Time-of-Flight Diffraction (TOFD) Services
TOFD uses diffracted ultrasonic signals from flaw tips for precise defect sizing and is often paired with PAUT.
What is Time-of-Flight Diffraction?
Time-of-Flight Diffraction (TOFD) is an advanced ultrasonic technique that uses the time of flight of diffracted signals from the tips of defects to accurately determine flaw height and through-wall extent. TOFD is widely used for critical weld inspection and is often combined with PAUT to provide comprehensive inspection coverage.
How TOFD Works
Two transducers in pitch-catch configuration
Diffracted signals from crack tips measured
Time-of-flight determines defect position and size
Less operator-dependent than conventional UT
Applications of Time-of-Flight Diffraction
Advantages
- Accurate defect sizing
- High probability of detection
- Permanent digital record
- Less operator-dependent
- Full weld volume coverage
- Fast scanning speed
Limitations
- Dead zones at surfaces
- Requires parallel scanning surfaces
- Specialized training needed
- Not ideal for thin materials
- Equipment cost higher than conventional UT
Applicable Standards & Codes
Industries Using TOFD
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Other NDT Methods
Ultrasonic Testing uses high-frequency sound waves to detect internal flaws, measure material thickness, and characterize material properties.
Learn moreRadiographic Testing uses X-rays or gamma rays to create images of a component's internal structure, revealing hidden defects.
Learn moreMagnetic Particle Testing detects surface and near-surface defects in ferromagnetic materials using magnetic fields and iron particles.
Learn moreLiquid Penetrant Testing reveals surface-breaking defects by applying a colored or fluorescent dye that seeps into cracks and discontinuities.
Learn more