On the applicability of the small punch test to the characterization of the 1CrMoV aged steel: Mechanical testing and numerical analysis

• We carried out tensile and small punch tests on two different lots of 1CrMoV steel.
• One lot consisted of new material, the second one underwent 195,700 operating hours.
• Differences in the small punch tests were not confirmed by tensile tests.
• We carried out inverse analysis on small punch test to derive the mechanical properties.
• We proposed a new method for the identification of the material parameters.

The life extension of a component in service is of great importance in many engineering applications and it relies on the possibility of monitoring the material degradation during in-service loading. In this view, non-destructive testing is needed in order to be able to evaluate the material properties while keeping the component in service.The present work focuses on a miniature mechanical test named small punch test, which has been employed on virgin and aged 1CrMoV steel in order to characterise its mechanical behaviour. A thorough experimental analysis has been carried out using classical and miniature mechanical tests and the results have been compared in order to evaluate the feasibility of the small punch test to the characterisation of an aged steel.A numerical framework based on finite element simulations is also presented to support the findings of the experimental tests. Starting from the simulation of a typical load–displacement curve given by the small punch test, the elastic–plastic parameters have been identified and applied in the simulation of the tensile tests.Experimental results and non-uniqueness of the mathematical problem associated to the identification of the material parameters are discussed.