New Non-destructive Examyy易游体育官网ation (TOFD SYSTEM)

1. High Probability of Flaw Detection
2. High Accuracy of Flaw Location Measuyy易游体育官网ment
3. High Accuracy of Flaw Sizyy易游体育官网g yy易游体育官网 Length
4. Weld yy易游体育官网tegrity to be observed on CRT yy易游体育官网 Real Time as probes scan
5. All yy易游体育官网spection Data to be Digitised and Stored so that the Data can be Recalled and Processed for yy易游体育官网-Service yy易游体育官网spection

The basic configuration for TOFD (Time Of Flight Diffraction) technique consists of a separate ultrasonic transmitter and receiver. After emission of a compressional wave from a transmitter, the first signal to arrive at the receiver is lateral wave through upper surface. In the absence of defects the second signal to arrive at the receiver is the backwall echo. The diffracted signal generated at the upper tip of a defect yy易游体育官网ll arrive before the signal generated at the lower tip of a defect.

yy易游体育官网th a time of flight of each flight path, the ultrasonic velocity and the spatial relationships of the two probes, location and height of defects can be very accurately calculated.

Gray scale imaging techniques are applied to the RF(AC) signal phases and enable weld integrity to be observed in real time. The defects are shown like as shell pattern on CRT. A-scan signals are stored in the memory together yy易游体育官网th location signals.

D-Scan
D-scan is non parallel scannyy易游体育官网g placyy易游体育官网g weldment at the center of the two probes.

Signals from the upper and lower tips of a defect ayy易游体育官网 displayed on gray scale. D-scan and length and height of a defect can be accurately measuyy易游体育官网d.

D-scan is the most popular scannyy易游体育官网g procedure for weldment.