Eddyfi Technologies has been synonymous with electromagnetics for many years now, so it doesn’t come as a surprise that magnetostrictive collars have been introduced as part of its new Sonyks™ guided wave product line. Eddyfi is not the first NDT equipment manufacturer to use electromagnetic guided wave transduction. However, it is the first to offer piezo-electric and magnetostrictive as part of its guided wave product portfolio. Let’s look at why we decided to offer both options and see how this exciting new product stacks up against the competition.

Eddyfi Technologies initially decided to replace its existing Mini-Test Piezo kit with magnetostrictive collars. This means that 2-, 3-, and 4-inch collars will now only be available as a magnetostrictive option. The driving force behind making this change was based on several factors.


The magnetostrictive collars do not require any pneumatic force for coupling. The coupling is achieved mechanically. Benefits here are found in increased productivity and a reduction in battery consumption as the internal pump is not required.


The magnetostrictive collars are a single component. They have no removable modules, and the transducers are embedded. This removes any setup time and makes the collars ultraportable.

Reduced size

Due to the lack of external modules, the collars have an ultra-slim profile allowing the inspection of pipes that may not have been previously available due to radial clearance issues.


Eddyfi Technologies’ magneto collars are available in three frequency ranges: 32kHz, 64kHz and 128kHz.

The choice of which option is most suitable can be guided by the following table.

GWUT Magneto Utilization TableLooking at the 128kHz option, we are now moving into Medium-Range Ultrasonic Testing (MRUT). This frequency range was previously unavailable due to the maximum frequency that the piezo transducers were limited to.

Moving into this frequency range provides some tangible benefits such as improved resolution, improved sensitivity (the ability to identify smaller defects), and a reduced dead zone.

These benefits open up a whole new range of previously unavailable inspection applications such as short flange lengths, complex geometry, and assessing regions close to the tool like bund and wall penetrations with limited access.

Sonyks with Magneto Tool

The A-scan below is a 114kHz scan displaying four through-wall defects corresponding to the below pipe drawing.

A-Scan 114kHz scan with four through-wall defectsSonyks Pipe Drawing

The defects have the following Cross-Sectional Loss (CSL):

2.3m (6.44mm)

2.9m (6.42mm)

3.5m (4.43mm)

4.2m (4.41mm)

0.73% CSL

1.14% CSL

1.41% CSL

2.41% CSL

Inspecting this section of pipe with standard piezo or lower frequency magneto collars would not identify any of the defects in the previous table except maybe the largest at 4.2m from datum. This clearly illustrates the advantage of higher frequency magneto collars for applications that require greater sensitivity and resolution.

Unlike conventional magnetostrictive guided wave collars, Eddyfi Technologies’ offering is unique because it is segmented. Non-segmented versions cannot differentiate between reflected axisymmetric and flexural waves. This means that a significant amount of information is not presented in the A-scan. In addition, Eddyfi Technologies’ segmented tool means that users also benefit from focusing which provides circumferential information and a more detailed diagnosis of any defects present.

We are excited about this new tooling and believe it will be popular with guided wave users. Remaining customer-centric, we will continue to monitor the market and be ready to respond to any demands for magneto tooling for pipe sizes in excess of the original offering.

For further information on Eddyfi Technologies’ magneto tooling, we invite you to contact our team of experts happy to answer your questions and discuss how our industry leading solutions can keep you Beyond Current.