SU590659A1 - Ultrasonic method for quality control of butt welds - Google Patents

Description

one

The invention relates to non-destructive quality control of materials and products, in particular, ultrasonic inspection of welds.

There is a method of ultrasonic echo-pulse quality control of welds, due to the fact that they are inclined into the metal and receive ultrasonic pulses repeatedly reflected from the pipe walls with simultaneous frequency deviation of the probing pulse.

However, due to the insufficient magnitude of the frequency modulation and the instability of the acoustic contact, this method does not provide sufficient reliability for detecting defects.

The purpose of the invention is to increase the reliability of the control.

To do this, according to the proposed method, the frequency of the probing pulses of the defectoscope is varied up to ± 50% of its average value and the arithmetic mean increase in the maximum and minimum amplitudes of the echo signals from defects during the period of changing the frequency of filling the probe pulses is recorded.

The drawing shows a diagram of the device for implementing the proposed method when using X-shaped sound

a weld in which individual searchers are used to emit and receive a UTF.

The device includes radiating transducers 1 and 2 and receiving transducers 3 n 4, a generator of 5 probe pulses with a discrete varying pulse filling frequency, an amplifier 6, blocks 7, 8 and 9 of the processing of echo signals, and an adder-divider 9 of amplitude, whose operation is synchronized generator 5. Signal processing unit with, held connected to the output of amplifier 6, blocks 7 and 8, serving to separate the maximum and minimum amplitudes of the signals from the defect. The outputs of these channels through block 9 are connected to the identifier 10, which serves to register the detected defects.

The signal processing unit starts working from the moment the oscillator frequency 5 is changed. Block 7 selects and fixes the maximum amplitude of the echo signals using an integrating RC circuit, block 8 - the minimum amplitude. At the end of the frequency change, the signal from the generator 5 recorded in blocks 7 and 8 of the amplitudes of the signals is fed to block 9, the output of which takes the arithmetic average of the signals received at its input. Amnlituda signals at the output of block 9, exceeding the registration threshold, are received on the indicator 10.

Claims (1)

Invention Formula The method of ultrasonic quality control of butt welds, for example, in pipes, which consists in an oblique insertion into the metal and the reception of ultrasound pulses that are repeatedly reflected from the pipe walls with simultaneous deviation of the frequency of the probing pulses, characterized in that, in order to increase the reliability of control, pulses are changed to within ± 50% of its average value and the arithmetic average value of the maximum and minimum amplitudes of the echo signals from the defects during the period of change is fixed filling pulse probes.