"Free ultrasonic testing calculators for NDT technicians: transducer near field, beam spread at any dB edge, maximum pulse repetition frequency, encoder PPR correction, and phased array step size, with notes on when each one matters.
Calculates the amount of change when the gain is changed on an ultrasonic instrument. Calculates the Pulse Rep. Freq. and Max depth for sound beam. Encoder calibration gives step resolution based on the PRF and the encoder wheel diameter. Calculates the wavelength produced in the material when the frequency and material velocity in m/s are known. (for Snell's Law use he calculator below this one)
Gives refracted and incident angles for various velocity ratios in material's and provides a ray visualization.
Calculates the half-angle of beam divergence from transducer diameter, frequency, and velocity using sin(θ/2) = K·v / D·f. The K value sets which edge of the beam you are calculating: K = 1.22 gives the 0 dB (null) edge, and K = 0.70 gives the −6 dB edge commonly used for beam-width and coverage checks. Larger diameters and higher frequencies produce narrower beams.
Calculates the percentage of relection of an ultrasonic wave as it crosses the boundary between two materials.
Calculates the near field length (N) of an ultrasonic transducer from element diameter, frequency, and material velocity using N = D²f / 4v. The near field is where sound pressure fluctuates, so flaw sizing and DAC/TCG reference reflectors are most reliable beyond it. Use this to check whether your calibration block reflectors sit past the near field for your probe and material.
Note: Changing the "K" value will calculate the edge of the beam where the sound pressure is equal to some value for example -6dB from max pressure. A "K" of 1.22 is 0 dB. 0.70 is -6 dB.
When setting your PRF for an inspection, ensure your Time Interval ($\Delta t$) is longer than the total time required for the sound to travel to the back wall and return to the transducer. If $\Delta t$ is shorter than the material travel time, the next pulse will fire before the previous one has returned, causing phantom signals.
Corrects encoder pulses-per-revolution when measured scan distance does not match actual distance. If your software reports 498 mm over a true 500 mm, the system is reading short; the calculator gives the corrected PPR to enter in your instrument. Encoder calibration is required for encoded phased array, TOFD, and automated UT scans and, under ASME Section V Article 13 (Acoustic Emission), now falls under the Subsection C structure.
Correction Factor: If your software reports 498mm but the actual distance was 500mm, your system is "short." Use the New PPR calculated above to adjust your software settings.
Subsection C Relocation: If you are using encoders for Article 13 (Acoustic Emission), this calibration is now governed under the new Subsection C structure.
Scan Resolution: Ensure your "Theoretical Step Size" does not exceed the maximum allowed for your procedure (often 1mm or less for high-sensitivity phased array scans).
These calculators are for educational purposes only. Always verifiy the results or consult NDT professionals for critical applications..