Assessment of creep constitutive properties from three-point bending creep test with miniaturized specimens

Abstract

Three-point bending creep tests using miniaturized specimen are proposed to assess creep constitutive properties of materials. Based on Norton’s creep law, the analytical model for the three-point bending specimen is given. Through the analytical model, creep parameters can be obtained by regressing the bending test data. Maximum stress approach and reference stress approach are used to convert bending test data to equivalent uniaxial tensile test data. In order to verify these approaches, both three-point bending and uniaxial creep tests of 23CrMoNiWV88 steel are performed. The results show that the derived creep parameters from the bending test data are in reasonable agreement with those obtained from conventional uniaxial creep tests. The equivalent uniaxial creep data converted using reference stress approach are more reasonable than that using maximum stress approach. It has also been found that the large deformation may have a significant influence on the conversion relationship. The results are only accurate at relatively low load levels during testing.