用于管道焊缝检测的激光超声系统

针对石油管道焊缝检测中被测样品粗糙,作业环境恶劣等问题,基于光折变晶体内双波混合干涉原理,研制了高频激光超声测振仪,结合激光超声的激励技术,设计了一种可用于检测石油管道表面及内部焊缝缺陷的激光超声检测系统.利用该系统分别对缺陷在表面和内部的管道焊缝试块进行了超声激励和检测实验.实验结果表明,该系统能有效地分析出被测样品表面以及内部缺陷的位置以及相应深度,检测分辨率达到0.01 mm,缺陷位置检测误差控制在2%以内.该检测系统结构紧凑可靠,操作简便,开发的高频激光超声测振仪能工作在管道焊缝检测的常见作业环境(70~75 d B低频环境噪声),具有一定的适用性.

Laser Ultrasonic Testing System for Weld Flaw Inspection of Pipelines

In order to tackle the problems caused by rough test samples and harsh operation environment in weld flaw inspection of gas and petroleum pipelines, a laser ultrasonic inspection scheme for detecting surface crack and internal defects of welds was proposed. A high frequency laser ultrasonic receiver based on two-wave mixing in photorefractive crystals was developed, which can effectively detect high frequency ultrasonic signals on rough surfaces. This system was utilized to inspect weld flaws of pipeline specimen and the location of surface cracks and the depth of the internal defects can be effectively determined with the experimental data. The detection spatial resolution is 0.01ram and the detection error of defect location is under 2%. Experiments indicated that this system has a compact and reliable structure, user-friendly control, and the high frequency laser ultrasonic receiver can work in typical environment for weld flaw inspection of pipelines, i.e. 70-75 dB environment noise. These features make it suitable for industrial applications.