The Rearch On Pipe Electromagnetic Ultrasonic Flaw Detection Data Processing Technology

There are many ways of Nondestructive Testing, in recent years, the EMAT technique arises the society's wide concern. Based on the EMAT, the technique needs no coupling medium, applied to the workpiece testing at a high speed, can easily meet the demand of surface and near surface testing of the workpiece, more and more pipe tests are carried out by EMAT.This paper refers to a large number of domestic and foreign literature on the basis of EMAT principles, application scope and the advantages and disadvantages are analyzed, summarized and compared, put forward a way of using the hardware circuits and software programming to combine for signal processing, improve the echo signal noise ratio and resolution of the EMAT pipeline.The design of signal processing circuit, through the limiter circuit protection circuit to avoid excessive current voltage, damage to the circuit. Multi-level attenuation circuit, multi-stage amplifier circuit, full-wave rectifier circuit and filter circuit and the complementary output circuit, adjustment the signal amplitude circuit to remove noise, improve SNR and resolution. After experiments, the results achieved the expected goals, signal to noise ratio and resolution to a certain extent improvement. However, the effect of signal processing still has to be improved. On the MATLAB interface to the echo signal data processing, the elimination of noise signal, the experimental simulation results are satisfactory, get a high signal to noise ratio and high-resolution signal.The echo signal that after process has low noise, high SNR, high-resolution, high-precision, such as the advantages of the detection can achieve better effect. This paper shows the EMAT technology research and development direction, and there is still much room for the result of echo signal processing methods.