SU1439490A1 - Method of ultrasonic inspection of quality of welded joints - Google Patents

Abstract

The invention relates to non-destructive quality control of products and can be used to detect discontinuities with small opening, for example, in joints of parts using pressure welding. The aim of the invention is to increase the sensitivity to planar defects with a small opening in the control of welded joints. The location of the plane of polarization of the transverse-wave pulses emitted into the controlled product is normal to the plane of the disclosure of the assumed discontinuity, which makes it possible simultaneously with the signals that have passed through the controlled product at. to ignore the signals received during the transformation of the singed waves on the pre-provision. generated discontinuity in stonley waves. In this case, the signal from the transformed wave on the flaw detector screen is located next to the main signal. And the presence of a defect is judged by the ratio of the parameters of the received signals from the pulses that have passed through the product and are transformed into discontinuities. in the stonley waves. .4 Il S (l

Description

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The invention relates to non-destructive quality control of products, such as compounds made by pressure welding, and can be used to detect planar discontinuities with a small opening.

The purpose of the invention is to increase the chu: - to the flat defects with a small disclosure when controlling weld joints.

Figure 1 presents the scheme of implementation of the proposed method; figure 2 - section aa in figure 1; Fig. 3 shows the signal arrangement on the flaw detector screen (not shown) in the absence of non-failure; figure 4 - the same, in the presence of discontinuity.

The diagram shows the radiating 1 and receiving 2 oblique ultrasonic transducers, as well as the controlled, product 3, which is a butt joint of pipes, made by resistance-wired welding. The expected defect 4 in this case is the non-fused portions along the connecting pipe ends, which are discontinuities with a small opening.

Both converters 1 and 2 are located on the product along the junction line so that the transverse waves radiated into product 3 propagate along the alleged defect 4-. Positions 5-7 designate the probing, primary and secondary signals, respectively.

Transducers 1 and 2 are moved along the junction with a constant distance between them. The emitting transducer 1 is transmitted by pulses of transverse waves, which are represented in the diagram as probe signals 5, while the plane of polarization of transverse waves is normally located in the plane of the disclosure of the expected non-continuity, i.e. perpendicular to the pipe ends,

A part of the transverse waves, reaching the defect 4, is transformed on it into Stoneley waves, which, after passing along the discontinuity, are again transformed into transverse waves AND enter the receiving transform / EB 2 as additional signals 7, the other part of the transverse waves passes the discontinuity unchanged to hit

The signal into the receiving transducer 2 in the form of the main signals 6. The signals 7 lag behind the signals 6, since the propagation velocity of the Stoneley BOJU is 0.9 of the velocity of the propagation of the transverse waves.

In the absence of discontinuities on the flaw detector screen, there are two types of signals: the probe signal 5 and the main transmitted signal 6.

The amplitudes of the signals received on the flaw detector screen (transducer 2) are measured. A rejection indicator is defined as the difference between the amplitudes of the signals that have passed through the product and the wave signals transformed on discontinuities into Stoneley waves. The rejection rate is compared with the specified rejection level and the presence of rejection is determined.

The ratio and amplitude of the arrival time of the signals determine the length and width of the detected defect.

Example. The control of welded specimens made in the form of a butt joint of pipes mm with wall thickness mm was carried out. Pipes are welded together. Grating is removed. The control was carried out with a UD-11PU ultrasonic flaw detector using oblique transducers with a prism angle of 50. The frequency of the emitted pulses is f 5 MHz. The amplitude A of the signals that passed the product with the usual defect is 16 dB, and the amplitude A of the signals of the waves transformed On a planar discontinuity into a Stoneley wave, is equal to 9 dB.

Claims (1)

Invention Formula The method of ultrasonic quality control of welded joints, consisting in that using a radiating ultrasound transducer, excites ultrasonic transverse wave pulses in a joint, and receives ultrasonic transducer transduced ultrasonic transverse wave pulses, according to the parameters of which determine the presence and size of the weld joints. , characterized in that, in order to increase sensitivity to planar defects with small pacKpbiTneNf during the inspection of welded joints, radiating transducer and primer transducer ustyv Pour along lengthwise5 0 five The symmetry axis of a welded joint, the excitation of pulses of transverse waves is carried out so that the plane of polarization of transverse waves is perpendicular to the plane of symmetry of the welded joint, the presence of planar defects is determined by the appearance of additional transmitted pulses caused by the transformation of transverse waves at a defect into stonley waves, and the dimensions of plane defects are determined by the ratio of arrival times and amplitudes of the main and additional transmitted pulses. R IG, 2 Fig.Z U8.4