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ToFD and Phase Analysis Webinar: Benefits for Defect Sizing

Tue, 05 November, 2024

TWI India recently held an engaging and informative webinar on the Time-of-Flight Diffraction (TOFD) technique, an ultrasonic testing method highly valued for its precision in detecting and sizing defects in various materials. This session offered a comprehensive look at TOFD and its applications, making it an ideal resource for professionals looking to expand their knowledge in advanced Non-Destructive Testing (NDT) techniques.

The webinar underscored the absolute benefits of TOFD for high-accuracy defect detection and emphasized the critical importance of phase analysis for determining the vertical extent of defects. With TOFD becoming a preferred technique across industries that demand high reliability, the insights shared in this session are valuable for practitioners seeking to stay ahead in the field of NDT. 

Key Topics Covered

The session was meticulously structured to cover every aspect of TOFD, from foundational principles to advanced analysis methods. Here is a summary of the main topics discussed:

  1. TOFD Basics and Principles

The webinar began with an introduction to TOFD, explaining the underlying principles of this advanced ultrasonic method. Attendees learned about TOFD’s unique approach to capturing diffraction signals from the tips of defects, which enables accurate flaw detection and sizing, even in challenging applications.

  1. Equipment Setup: Probe Selection, Intersection Depth Range, and PCS

An essential component of the session was understanding how to set up TOFD equipment. The importance of selecting the correct probes, determining the appropriate intersection depth range, and establishing the probe center separation (PCS) were highlighted as critical factors that significantly influence testing accuracy.

  1. Scan Types for Various Applications

To ensure that TOFD is used effectively, different scan types were explored for various applications. These tailored scanning methods allow for customization based on the requirements of specific projects, such as pipeline inspection, weld integrity assessments, and structural evaluations.

  1. Data Acquisition and Analysis: Sizing Methodologies and the Phase Reversal Technique

The webinar delved into data acquisition and analysis, introducing participants to TOFD’s sizing methodologies. A focal point was the phase reversal technique, a powerful approach in defect sizing that provides clearer data interpretation. This phase analysis is especially important for accurately measuring the vertical extent of detected defects, which is critical in high-stakes projects where precise defect characterization is necessary.

  1. Advantages, Limitations, and Applicable Codes and Standards

Finally, the session provided a balanced view of TOFD by discussing its advantages—such as high accuracy, fast inspection speeds, and minimal requirements for surface preparation—as well as its limitations, like challenges in detecting small planar defects. The importance of adhering to industry codes and standards for TOFD inspections was also covered, giving participants an understanding of compliance requirements and quality expectations.

Why TOFD Matters in Today’s NDT Landscape

As industries increasingly require high-precision testing methods, TOFD has emerged as a valuable tool that enhances safety and reliability in operations. This webinar reinforced TOFD’s role in elevating defect detection standards while also introducing practical techniques for data interpretation and accuracy in sizing. By mastering TOFD and phase analysis, NDT professionals can confidently assess material integrity, avoid potential failures, and contribute to safer project outcomes.

TWI India remains committed to delivering specialized training and resources for NDT professionals. This webinar exemplified that mission, equipping participants with the knowledge and skills to apply TOFD effectively in their work.

For those interested in further training or joining future webinars on NDT techniques, please contact: enquiries@twiindia.com

For more information please email:


enquiries@twiindia.com