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How to Choose the Right Ultrasonic Transducer?

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Choosing the right ultrasonic transducer is very important. Are you wondering why it is this important? Here is why. Ultrasonic testing has been chosen as the most accurate non-destructive method for checking the integrity and quality of materials.  Ultrasonic testing is used in various important applications such as gas and oil, power generation, the aeronautical sector, and architecture. 

Serious accidents that may lead to death can occur if the right ultrasonic testing on architectural structures and aircraft, for example, is not done. That is why we cannot afford to compromise on the quality of ultrasonic results by using the wrong kind of probe. In this post, we will discuss more reasons why choosing the right ultrasonic probes is important, what you need to consider when choosing a probe, and some tips on buying an ultrasonic transducer.  If you are ready, let’s start.


I. Why Choosing the Right Ultrasonic Probes is Important?


how to choose the right ultrasonic transducer 

If you are looking to improve the efficiency and reliability of your ultrasonic testing activities then you must choose the right ultrasonic probe for your work and business. The importance of choosing the right ultrasonic transducer are:


  • Application 

Different applications require different kinds of probes.  For example, the probe for analyzing thick metal components will be different from one that is used for thinner components.  And a probe used for thickness testing only will differ from a probe used for flaw detection and flaw sizing.  Using the right probe ensures you get the clear and correct information for proper decision-making. 


  • Simple to use  

No matter what you intend to use an ultrasonic probe for, it has to be easy to operate and compatible with your type of ultrasonic testing. This way, you will avoid straining during work, and you will also save time and cover more ground in your material testing endeavor.


  • Boost efficiency

With the right transducer, you are able to make quick and easy inspections while maintaining top-quality accuracy of your data.  The right data goes a long way in helping to schedule and make proper repairs or maintenance for your components thereby increasing the competency of your structural material.


  • Improve reliability

Properly diagnosed flaws or wall thickness measurements help to optimize the integrity and reliability of structures through faster and smarter risk management.


  • Cut maintenance costs

Frequent component testing by using the right ultrasonic probes helps keep the components in check and within optimal working conditions. This, in turn, reduces maintenance costs as serious machine breakdowns will be avoided.



II. What Factors do you need to First Consider?


For proper choosing of your ultrasonic transducer in any testing operations, there are factors that you need to consider first like;


  • Material type

Different types of materials transmit ultrasonic sound waves in different ways.  Some materials such as metals, glass, and ceramics, which are used in many engineering applications are efficient ultrasound transmitters and can be measured easily no matter the thickness of the materials.  Moreover, some composites such as rubber and fiberglass are more attenuating and will need you to use transducers with lower frequencies and high penetration.  Other materials like plastics have a limited maximum thickness range because they absorb ultrasonic energy quicker, but ultrasonic testing can still be done on them efficiently in industrial settings.

Because of such reasons, the type of materials that you use for your applications is the first thing that should guide you when choosing an ultrasonic transducer.


  • Defects type

Generally, ultrasonic testing can detect more defects than other kinds of material testing.  But this does not come automatically.  The type of transducer used in UT greatly affects the kind of information that the technician gets after testing.

Some probes are able to detect even the small and hard-to-find flaws such as the phased array transducers.  While some other probes are only able to detect obvious surface and subsurface abnormalities.  In this case, knowing the type of defects you encounter in your workplace will guide you on the right ultrasonic transducer to get.



III. Other Important Considerations


  • Frequency

The probe frequency is an important factor that affects the accuracy of test results in ultrasonic testing.  Most ultrasonic transducers have frequencies that range from 0.1MHz to 15MHz, while some can be customized up to 50MHz frequency, for special precision testing. Low frequencies are ideal for measuring thick components while higher frequencies are good for thinner materials.


  • Crystal diameter

A bigger crystal diameter results in lower frequencies, and high sensitivity, while a smaller crystal diameter leads to high frequencies and less sensitivity.  You can choose a crystal diameter size depending on the kind of UT data you are interested in.  Transducer crystal diameters vary depending on the type of transducer.  For example, in array transducers, while you might be confused by the overall sizable diameter, it is a probe that comprised several small diameter crystals in one.


  • The thickness of test parts

Most ultrasonic testing instruments work efficiently on any size/ thickness of the material, it all comes down to the kind of transducer that is used for measurement.  As mentioned, lower frequency transducers are ideal for measuring thick test parts and high frequencies are ideal for thinner parts.  On some rare occasions, you might need to combine several types of transducers in order to measure very thick or multiple layer materials.


  • The shape of test parts

The coupling effectiveness between a probe and the surface to be tested is affected by the shape of test parts.  A flat surface can be scanned efficiently using either small or large diameter transducers. 

However, curved surfaces like narrow pipes and components with convex and concave shapes require either special transducers such as non-contact immersion transducers or small diameter probes to get proper coupling and therefore accurate and efficient results.


  • The temperature of test parts

Every transducer comes with information on the minimum and maximum operational temperatures, with most of them enabling a maximum temperature of 50 degrees Celsius.  Depending on your operational temperatures, choose a probe that will work efficiently.  High temperatures may cause probe parts to expand and permanently damage the probe, while very low temperatures may cause it to malfunction



IV. Tips you should Follow when Buying your Ultrasonic Transducer


From the considerations that you need to follow when choosing an ultrasonic transducer, let’s now look at some important buying tips for you to follow.


  • Low-frequency ultrasonic transducers are ideal for measuring thick, highly scattering, and high attenuating components.  Low frequencies are from 2.25MHz and below.  Low frequencies allow for greater energy and better material penetration.  Using a low-frequency transducer in thick materials increases the quality of return echo and thus the quality of measurement results
  • High-frequency ultrasonic transducers are ideal for optimizing resolutions in thin, non-scattering, and non-attenuating components.  This is because high frequencies reduce material penetration but at the same time increase probe sensitivity to smaller defects.  High-frequency probes are great for precision measurement as they emit a highly focused pulse, reducing any chances of noise that may otherwise affect the measurement.
  • Large diameter probes are better for thick or long components due to their deeper penetrating abilities.  A large crystal diameter produces more soundwaves that are powerful, thereby increasing probe sensitivity.
  • Smaller ultrasonic transducers are better for curved, convex shaped components and hard-to-reach areas in a test material.  Small size transducers are mainly used in process industries for material quality monitoring on components such as thin pipes and valves because they couple well with the shapes of these test materials.


➤ Related Article: Custom Ultrasonic Transducer

➤ Related Article: Ultrasonic Transducer Types: How to Choose Your Right Ultrasonic Transducer?

➤ Related Article: Top 8 Ultrasonic Transducer Manufacturers


V. Where can you Buy the Best Ultrasonic Transducer?


Once you have settled on the type of ultrasonic transducer that fits your applications, the next step is to figure out where to purchase the transducer.  The good news is that there are countless available options on where to buy the best ultrasonic transducer from the best transducer manufacturers all over the world.

Your requirements for frequency range and operational temperatures among other features will all be catered for.  Here is our recommendation for the best top 10 ultrasonic transducer manufacturers.




In summary, the quality of your ultrasonic testing results all comes down to the choice of ultrasonic transducers that you will pick to do your measurements.  Because of that, picking the best ultrasonic transducer is of utmost importance.  There are factors that you need to consider to make the right decisions which include the type of material and the type of defects you encounter, among others.

After giving you details on the considerations you need to make and the buying tips, the choice is now left to you to select where you want to buy an ultrasonic probe that ticks all the features and specifications you require for your applications.  Numerous ultrasonic probe manufacturers and countless models of ultrasonic transducers are available in the market, hopefully, you will consider all our tips to make your buying experience as easy as can be.

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