通过试验确定了不同材质钢管的磁致伸缩曲线，得到了不同材质钢管缺陷检测的电磁超声传感器(EMAT)直流电磁铁的励磁电流与超声波幅值的关系，确定了最佳励磁电流，并得出其变化规律与磁致伸缩曲线变化趋势一致的结论。为电磁超声传感器设计和开发提供了依据。

The magnetostrictive curve of different material steel pipes was determined by experiments, the relation between the amplitude of the ultrasonic waves and the excitation current of the electro-magnetic field in electromagnetic acoustic transducer(EMAT) testing the defects in different material steel pipe was identified by experiments, the optical excitation current was determined, and the vary rule was resembled with vary trendent of pipes magnetostrictive curve .The provided basis for EMAT products design and explorement.