New approach to determine uniaxial creep properties from small punch creep curves

摘要

A key issue in the small punch creep test (SPC) is to determine the equivalent stress that results in the same time to rupture in a uniaxial creep test (UAC). A new approach is proposed based on formulas between the ratio of force in SPC to stress in UAC and the deflection at the minimum deflection rate. Another formula is defined between the minimum deflection rate and the minimum strain rate. In both cases, they were created from a large experimental data pool of high temperature creep-resistant steels. The predicted Norton law and the rupture time dependence on stress are in good agreement with the experimental UAC results. In all cases, the predictions using the present approach are much better than those based on Chakrabarty membrane stretch model.