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Pipeline Scanning | Ultrasonic
Weld Testing | TOFD | Engineering
Critical Assessment | AUT
Weld Equipment
Time of Flight Diffraction
TOFD – Time of flight diffraction
Time of Flight Diffraction (TOFD) is included in the UT Scan Quality Assurance System as an additional inspection method. TOFD is utilized to collect additional information such as evaluating, characterizing and locating indications with unaccepted orientations and/or defect locations. It is implemented for accurate sizing and provides a safety net.
TOFD is a well-proven, extremely reliable, advanced ultrasonic testing method used to inspect welds that is more sensitive than radiography and also doesn't have the safety hazards of the latter method. TOFD can also replace AUT when it is more practical to do so. It utilizes two angle compression wave probes in a pitch-catch arrangement. The wave probes are placed on both sides of a weld and aimed at the same point in the weld volume. The weld is then flooded with ultrasound using a single uni-axial scan pass along the weld length. Based on the measures, TOFD determines the arrival times of the various signals. In this way, TOFD can effectively determine the height, length and location of any weld defects.
In addition, TOFD is relatively unaffected by the size, shape, location or position of flaws. These factors can pose more of a challenge using AUT thus TOFD is a perfect back-up partner in the weld testing process.
Benefits of TOFD
- Options for scanning include semi or fully automated, or manual
- Quick setup time
- Exceptional application for unique weld geometries such as flanges or buckle arrestors
- Provides reliable results
- Rapid single-pass weld inspection