05 Feb Time of Flight Diffraction (TOFD) Testing

What is Time of Flight Diffraction (TOFD) Testing Method in NDT ?

Time of flight diffraction is a reliable non destructive testing method mainly used to find flaws in the welds. Like all other ultrasonic testing methods, TOFD uses ultrasonic pulse to locate the irregularities.

What makes TOFD different from other ultrasonic testing methods is that it measures the response time of both the high amplitude and low amplitude sound waves that reflect from the back of the component. Most UT methods only measure the high amplitude sound waves.

TOFD method uses a pair of ultrasonic transducers, one of which acts as a transmitter and the other as a receiver. The low frequency waves always travel at an angle and only diffract back to the receiver when they hit a defect. When it hits a defect, the time it takes for both the high and low frequency waves to make it to the receiver can be used to develop the complete image of weld.

This makes the flight of diffraction testing method the most precise and fastest nondestructive testing method

Advantages of using  time of diffraction testing method

• Fastest method to detect discontinuities
• Precise and accurate sizing and positioning of discontinuities
• Can be reproduced with less than 0.5mm accuracy
• Can create permanent digital records with graphic images
• Can detect discontinuities regardless of type and orientation.
• Compliant to ASME code case 2235
• Gives consistent results  between pre and post heat treatment
• Consistent results between pre and in-service inspections
• Has a higher probability of detection compared to other UT methods
• No radiation is used during the operation
• The results of testing are immediately available
• This testing method can be carried out at above 200 degree Celsius temperature.

Application of TOFD testing method

• Petrochemical, oil refining and power plants
• Marine and offshore industry
• Manufacturing industry
• Nuclear plants
• Aerospace and defence sector
• Construction industry

Enrol for 1 month preparatory classes for TOFD testing exam

Gamma NDT academy offers NDT preparatory classes for candidates who intend to appear for the ASNT Level 2 and 3 TOFD and UT  certification exam. 

We will cover all the syllabus under ASNT for TOFD and UT certification exam and conduct mock tests to prepare you for the exam. We will also share study materials and sample questions which you need to revise. We have a 100% success rate for NDT certification courses.

Gamma NDT academy training institute is located in Kerala, India. We provide online classes for candidates who cannot attend our training sessions in-person.