5. Conclusions
Accurate characterization of planar flaws, in terms of orientation and depth, was carried out using an approach combining a linear array and SAFT. The major advantages of this approach are: (i) a single channel instrument with multiplexer is sufficient for data acquisition, (ii) divergent sound beam because of small element size, and small pitch of an array, results in effective SAFT processing and (iii) no computation of focal laws is required, which is a must for conventional phased array. The approach involves SAFT processing of B-scan data collected by divergent sound beam emanating from a single element of a linear array. During this process, the signals from flaw extremities get enhanced and the un-wanted mode converted signals are eliminated. Moreover, with this approach full-face mapping of flaws, especially those which are oriented at higher angles, is possible. Results obtained using SFLA approach on stainless steel plate with simulated planar flaws and carbon steel plates with real weld planar flaws have shown good accuracy in assessment of flaw orientation and flaw height, which are crucial parameters for fitness-for-service assessment.
