An evaluation of the capability of data conversion of impression creep test

Abstract

High temperature power plant components are now working far beyond their operative designed life. Therefore, establishing their in-service material properties is a matter of significant concern. Reliable secondary creep data can be produced by impression creep test (ICT), which requires a small volume of material that can be scooped from in-service critical components. This paper presents an overview of ICT to highlight the capability in determining the minimum creep strain rate (MSR) data by use of conversion relationships that relates uniaxial and impression creep tests data. Some existing ICT data are critically reviewed. Furthermore, this paper presents some new impression creep test data and their correlation with uniaxial data, obtained from a number of steels at different stresses and temperatures. The presented data, in terms of MSR against the reference uniaxial stress, are used to assess the capability and reliability of the ICT method.