焊缝本身材料以及表面状态的不均匀会带来探头耦合的不均匀，焊缝涡流检测时最大的难题在于本底噪声较大，信噪比较低。针对核电站蒸汽发生器传热管与管板结合密封焊缝的涡流检测，设计了专用旋转探头和不同型号的检测装置，以及独特的线圈类型和柔性结构设计，在最大程度上减小了噪声，提高了信噪比。检测工艺的试验结果表明，涡流检测可用于在役或制造期间蒸汽发生器传热管管板密封焊表面和近表面的缺陷检测。该检测系统和工艺可广泛用于其他工业领域换热器管板的密封焊涡流检测。

Due to the heterogeneity of welding material and the coupling heterogeneity of probe caused by the heterogeneity of surface state, the biggest difficulty in eddy current testing of welding seam lies in the large local noise and low signal-to-noise ratio noise. In this paper, a special rotating probe and different types of detection devices are designed for eddy current detection of sealed welding between heat transfer pipe and tube-plate of steam generator in nuclear power plant, and a unique coil type selection and flexible structure design are designed to minimize noise and improve SNR. The testing technology has been systematically tested and the results of surface eddy current testing can be used to detect the sealing and welding surface and near-surface defects of steam generator heat transfer tubes and plates during service or manufacturing. The system and process can be widely used in eddy current testing of heat exchanger tube sheet seal welding in other industrial fields.