NONDESTRUCTIVE FLAW DETECTION AND DENSITY MEASUREMENTS IN POWDER METALLURGY PARTS

THE USE OF POWDER METALLURGY (P/M) FOR NET OR NEAR-NET SHAPE FORMED PARTS IS EXPANDING AT A VERY RAPID RATE. THIS RAPID GROWTH IS DUE TO THE MAJOR SAVINGS IN LABOR, MATERIALS, AND ENERGY THAT CAN ARISE FROM THE USE OF P/M TECHNOLOGY COMPARED TO CONVENTIONAL METALLURGICAL AND MACHINING PROCESSES. P/M HAS THE ADVANTAGE OF BEING A VERY RAPID AND ECONOMIC PRODUCER OF NET SHAPE AND NEAR NET SHAPE PARTS, WHILE USING LESS ENERGY THAN CASTING, FORGING, OR MACHINING. THE QUALITY AND RELIABILITY OF P/M PARTS COULD BE IMPROVED DRAMATICALLY BY THE DEVELOPMENT OF A RELIABLE AND ECONOMIC NONDESTRUCTIVE INSPECTION METHOD CAPABLE OF DETECTING CRACKS, LAMINATIONS, AND OTHER PARAMETERS AFFECTING A PART PERFORMANCE. RECENT WORK INDICATES THAT EDDY-CURRENT METHODS HAVE EXCELLENT POTENTIAL FOR NONDESTRUCTIVE INSPECTION OF P/M PARTS. IT IS ALSO EVIDENT THAT EDDY-CURRENT RESPONSES FROM P/M PARTS ARE OFTEN MUCH MORE COMPLEX THAN FROM CONVENTIONAL METALLURGICAL PARTS AND ADDITIONAL RESEARCH IS REQUIRED TO PERMIT APPLICATION OF EDDY-CURRENT TECHNOLOGY ROUTINELY TO P/M PARTS, PARTICULARLY GREEN OR UNSINTERED P/M PARTS. THE RESEARCH IS DEVELOPING THE EDDY-CURRENT TECHNOLOGY (PROBES, INSTRUMENTATION, DATA PROCESSING, AND TEST PROCEDURES) NECESSARY TO PERMIT ROUTINE INSPECTION OF P/M PARTS. THE TEST INSTRUMENTATION IS BASED ON THE SMARTEDDY 3.0, A GENERAL PURPOSE, COMPUTER BASED, MULTI-FREQUENCY INSTRUMENT. THE FEASIBILITY OF USING COMPUTER BASED EDDY-CURRENT METHODS TO DETECT CRACKS AND OTHER ANOMALIES, AND MEASURE DENSITY AND OTHER VARIABLES, IN BOTH FERROUS AND NON-FERROUS, GREEN AND SINTERED P/M PARTS IS DEMONSTRATED.