Time of Flight Diffraction (TOFD)
The Time of Flight Diffraction (TOFD) ultrasonic method was developed in the late 1970s by Dr. Maurice Silk after a series of trials in the nuclear reactor PWR in the United Kingdom, due to the need in developing a more accurate ultrasonic method in the dimensioning of flaws.
It is used in various industrial sectors for detecting and sizing defects, especially in the onshore and offshore oil and gas industry, as well as in the nuclear industry. Nowadays, it used in multiple industrial sectors as detection and dimensioning tool, due to the multiple benefits that it has to offer.
The main advantage that it offers is that a single scan with TOFD probes across the weld is able to show all the defects within the weld, as well as the ability to collect, store, and process all the data collected from the inspection.
This method is very sensitive for all types of defects, it does not depend on the orientation of the defects, improving the overall probability of detection, providing improved dimensioning accuracy and minimizing false calls.
Course Content
- Principles of TOFD probes
- Principles of Inspection Sensitivity
- TOFD Instrument
- Scanning with TOFD probes
- Calibration and Equipment performance Checks
- Setting up of equipment
- Software for data collection
- Software familiarity
- Extensive practical element
- Procedures for verification of flaw existence and position
- Reporting
- Software for data analysis
- Principles of data analysis
- Use of software tools for detection and analysis
- Data analysis
- Relevant standards
- Extensive practical element
Responsibilities of a TOFD Testing Level 2 NDT professional:
- Select the TOFD technique for the test method to be used
- Define the limitations of application of the testing method
- Translate NDT codes, standards, specifications and procedures into NDT instructions adapted to the actual working conditions
- Set up and verify equipment settings
- Perform and supervise tests
- Interpret and evaluate results according to applicable standards, codes, specifications or procedures
- Prepare TOFD written instructions
- Carry out and supervise all tasks at or below level 2
- Provide guidance for personnel at or below level 2
- Report the results of TOFD tests
