Improved ultrasonic standard reference blocks

NIST calibration of ASTM E127-type ultrasonic reference blocks

“…5 hole set. Previous research at NIST has shown that these procedural differences yield more precise and meaningful reference block calibration data, in consonance with E127-92a [6].…”

“…The transducer beam profiles, taken on a 12.7 mm (0.5 in) diameter steel sphere target, are shown in Figs. [4][5][6] Commercial equipment or materials are identified in this paper in order to specify adequately certain calibration procedures. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the material or equipment identified is necessarily the best available for the purpose.…”