PHASED ARRAY TECHNOLOGY

PHASED ARRAY TECHNOLOGY The laws of physics apply to phased array as well as to classical ultrasonic testing. Element Size: Maximum Sweep Range of Phased Arrays is determined by the element size. This is done using the classical UT formula for calculating beam spread (γ). Smaller the element size, higher is the sweep range. This is what gives Phased Arrays the ability to sweep large angles. Once the desired beam sweep is achieved there is little point using smaller elements. A 5 MHz, 1mm element size will give an approximate sweep of 70 degrees for S-wave in steel and 140 degrees for L-waves in steel. Reducing the element size and thereby...

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PHASED ARRAYS FOR WELD INSPECTION

The concept of weld inspection is shown below. A probe is selected that illuminates the weld as shown below. In the first leg, only the bottom half of the weld is illuminated. However, with reflection from the ID surface the entire weld is illuminated and the complete weld volume can be inspected. For example, the indication ‘a’ in the weld is detected by the reflected sound and displayed as the mirror image ‘a-’ in the second leg. Similarly other flaws are displayed in the image. Concept of phased arrays for Weld Inspection. Indication ‘a’ detected by the reflected beam is displayed as a mirror image ‘a-‘ in second leg Examples...

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PHASED ARRAYS FOR WELD INSPECTION

The concept of weld inspection is shown below. A probe is selected that illuminates the weld as shown below. In the first leg, only the bottom half of the weld is illuminated. However, with reflection from the ID surface the entire weld is illuminated and the complete weld volume can be inspected. For example, the indication ‘a’ in the weld is detected by the reflected sound and displayed as the mirror image ‘a-’ in the second leg. Similarly other flaws are displayed in the image. Concept of phased arrays for Weld Inspection. Indication ‘a’ detected by the reflected beam is displayed as a mirror image ‘a-‘ in second leg Examples...

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What are Ultrasonic Phased Arrays?

What are Ultrasonic Phased Arrays? Ultrasonic phased arrays use a multiple element probe whereby the output pulse from each element is time delayed in such a way  so as produce constructive interference at a specific angle and a specific depth. These time delays can be incremented over a range of angles to sweep the beam over the desired angular range. For example, 40 to 75 degree beam sweep would be produced by calculating the time delays to produce constructive interference at 40, 41, 42 ...75 degrees. This NDT technology is also referred as Swept Beam Ultrasonic testing. The main advantages of phased array in NDE are: 1....

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Brief Description of ASME P-Numbers

ASME P-Numbers To reduce the number of welding and brazing procedure qualifications required base metals have been assigned P-Numbers by the ASME BPVC.  Ferrous metals which have specified impact test requirements have been assigned Group Numbers within P-Numbers. These assignments have been based on comparable base metal characteristics, such as:             Composition             Weldability             Brazeability       ...

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