Positioning method of transverse wave TOFD (Time of Flight Diffraction) defect

Abstract

In the ultrasonic nondestructive testing field, the traditional time of flight diffraction (TOFD) is used for finding defects of a welding line by only using a longitudinal wave scattering signal; because the type of used signals is single, the three-dimensional positioning of the internal defect of the welding line cannot be realized by the single linear scanning. Aiming the problem, the invention provides a transverse wave TOFD detecting method; one pair of transverse wave probes are used for performing the single linear scanning along the welding line; at the same time, the longitudinal wave and the transverse wave scattering signals of the internal defect of the welding line are used for analyzing to point out that the defect is located on an elliptic trajectory determined by the transverse wave scattering signal and is also located on a circular trajectory determined by the longitudinal wave scattering signal, thus the three-dimensional positioning of the internal defect of the material can be realized by obtaining the intersecting point of the two curves.

Description

1. Technical field [0001] The invention relates to the field of ultrasonic non-destructive testing, and proposes a shear wave TOFD defect positioning method, which uses a pair of shear wave probes to perform a single linear scan along both sides of the weld, and uses the longitudinal wave and shear wave scattering signals of the defect to find defects in the weld. And accurately locate the defect. 2. Background technology [0002] Ultrasonic time of flight diffraction (TOFD for short) can efficiently detect and locate internal cracks in components, and is gradually being promoted and applied in the industrial field. When ultrasonic waves are incident on the surface of defects (air holes, cracks, inclusions, etc.), the sound wave energy will form scattered waves at the corners of the defects, and the scattered energy spreads in all directions, so scattered echoes can be received from almost all directions. Ultrasonic diffraction time-of-flight method is an ultrasonic non-des...

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