Experimental Study of Biaxial Creep Damage for Type 304 Stainless Steel

This paper studies the biaxial creep damage of type 304 stainless steel at 923 K. Biaxial tension creep tests were carried out using cruciform specimens and the effect of stress biaxiality on rupture lifetime and creep voiding was discussed. Mises equivalent stress and the equivalent stress based on crack opening displacement were a suitable parameter to assess the biaxial creep damage. The equivalent stress proposed by Huddleston overestimated the biaxial creep damage by more than a factor of two. Stress biaxiality had almost no influence on the orientation of voided grain boundaries and the critical value ofparameter A. Tests of alternative loading direction significantly dispersed the biaxial creep damage resulting in larger creep lifetime.