Eddy Current Testing

Aptest NDT technicians have numerous years of experience with this type of conductive material inspection and are able to set up individual testing parameters to best meet your needs. If you need to detect flaws in conductive material, eddy-current testing is one of the most reliable ways, giving you the capability to detect very small cracks in or near the material’s surface.

Eddy Current Testing

Eddy-current testing uses electromagnetic induction to detect flaws in conductive materials. It can detect very small cracks in or near the surface of the material.

Parts capable of inducing current are put in contact or near a probe that emits electromagnetic currents through the part. The probe also looks for changes in how the current travels through the part. It picks up the changes and shows the irregular flow. This process can detect slight changes in the piece being inspected. The changes may be due to a hardness difference, change in material, or a void or crack in the part.

The material surface needs minimal preparation, and physically complex geometries can be investigated. It is also useful for making electrical conductivity and coating thickness measurements.

Eddy-current testing equipment is relatively expensive and complex in nature, so having experienced personnel and quality equipment is a must.

Benefits at a Glance

With eddy-current testing services from Aptest NDT services you can be sure of:
1. Minimal surface preparation
2. Fast results with a portable device

Common applications 

Weld Inspection - Many weld inspections employ ultrasonic NDT for subsurface testing and a complimentary eddy current method to scan the surface for open surface cracks on weld caps and in heat affected zones.

Conductivity Testing - Eddy current testing's ability to measure conductivity can be used to identify and sort ferrous and nonferrous alloys, and to verify heat treatment. 

Surface Inspection - Surface cracks in machined parts and metal stock can be readily identified with eddy current. This includes inspection of the area around fasteners in aircraft and other critical applications. 

Corrosion Detection - Eddy current instruments can be used to detect and quantify corrosion on the inside of thin metal such as aluminum aircraft skin. Low frequency probes can be used to locate corrosion on second and third layers of metal that cannot be inspected ultrasonically. 

Bolt Hole Inspection - Cracking inside bolt holes can be detected using bolt hole probes, often with automated rotary scanners.   

Tubing inspection - Both in-line inspection of tubing at the manufacturing stage and field inspection of tubing like heat exchangers are common eddy current applications. Both cracking and thickness variations can be detected.