How Phased Array Works
Couplant is coated on the pipe to ensure there is no space between the transducer and the pipe. Without the couplant, the technology would not work properly. Sound waves travel in their directed position through the couplant where they would not if there was any space between the transducer and the pipe.
Using the equipment computer, technicians are able to set beam parameters such as angle, focal distance, and focal point size. Technicians are also able to adjust the angle of the sound beam, or set it to emit sound beams in multiple angles. Adjusting the angles of the sound beams allows for accurate flaw detection of components.
Since the technology utilizes ultrasonic sound waves to inspect components, there are no safety hazards associated with it. It is also a quick inspection method which can be used effectively on pipe welds of large sizes.
How To Interpret The Results
The images above are two different ways of looking at the weld. The image of the left is as if you were looking through the weld sliced in half. The dark blue area on the far left, near where the scan is narrow, indicates the root. As you move right through the picture, it is as if you are moving through the weld. The surface of the weld is where the blue ends and solid white begins. In this view, technicians are able to measure the depth of a flaw.
the image on the right is as if you are looking directly on the weld. The root is at the bottom of the picture and the surface of the weld is at the top. In this view, technicians are able to measure the length of a flaw.
Skilled phased array technicians have taken multiple training courses on the technology and have thousands of hours of in the field experience with phased array. The technology is difficult to understand at first. We were happy to converse with the welders about phased array while on the most recent job site. NDT technicians understand that the technology can be confusing, so we are happy to take a few minutes to explain it. The next time you have questions about phased array, do not hesitate asking the NDT technician on site.