METHOD OF DETERMINING GRAININESS CHARACTERISTICS OF FLAT METAL ARTICLES USING ULTRASOUND Russian patent published in 2010 - IPC G01N29/04 

FIELD: physics.

SUBSTANCE: elastic waves are successively emitted by transducers normal to the surface of an article and normal to the surface of an tuning specimen at two frequencies f₁, f₂, first bottom pulses are received on these frequencies and their amplitude is measured. A third frequency f₃ is also emitted, where f₁<f₂<f₃. Material of the tuning specimen is selected based on the condition for obtaining a negligibly small attenuation coefficient on ultrasound frequencies used and the value of its height is not less than 3 closest zones of the transducer. The difference between amplitude values B₁, B₂ and B₃ of pulses received from the tuning specimen and article at the same frequencies is measured and two difference values between amplitude values B₁-B₂ and B₁-B₃ and between the measured difference at minimum frequency and each of the measured differences at the remaining two frequencies are measured, after which the value of the graininess characteristic is determined based on the obtained data.

EFFECT: possibility of measuring not only the average grain diametre, but uniformity of the structure of an article.

1 dwg