The eddy current flaw detector is characterized by its effectiveness on conductive materials, not necessarily magnet materials, but the actual effect on magnet materials is weak. Secondly, the smoothness, flatness and edge interface of the workpiece surface of the product to be explored are very harmful to eddy current testing. Therefore, eddy current testing is often used to test the workpiece of non-ferromagnetic materials such as air conditioning copper pipe with standard appearance and smooth surface.
There are many factors that can jeopardize the results of eddy current testing, such as material changes, specifications of product artifacts and inspection solenoid coils, the appearance and location of defects, and testing standards, all of which jeopardize the proper evaluation of testing results. In the eddy current testing of copper and alloy copper tubes, most of the eddy current testing is dominated by passing solenoid coils. The various influencing factors are summarized as follows:
(1) Defects: including the depth, length and total width of the defect, the location of the defect (inner surface, outer surface), the type of the defect (hole, groove), etc.
(2) Material: the harm of copper and alloy copper tube material to eddy current testing is mainly reflected in the conductivity level. In the material of the same aluminum alloy composition, shrinkage, residual in-situ stress and so on will cause the difference of conductivity.
(3) Specifications and filling index of the pipe: the size of the pipe that immediately harms the filling rate after transformation.
(4) Thickness of wall thickness: noise data signal caused by the change of copper wall thickness.
Eddy current testing is caused by alternating current circuit alternating electromagnetic field acting on the conductive material to be tested, magnetic induction eddy current. If there is a defect in the raw material, it will affect the resulting eddy currents, that is, electromagnetic interference. The condition of the defect can be understood by testing the electromagnetic interference with an eddy current flaw detector.
Harm eddy current eddy current flaw detection of many elements, that is to say by years of rich and colorful data in eddy current signal, the data signal is associated with many factors of raw material, in which how to make effective data signal extracted from the data signal of many, is the current difficulties of eddy current scientific research personnel, for many years already had some progress, Some difficult problems can be dealt with under certain standards, but it is far from the regulation on the spot, and eddy current testing needs to be promoted.