High temperature components such as boiler tubes and jet engine turbine blades undergo multiaxial creep damage due to their complex shapes and combination of mechanical stress and inner pressure for a steam tube. Although multiaxial creep investigation is required for the safety of high temperature components designing, there are only a few commercial testing machines that can conduct multiaxial loading at high temperatures. The authors have developed a miniature cruciform specimen having a 5 mm square size plane stress condition gauge section and a biaxial tensile loading testing machine. This study discusses multiaxial creep rupture time and creep properties of type 304 stainless steels at 923 K using the miniature cruciform specimen. A specimen deformation during the creep tests could be observed clearly and the displacement of the specimen also could be measured using a developed non-contact measuring method. Creep rupture time under multiaxial stress condition was shorter than that of uniaxial stress loading.
