Ultrasonic Flaw Detection of Edges in Automatic Testing Through Object Extension

Edge flaw detection is a complicated task in ultrasonic testing for both ends of a tube or theedge of pieces. That's why a majority of globally known automatic testing systemmanufacturers exclude this feature from their products. As a rule of thumb, a span of ۱۰ to ۲۰cm from each end of objects is defined as an outlier and the user needs to find an alternativetesting solution. The main reason for this situation is the geometrical limitations that a probeholder suffers in covering the body of pieces to be tested. Because an array of different probesare included in a casing larger than the probe itself to scan the piece, all probes can't disseminatetheir signals on the piece's edges at zero testing time (the starting time of a test from one endof a piece). This is an inevitable issue in the manual approach too when the wave projectionand scan direction are the same. To resolve the problem, the full-immersion method can beapplied where both the object and probes are submerged in a liquid. Although, the need forsinking parts in a couplant makes it slow and costly for sizable parts like pipes and cylinders.This paper proposes a new contact technique for ultrasonic edges based on the extension of theobjects’ ends that offers a higher speed and less complexity compared to the full-immersionmethod.

Keywords:

Non-destructive testing , Ultrasonic , Automatic test , Immersion , Couplant , Probes