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 nondestructive testing of blade roots

especially for T-type blade roots of the high-pressure rotor.