The Design Of Electromagnetic Fusion Nondestructive Testing Instrument

With the development of economy, science and technology and modern industry, the use of machinery and equipment has become more widespread. Ferromagnetic material is widely used in manufacturing a variety of devices and components, for the nondestructive testing of ferromagnetic material is very important. This paper develops electromagnetic fusion NDT system.First of all, this paper describes the research status of electromagnetic fusion nondestructive testing technology, and clarify the theoretical basis of eddy current and Barkhausen fusion detection from the aspect of detection principle and feasibility. Describe the eddy current principle and analytical methods from electromagnetics; Explaine the mechanism, factors and analysis methods of Barkhausen signals in terms of microstructure.Secondly, this paper developed an electromagnetic fusion non-destructive testing system. The different sensors are designed by using different excitation coil and the detecting element. Then describe the design of signal generating circuit, power amplifier circuit, current measurement circuit, and signal conditioning circuit. The software part introduce the virtual instrument and its development environment. The software was developed by LabVIEW and divided into three modules: parameter setting, system control and data analysis.Finally, a series of experiments was conducted by the electromagnetic fusion nondestructive testing system. Analysis the impact of excitation signal parameters and liftoff effect on the test results. The eddy current and the Barkhausen time domain characteristic values, the envelope characteristic value and the characteristic value of the hysteresis loop are extracted and detected. By using those characteristic values studied the detection results of plastic deformation, slotted defects and different materials.