Eddy Current Testing Solutions in Manufacturing, Aerospace, and Military

The implication of unattended flaws in manufacturing or infrastructural components can be detrimental in terms of human life, operational failure, or incurred costs. Non-destructive testing (NDT) technology has been an effective inspection tool for manufacturers and asset owners around the world, allowing them to detect damage and discontinuities and keeping costly disasters off the bay. NDT achieves all this without damaging the component or interfering with the production, all while improving the product quality.

Among many NDT technologies developed over the years, eddy current is undoubtedly one of the popular inspection technologies in many industries. Especially in high-stake industries like manufacturing, aerospace, or military, eddy current and eddy current array (ECA) testing solutions have proven their advantage with the ability to accurately identify flaws and irregularities, improve productivity, reduce cost, and ensure the safety of the equipment.

The Value of Eddy Current Testing

Eddy current testing utilizes a simple concept of electromagnetic induction. A supply of alternating current excites a wound coil which induces a magnetic field around it. As the coil nears a conductive material, the magnetic field triggers the induction of opposing current—eddy current—in the material. Any flaw in the material is identified by the variation observed in the current flow. This simple mechanism, in turn, provides great benefits for industries as it facilitates:

Identification of surface or near-surface flaws like cracks, inclusions, porosity, and so on
Multi-layer flaw detection, irrespective of the presence of surface coating
Minimal surface preparation
Flexibility in the inspection of simple or complex geometrical structures with portable eddy current testing equipment

For industries, these features mean the ability to ensure quality control, reduce waste, improve productivity, and save costs.

Use of Eddy Current Testing Across Industries

While the reasons may differ, the goal in industries like aerospace, defense, and manufacturing remains the same—flaw-free, quality products and equipment. Eddy current testing can help.

Eddy Current Testing in Manufacturing

Eddy current testing technology offers inspection of pipe, tubes, and heavy-duty machinery applicable across a wide range of manufacturing processes. With advanced eddy current probes and instruments, it is possible to detect metallurgical flaws and irregularities to ensure the quality and safety of the final product. With the accuracy and speed of the eddy current testing, manufacturers can achieve higher productivity, thus, higher returns.

Eddy Current Testing in Military and Defense

As the military and defense industry takes care of national security and intelligence, it is imperative that the artillery and equipment remain in top shape. Armored vehicles, naval vessels, aircraft, and missile systems are just some examples of infrastructure systems that need to be sturdy and durable to meet military demands. As these systems face high stress, it is extremely crucial to examine them for possible corrosion, cracks, inclusions, lack of bonds, etc.

Eddy Current Testing in Aerospace Industry

For both civilian and military purposes, NDT testing is an important part of the aircraft manufacturing process. For manufacturing and maintenance purposes, aircraft need an inspection for material structures, turbines, jet engines, wheels, struts, propellers, airframes, longerons, etc. Eddy current testing can effectively identify corrosion or cracks that may be induced due to fatigue and stress in the components.

Longerons in aircraft help in carrying some of the load as well as support transfer of the load to the internal structure. Due to this reason, fatigue and stress cracking may be observed around the fasteners supporting the longerons. Hidden corrosion can also be an issue due to the multilayer nature of the structure. With eddy current testing, stress cracks and corrosion near the fasteners, or between the attached longeron surface can be easily identified.

Learn more about eddy current testing of aircraft longeron.

The aircraft wheel is another flaw-prone part due to its exposure to high temperature and stress, especially due to braking force. This condition can be a source of heat and fatigue-induced cracking. With eddy current array (ECA) probes, any indication of damage in the wheel hub can be detected accurately. The flexibility of the ECA probes also enables inspection for a wide range of wheel radius and along changing curves and angles to provide complete coverage.

Learn more about aircraft wheel eddy current inspection.

Similar to wheels in aircraft, turbines, and rotor shafts are also subjected to extreme stress and vibration. This is mostly due to the high temperature and speed required for turbines to operate. This can lead to turbines being prone to cracks, which if not detected can lead to engine failure. Eddy current testing can ensure complete inspection to ensure material or weld quality.

Learn more about NDT inspection of turbine blades.

Bolt hole inspection is an important part of aircraft or automotive safety assurance. Not only is the material adjacent to bolt holes prone to stress cracking, the multiple layers that the bolt combines also creates difficulty in identifying the exact layer of flaw initiation. With ECA testing, minor cracks or other irregularities can be identified in less time.

Applications of Eddy Current Testing in Industries

Across the military, manufacturing, and aerospace industries, eddy current testing serves a similar purpose: assessing materials and parts to ensure safety.

Material such as galvanized steel is the popular choice of industries where corrosion is a problem. Mostly seen in the building of refineries, pipes, or naval ships for its corrosion-resistant properties, the material can still be prone to corrosion and cracking due to long-term exposure. Corrosion, cracks, and other surface and subsurface flaws can be easily identified with eddy current probes which can collect the current flow data on the metal. With powerful eddy current instruments, this data can be analyzed to identify issues in the galvanized steel and potential solutions to mitigate them.

The effectiveness of eddy current testing can also be seen in the measurement of coating thickness. The thinning of surface coating can present issues like corrosion that can affect the integrity of the components. The right eddy current testing instruments and probes can help in this precision-oriented and capture the minor change in thickness of the coating.

Welds are an integral part of many heavy-duty manufacturing industries and infrastructural projects. From airframes to storage tanks to marine hulls, welding is a necessary process. However, given the nature of different welding processes and differing parameters, inspection for cracks, inclusions, and lack of bonds becomes crucial.

ECA makes sure that the welded surface is inspected with accuracy and speed irrespective of surface conditions and geometries. The ability to identify minor flaws prevents potential operational failure.

Eddy Current Testing Solutions for Quality Results

Accuracy, precision, flexibility, and portability are some features that industries seek in their inspection technology. Zetec’s eddy current testing instruments, probes, and software can adapt to a wide range of industrial testing needs. Identifying the right eddy current testing solution is the key to ensure industry standards and deliver flawless products.

Zetec has been a leading provider of high-performance NDT solutions for decades. Our eddy current testing solutions can provide easy inspection and accurate analysis to fit your inspection needs. To learn more, contact Zetec today.

NDT Product Department

Zetec’s designers are industry-leading experts in ultrasonic and eddy current technologies, and we can help you navigate any of our NDT testing solutions or devices.