Feasibility Study to Demonstrate Detection of Low Levels of Oxygen Contaminant in Titanium Using Eddy Current and Ultrasonic NDE (Nondestructive Evaluation) Techniques,
ADAPTRONICS INC MCLEAN VA
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An eddy current and two ultrasonic techniques were employed to establish the feasibility of detecting low levels of oxygen contaminant in 6-2-1-1 titanium plates. The eddy current technique consisted of two probes used in a transmitreceive mode. The transmitter was stationary and generated eddy currents at driving frequencies between 250 kHz and 1 MHz. The receiver was varied in distance from the transmitter over a 0.125 to 1.0 inch range. It was found that the eddy current response was independent of oxygen content over the frequency and distance range considered. One ultrasonic technique measured the ratio of longitudinal velocities at 5 MHz and 20 MHz. No stron correlation was found between the velocity ratio and oxygen content. The second ultrasonic technique measured the ratio of the shear wave velocity to the longitudinal wave velocity at 5 MHz, where each wave traveled normal to the surface of the plate. A strong correlation ws found between the is velocity ratio and oxygen content. It is concluded that the shearlongitudinal velocity is related to the oxygen content. A proposed field implementation using this technique is presented.