Time-of-Flight Diffraction (TOFD)
Method Overview
Precision diffraction-based flaw sizing and monitoring, providing high-accuracy weld integrity assessments.
Core Method Specifications
Target Applications & Governing Standards
2 Scopes ConfiguredMethod Limitations & Operational Boundary Conditions
Critical physics limits, thermal envelopes, blind spots, and ASME Sec V / API procedural boundaries for TOFD.
Lateral wave transit time drifts with elevated temperatures, corrupting flaw depth calculations if uncompensated.
Lateral wave duration masks upper 2.0 mm to 4.0 mm of wall; backwall echo rings down over bottom 1.0 mm to 2.0 mm
Constant pressurized water delivery line to both transmitter and receiver wedges
Omnidirectional diffraction energy from crack tips; highly insensitive to defect tilt angles
- •OD Near-Surface Lateral Wave Blind Zone: Flaws in top 2-4 mm hidden behind the direct surface wave pulse
- •ID Backwall Dead Zone: Flaws within 1-2 mm of inner diameter obscured by high-amplitude backwall reflection pulse
- •Transverse cross-weld cracks parallel to sound beam axis generate minimal diffraction signals
Lateral wave straightening artifacts distorting depth readings near uneven plate root gaps
Mandatory tandem pairing: PAUT pulse-echo inspects OD/ID dead zones missed by TOFD
Rapid surface verification of OD weld cap and toe crack indications
Technique-to-OEM Compatibility Matrix
Verified manufacturers, instrument models, and diagnostic portals supporting TOFD.
Sonatest
Pioneering British manufacturer of rugged ultrasonic flaw detectors, phased array instruments, wheel probes, and precision UT transducers.
Zetec
Advanced eddy current and ultrasonic NDT technology subsidiary of Eddyfi/Roper for nuclear power generation, aerospace, and balance-of-plant tube inspections.
JIREH Industries
Canadian manufacturer of precision manual and automated ultrasonic scanners, circumferential pipe crawlers, and encoder accessories for weld and corrosion mapping.
EKOSCAN Integrity
French manufacturer specializing in advanced ultrasonic testing (UT), Phased Array (PAUT), specialized transducers, calibration blocks, and automated weld scanners.
Electronic & Engineering Co. (EECI)
Renowned Indian manufacturer of custom ultrasonic probes, phased array wedges, automated ultrasonic inspection systems, and magnetic particle test benches.
Phoenix ISL
UK boutique designer of specialized ultrasonic transducers, custom PAUT phased array probes, and automated robotic scanners for nuclear and aerospace.
Evident Scientific
OEM Manufacturer for TOFD inspection systems.
Waygate Technologies
OEM Manufacturer for TOFD inspection systems.