Electromagnetic ultrasonic detection technology. Electromagnetic ultrasonic testing (EMAT) is a new ultrasonic testing technology, compared with the traditional piezoelectric ultrasonic and magnetic flux leakage testing technology, has the following advantages; A. Non-contact detection, no coupling required, suitable for liquid and gas pipelines. B. Can effectively and accurately detect stress corrosion cracking, cracks, abnormal grooves, etc. C. It can comprehensively analyze the detection results of different detection signals, with high detection sensitivity and precision. C. It can comprehensively analyze the detection results of different detection signals, with high detection sensitivity and precision. It can detect pipe anticorrosion coating defects and cracks or crack - like defects.