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Proceedings Paper

Longitudinal seam weld characterization by focused ultrasonics
Author(s): Laney H. Bisbee; Lawrence Nottingham
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Paper Abstract

Increasingly, the detectability limits placed on inspection methodologies applied to the assessment of critical high energy components in fossil fuelled power plants are being forced to lower values. Most notably, recent events involving longitudinal seam welded piping have raised the question of lowering the detectibility limit for ultrasonics to a level necessary for resolving incipient creep damage. Historically, several testing methods were required for the detection of defects over the range of anticipated flaw sizes in an economically and technically acceptable manner. However, unyielding limitations exist for several of these currently used methods. While accepting that the detection of isolated creep cavities is not technically feasible with current conventional ultrasonic methods, the detection of high density cavitation sheets or zones prior to microcrack initiation has been demonstrated and successfully applied to field inspection of critical welds using focused ultrasonics. This paper describes the equipment and verification process used to extend the detectability limit of a field ultrasonic systems for longitudinal seam weld evaluations to approaching that of an acoustic microscope for the identification of incipient creep cavitation.

Paper Details

Date Published: 14 November 1996
PDF: 12 pages
Proc. SPIE 2947, Nondestructive Evaluation of Utilities and Pipelines, (14 November 1996); doi: 10.1117/12.259155
Show Author Affiliations
Laney H. Bisbee, Structural Integrity Associates, Inc. (United States)
Lawrence Nottingham, Structural Integrity Associates, Inc. (United States)


Published in SPIE Proceedings Vol. 2947:
Nondestructive Evaluation of Utilities and Pipelines
Martin Prager; Richard M. Tilley, Editor(s)

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