Ultrasound Precision for Perfect Welds: TOFD at Work
TOFD technology detects and measures cracks in welds using ultrasound waves.
Time of Flight Diffraction is used for a variety of applications, being the primary use is rapid weld testing of circumferential and axial weld seams, also known as perpendicular TOFD scanning.
TOFD is performed using longitudinal waves as the primary detection method through the ultrasonic sensors that are placed on each side of the weld. One sensor sends the ultrasonic beam into the material and the other sensor receives reflected and diffracted ultrasound from anomalies and geometric reflectors.
Using ultrasonic beam spread, TOFD provides a wide area of coverage for anomaly detection in the material being tested. When the beam comes in contact with a tip of a flaw, or crack, diffracted energy is cast in all directions. Measurements of the time of flight of this diffracted beam enable accurate and reliable flaw detection and sizing.
This is the case even if the crack is not oriented to the initial beam direction. During typical TOFD inspections, A-Scan is collected and used to create B-Scan (Side View) images of the weld. Post-acquisition analysis is done using software to measure the flaw length and through-wall height.
- Inspection of high-pressure and high-temperature pipe welds on circumferential and seams weld between 20mm to 75mm wall thickness.
- Sizing of known defects has been performed all around the country on pipeline welding, and high-pressure vessels. A generated analysis report outlining the sizing of defects can be provided to the client for their reference.
