A Numerical and Experimental Assessment of the Small Punch Creep Test for 316L(N) Stainless Steels

This paper presents a finite element analyses of the small punch creep test for 316L(N) which is compared with experimental data for 650 and 700°C. Special emphasis is given to assessing the influence of friction and two creep models: simple Norton creep as well as more general creep model. The computed normalized deflection rate versus time is almost identical for all cases, which allows scaling of the results. The computed time to rupture increases linearly with the friction coefficient due to a reduction in the mean stress. There is an overall good agreement with experimental values with computed deflection rate for a friction coefficient of around 0.3. It is shown that the initial reduction in deflection rate is due to stress relaxation and homogeniza-tion, and only marginally affected by primary creep hardening. The computed results are com-pared with the equivalent stress and strain rates in the recently published small punch standard. The computed von Mises stresses at minimum deflection decreases linearly with the friction co-efficient but is consistently slightly higher than the equivalent stress in the standard. For the strain rates, the computed values are significantly higher than the equivalent values in the standard. The presented simulations give a deeper insight of the small punch creep and impact of key parameters such the friction coefficient and in general as a guidance to refinement and improvement of the empirically based formulae in the standard.

NILSSON Karl-Fredrik;  BARALDI Daniele;  HOLMSTROM Bjorn;  SIMONOVSKI Igor; 

2021-10-12

MDPI

JRC126470

2075-4701 (online),   

https://www.mdpi.com/2075-4701/11/10/1609,    https://publications.jrc.ec.europa.eu/repository/handle/JRC126470,   

10.3390/met11101609 (online),