Location

La Jolla, CA

Start Date

1-1-1987 12:00 AM

Description

The occurrence of creep damage limits the lifetime of component that are exposed to stresses at temperatures higher than approximately half the melting temperature. Such conditions are generally met by a lot of structural components especially in power plants (pipes, turbines, etc.). According to conventional safety rules critical parts are usually exchanged long before any failure has to be expected. This procedure is based on statistics drawn from material tests by standardized methods rather than on the actual state of the component concerned. During the last years an increasing need can be stated to develop NDE methods for the detection of early damage stages in order to improve the reliability and safety of components. Basically, techniques are required which are sensitive to either small strains or, better, to small concentrations of micropores and microcracks, respectively. With regard to in-field applications, only replica techniques are used successfully for that purpose up to now [1,2]. These metallographic techniques are restricted to surfaces where appropriate spots have to be selected and to be prepared carefully. In this work the influence of creep damage on the ultrasonic velocity has been investigated on a representative high-temperature alloy for tube components, i. e., Alloy 800 H (X10 NiCrAlTi 32 20).

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

6B

Chapter

Chapter 8: Materials Characterization

Section

Properties

Pages

1453-1462

DOI

10.1007/978-1-4613-1893-4_164

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

The Influence of High-Temperature Creep on the Ultrasonic Velocity in Alloy 800H

La Jolla, CA

The occurrence of creep damage limits the lifetime of component that are exposed to stresses at temperatures higher than approximately half the melting temperature. Such conditions are generally met by a lot of structural components especially in power plants (pipes, turbines, etc.). According to conventional safety rules critical parts are usually exchanged long before any failure has to be expected. This procedure is based on statistics drawn from material tests by standardized methods rather than on the actual state of the component concerned. During the last years an increasing need can be stated to develop NDE methods for the detection of early damage stages in order to improve the reliability and safety of components. Basically, techniques are required which are sensitive to either small strains or, better, to small concentrations of micropores and microcracks, respectively. With regard to in-field applications, only replica techniques are used successfully for that purpose up to now [1,2]. These metallographic techniques are restricted to surfaces where appropriate spots have to be selected and to be prepared carefully. In this work the influence of creep damage on the ultrasonic velocity has been investigated on a representative high-temperature alloy for tube components, i. e., Alloy 800 H (X10 NiCrAlTi 32 20).