Section 2: TOFD Theory
- Butt welds
- Digital instrument, pulser/receiver, digitizer, filters, gain
- Probes, frequency spectrum, signal waveform
- Wedges, hard wedges
- Scanner, encoder
- Huygens’ principal, diffraction
- Snell’s law, incident vs. refracted, critical angles
- TOFD A-Scan, phase shift, phase difference, averaging
- PCS, transit time, depth calculation, height calculation, position uncertainty
- Beam spread, beam spread in-wedge, beam spread in-part, frequency spectrum
- Lateral wave, backwall, mode-converted backwall
- Dead zones, accuracy, resolution
- B-Scan, gray scale
- Whisker effect, parabolic cursors
- Non-parallel and parallel scans
- Multiple scans
- Influence of frequency on coverage, dead zones
- Influence of wedge angle on time scale, coverage
- Influence of PCS on dead zones, resolution, coverage
- How to optimize the digitizing frequency, filters, averaging, time window, sensitivity, PRF
- Calibration of the beam index point, velocity
- Scanning speed
- Wedge delay calibration, lateral wave straightening, lateral wave removal
- Interactive exercises on setups, beam index point and velocity calibration, scanning
- Interactive exercises on wedge delay calibration and lateral wave straightening
- Section’s test
| Category | Page |
|---|---|
| Theory | 13 |
| Movies | 34 |
| Interactive Exercices | 57 |
| Section's Test | 1 |