Defect Detection in Billet Using Plane-Wave and Time-of-Flight Deviation with Transmission Method

In this paper, we introduced a one-shot measurement using plane-wave with time-of-flight (TOF) based transmission method and validated the method using wave propagation simulations. The defect in billet can be detected regardless of the defect position even in the vicinity of the surfaces of a billet. Although TOF deviation is smaller and range of transducer position $X$ where TOF deviates are wider than that of conventional transmission method with TOF, one- shot measurement using plane-wave with TOF can accelerate the speed of the inspection of steel billet using transmission method.