CIVA Comparison of Responses from Planar Flaws on Weld Bevel Surfaces

It is well known that an ultrasonic beam provides a maximum echo reflection when the beam impinges at right angles to the surface. To this end, some inspection standards recommend using refracted angles that provide normal incidence to a weld bevel in order to detect lack of fusion indications. However, perpendicular incidence cannot always be achieved and it is often not even possible to know the exact angle that a weld bevel was prepared. Although incident angle is an important factor in flaw detection, it is not the only factor that should be considered when preparing an ultrasonic weld inspection procedure. Civa simulations and experimental tests are used to assess the effects of angle, frequency and flaw size on the probability of detection of ideal planar flaws located on weld bevel surfaces.