Dynamic mechanical properties at high temperature of austenitic stainless steels for nuclear applications

The dynamic mechanical properties of some austenitic stainless steels, such as AISI 321, AISI316L, AISI 316H, AISI 304L, and DIN 4981 in virgin, welded, thermally aged and irradiated conditions, have been determined at strain rates up to 600 s-1 and temperatures up to 9500C. The dynamic response of virgin austenitic steels at temperatures of 400 and 5500C is widely spread, passing from a substantial dynamic hardening behaviour to dynamic softening behaviour. More homogeneous is the dynamic response of the same austenitic stainless steels damaged by welding, thermal aging and irradiation. In fact, all these damaged materials, tested at 400 and 5500C, show a grade of dynamic softening and reduction of ductility which will influence the safety coefficients and the maximum allowable strain for structures submitted to extreme dynamic loading conditions. (author)