Abstract
Nowadays, 316L stainless steels are mostly used in high temperature structures because of their superior high-temperature strength and ductility. The materials in high temperature structures are subjected to combined creep-fatigue damage. It is very important to predict the fatigue life of materials under creep-fatigue condition in order to use the materials safely and efficiently at high temperature. In this research, we could quantify the effect of tensile hold time on the fatigue life of 316L stainless steels through creep-fatigue tests with a tensile strain-hold wave form. In these tests, the creep loading and fatigue loading were repeated alternately. A new creep-fatigue life prediction model is formulated with the linear damage summation rule. When the sum of the fatigue damage and creep damage is equal to unity, the failure of materials occurs. Then the fatigue damage component was derived from the cycles ratio and the creep damage component was formulated as a function of the amount of stress relaxation. A new purposed creep-fatigue life prediction model was more accurate than classical life prediction methods (Time fraction rule, ductility exhaustion rule).
