SU1441299A1 - Ultrasonic method of inspecting articles for presence of vertically oriented planar flaws - Google Patents

Abstract

This invention relates to acoustic methods of non-destructive testing. The aim of the invention is to improve the accuracy of determining the height of the defect by determining it by taking into account the propagation time of the longitudinal wave transformed at the defect due to the independence of the measured parameter from changes in the reflecting properties of the bottom surface of the product. The product emits impulses of longitudinal ultrasonic (US) vibrations in the direction coinciding with the plane of the defect and perpendicular to the bottom surface of the product. At the defect, a portion of the energy of the longitudinal wave is transformed into an ultrasonic wave propagating in the same direction. When the defect is reached, the surface wave is again transformed into a longitudinal wave. Simple ultrasonic longitudinal oscillations and ultrasonic longitudinal vibrations transformed at a defect are received by the bottom surface of the product and the difference in their propagation time is measured. The presence of a second reflected bottom surface of the product signal determines the presence of a vertically oriented planar defect, and according to {measured difference - the height of the defect. 2 Il.

Description

one

 14

This invention relates to acoustic methods of non-destructive testing and can be used with ultra sound (US) inspection of products.

The purpose of the invention is to improve the accuracy of determining the height of the defect due to the independence of the measured parameter from changes in the reflective properties of the bottom surface,

Fig. 1 shows the implementation scheme of the ultrasonic testing of products for the presence of vertically oriented planar defects in Fig. 2, an ultrasound scan of the flaw detector for detecting a vertically oriented planar defect.

An ultrasonic method for inspecting products for vertically oriented planar defects is as follows.

In the product, ultrasonic pulses are excited by longitudinal vibrations in the direction coinciding with the plane of the defect and perpendicular to the bottom surface of the product. The oscillations reflected by the bottom surface of the product are taken and the difference between the time of propagation of the longitudinal vibrations and the longitudinal vibrations transformed at the defect is measured. The presence of the defect is determined by the amplitude of the reflected bottom surface of the product transformed at the longitudinal vibration defect, and the height of the defect is determined by the measured time difference.

The ultrasonic method of monitoring products for the presence of vertically oriented flat defects is implemented in the following manner.

t, 2H / ce,

where Cg is the propagation speed

longitudinal oscillations in the material of the product 1. A part of the longitudinal wave emitted by the transducer 2 is transformed when it hits a defect 3 into a Rzleev wave, which, having reached the lower end of defect 3, is again transformed into a longitudinal wave. Thus, the bottom pulse 5 is observed to have a pulse 6 of a longitudinal wave reflected from the bottom surface of the product 1 after transformation at defect 3 with a propagation time t determined from the expression

20 t2 2H / Cj-2h / Cj + 2h / c

R

where c.

- the propagation velocity of the surface wave in the material of the controlled article 1,

The presence of a pulse 6 on the screen of the ultrasonic detector of the flaw detector 6 determines the presence of defect 3 in the product 1. Then the time interval is measured and the height h of defect 3 is determined using the formula

h

ce-C (fAt

2 (ce-cr}

Similarly, it is possible to determine the presence and height of a vertical planar defect and with an ultrasonic shadow control method realized when the radiating and receiving ultrasonic transducers are located coaxially on opposite surfaces of the product.

An ultrasonic transducer 2, for example, a direct ultrasonic transducer from a serial ultrasonic flaw detector kit, is installed on the surface 1 of product 1 with thickness. Using transducer 2, ultrasonic longitudinal oscillation pulses are emitted and the reflected bottom surface of oscillation device 1 oscillates. of defect 3, for example, a crack with height h, the picture is shown, represented in Fig. 2, to the right of the probe pulse 4 on

the impulse 5 of the longitudinal wave is observed,

reflected from the bottom surface of the product with the propagation time

H

delimiter e a M from the expression

five

0

five

Claims (1)

Invention Formula The ultrasonic method of testing products for the presence of vertically oriented planar defects, which consists in exciting impulses of longitudinal ultrasonic vibrations in the product in the direction coinciding with the plane of the defect, receives oscillations reflected by the bottom surface of the product, measures their parameters and determines the defect characteristics with their help. wherein, in order to increase the determination of the height of the defect, the difference between the propagation time of the reflection is used as the measured parameter GOVERNMENTAL bottom povvr 1441299 The longitude of the longitudinal oscillations and the time reflected by the bottom surface after spreading the reflected don-transformed at the defect by the penetrated surface of the transformed partial oscillations, and the height of the defect on the defect of the longitudinal oscillations, are determined by the changed difference of the defect by presence. R 2  2 L. n fae. one Ll tz Phie. 2