Development Of Ferromagnetic Material Hardness Sorting Device Based On Amplitude And Phase Analysis

As the representation of ferromagnetic material, steel plays an important part in the industrial areas. Steel has a wealth of physical and chemical means to alter the material properties of steel parts. The heat treatment is a common way to improve the surface hardness of the machinery products. It is very important to conduct the study of detecting the surface hardness of heated workpiece. Commonly, the method of electromagnetic and ultrasonic vibration can be used to test the surface hardness of the workpiece. The electromagnetism theory is used as the principle of the equipment. Firstly, the sensor signal is acquired through the date acquisition card; then the computer can analyse amplitude and phase of the sensor data. The main contents of this paper are as follows:(1) Surface hardness testing method of steel material after heated treatment. New corss-detecting sensor is designed based on the testing piece and the relationship between the initial permeability and surface hardness of steel material. The alternative excitation signal is loaded on the surface of the testing part, then the relationship between the two sensors' voltage signal and the specimen surface hardness and surface cracks is analysed.(2) Harware circuit of the sorting device. Analysing the requirements of the hardware function, mainly include the designing of signal source circuit, power amplifier circuit, pre-processing circuit and selection of the data acquisition card.(3) Software of the sorting device. The amplitude and phase of the collected data are analysed by the host computer. The sorting mechanism is controlled by the lower computer.(4) Experiment and date analysing. The hardness sorting device is developed to detect the surface hardness of steel specimens, and analyse the relationship between the measured data and the surface hardness, surface cracks of specimens.