Patent ID: 6125703
Filing Date: 2000-10-03
Classification: G01N

Abstract:
A method for detecting damage in a ferromagnetic workpiece, comprising the steps of:positioning a pair of EMAT coils adjacent to an outer surface of the workpiece at a non-zero angle with respect to one another;applying a spike pulse to one of the EMAT coils for a period of time which is less than the time required to generate a toneburst signal in the one of the EMAT coils in order to magnetostrictively generate a shear horizontal polarized wave in the workpiece, wherein the shear wave is capable of being reflected by a flaw in the workpiece;receiving a reflected wave from a flaw in the workpiece at the other EMAT coil; andanalyzing the received reflected wave and comparing an amplitude thereof to an amplitude of a reflected wave produced by a known calibration standard flaw and producing an indication that a flaw has been detected in the workpiece when the amplitude of the received reflected wave exceeds a predetermined percent of the amplitude of the reflected wave produced by the known calibration standard flaw.