SO-3R calibration block enables to:
- define the beam index of ultrasonic waves and the probe X-value, with the error of ± 0.5 mm;
- determine the refracted angle of ultrasonic waves, with the error of ±1 angular degree;
- estimate an untested “dead” zone (in steel) of the flaw detector with UT probe that is set to a specified sensitivity;
- adjust the scanning speed of the flaw detector with the probe;
- set up the flaw detector with the probe to a specified conditional sensitivity.
The velocity of propagation of longitudinal ultrasonic waves in the calibration block material at frequency of 2.5 MHz and temperature of (20±5) ºС is equal to (5900±59) m/s.
The time of ultrasonic wave propagation during the sweep setup is (20±0.5) μs.
The scale zero for determination of the probe beam index coincides with the center of calibration block radius, at accuracy of (±0.1) mm.
The geometrical dimensions of calibration block conform to GOST 18576-85.