The Inquiry of Improving Quantitative Accuracy of Flaw Length in TOFD Technique Based on SAFT

In ultrasonic time of fight diffraction (TOFD) inspection,the arcs at the ends of flaws will reduce the quantitative accuracy of flaw length.To solve this problem,numerical simulation with CIVA software was performed,and the synthetic aperture focusing technology (SAFT) was developed to process and reconstruct the D-scan image.Nine rectangular defects with the lengths ranged from 5.0 to 45.0mm were investigated.The results showed that D-SAFT processing technique was effective to weaken the arcs of flaw,and the maximum defect quantitative error was reduced from 5.0mm to 0.6mm.In addition,based on the angle dependent deconvolution (ADD) method combined with SAFT,the improving method of flaw quantitative accuracy in TOFD technique was prospected.