Karthik Narayan, Derrick D. Hongerholt and Joseph L. Rose 114 Hallowell Building, The Pennsylavania University University Park, PA 16801
Keywords: Ultrasonic density gradient, velocity measurement, broad band, narrow band, pressed metal parts
ABSTRACT
A variety of different ultrasonic bulk and guided wave techniques are explored to evaluate the density and density gradient levels of pressed iron metal components. In particular, bulk longitudinal and shear wave measurements are used to depict certain manufacturing parameters used in various pressed parts. These waves are also used to examine the influence of packing pressure, particle size, particle shape, and base material on the received signal. The features that are studied from the received ultrasonic signal are velocity, frequency, and attenuation measurement. The potential for using narrow band versus broadband excitation is also studied in conjunction with the effects of varying excitation frequency. The results are used as an aid in the characterization of pressed powder metal parts prior to the sintering process. Characterization of specimen quality prior to sintering is desired, since sintering low quality parts is not cost effective. Basic parameters of wave velocity are studied on a "C" scan basis. Guided surface wave techniques are used to explore density gradient with depth using the dispersive character of the Rayleigh surface wave velocity. Some signal processing techniques to clarify the classification process are also discussed. Excellent results are obtained.
Publication Source: Trends in NDE Science & Technology; Proceedings of the 14th World Conference on Non-Destructive Testing, New Delhi, 8-13 December 1996.Vol. 2, pages 549 - 552 Publisher:Ashgate Publishing Company
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