d = √((c · t / 2)² − S²)
Worked example PCS 70 mm, 15.1 µs, probe delay 2.5 µs d = 12.51 mm half path 37.17 mm
NDT calculators · TOFD
TOFD calculators.
Probe separation, timing, depth, sizing and the dead zones of a ToFD set-up. Each of the 17 shows the governing formula, a worked example and the standard it comes from.
1 works without an account; the other 16 open with a free member account. Join free or sign in.
Time of flight diffraction 17
Probe separation, timing, depth, sizing and the dead zones of a ToFD set-up.
TOFD Depth and sizing
ToFD depth from time of flight
Converts a measured ToFD arrival time into the depth of the diffracting tip below the scanning surface.
ISO 10863 · ASME V Free
TOFD Dead zones and errors
ToFD near-surface dead zone
Calculates the depth below the scanning surface within which diffracted signals are masked by the lateral wave pulse.
ISO 10863 · BS 7706
TOFD Timing, gates and scanning
ToFD lateral wave arrival time
Predicts where the lateral wave should appear on the ToFD A-scan for a given probe centre separation, velocity and probe delay.
ISO 10863 · ASTM E2373
TOFD Probes and PCS
ToFD beam spread and wall coverage
Computes the beam divergence from the probe crystal diameter and frequency, and the band of wall depth a single ToFD setup actually insonifies at the weld centreline.
ISO 10863
TOFD Depth and sizing
ToFD flaw through-wall height
Sizes a planar flaw by converting the upper and lower tip diffraction times to depths and taking the difference.
ISO 10863 · ISO 15626
TOFD Probes and PCS
ToFD PCS for a target crossing depth
Sets the probe centre separation so the two ToFD beam axes intersect at a chosen depth in the wall.
ISO 10863 · ASME V
TOFD Probes and PCS
ToFD PCS from the two-thirds wall rule
Gives the standard single-setup ToFD probe centre separation for beams crossing at two-thirds of the wall thickness.
ISO 10863 · ASTM E2373
TOFD Timing, gates and scanning
ToFD backwall arrival time
Predicts the backwall reflection time on a ToFD A-scan and the time window between the lateral wave and the backwall.
ISO 10863 · ASME V
TOFD Timing, gates and scanning
ToFD gate start and width
Derives the digitising gate start, end and width from the predicted lateral wave and backwall arrival times plus operator margins.
ISO 10863 · ASME V
TOFD Probes and PCS
ToFD depth zone division
Splits a thick wall into ToFD depth zones and gives the PCS and arrival-time window for the selected zone.
ISO 10863 · ASME V
TOFD Probes and PCS
ToFD probe delay and velocity from lateral wave and backwall
Solves the material compression velocity and the total wedge delay from the measured lateral wave and backwall arrival times on a known thickness.
ISO 10863 · ASME V
TOFD Dead zones and errors
ToFD backwall dead zone
Calculates how close to the far surface a diffracted signal can be resolved before it is masked by the backwall reflection.
ISO 10863 · BS 7706
TOFD Depth and sizing
ToFD depth resolution against depth
Converts a timing uncertainty into a depth uncertainty at a stated depth, using the gradient of the ToFD time-to-depth curve.
ISO 10863
TOFD Timing, gates and scanning
ToFD scan increment and speed
Checks the ToFD scan increment against the allowed value and the encoder resolution, and gives the maximum scan speed for the pulse rate and averaging in use.
ISO 10863 · ASME V
TOFD Probes and PCS
ToFD probe selection by wall thickness
Recommends ToFD probe frequency, beam angle, element size and number of setups for a given wall thickness, with the resulting PCS and near-surface dead zone.
ISO 10863 · ASTM E2373
TOFD Dead zones and errors
ToFD depth error from PCS error
Shows how much depth error an error in the probe centre separation produces at a given flaw depth, and the PCS tolerance needed for a target depth accuracy.
ISO 10863
TOFD Dead zones and errors
ToFD off-axis depth error
Gives the apparent depth of a diffractor that is not on the centreline between the probes, for an offset across the weld and along the scan axis.
ISO 10863
No calculators match
Check the spelling, try a method code such as UT or RT, or clear the filters.
193 calculations with worked examples
NDT calculators
FreeUTNear field length, circular probeNear-field (Fresnel zone) length N = D²f/4c for a circular single-crystal probe, with the wavelength it…Open calculator- FreeUTAngle beam sound path, surface distance and depthSolves the first-leg angle-beam triangle — sound path, surface distance and depth — from any one of the…Open calculator
- FreeTOFDToFD depth from time of flightConverts a measured ToFD arrival time into the depth of the diffracting tip below the scanning surface.Open calculator
- FreePAUTMaximum PAUT scan speedHighest encoded scan speed that still records every acquisition point, from the frame rate and the scan…Open calculator
- FreeRTSource decayCalculates the present activity of a gamma radiography source from its assay activity and the elapsed…Open calculator
- FreeMTCoil shot current, low fill factorAmpere-turns and coil current for longitudinal magnetisation in a low fill factor coil - part against…Open calculator
955 discussions · 383 answers
Latest forum discussions
NDTNDT technician roles and responsibilitiesNDT Inspect (admin) · 1 reply · 4 days agoNDT (non-destructive testing) technicians are responsible for using various methods to inspect and test…Read discussion
Phased ArrayPAUT Focusing problems (Near Field Length Compensation Options)ketkon · 1 reply · 13 days agoAbstractIn a previous report by the authors, the relative accuracy of Beamtool as it relates to calculations…Read discussion
Quality ControlWhat is the role of inspection in quality control?arsal · 1 reply · 13 days agoInspection involves measuring, examining and testing products, process and services against specified…Read discussion
Quality ControlBonding quality assessmentwilliam · 2 replies · 13 days agoDear sir, We are bonding steel and titanium alloys and assessing the bonding quality at the interface of the…Read discussion
Phased ArraySensitivity calibration in Phased Array UltrasonicsVisitor · 1 reply · 13 days agoHi,The manufacturer of the Phased Array equipment that I use indicates to calibrate the Sensitivity through…Read discussion- Hydrostatic TestingHelium Leak Test vs Hydrostatic Testwilliam · 2 replies · 13 days agoDoes anyone have experience or information on correlation of these tests? What will leak at hydro test vs…Read discussion