基于超声散射法的微小缺陷及近表面缺陷的检测

针对常规超声检测法存在对(?)1.0 mm以下的微小缺陷漏检及近表面检测存在盲区的问题,提出一种超声垂直发射背向散射的检测方法。分析了散射模式的声场传播特性,阐明了该模式的检测原理。通过对不同类型和尺寸的人工缺陷检测,分析了该散射方法的检测信号、检测灵敏度及成像图形;通过有限元分析,对散射波声场分布的可靠性进行了验证。结果表明,超声散射法能够识别常规超声检测方法容易漏检的微小缺陷及无法辨别的近表面缺陷,可有效检测(?)0.4 mm的微小缺陷及埋藏深度1.0 mm的近表面缺陷。

The Detection of Tinny Defect and Near Surface Defect Based on Ultrasound Scattering Technique

Aiming at the problems of undetected tinny defect of φ 1.0 rnm and near surface dead zone,a scattering-based ultrasonic testing method of vertical launch ultrasonic and backscattering was proposed in the paper,which analyzed the characteristics of sound distribution and illustrated testing principle.Through the artificial defect testing,the feature of tested signal,sensibility and image are recognized.The reliability of scattering wave sound field distribution is tested by finite element analysis.The experimental results show that ultrasonic scattering test can identify the near surface defect and tinny defect that can not be distinguished by conventional ultrasonic test,and the near surface defect with buried depth 1.0mm and φ 0.4 mm can be effectively detected.