Eddy Current Encircling Coils for Structure Tests
Flat Coils, Rectangular, Inner Diameter Probes

Coils for all applications: coils and probes for the structure test offered by ibg

The Proper Solution For Each Test Task

Our wide range of standard eddy current accessories includes encircling coils, rectangular coils, inner diameter coils, flat coils and probes. Customized products for special test tasks are provided by our in-house design and manufacturing departments. ibg eddy current coils stand out due to highest test sensitivity and temperature stability. Furthermore, they offer a maximum of investment security as they may be operated with all ibg structure test instruments. So you can replace an old ibg test instrument by a new generation instrument, and the coils can still be used.

Structure test on screws: typical application for circular coils

Standard and Custom Eddy Current Colis for All Applications

Encircling coils are generally used when testing for correct heat treatment with the Preventive Multi-Frequency Technology and Simultaneous Harmonic Analysis by ibg. Standard diameters from 5 mm up to 300 mm are available (larger coils on request), and our experience shows that 90% of all applications can be successfully tested within that range. Typical applications include testing for correct hardness, case depth, material mix, alloy, crystalline structure - just to mention a few examples. Special applications sometimes require special coils and sensors designed for a certain test task. Our in-house coil design & manufacturing department, which fundamentally produces all ibg probes and coils, specializes in exceptions and is able to manufacture coils for each field of application. It may be sensible to use rectangular coils when testing bearing rings, for example, in order to ideally penetrate the material with the magnetic field. Testing of con-rods is also an application for rectangular coils. When differences in positioning of the hardening zone e.g. in the induction hardening process needs to be detected, special shielded coils can be manufactured. The magnetic field is shielded such that only the critical area is tested. Ambient influences are nearly excluded. Even smallest deviations in position of only 0.5 mm can be reliably detected depending on part geometry and material.

ibg-coil for the test on internal diameter: the cut test part shows clearly the shifted hardness profile

Special ibg-coils for the test of very small components

ibg-special coils and their test parts (from front to back): shielded circular coil, ID coil, rectangular coil

ID Coils for Testing Boreholes and Inner Diameters

Typical eddy current encircling coils where test parts are placed inside do not reach areas on the inner diameter or in boreholes in most cases. The magnetic field of these coils cannot penetrate the material from outside sufficiently for a reliable test. Typical examples are races in a hub or the inside of bells of a constant velocity joint (CV-joint / tripode). ibg has developed ID coils in order to test such applications with appropriate sensitivity and reliability. The coils are tailor-made for a certain application, the areas to be tested inside the test part are directly reached. The photos show such test coils for constant velocity joints. ID coils are supplied in the diameter range from 5mm. Designs in stainless steel are also offered which guarantee a long lifetime for applications with a high number of parts and short cycle times.

Custom Eddy Current Coils for Testing Smallest Parts

It is unbelievable, but the smallest parts are often responsible for the breakdown of an entire component. Geometrically unimposing, not even very precisely manufactured, and a few millimeters length or height. But if their heat treatment is incorrect or non-treated and are mounted in the actual component, e.g. injection pumps or steering, this may cause malfunction of the entire component. A 100% test of such components for correct heat treatment, as well as a safe internal material process flow with locked containers avoids such errors. The coil manufacturing at ibg is specialized in testing small and very small components and may offer custom solutions to test such minis. Most often encircling coils are used, round or rectangular, which are designed specially for your test parts. In combination with the Preventive Multi-Frequency Technology well proven for such product groups and the Simultaneous Harmonic Analysis in all ibg eddy current structure test instruments, we offer the optimum solution for your difficult task.

Standard Range Eddy Current Circular Coils

gefuegepruefung-tabelle-rundspulen Size Dimensions b [mm] x t [mm] x h [mm] Inner diameter [mm]
 1 80 x 80 x 35 10, 16, 25, 40
 2 150 x 150 x 50 50, 63, 80, 100, 125
 3 250 x 250 x 50 160, 180, 200
 4 380 x 380 x 50 250, 300

Other inner diameters can be made to specification.

Available frequency ranges: 25 Hz - 25 kHz (standard)/ 5 Hz - 5 kHz/ 100 Hz - 100 kHz

Standard Range Structure Probes

Diameter d [mm] Length l [mm] Frequency range
10 46 2,5 kHz - 250 kHz
16 47 250 Hz - 25 kHz
25 51 25 Hz - 2,5 kHz

Recommended Coils According to the Application

ibg NDT Systems - Designers and manufacturers of state-of-the-art NDT eddy current testers, coils, probes, instruments and systems for automotive, bearing and other metal components including fastener, forged and cast parts, hard metals, precision stamped parts, etc.