality inspection of articles - Google Patents

Description

one

The invention relates to the field of acoustic methods of non-destructive testing and can be used to detect defects in products, for example, to detect defects in hot-rolled metal sheets.

The purpose of the invention is to increase the sensitivity of monitoring by detecting defects in the microstructure of materials that have a low reflection coefficient of ultrasonic klibaniya, for example rolled into a thin layer of graphite inclusions, thin oxide films, deformed slag inclusions, etc., due to the dependence of the envelope shape of the total spectrum on the phases the amplitude-h of the astrotic components of the bottom echo pulse, which change when passing through a deflector with a low reflection coefficient.

Figure 1 shows the functional diagram of the device implementing the method of ultrasonic quality control of the product} in figure 2 - the envelope of the total spectrum obtained on the defect-free product, in figure 3 - the same on the product with a defect in the form of graphite rolled in one layer opening of 0.04 mm; figure 4 is the same, on the product with a defect in the form of an oxide film with a disclosure of 0.05 mm.

A device that implements the method, contains a series-connected short-pulse generator 1, a broadband amplifier 2, a time selector 3, and a spectrum analyzer 4. The device also contains a series-connected generator 5 delayed clock pulses and the generator 6 radio pulses. The input of the generator 6 is connected to the input of the analyzer 4 of the spectrum. In addition, the device contains a wide-band converter 7 connected to the output of the generator 1

2066902

The proposed method is as follows.

A wideband transducer 7 is installed, for example, operating in a frequency band from 2 to

6 MHz,. On the controlled product 8 and excite it with a generator 1 short pulses. Converter

7 radiates into the product 8 ultrasonic vibrations with a certain

the maximum frequency of the spectrum component i, e.g. 4.5 MHz. Ultrasonic vibrations propagated in article 8 are reflected from

15 of its bottom surface and returned to transducer 7, which receives them and converts them into an electrical signal. This signal is amplified by a wideband amplifier 2 Lem 2 and through a time selector 3, which selects the bottom echo from other interfering signals, to the inputs of the generator 5 and the analyzer 4 of the spectrum. Generator.5 generates time-delayed synchro pulses relative to the bottom echo pulse, which is selected from the ratio 1/1 and at io 5 MHz 0.22 μs.

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This sync pulse triggers a waiting generator of 6 radio pulses, forming radio pulses whose amplitude is equal to the amplitude of the bottom echo pulse, and the spectrum is wider than the spectrum of the bottom echo pulse. Radio pulses are received by a spectrum analyzer 4, which is used to determine the total spectrum

40 received pulses. According to the shape of the envelope of the total spectrum, shown for defect-free and defective products in FIG. 2-4, determine the quality of the product, for example,

XJ, as a rejection criterion, is i, the first frequency minimum of the total spectrum.

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VNIIPI Order 8703/45 Circulation: Branch PPP Patent, Uzhgorod,

Claims (1)

METHOD OF ULTRASONIC QUALITY CONTROL OF THE PRODUCT, which consists in emitting ultrasonic vibrations into the product, receiving echo pulses from the bottom surface of the product, characterized in that, in order to increase the sensitivity, they generate a radio pulse with a delay t relative to the bottom echo pulse, take it , determine the total spectrum of received pulses and determine the quality of the product by the shape of the envelope of the total spectrum, and the delay i is selected from the expression b - H, where 4 ₀ is the maximum frequency component of the spectrum of the emitted into the product ultra sound vibrations. a "1.20661