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Ultrasonic Noise and the Volume of the Ultrasonic Pulse

  • P. J. Howard
  • R. S. Gilmore

Abstract

The ultrasonic inspection of large grained engineering materials such as titanium alloys is often limited in finding low reflectivity targets due to reflections from grain boundaries. These unwanted signals are often referred to as grain noise. Recently, experimental work was performed showing the effects of ultrasonic scan parameters on grain noise level and signal to noise ratio. [1,2] Techniques such as using broadband ultrasonic pulses, subsurface focused beams, higher frequencies and smaller beam diameters were shown to dramatically improve SNR for both air-backed and low reflectivity targets in Ti6–4. There is one common element in all these items which reduce the ultrasonic noise level when compared to that of the target signal: a reduced ultrasonic beam volume. This paper will outline an experimental technique for measuring the volume of an ultrasonic pulse and demonstrate with experimental data that the level of ultrasonic grain noise in titanium alloys is proportional to that volume.

Keywords

Pulse Volume Noise Amplitude Ultrasonic Pulse Sample Block Focal Zone 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1996

Authors and Affiliations

  • P. J. Howard
    • 1
  • R. S. Gilmore
    • 2
  1. 1.GE Aircraft EnginesCincinnatiUSA
  2. 2.GE Corporate Research & Development CenterSchenectadyUSA

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