Development of Small Punch Tests for Creep Property Measurement of Tungsten-Alloyed 9%Cr Ferritic Steels

A small punch creep (SP-C) testing technique using miniaturized specimens has been demonstrated for evaluating creep properties and material deterioration due to thermal aging. This technique has been applied to tungsten-alloyed 9%Cr ferritic steels. Experimental results revealed that the overall shapes of the creep curves obtained from the SP-C tests were qualitatively similar to those obtained from conventional uniaxial creep tests and reflected closely the degradation of creep rupture strength of the materials. A correlation with uniaxial creep was also determined in terms of stress (load) exponent and apparent activation energy for creep deformation. The correlation suggests that the SP-C testing technique may provide a useful tool for evaluating degradation of creep properties for structural components in-service.