电磁超声检测技术因具有无需耦合剂、可非接触检测的优点，广泛应用于极端温度、未经打磨等工况下的设备检测。电磁超声检测灵敏度是电磁超声检测能力的重要表征，然而直入射检测灵敏度受设备、探头、被检材料等因素影响，实际表现参差不齐。研究了线圈外径和激励频率对电磁超声检测灵敏度的影响，然后根据仿真结果设计了新的电磁超声传感器并进行检测试验。试验结果表明，优化后的电磁超声传感器检测灵敏度有所提升，可检测到碳钢中φ 2 mm平底孔缺陷。综合仿真与试验结果可知，减小线圈外径与提高激励频率，能够提高电磁超声的检测灵敏度。

Electromagnetic ultrasonic testing technology is widely used in equipment detection under extreme high and low temperature conditions, or without grinding because of its advantages of no coupling and non-contact detection. The sensitivity of electromagnetic ultrasonic flaw detection is an important representation of the ability of electromagnetic ultrasonic testing. However, the normal incidence electromagnetic ultrasonic flaw detection sensitivity is affected by equipment, probe, materials tested and other factors, and the actual performance is uneven. In this paper, the influence of different coil diameter and excitation frequency on the sensitivity of electromagnetic ultrasonic detection was studied, and a new electromagnetic acoustic transducer was designed based on the simulation results. The experimental results show that the sensitivity of the optimized electromagnetic acoustic transducer has been improved to some extent, and it can detect the φ2mm flat bottom hole in carbon steel. The comprehensive simulation and experiment showed that the sensitivity of electromagnetic ultrasonic flaw detection can be improved by reducing the outer diameter of the coil and increasing the excitation frequency.