TOFD

This paper discusses a concept of multiframe model and adopts multiple TOFD images, in the sense of the combination of wavelet transform and image registration, SNR and the quality of the image can be enhanced by blending the denoised images together.

In addition, unlike conventional ultrasonic techniques, TOFD uses an acceptance standard that is not dependent on the size of the return signal.

Key words: defect, non-destructive testing, TOFD, phased array, welded joint, remaining life

Typically, pipeline companies consider the use of ultrasonic inspection technologies such as shear wave, phased array, FAST and TOFD only in high-end weld investigations and while looking for cracks, dents and internal defects.

TOFD detects and measures flaws in the steel by evaluating ultrasonic energy that is diffracted from the corners, or ends, of a defect.

Research is ongoing to determine the effectiveness of ultrasonic--including time-of-flight-diffraction (TOFD) and phased array (PA) -microwave and digital x-ray non-destructive techniques (NDE) and their ability to discern defects that are typically encountered in the field.