电子束焊缝超声无损检测声场特性及回波特征

Sound field characteristic and echo wave feature in ultrasonic nondestructive test of electron beam weld

针对复杂结构的电子束环焊缝的检测问题,提出斜入射水浸聚焦超声C扫描成像的检测方法。研究了工件内二次焦点深度随轴向液程的变化关系,横波和纵波检测时缺陷波的识别问题,以及折射角和焦点张角对检测灵敏度的影响。结果表明,工件内二次焦点深度的试验测量值大于理论计算值,随着轴向液程的增加,测量值和计算值误差增大。利用横波检测根部未焊透缺陷,无表面回波干扰,缺陷波容易识别。在工件上声波入射面较小的情况下,焦点张角越小,检测灵敏度越高。

Angle beam immersion focus ultrasonic C-scan was applied to test an electron beam circumferential weld with complex construction.The relationship between axial liquid path and second focus depth in the workpiece,identification of defect wave by using longitudinal and shear wave,the effects of refraction angle and focus flare angle on detection sensitivity were investigated.The results show that the measured values of second focus depth are higher than the calculated ones and the error increases with the increment of axial liquid path.Without disturbance of surface echo wave,defect wave is easily identified by using shear wave to detect lack of penetration in the root segment.It is also found that for small entrance area,the smaller focus flare angle,the higher detection sensitivity.