Phased array and time-of-flight diffraction are the advanced end of ultrasonic testing. Where conventional UT gives a reading at a single point and a single angle, these techniques build an image of the weld — one you can review, store, and compare against a later inspection.
Phased Array (PAUT)
A phased array probe contains many small elements instead of one. By firing them in a controlled sequence, the beam can be steered through a range of angles and focused at different depths electronically — without moving the probe or changing wedges. The result is a sectorial image of the weld cross-section, captured as the probe travels along the joint.
- Full volumetric coverage of the weld in a single pass
- Flaws located and sized in a recorded, reviewable image
- Encoded scans that can be archived and compared over time
- Effective on complex geometry — nozzles, branch connections, and thick sections
Time-of-Flight Diffraction (TOFD)
TOFD uses a pair of probes facing each other across the weld. Rather than relying on the strength of a reflected echo, it measures sound diffracted from the tips of a flaw. Because the measurement is based on timing rather than amplitude, TOFD sizes flaw height with a precision conventional techniques cannot match — which is exactly what matters when deciding whether a defect is acceptable or must be repaired.
- Highly accurate flaw height sizing
- Fast coverage of long weld runs
- Excellent detection of flaws regardless of their orientation
- Permanent digital record of the scan
PAUT and TOFD are frequently applied together — TOFD for rapid screening and accurate height sizing, PAUT for detailed characterisation and coverage of the near-surface zones where TOFD is weakest.
Why Choose PAUT and TOFD Over Radiography
- No radiation — no exclusion zone, no evacuation, no permit, and no shutting down surrounding work
- Work continues around you — inspection proceeds during normal shifts instead of overnight
- Immediate results — no film processing delay; findings are available on site
- Better height sizing — radiography shows a flaw’s length well but its through-wall height poorly
- Digital records — scans are archived and re-examined without storing or retrieving film
Where We Apply Them
- Pressure vessel and boiler welds, including thick-section seams
- Process and transmission pipeline girth welds
- Structural and offshore fabrication welds
- Nozzle and branch connection welds
- Corrosion mapping across defined areas
- Weld overlay and clad bond inspection
Why Work With Us
- Personnel qualified and certified in accordance with ASNT SNT-TC-1A and ISO 9712
- Approved service supplier for ABS, BKI, BV, RINA, ClassNK, KR, DNV, IRS and LR
- IRATA-certified rope access technicians who also hold NDT qualifications
- Encoded, archived scan data supplied with the report
- Based in Batam, close to the yards and facilities we serve
Request a Quote
Phone / WhatsApp: +62 813 7202 1412
Email: info@htmarineinspection.com
Office hours: Monday – Friday 08.00 – 17.00, Saturday 08.00 – 14.00