HIGH-TEMPERATURE-STRAIN FATIGUE TESTING WITH A MODIFIED DIRECT-STRESS FATIGUE MACHINE

摘要

Information on the ability of ductile materials to withstand thermally induced, cyclic strain is frequently needed in reactor design. Since information of this na¬ture is available only on a very limited number of materials, strain fatigue tests were conducted on AISI type 304 stainless steel at room temperature and 1000*F. A commercially available, direct-stress fatigue machine was modified to provide facilities for this high-temperature-strain fatigue testing, thus expediting the Thermal Stress Fatigue Study Program and related research. A description of the modification required and operation of the modified machine is presented herein. Initial data indicate that type 304 stainless steel behaves according to the previously proposed plastic fatigue relation for other materials, where k = -0.37 and C = 6.56 at room temperature and k = -0.80 and C = 0.476 at 1000° F.