为满足100mm(4 in.)小管径海底管线检验的要求，在现有设备基础上，制定AUT(全自动相控阵超声检测)设备改造方案，使其适用于 100 mm海底管线检验，避免海底管线铺设过程中射线辐射危害。通过实际海底管线检验，改造后AUT设备的整体性能满足灵敏度、检验精度和稳定性要求。

To meet the inspection requirements of 4-inche small diameter subsea pipeline, the existing AUT equipment was improved to be applied to 4-inch subsea pipeline inspection in order to avoid ray radiation hazards in the process. On the basis of existing equipment, the solution programs were outlined and its whole properties were analyzed to meet the standard requirements. The improved equipment was successfully applied in the subsea pipeline project, and could meet the sensitivity, accuracy, stability requirements.