Time of Flight Diffraction (tofd), an Advanced Non-destructive Testing Technique for Inspection of Welds for Heavy Walled Pressure Vessels
نویسنده
چکیده
TOFD technique is based on diffraction of ultrasonic waves on the tips of discontinuities instead of reflection on the interface of discontinuities. When ultrasound is incident at linear discontinuities such as crack diffraction takes place at its extremities in addition to the usual reflected wave. The diffracted energy is emitted over a wide angular range, presumed to originate at the extremities of the flaw.
منابع مشابه
A Novel Method for Ultrasonic Evaluation of Horizontal Defects Using Time-of-Flight Diffraction
Time-of-flight diffraction method (ToFD) is an amplitude-independent sizing method which is based on the measurement of time-of-flight of defect tip diffracted waves. Although ToFD can measure through-wall length of defect accurately, this method is not capable of measuring horizontal defect size. In this paper, a new ToFD method for evaluating horizontal planar defects is presented. The finite...
متن کاملFeasibility Study Using Time of Flight Diffraction Technique in Lieu of Radiography on Heat Exchanger Shell Weld Joint
Welded constructions play a vital role in power plant components. Power industry utilization of radiography for integrity of welds is a common practice in the vessel manufacturing industry. Recent developments in the field of ultrasonic utilize Time of Flight Diffraction Technique (ToFD) for evaluation of welds with respect to Engineering Critical Assessment approach for evaluation of welds. Re...
متن کاملAutomatic Classification of Defects in Time-of-flight-diffraction Data
Ultrasonic Time-Of-Flight Diffraction (TOFD) is a recent innovation that has proved highly effective for the inspection of steel plates and tubular pipelines and has started to take its way to replace the other ultrasonic testing techniques. TOFD technique has a lot of advantages which make it the preferable technique in material testing. This technique gives accurate sizing, positioning and ch...
متن کاملFourier Analysis of Ultrasonic TOFD Signals for Defect Detection in Austenitic Stainless Steel Welds
Non Destructive testing of structural materials is an important activity in many industries. Ultrasonic NDT is one such method widely used in this field. Pulse Echo and Through Transmission are conventional testing techniques which use reflected and transmitted sound energy respectively. But these techniques are highly dependent on defect orientation. Time of Flight Diffraction (TOFD) is a rece...
متن کاملAcoustic Emission Inspection of Spherical Metallic Pressure Vessels
Non destructive evaluation of metallic, spherical pressure vessels is crucial to the safety and operations of a plant due to the large volume of hazardous products stored at high pressures. Sizes of such spheres vary and diameters may range from 10 to 25 meters, even more, while total length of welds can be hundreds of meters. Additionally, accessibility for inspection is often limited, as is t...
متن کامل