SHAPE  \* MERGEFORMAT Pre-multi-frequency eddy current sorter is an advanced eddy current sorter. The material composition, hardness, heat treatment state and mixture of bearing rings, rollers and steel balls can be identified and sorted.

The magnetic induction of the tested material is carried out by the excitation coil. The induced electromotive force received by the detection coil is related to the shape and size of the material hysteresis loop. When the low-frequency sinusoidal excitation voltage is magnetically induced, the induced electromotive force obtained is also sinusoidal waveform, usually including the fundamental wave. By measuring the fundamental wave composition of the induced electromotive force of the detection coil. It can detect the alloy composition and heat treatment status, so as to realize the material hardness sorting.

The mechanism of self-contrast Differential Eddy current testing technology is to obtain a proportional balance of eddy current signals with different parts of the same sample as their reference objects, so as to avoid the difference of chemical composition, metallographic structure and surface shape of metal materials under the action of external alternating electromagnetic field. Differential effects of conductivity and permeability. 
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1.Non-destructive testing, no special requirements for workpiece surface. (Avoiding the need to destroy the surface state of the workpiece by traditional detection methods, only two standard samples are needed in the same material and workpiece when debugging the instrument.)
2.Fast, accurate and convenient. (When testing, only the workpiece can be put into the probe, and the efficiency is tens or even hundreds of times that of the traditional detection method. It has sound and light alarm function for qualified and unqualified parts.
3.High sensitivity. (Continuous adjustable gain and frequency for different materials and heat-treated parts)
4.Simple operation. (The human-computer dialogue function is set in the instrument.)
5.Display intuition. The software compiled by WINDOWS operation platform makes the instrument more convenient and intelligent.
6.Suitable for large-scale testing needs, to ensure product quality assurance. (100% inspection of all raw materials and finished bearings, instead of conventional sampling inspection)