Model-based enhancement of the TIFD for flaw signal identification in ultrasonic testing of welded joints

Flaw signal identification of ultrasonic testing is usually carried out prior to the quantitative evaluation of flaws for classification and sizing. In many practical inspection of welded joints, it becomes a truly difficult task due to the presence of non-relevant indications caused by various geometric reflectors. To overcome such a difficulty, the TIFD (Technique for Identification of Flaw signals using Deconvolution) has been proposed previously. In the present work, model-based enhancement of the TIFD is considered for the convenience of practical application. The current, enhanced approach adopts only one reference signal which is the reflection from the circular part of the STB-A1 block. Deconvolution patterns for the geometric reflections and flaw signals are predicted by use of theoretical ultrasonic testing models. The deconvolution patterns are strongly dependent on the type of the flaws, and are useful for the screening of flaw signals from the non-relevant indications caused by geometric reflections.