THE PROPOSED EFFORT IS BASED ON A POTENTIALLY POWERFUL UNEXPLORED NONDESTRUCTIVE TESTING TECHNIQUE "ELECTRO-ELASTICSELF-SCANNING CRACK DETECTOR", U.

THE PROPOSED EFFORT IS BASED ON A POTENTIALLY POWERFUL UNEXPLORED NONDESTRUCTIVE TESTING TECHNIQUE "ELECTRO-ELASTICSELF-SCANNING CRACK DETECTOR", U.S. PATENT NO. 4,481,821 (J.R. CHAMUEI = I9S4) CAPABLE OF DETERMINING IN REAL TIME THE PRESENCE, LOCATION, NUMBER, AND SIZE OF DEFECTS PRESENT ALONG A LINEAR PATH ON THE SURFACE OF A CONDUCTIVE MATERIAL UNDER TEST PIPES, TUBES, PLATES) WITH A CONTACTLESS SENSOR. THE SENSOR CONSISTS OF A MAGNETOSTRICTIVE DELAY LINE PLACED IN CLOSE PROXIMITY TO THE SURFACE TO BE INSPECTED. A CURRENT CARRYING WIRE PLACED ADJACENT AND PARALLEL TO THE DELAY LINE IS USED TO INDUCE EDDY CURRENTS IN THE MATERIAL. THE PRESENCE OF A FLAW IN THE MATERIAL CREATES TRANSVERSE EDDY CURRENTS. THE ELECTROMAGNETIC FIELD OF THE TRANSVERSE EDDY CURRENT COMPONENTS INTERACTS LOCALLYWITH THE MAGNETOSTRICTIVE DELAY LINE LAUNCHING ULTRASONIC WAVES IN THE DELAY LINE. PULSED ULTRASONIC WAVES ARE GENERATED BY USING PULSED ELECTRICAL CURRENTS IN THE CURRENT CARRYING WIRE. THE ULTRASONIC WAVES ORIGINATE AT THE FLAW EDGES LOCATIONS ALONG THE DELAY LINE. SRATIAL INFORMATION REGARDING FLAW EDGE LOCATIONS IS PRESERVED IN THE TIME INFORMATION OF THE ULTRASONIC WAVES PROPAGATING IN THE DELAY LINE. AN ULTRASONIC RECEIVER COUPLED TO THE DELAY LINE IS USED TO DETECT THE TRAVELING WAVES. THE NUMBER OF ULTRASONIC PULSES INCREASES AS THE NUMBER OF FLAWS INCREASES. THE CONTACTLESS PROBE IS NOT SUCCEPTIBLE TO THE PRESENCE OF MECHANICAL VIBRATION NOISE IN THE MATERIAL AND CAN OPERATE AT HIGH TEMPERATURES. THE PROBE WHEN FORMED IN A CIRCULAR OR HELICAL PATH AROUND A PIPE WOULD AUTOMATICALLYSELF-SCAN THE PATH AND PROVIDE INFORMATION REGARDING THE PRESENCE, LOCATION, NUMBET, AND SIZE OF CRACKS. THE LOCATION OF A CRACK IS DETERMINED FROM THE TIME OF ARRIVAL OF THE CORRESPONDING ULTRASONIC PULSE IN THE DELAY LINE. THE CONCEPT IS POWERFUL AND UNIQUE SINCE IT COMBINES THE ADVANTAGES OF ULTRASONIC, EDDY CURRENT, AND ELECTROMAGNETIC NDE TECHNIQUES. THE OBJECTIVE OF PHASE I IS TO ASSESS THE APPLICATION OF THE PROPOSED TECHNIQUE TO HIGH-SPEED RELIABLEINSPECTION OF HOT PIPES AND COMPONENTS WITHOUT COUPLANTS.