Fundamentally, Eddy Current Testing has not changed since it was first introduced in 1879, still, it is known as the best inspection technique used in various cases till dates. With the unaltered technology, its applications have turned out to be much more sophisticated, majorly in the last 20 years. The experts of the inspection across various fields like manufacturing, aerospace, oil, and gas, power generation, etc are capable to perform inspections along with detection, seek the size flaws with greater speed and accuracy.
However, the time and technique of the eddy current testing have evolved remarkably, and the digital age has broadly influenced the inspection technology. The latest advancements in the eddy current tools have not only reduces the complexity of the inspection process but also the tutoring and the process regarding collaboration that is involved in the industries, eventually increasing the application scope and utility of the technology. Inspection technologies have grown exceptionally, and the need to recruit, train, qualify and maintain skilled non-destructive examination personnel grows important, particularly in an industry where the workforce is quickly thriving.
A noteworthy trend is the latest urgency of powerful, networked portable devices. Previously used inspection technologies often needed the technician to perform the test, carry the unmanagable equipment, diagrams, maps, and other documents that contained the information regarding testing processes and the standard equipment. Inspectors work in complex and harsh industrial environments, this is extremely different from the staple and introduces a range of different variables that could influence the accuracy of test results.
Earlier, ET devices were the only units to perform a reading- necessarily like a very far-fetched pocket compass merged with a comprehensive information system. This allowed technician not only to capture the readings but also future versions of the system that is able to seek and access the information on the network. The inspector does not need to carry the documents as they are directly indicated on the instruments tablet. Physical documents can expire whereas the online one can be managed to offer only current information. The latest systems are also capable of creating standardized inspection work process. Its ability to automate the test process seems a tiny advancement that could impose tremendous implications. In the huge organizations with the presence of numerous inspectors at various facilities may encounter that their eddy current test performs differently, with slightly varied results achieved by every inspector.
Development of standard practice can make the company confident about its weld inspections, like, that are being performed in a similar way, with the results that are capable of duplication by any test technicians. Eddy current could be said that it is today one of the most useful and essential modalities for NDE.
In the appropriate circumstances, eddy currents can be used for:
• Crack detection
• Measurements of material thickness
• Measurements of coating thickness
• Conductivity measurement for:
o Identification of material
o Heat damage detection
o Determination of case depth
o Heat treatment monitoring
Let us take a look at some of the advantages of eddy current inspection
• Sensitive to the smallest cracks and various other defects
• Defective surfaces and near surface defects
• Inspections provide immediate results
• Highly portable equipment
• The technique can be used beyond flaw detection
• Needs least part preparation
• Test probe need not contact the part
• The sizes and shapes of conductive materials are examined
Following are the limitations of eddy current inspection:
• It inspects only conductive materials
• The probe has an accessible surface
• Extensive skill and training required compared to other
• Setup demands the reference standard
• Penetration depth is restricted to some limit
• Delamination flaws lying parallel to the probe coil winding and probe scan detection are undetectable.