Residual Life Assessment of In-Service High Temperature Components by Small Punch Creep Test

Abstract

The knowledge of mechanical long term behaviour under static loading for high temperature components requires methodologies for residual life assessment in order to employ the full potential of materials, particularly in non-destructive methods. In this paper, in order to apply small punch creep (SPC) test to the residual creep life assessment of in-service high temperature components, a variety of SPC tests for Cr5Mo steel in a protective Argon atmosphere were carried out, which used disc test specimens of 10mm in diameter and 0.5mm in thickness extracted both new material and in-service high temperature components. The relationship of the creep deflection curve, the test load, rupture time and ductility of miniature specimens were investigated. Based on SPC test and finite element numerical analysis methods, a novel residual life assessment method was proposed to substitute conventional uniaxial creep life analysis method by introducing an initial creep damage parameter. Moreover, the fractographic observation and the structural damage detection analysis were examined. Finally, the results using conventional uniaxial creep life analysis method were studied to validate the reliability of SPC life assessment method.