Time of Flight Diffraction (ToFD)

Introduction

Time of Flight Diffraction (TOFD) is an Ultrasound Testing Technique uses the time of flight of an ultrasonic pulse to determine the position and size of a discontinuity. A pair of probe is used in pitch-catch mode, one probe as transmitter and other as receiver. The Time of Flight Diffraction (TOFD) ultrasonic test method is very sensitive and is very accurate.

Application

Inspection of Weld joints using Ultrasonic ToFD during construction to detect and size discontinuities and dispose them according to the construction code.

In-service inspection to detect the presence of service induced discontinuities Cracks, weld root erosion, HIC and Blisters. ToFD can be done for base line inspection and also for growth monitoring of any detected indication.

Benefits

• Ultrasonic ToFD is a well-established technique and recognised by many international codes (ASME, API, BSI, EN etc.) as a replacement to Radiography during construction activities.
• TOFD is a fast inspection tool based on diffraction principles, hence detectability does not depend on defect orientation and very thick components can be inspected.
• Superior sizing capabilities and generates vital information's for ECA and FFS studies.
• Inspection setups and data can be stored electronically enabling easy recalling/ comparison in subsequent inspections.