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Title: Measurement of creep damage in CrMoV steels using ultrasonic test techniques
Author: Thomas, A. V.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1995
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Low alloy steels are widely used in components which operate at high temperatures and pressures, and thus are susceptible to creep. This process involves microstructural changes and degradation of the material which leads to rupture if not detected. Available methods for assessing these factors are currently limited to destructive tests, or to investigation of selected areas of the component surface. Consequently, reliable methods for the detection of creep damage are indispensable, both to guarantee safe operation during the designed lifetime, and to ensure that components possess the physical properties suitable for their required use. Presently, methods including magnetic particle inspection and replication metallography are available for the detection of surface cracks and creep damage. However, there are significant benefits to identifying damage at an earlier stage. A successful plant life strategy demands techniques capable of identifying the initiation of in-service damage within the bulk of structure. Due to the limited availability of test material which may be obtained and the demand for volumetric material characterisation, acoustic NDE techniques offer an attractive means to obtain this information. However, for the effective application of non-destructive characterisation of creep damage, it is fundamentally important to firstly establish an understanding of how acoustic NDE signatures relate to material properties. The research programme undertaken to meet these requirements involved the application of acoustic NDE techniques to meet this task. A specific test programme was developed so that variations in selected microstructural parameters were characterised in terms of structure and properties. These fully characterised specimens then provided the standards required for assessment of volumetric and surface ultrasonic techniques, in both the time and frequency domains.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available