Basic Knowledge of Eddy Current Flaw Detectors

Basic Knowledge of Eddy Current Flaw Detectors

Eddy current flaw detector has the characteristics of multi-function, strong practicability and a high performance/price ratio. It combines many years of experience in manufacturing eddy current detectors to meet the needs of various users. Eddy current flaw detectors can be widely used in online and offline flaw detection of various non-ferrous and ferrous metal pipes, rods, wires, wires and profiles. It has high detection sensitivity for the defects of metal pipes, rods, wires, wires and profiles, such as surface cracks, dark seams, slag inclusions and open cracks.


1. The performance characteristics of eddy current flaw detector

Portable battery-operated eddy current testing instrument with excellent performance, suitable for maintenance testing, or other eddy current testing. The instrument can quickly, conveniently and intuitively detect tiny cracks or folds on the surfaces of various metals and graphite with a conductivity of 0.5-60s/m, and is free from thin insulating layers on the metal surface such as anodized layers, paints, oil stains, oxide film, etc.

Eddy current test set can effectively detect planes or regular samples. After being equipped with probes or other additional fixtures, it can check groove edge cracks, inner holes, and cone-shaped inner wall cracks.

Eddy current flaw detection instrument can be used for non-ferrous steel and austenitic metal at the same time with light alarm and sound alarm, and can also be used for metal mixture sorting. The instrument is widely used in the inspection of parts and components in the machinery manufacturing industry, the maintenance of aircraft and engines, and the detection of the valve (valve core) of railway locomotives. The eddy current testing equipment has the characteristics of easy operation, reliable performance, durability and easy portability.

2. The detection of eddy current flaw detector

The detection of the eddy current flaw detector is to bring the conductor close to the coil with alternating current, and the alternating magnetic field is established by the coil. The eddy current in the conductor also generates its own magnetic field. The effect of the eddy current magnetic field changes the strength of the original magnetic field, which in turn leads to changes in the coil voltage and impedance.

When a defect occurs on the surface or near-surface of the conductor, it will affect the intensity and distribution of the eddy current flaw detector. The change of the eddy current will cause a change in the voltage and impedance of the detection coil. According to this change, the defects in the conductor can be indirectly known. 

Due to the different shapes of the test pieces and the different detection parts, the shape of the test coil and the way of approaching the test piece are not the same. In order to meet various testing needs, people have designed various testing coils and eddy current test sets.

Eddy current flaw detector is a conventional non-destructive flaw detector for non-destructive testing. Eddy current flaw detector is suitable for the processing and welding quality of materials and parts such as pipelines, aircraft, vehicles and bridges in industries such as petroleum, transportation and construction, as well as the quality of various light metals, steel pipes, copper pipes, aluminium pipes and other processed parts.

Eddy current flaw detectors use metal parts. Because of the non-continuous existence, the magnetic lines of force on the surface of the workpiece and near the surface are partially distorted, and the magnetic powder applied on the surface of the workpiece is adsorbed to form magnetic marks that are visually visible under suitable illumination, and then show The position, shape and size of discontinuity.

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