直缝焊管焊缝质量电磁超声检测方法研究

为实现直缝焊管焊缝内缺陷检测，采用周向电磁超声SH0导波检测技术，研究了基于磁致伸缩效应激励周向SH0模态导波，确定了周向SH0导波激励频率，设计了一款一发双收差分接收的直缝焊管焊缝缺陷检测探头。结果表明:该系统能够激发单一模态周向SH0导波，实际波速与模型分析结果吻合；针对直径116 mm、壁厚3.5 mm的激光直缝焊管焊缝的Φ0.6 mm盲孔和Φ1.0 mm通孔，通过差分探头的信号处理，能够实现焊缝处Φ1.0 mm通孔和Φ0.6 mm盲孔缺陷的检测。

Electromagnetic Acoustic Transducer Method of Welding Seam Quality of Longitudinal Welded Pipe

In order to detect the defects in the weld of longitudinal welded pipe, circumferential electromagnetic ultrasonic SH0 guided wave detection technology is adopted. The circumferential SH0 guided wave excited by magnetostriction effect is studied, the excitation frequency of circumferential SH0 guided wave is determined, and a probe for detecting weld defects of longitudinal welded pipe with one transmitter and two receivers is designed. The experimental results show that the system can excite a single?ode circumferential SH0 guided wave, and the actual wave speed is in good agreement with the model analysis results. The experimental study of Φ0.6 mm blind hole and Φ1.0 mm through hole is carried out at the weld seam of laser straight seam welding with a diameter of 116 mm and a wall thickness of 3.5 mm. Through the signal processing of differential probe, the defects of 1.0 mm through hole and 0.6 mm blind hole at the weld seam can be detected.