Abstract: Ultrasonic testing methods and units for characterizing planar flaws in hard-to-inspect materials such as welded and cladded pipes containing intergranular stress corrosion cracks. The invention characterizes flaws with pitch-catch transducers positioned front to back on a single module. One module uses a bimodal transducer to transmit longitudinal and shear waves to produce, through surface wave mode conversion, reflection and diffraction, a triplet of associated longitudinal and shear wave signals received by another bimodal transducer. Other modules use pitch-catch transducers to produce a doublet of associated shear wave signals from diffraction of an incident longitudinal and/or shear waves at the upper and lower extremities of underclad fatigue cracks and buried cracks. The signals are enchanced by multiple one sided cross focusing on preselected target areas in the test specimen and are cognizable by pattern recognition.

Abstract: A reliable ultrasonic method for testing inner diameter cladded pipe adjacent to welds comprising use of multiple beams, bands and pulses in addition to pulseshaping and beamforming, spectral and directional averaging, as well as spatial filtering and pattern recognition. An automated inspection mode aims short shear-wave pulses from different source locations and different beam orientations to detect signals characteristic of defects. A manual confirmation mode aims both longitudinal waves and shear waves at the suspected defect and analyzes the detected returned pulses by an associated pulse pattern recognition method.

Abstract: A nondestructive testing method of ultrasonic defect characterization based upon the separation in time-of-arrival between the reflected pulse and its leading diffracted satellite pulse in the case of a crack-like defect and its lagging scattered satellite pulse in the case of an inclusion-like defect is shown. The angle beam, single probe type, echo ranging technique differentiates the main defect reflection from the satellite pulses of the defect and uses the sequence and magnitude of the separation in time-of-arrival between the pulses to determine the shape and size of the defect. Due to a discovered linear relationship between the ultrasonic delay time and defect size, the time scale of an oscilloscope's screen can be adjusted to read directly in terms of crack depth or inclusion diameter. Beyond the need to recognize returning pulses, the relationship is independent of wave amplitudes and the technique is thus easily utilized and is compatible with many different types of materials to be tested.