基于变型波的汽轮机叶片叶根超声检测

A new method to detect the blade roots of steam turbines based on ultrasonic transformed wave

对汽轮机叶片叶根进行有效可靠检测,可为机组的安全经济运行提供重要的技术支持。本文提出了一种利用专用探头发射的横波,在叶根内部传播过程中发生波型转换而产生变型波,从而对叶根易产生裂纹的部位进行检测的新方法。该方法克服了目前在役汽轮机叶片叶根常规超声检验方法的技术局限性和现场适用条件的限制,达到了叶根0.3 mm深模拟裂纹的检测精度,其准确性、灵敏度及适用性获得显著提高,尤其在高压转子叶片T型叶根检测方面具有较好的推广应用前景。

Reliable nondestructive testing applied on the blade roots of steam turbines plays an important role in the safe and economical operation of the turbine generator unit. In this paper, a new method has been proposed to detect the cracks of blade roots based on the transformed wave, generated in the propagation of the shear wave by dedicated probe. The artificial crack with 0.3 mm deep can be detected through the new method, which greatly improved accuracy, sensitivity and on-site applicability compared with the current nondestructive testing methods, and largely overcome their technical limitations and on-site application weaknesses. It has a great potential for the application of the transformed wave technology to the nondesmactive testing of blade roots, especially for T-type blade roots of the high-pressure rotor.