SU771540A1 - Method of ultrasonic testing of joining of metallic articles with non-metallic coating - Google Patents

Description

one

The invention relates to the field of non-destructive testing and can be used for ultrasonic testing of metal joints with a non-metallic coating. five

The known method of ultrasonic testing of metal products with a non-metallic coating, which consists in that surface ultrasonic vibrations are introduced into the connection from the side of the coating, are accepted. the vibrations that have passed the controlled region of the joint, and the oscillations reflected from the boundary of the coating with the product, and the quality of the joint is judged by the duration of the received oscillations ij.

When inspecting products with a coating having a low zat-a-factor. The ultrasound waves, oscillations reflected from the greenhouse, products with a coating of 20 tium, are damped on the side of the coating.

The disadvantage of this method is the low reliability of control of the compound, the coating of which has a low attenuation coefficient of ultrasound, since the heterogeneity of the structure of the coating and the product, the different roughness of the combined behavior often causes the same duration of the surface and reflectance.

vibrations. This is particularly evident at short distances between the input and output points of the oscillations, which is necessary to achieve maximum control sensitivity.

The aim of the invention is to increase the intrinsic control.

The goal is achieved by additionally 1 registering the drive time of the received oscillations and taking it into account when assessing the quality of the connection,

FIG. 1 shows a scheme for implementing the method and wave propagation in the event of a defect, FIG. 2 - the same for a defect-free compound; in fig. 3 - temporary diagrams of the reflected signals are given: a) - in the presence of a defect (unclosed); b) - in the absence of a defect; c) - if there is a defect with mln duration longer than max duration of received oscillations in the absence of a defect.

The method is as follows.

In the controlled connection of the product 1, ultrasonic longitudinal vibrations are introduced from the side of the coating 2 by means of the radiating transducer 3. By varying the angle of entry of vibrations, a surface wave in product 1 is obtained. One part of the oscillation is repeatedly reflected from the boundary of the coating product and enters the receiving transducer 4. Another part of the multiple reflection path enters product 1, the transducer springs into the surface wave and also enters to the transducer 4. In turn, part of the surface wave in its propagation path is again partially transformed into a longitudinal wave in the coating 2, the incoming transducer 4. The received oscillations analyze by time of arrival and duration.

If the time of arrival is shorter than the minimum possible time of arrival of pulses in the defective area, then this area is considered qualitative for any pulse duration.

If the arrival time of ultrasonic pulses is longer than the maximum possible arrival time of ultrasonic pulses at quality sites, then the area is considered defective for any pulse duration, if the arrival time of ultrasonic pulses corresponds to an intermediate value between the minimum possible pulse time for the defective area and the maximum possible arrival time of pulses then this time interval is divided into two (if necessary, 3 4) zones in time. For each of these zones, an imperfection criterion is established depending on the duration of the ultrasonic pulses. This increases the reliability of the control.

Claims (1)

1. USSR author's certificate W 608092, cl. G 01 N 29/04j 1977 (prototype). 12 G, “G; Tfutj ti Fig.)