Using Focused vs Non-Focused Transducers
When presented with a quote for a new NDE system, let’s say for a tube and pipe
application, ask the NDE equipment manufacturer if they plan to use Focused or
Non-Focused transducers and why.
There are clear advantages for each type of transducer, but where a Non-Focused
transducer can be used on many diameters and wall thicknesses, a Focused
transducer is specific to a small range only. This
means that if your NDE system uses focused transducers, you would require many
sets to ensure full coverage of all diameters and wall thickness variations.
drawback for using Focused transducers, is the smaller amount of weld wonder
possible before a defect cannot be detected enough to trigger an alarm.
E273_15 Section 7.1.5 states “The focal length of focused search units shall be at
least equal to the radius of the material plus a suitable water path so that
initial focus may be on the tube or pipe central axis.”
these factors and many more play a huge factor in not only the equipment
choice, product quality but also the initial cost of the equipment as well as
the long-term expenses. This is a very good reason to have the NDE equipment
manufacturer mention their compliance with ASTM E273 on the quote for a new NDE