A nondestructive testing device, consisting of a scanner and signal processing circuits was developed to detect cracks in turbine disk roots. The scanner consists of a longitudinal feeder and a fir-tree-shaped sensor probe. The feeder inserted the sensor probe along the grooves of the turbine bladeattachment. Meanwhile, permanent magnets were placed in opposite direction, to generate a closed magnetic field between the magnetic sensors located on the crests of the sensor probe. The fatigue crack in the turbine disk root occurred in the circumferential direction of the turbine. As a result, magnetic flux leakage was caused by disturbing the flow of closed magnetic field by permanent magnets. The magnetic flux leakage was measured by a magnetic sensor. The effectiveness of the proposed device has been verified using artificial defects introduced into the turbine disk roots by electric discharge machining.

中文翻译：

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使用固态GMR传感器阵列和轴向方向扫描系统对涡轮盘根部进行无损检测

开发了一种由扫描仪和信号处理电路组成的无损检测设备，以检测涡轮盘根部的裂纹。扫描仪由纵向进纸器和枞树形传感器探头组成。进纸器将传感器探头沿涡轮叶片附件的凹槽插入。同时，将永磁体沿相反方向放置，以在位于传感器探头顶部的磁传感器之间产生闭合磁场。涡轮盘根部的疲劳裂纹在涡轮的周向上产生。结果，由于永磁体干扰闭合磁场的流动而引起磁通量泄漏。通过磁传感器测量磁通量泄漏。