Using longitudinal ultrasound waves for detecting root cracks in welded joints in steam turbine rotors
The results of analysis of the defects carried out after opening welded joints rejected in ultrasonic inspection of rotors showed that the root zone of the welded joints contains vertically oriented cracks extending to the bottom surface. These cracks form in most cases in the heat-affected zone in the vicinity of the boundary between the parent and deposited metal and during service of the rotor the crack can grow until it reaches the surface of the welded joint. In previous work, the acoustic circuit of the direct transducer was analyzed for a model of a crack extending to the free surface on the condition that the axis of the transducer is parallel to the surface and perpendicular to the crack plane. In this paper, the results are generalized for the case of inclined incidence of a longitudinal ultrasound wave on a root crack with the limited size of the free surface. It is shown that in the current design of the rotors, it is possible to detect root cracks in inspecting the welded joints on the disk side.
- Research Organization:
- Scientific and Production Organization of the Central Scientific-Research Institute of Heavy Engineering, Moscow (USSR)
- OSTI ID:
- 5909616
- Journal Information:
- Sov. J. Nondestr. Test. (Engl. Transl.); (United States), Vol. 24:4; Other Information: Translated from Defektoskopiya; 24: No. 4, 45-50 (Apr 1988)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
CRACKS
DETECTION
STEAM TURBINES
ULTRASONIC TESTING
ULTRASONIC WAVES
INCIDENCE ANGLE
WELDED JOINTS
AMPLITUDES
DEFECTS
INSPECTION
REFLECTION
ROTORS
SIGNALS
TRANSDUCERS
WAVE PROPAGATION
ACOUSTIC TESTING
JOINTS
MACHINERY
MATERIALS TESTING
NONDESTRUCTIVE TESTING
SOUND WAVES
TESTING
TURBINES
TURBOMACHINERY
420500* - Engineering- Materials Testing
360103 - Metals & Alloys- Mechanical Properties